Business Combinations - Narrative - CBR Acquisition (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 17, 2015	Aug. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill			$ 639,188	$ 639,484	$ 639,188	$ 205,824
Increase in goodwill				296	(7,711)
Net deferred tax liability			189,145	197,066	189,145
Acquisition-related costs				0	11,232	$ 9,478
CBR
Business Acquisition [Line Items]
Goodwill	$ 441,371
Cash consideration	700,000
Increase in goodwill			1,800	$ 300
Adjustment financial assets			1,900
Adjustment financial liabilities			500
Subsequent recognition of deferred tax asset			$ 600
Gross contractual amount of accounts receivable	11,700
Fair value accounts receivable	8,660
Net deferred tax liability	$ 144,800
Combined federal and state statutory income tax rate (percent)	37.00%
Deferred income tax liabilities	$ (149,873)
Deferred tax assets	$ 5,062
Acquisition-related costs					11,200
Commitment fee					6,800
Revenue of acquiree since acquisition					$ 24,100
CBR | Customer relationships
Business Acquisition [Line Items]
Expected useful life (years)		20 years		20 years