Revenue - Summary of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	$ 314,122	$ 266,312
Non-topic 606 revenues	117,557	115,564
Total revenues	431,679	381,876
Fleet Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	138,982	131,194
Non-topic 606 revenues	110,865	101,588
Total revenues	249,847	232,782
Travel and Corporate Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	82,102	71,688
Non-topic 606 revenues	2,257	9,960
Total revenues	84,359	81,648
Health and Employee Benefit Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	93,038	63,430
Non-topic 606 revenues	4,435	4,016
Total revenues	97,473	67,446
Payment processing revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues		186,798
Total revenues	204,037	186,798
Payment processing revenue | Fleet Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	113,323	107,408
Total revenues	113,323	107,408
Payment processing revenue | Travel and Corporate Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	70,268	59,998
Total revenues	70,268	59,998
Payment processing revenue | Health and Employee Benefit Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	20,446	19,392
Total revenues	20,446	19,392
Account servicing revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	79,003	54,647
Total revenues	113,840	87,086
Account servicing revenue | Fleet Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	4,371	6,800
Total revenues	39,208	39,239
Account servicing revenue | Travel and Corporate Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	11,063	10,585
Total revenues	11,063	10,585
Account servicing revenue | Health and Employee Benefit Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	63,569	37,262
Total revenues	63,569	37,262
Finance fee revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	55,927	46,373
Finance fee revenue | Fleet Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	55,342	45,864
Finance fee revenue | Travel and Corporate Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	535	357
Finance fee revenue | Health and Employee Benefit Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	50	152
Other revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	31,082	24,867
Total revenues	57,875	61,619
Other revenue | Fleet Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	21,288	16,986
Total revenues	41,974	40,271
Other revenue | Travel and Corporate Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	771	1,105
Total revenues	2,493	10,708
Other revenue | Health and Employee Benefit Solutions
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Topic 606 revenues	9,023	6,776
Total revenues	$ 13,408	$ 10,640