Acquisition - Additional Information (Details) client in Thousands, $ in Thousands			12 Months Ended
	Apr. 28, 2017 USD ($) client	Aug. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
STP
Business Acquisition [Line Items]
Aggregate purchase price		$ 1,230,000
Cash acquired from acquisition		40,200
Customer relationships and other identifiable intangible assets		584,274
Contingent liabilities		13,500
Indemnification assets		13,000
Contingent consideration minimum possible value		13,500
Contingent consideration maximum possible value		18,600
Other
Business Acquisition [Line Items]
Aggregate purchase price			$ 76,700
Cash acquired from acquisition			11,100
Customer relationships and other identifiable intangible assets			$ 61,823
Non-compete agreements | STP
Business Acquisition [Line Items]
Customer relationships and other identifiable intangible assets		$ 21,600
Subsequent Event | Cambridge
Business Acquisition [Line Items]
Aggregate purchase price	$ 675,000
Amount of cross boarder payments processed annually	$ 20,000,000
Number of clients | client	13