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           Business combinations (Details) 
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        6 Months Ended | 0 Months Ended | 0 Months Ended | 0 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
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           Mar. 31, 2014
 
          USD ($) 
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           Mar. 31, 2015
 
          USD ($) 
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           Sep. 30, 2014
 
          USD ($) 
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           Apr. 01, 2015
 
          Acentia LLC
 
          Subsequent events
 
          USD ($) 
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           Apr. 01, 2015
 
          Acentia LLC
 
          Subsequent events
 
          USD ($) 
         | 
        
           Apr. 01, 2015
 
          Acentia LLC
 
          Customer relationships
 
          Subsequent events 
         | 
        
           Apr. 01, 2015
 
          Acentia LLC
 
          Customer relationships
 
          Subsequent events
 
          USD ($) 
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           Apr. 07, 2015
 
          Remploy
 
          Subsequent events
 
          USD ($) 
         | 
        
           Apr. 07, 2015
 
          Remploy
 
          Subsequent events
 
          GBP (£) 
         | 
        
           Apr. 07, 2015
 
          Remploy
 
          Subsequent events
 
          GBP (£) 
         | 
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| Business combinations | ||||||||||
| Share capital acquired (as a percent) | 
100.00%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
        
70.00%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired / us-gaap_BusinessAcquisitionAxis = mms_RemployLimitedMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Share capital held in trust for the benefit of employees (as a percent) | 
30.00%mms_BusinessAcquisitionPercentageOfVotingInterestsHeldInTrustForBenefitOfEmployees / us-gaap_BusinessAcquisitionAxis = mms_RemployLimitedMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Preliminary Purchase Price Accounting | ||||||||||
| Cash consideration, net of cash acquired | $ 2,670,000us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired | 
$ 294,005,000us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Percentage of goodwill anticipated to be deductible for tax purpose | 
70.00%mms_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductiblePercentage / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Acquisition consideration | 
3,000,000us-gaap_BusinessCombinationConsiderationTransferred1 / us-gaap_BusinessAcquisitionAxis = mms_RemployLimitedMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
        
2,000,000us-gaap_BusinessCombinationConsiderationTransferred1 / us-gaap_BusinessAcquisitionAxis = mms_RemployLimitedMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Net assets | 
0mms_BusinessCombinationNetAssetsOnAcquireeBalanceSheetOnDateOfAcquisition / us-gaap_BusinessAcquisitionAxis = mms_RemployLimitedMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Billed and unbilled receivables | 
35,087,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Other assets | 
3,635,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Property and equipment | 
1,619,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Intangible assets | 
69,900,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Total identifiable assets acquired | 
110,241,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Accounts payable and other liabilities | 
30,676,000mms_BusinessAcquisitionPurchasePriceAllocationCurrentLiabilitiesAccountsPayableAndOtherLiabilities / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Deferred revenue | 
251,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Total liabilities assumed | 
30,927,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Net identifiable assets acquired | 
79,314,000mms_BusinessCombinationRecognizedIdentifiableAssetsExcludingGoodwillAndLiabilitiesAssumedNet / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Goodwill | 162,214,000us-gaap_Goodwill | 170,626,000us-gaap_Goodwill | 
214,691,000us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Net assets acquired | 
$ 294,005,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet / us-gaap_BusinessAcquisitionAxis = mms_AcentiaLlcMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember  | 
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| Amortization period of intangible assets | 14 years | |||||||||
| X | ||||||||||
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- Definition 
          Percentage of voting equity interests held in trust for the benefit of the employees at the acquisition date in the business combination. No definition available. 
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- Definition 
          The amount of acquisition cost of a business combination allocated to accounts payable and other liabilities of the acquired entity. No definition available. 
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- Definition 
          The percentage of goodwill arising from a business combination that is expected to be deductible for tax purposes. No definition available. 
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- Definition 
          Net assets on acquiree's Balance Sheet on date of acquisition. No definition available. 
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- Definition 
          The net amount recognized as of the acquisition date for the aggregate assets, excluding goodwill, in excess of or less than the aggregate liabilities assumed. No definition available. 
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- Definition 
          Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Amount of assets acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of deferred revenue expected to be recognized as such within one year or the normal operating cycle, if longer, assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The amount of identifiable intangible assets recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of liabilities assumed at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          The amount of property, plant, and equipment recognized as of the acquisition date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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