Fair Values of Assets and Liabilities - Losses Realized on Assets Measured on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Impaired loans	$ 386	$ (2,838)	$ (13,982)	$ (3,532)
Other real estate owned	(114)	(78)	(331)	(1,205)
Total losses	$ 272	$ (2,916)	$ (14,313)	$ (4,737)