| Revenue Recognition - Remaining Performance Obligation (Details) $ in Millions | Dec. 31, 2018  USD ($) | 
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| Revenue from Contract with Customer [Abstract] | |
| Revenue, remaining performance obligation, amount | $ 320 | 
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | |
| Revenue, remaining performance obligation, percentage | 65.00% | 
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- References No definition available. 
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- Definition Amount of transaction price allocated to performance obligation that has not been recognized as revenue. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Percentage of remaining performance obligation to total remaining performance obligation not recognized as revenue. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Details 
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