Loans and Allowance for Loan Losses - Non-Accrual Loans, Loans Still Accruing and Past Due 90 Days or More and Restructured Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Receivables [Abstract]
Non-accrual loans	$ 33,712	$ 28,601	$ 21,788
Loans still accruing and past due 90 days or more	107	341	49
Troubled debt restructured loans	750	199	204
Total	$ 34,569	$ 29,141	$ 22,041