Fair Value Measurement - Reconciliation of Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) on Recurring Basis (Detail) - Mortgage Servicing Rights [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 6,720	$ 7,814	$ 7,618	$ 7,378
Additions	287	238	788	659
Change in fair value	(799)	(585)	(2,198)	(570)
Balance at end of period	$ 6,208	$ 7,467	$ 6,208	$ 7,467