Basis of Presentation and Summary of Significant Accounting Policies - Revenue (Details)	12 Months Ended
Dec. 31, 2017
Revenue
Account life for GPR cards	6 months
Minimum \| Merchant contract
Revenue
Term of contract	30 days
Minimum \| Merchant processing contracts
Revenue
Term of contract	3 years
Maximum \| Merchant contract
Revenue
Term of contract	5 years
Maximum \| Merchant processing contracts
Revenue
Term of contract	8 years

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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