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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning	$ 87	$ 103	$ 43	$ 240
Issuances	71	54	158	157
Settlements	(87)	(103)	(130)	(343)
Balance at ending	$ 71	$ 54	$ 71	$ 54