Fair Value Measurement of Assets and Liabilities - Assets and Liabilities Measured at Fair Value on Recurring and Non-Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Unpaid principal balances of loans held for sale	$ 17,500		$ 17,500		$ 16,900
Change in fair value of loans held for sale	660	$ 81	813	$ 453
Covered real estate owned	$ 1,300		$ 1,300		$ 3,200