Federal Income Taxes - Components of Net Deferred Tax Asset (Liability) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Deferred tax assets:
General loan loss allowance	$ 3,589	$ 4,130
Deferred loan fees	169	184
Deferred compensation	1,345	1,046
Other assets	1,197	1,357
Non-accrual interest	166	163
Unrealized loss on securities designated as available for sale	610	0
Tax credits and low income housing credits	2,330	2,134
NOL carry forward	1,396	1,341
Total deferred tax assets	10,802	10,355
Deferred tax liabilities:
FHLB stock dividends	(1,660)	(1,660)
Mortgage servicing rights	(948)	(1,103)
Book versus tax depreciation	(707)	(697)
Original issue discount	(684)	(708)
Unrealized gain on securities designated as available for sale	0	(51)
Prepaid expense for FHLB advance restructure	(140)	(140)
Purchase price adjustments	(128)	(128)
Total deferred tax liabilities	(4,267)	(4,487)
Valuation Allowance	0	(5,868)
Net deferred tax asset (liability)	$ 6,535	$ 0