Intangible Assets - Acquired Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amount acquired	$ 184,903	$ 12,551
Merchant and Bank Branding Contracts / Relationships
Finite-Lived Intangible Assets [Line Items]
Amount acquired	$ 174,210	$ 12,551
Weighted average amortization period	8 years	5 years 7 months 6 days
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Amount acquired	$ 10,693
Weighted average amortization period	3 years