Regulatory Capital Matters - Additional Information (Details) - USD ($) $ in Millions |
Dec. 31, 2016 |
Dec. 31, 2015 |
Jan. 31, 2015 |
|---|---|---|---|
| Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items] | |||
| Tier 1 leverage capital ratio | 13.71% | 13.42% | 4.00% |
| Tier 1 risk based capital ratio | 18.93% | 17.76% | 6.00% |
| Total risk-based capital ratio | 20.19% | 19.02% | 8.00% |
| Investment securities | $ 9.1 | $ 8.7 | |
| Common Shares | |||
| Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items] | |||
| Tier 1 risk based capital ratio | 4.50% |