Disclosures About Fair Value of Financial Instruments - Statement of Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis (Detail) - Significant Unobservable Inputs (Level 3) - Residential Mortgage Loan Commitments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning	$ 157	$ 71	$ 45	$ 43
Issuances	85	70	315	228
Settlements	(157)	(71)	(275)	(201)
Balance at ending	$ 85	$ 70	$ 85	$ 70