Summary of Significant Accounting Principles - Revenue Recognition (Details) |
12 Months Ended |
|---|---|
Dec. 31, 2017 | |
| Accounting Policies [Abstract] | |
| Threshold period uncollected fees for write-off on card receivables | 180 days |
| Threshold period for uncollected fees for service charges on card receivables | 60 days |
| X | ||||||||||
- Definition Threshold Period Uncollected Fees for Write-off on Card Receivables No definition available.
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| X | ||||||||||
- Definition Threshold Period for Uncollected Fees for Service Charges on Card Receivables No definition available.
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| X | ||||||||||
- References No definition available.
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