Fair Value Measurement - Schedule of Gains and Losses from Nonrecurring Fair Value Adjustments (Detail) - Fair Value Nonrecurring Basis [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Losses from nonrecurring fair value adjustments	$ 861	$ 316	$ (556)	$ (449)	$ (762)
Impaired Originated & PNCI Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Losses from nonrecurring fair value adjustments	874	48	(570)	(38)	(660)
Foreclosed Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Losses from nonrecurring fair value adjustments	$ (13)	$ 268	$ 14	$ (411)	$ (102)