Goodwill and Intangible Assets - Intangible assets, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Intangible assets with finite lives:
Net	$ 312,623		$ 312,623		$ 294,997
Total intangible assets, net	331,122		331,122		313,483
Amortization expense related to intangible assets	11,500	$ 12,100	33,700	$ 33,400
Trademarks
Intangible assets with finite lives:
Gross carrying value	18,499		18,499		18,486
Merchant contract portfolios
Intangible assets with finite lives:
Gross carrying value	301,855		301,855		274,780
Accumulated amortization	(131,545)		(131,545)		(113,747)
Accumulated impairment losses	(5,658)		(5,658)		(5,658)
Foreign currency translation adjustment	(25,212)		(25,212)		(26,057)
Net	139,440		139,440		129,318
Marketing alliance agreements
Intangible assets with finite lives:
Gross carrying value	191,924		191,924		187,758
Accumulated amortization	(44,772)		(44,772)		(35,509)
Accumulated impairment losses	(7,585)		(7,585)		(7,585)
Foreign currency translation adjustment	(14,925)		(14,925)		(15,561)
Net	124,642		124,642		129,103
Trademarks
Intangible assets with finite lives:
Gross carrying value	29,931		29,931		25,084
Accumulated amortization	(10,141)		(10,141)		(8,485)
Foreign currency translation adjustment	(4,270)		(4,270)		(3,701)
Net	15,520		15,520		12,898
Internally developed software
Intangible assets with finite lives:
Gross carrying value	56,940		56,940		42,442
Accumulated amortization	(12,736)		(12,736)		(9,760)
Accumulated impairment losses	(9,324)		(9,324)		(9,324)
Foreign currency translation adjustment	(3,623)		(3,623)		(3,247)
Net	31,257		31,257		20,111
Non-competition agreements
Intangible assets with finite lives:
Gross carrying value	6,400		6,400		6,200
Accumulated amortization	(4,636)		(4,636)		(2,633)
Net	$ 1,764		$ 1,764		$ 3,567