Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenues, net	$ 643,422	$ 619,586	$ 584,985	$ 585,500	$ 609,991	$ 577,877	$ 541,237	$ 520,433	$ 2,433,492	[1]	$ 2,249,538	$ 1,831,546
United States (country of domicile)
Disaggregation of Revenue [Line Items]
Revenues, net									1,481,785		1,400,801	1,278,828
Brazil
Disaggregation of Revenue [Line Items]
Revenues, net									400,111		394,550	167,769
United Kingdom
Disaggregation of Revenue [Line Items]
Revenues, net									257,651		236,550	229,125
Other
Disaggregation of Revenue [Line Items]
Revenues, net									293,945		217,637	155,824
Fuel
Disaggregation of Revenue [Line Items]
Revenues, net									1,096,611		1,096,153	997,398
Corporate payments
Disaggregation of Revenue [Line Items]
Revenues, net									415,856		261,822	179,557
Tolls
Disaggregation of Revenue [Line Items]
Revenues, net									338,644		326,977	102,740
Lodging
Disaggregation of Revenue [Line Items]
Revenues, net									175,505		126,657	100,664
Gift
Disaggregation of Revenue [Line Items]
Revenues, net									186,645		194,099	184,743
Other
Disaggregation of Revenue [Line Items]
Revenues, net									$ 220,231		$ 243,830	$ 266,444

[1] Reflects the impact of the Company's adoption of Accounting Standards Update 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASC 606") and related cost capitalization guidance, which was adopted by the Company on January 1, 2018 using the modified retrospective transition method. The adoption of ASC 606 resulted in an adjustment to retained earnings in our consolidated balance sheet for the cumulative effect of applying the standard, which included costs incurred to obtain a contract, as well as presentation changes in our statements of income, including the classification of certain amounts previously classified as merchant commissions and processing expense net with revenues. As a result of the application of the modified retrospective transition method, the Company's prior period results within its Form 10-K and quarterly reports on Form 10-Q will not be restated to reflect ASC 606.