Allowance for Credit Losses - Summary of Provision for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Receivables [Abstract]
Provision for loans	$ 1,363	$ 4,382	$ 2,092	$ 4,382
Provision for unfunded letters of credit	66	118	137	118
Total provision for credit losses	$ 1,429	$ 4,500	$ 2,229	$ 4,500