Other Liabilities - Components of Other Liabilities (Detail) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Other Liabilities Disclosure [Abstract] | ||
| Deferred compensation | $ 6,725 | $ 7,408 |
| Pension liability | 26,182 | 26,798 |
| Joint beneficiary agreements | 2,529 | 2,728 |
| Low income housing tax credit fund commitments | 3,330 | |
| Accrued salaries and benefits expense | 3,851 | 5,407 |
| Loan escrow and servicing payable | 2,037 | 1,938 |
| Deferred revenue | 1,082 | 1,091 |
| Unsettled investment security purchases | 17,072 | |
| Miscellaneous other liabilities | 2,485 | 3,822 |
| Total other liabilities | $ 65,293 | $ 49,192 |