Concentration Risk (Details) - USD ($) $ in Billions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Concentration Risk [Line Items]
Average vault cash	$ 3.9	$ 3.5
ATM Purchase [Member] | Supplier Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk percentage			73.70%	60.00%
Top Five Merchants [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk percentage			30.90%	39.20%
Second Through Fifth Largest Customers | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk percentage			18.40%	21.00%
Seven Eleven [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk percentage			12.50%	18.00%