Segment Information - Reconciliation of Adjusted Operating Income to Income Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Adjusted operating income	$ 155,990	$ 147,142
Stock-based compensation	12,533	9,703
Operating income	74,829	68,935
Financing interest expense	(32,031)	(31,112)
Net foreign currency loss	(28,727)	(3,885)
Net unrealized gains on financial instruments	(32,047)	(11,912)
(Loss) income before income taxes	(17,976)	22,026
Fleet Solutions
Segment Reporting Information [Line Items]
Adjusted operating income	104,608	92,975
Travel and Corporate Solutions
Segment Reporting Information [Line Items]
Adjusted operating income	21,915	34,387
Health and Employee Benefit Solutions
Segment Reporting Information [Line Items]
Adjusted operating income	29,467	19,780
Segment reconciling items
Segment Reporting Information [Line Items]
Unallocated corporate expenses	16,543	16,942
Acquisition-related intangible amortization	42,538	33,888
Other acquisition and divestiture related items	7,942	9,780
Debt restructuring costs	78	4,400
Stock-based compensation	11,820	10,442
Restructuring and other costs	$ 2,240	$ 2,755