Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2013	Sep. 30, 2014
Loss Contingencies [Line Items]
Retained secondary credit loss exposure		$ 3,387	$ 7,644
Unpaid principal balance of loans repurchased from investors	$ 1,800		1,100	$ 1,000
Asset disposition related expense including reserves for repurchased loans	687		754	125
Reserve for unfunded commitment losses	4,664	2,574	2,557	$ 1,956
Increase (decrease) reserve for repurchase of previously sold loans		(310)	(1,300)
Investor loss reimbursement	(687)	212	$ (50)
Reserve for repurchase of previously sold loans		1,000
Letters of Credit
Loss Contingencies [Line Items]
Reserve for unfunded commitment losses	$ 4,700	2,600
Reserve for unfunded commitment losses					$ 2,700
Residential Loans
Loss Contingencies [Line Items]
Retained secondary mortgage loans originated for FHLB		$ 122,700