Segment Reporting - Revenue and EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting
Revenues	$ 93,567	$ 107,697	$ 95,536	$ 77,310	$ 87,865	$ 77,374	$ 53,236	$ 42,531	$ 374,110	$ 261,006	$ 196,370
EBITDA									83,401	47,023	37,620
Operating Segments | U.S. Debit and Credit
Segment Reporting
Revenues									263,668	153,015	91,626
EBITDA									78,981	37,547	18,871
Operating Segments | U.S. Prepaid Debit
Segment Reporting
Revenues									65,878	59,271	65,895
EBITDA									22,993	18,654	20,438
Operating Segments | U.K. Limited
Segment Reporting
Revenues									34,361	35,163	33,242
EBITDA									3,572	2,943	2,801
Operating Segments | Other
Segment Reporting
Revenues									17,420	23,908	24,678
EBITDA									(22,145)	(12,121)	(4,491)
Intersegment eliminations
Segment Reporting
Revenues									$ (7,217)	$ (10,351)	$ (19,071)