Other Liabilities - Components of Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Deferred compensation	$ 6,525	$ 6,725
Pension liability	26,645	26,182
Joint beneficiary agreements	3,007	2,529
Low income housing tax credit fund commitments	15,176	3,330
Accrued salaries and benefits expense	5,704	3,851
Loan escrow and servicing payable	2,146	2,037
Deferred revenue	726	1,082
Unsettled investment security purchases		17,072
Litigation contingency	1,450
Miscellaneous other liabilities	5,985	2,485
Total other liabilities	$ 67,364	$ 65,293