Real Estate and Other Assets Owned - Presentation of Balances in Other Real Estate and Other Assets Owned and Non-Accrual Loans Consisting Other Non-Performing Loan (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other assets owned	$ 1,736	$ 1,927	$ 1,954	$ 1,674
Total non-accrual loans	7,158	3,175	1,117
Past due 90 days still accruing	1,486
Total non-performing assets	$ 10,380	$ 5,102	$ 3,071
Non-performing assets / Total assets	1.18%	0.55%	0.33%
One-to-Four Family Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other assets owned	$ 55	$ 159	$ 120	350
Total non-accrual loans	1,427	1,501	407
Land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other assets owned	943	1,768	1,834	1,124
Total non-accrual loans	1,680	215	301
Past due 90 days still accruing	1,486
Non-Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other assets owned	738			$ 200
Total non-accrual loans	$ 672	$ 1,159	$ 101