Loans Receivable - Aging of the Loans Receivable Balance (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Financing Receivable, Recorded Investment, Past Due [Line Items] | ||
| Past due loans receivable (percentage) | 14.80% | 14.30% |
| Current loans receivable (percentage) | 85.20% | 85.70% |
| Balance of Loans Receivable on Nonaccrual Status | $ 2,016 | $ 1,072 |
| 30-59 Days Past Due | ||
| Financing Receivable, Recorded Investment, Past Due [Line Items] | ||
| Past due loans receivable (percentage) | 7.10% | 6.80% |
| 60-89 Days Past Due | ||
| Financing Receivable, Recorded Investment, Past Due [Line Items] | ||
| Past due loans receivable (percentage) | 3.60% | 3.20% |
| 90 or more Days Past Due | ||
| Financing Receivable, Recorded Investment, Past Due [Line Items] | ||
| Past due loans receivable (percentage) | 4.10% | 4.30% |
| Balance of Loans Receivable 90 or More Days Past Due and Still Accruing Interest and Fees | $ 0 | $ 0 |