Acquisition - Summary of Purchase Price Allocation (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 26, 2017	Aug. 09, 2017	Dec. 31, 2016	Aug. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 4,644,559			$ 4,195,150
Cambridge
Business Acquisition [Line Items]
Prepaid expenses and other			$ 79,725
Property and equipment			7,106
Other long term assets			10,025
Goodwill			436,138
Other intangible assets			358,168
Liabilities assumed			(187,664)
Deferred tax liabilities			(119,419)
Aggregate purchase price			$ 584,079
Russian fuel card provider
Business Acquisition [Line Items]
Trade and other receivables		$ 8,175
Prepaid expenses and other		783
Property and equipment		206
Other long term assets		46,034
Goodwill		9,209
Liabilities assumed		(11,078)
Deferred tax liabilities		(9,211)
Aggregate purchase price		$ 44,118
STP
Business Acquisition [Line Items]
Trade and other receivables					$ 243,157
Prepaid expenses and other					6,998
Deferred tax assets					20,644
Property and equipment					44,226
Other long term assets					14,280
Goodwill					663,040
Other intangible assets					548,682
Liabilities assumed					(315,082)
Aggregate purchase price					$ 1,225,945
Other
Business Acquisition [Line Items]
Trade and other receivables				27,810
Prepaid expenses and other				5,097
Deferred tax assets				146
Property and equipment				992
Goodwill				28,540
Other intangible assets				61,823
Liabilities assumed				(42,550)
Deferred tax liabilities				(5,123)
Aggregate purchase price				$ 76,735