Quarterly report pursuant to Section 13 or 15(d)

Business combinations and disposals (Schedule of the Valuation of the Intangible Assets Acquired) (Details)

v3.5.0.2
Business combinations and disposals (Schedule of the Valuation of the Intangible Assets Acquired) (Details) - USD ($)
$ in Thousands
 9 Months Ended
Dec. 15, 2015
Jun. 30, 2016
Ascend Management Innovations LLC    
Business Acquisition [Line Items]    
Finite-lived intangible assets acquired   $ 22,300
Customer relationships | Assessments Australia    
Business Acquisition [Line Items]    
Finite-lived intangible asset, useful life 6 years  
Customer relationships | Ascend Management Innovations LLC    
Business Acquisition [Line Items]    
Finite-lived intangible asset, useful life   19 years
Finite-lived intangible assets acquired   $ 20,400
Trade Names | Ascend Management Innovations LLC    
Business Acquisition [Line Items]    
Finite-lived intangible asset, useful life   1 year
Finite-lived intangible assets acquired   $ 1,700
Technology-Based Intangible Assets | Ascend Management Innovations LLC    
Business Acquisition [Line Items]    
Finite-lived intangible asset, useful life   8 years
Finite-lived intangible assets acquired   $ 200