Parent Company Only Condensed Financial Information - Condensed Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Aug. 20, 2012
Cash flows from operating activities
Net loss	$ (1,909)	$ (435)	$ (3,332)	$ (4,066)
Net cash used by operating activities			(1,350)	(89)
Cash flows from investing activities
Investments in banking subsidiary			(13,500)
Net cash from investing activities			31,084	38,694
Cash flows from financing activities
Net proceeds from issuance of common stock			20,286		22,500
Net cash used by financing activities			(26,023)	(9,064)
Net change in cash and cash equivalents			3,711	29,541
Beginning cash and cash equivalents			61,436	34,275
Ending cash and cash equivalents	65,147	63,816	65,147	63,816
Parent Company [Member]
Cash flows from operating activities
Net loss	(1,909)	(435)	(3,332)	(4,066)
Effect of subsidiaries' operations	1,724	255	2,920	3,401
Change in other assets and other liabilities			462	(156)
Net cash used by operating activities			50	(821)
Cash flows from investing activities
Investments in banking subsidiary			(13,500)
Investments in other subsidiaries			(2)	525
Net cash from investing activities			(13,502)	525
Cash flows from financing activities
Redemption of TARP obligation			(3,000)
Net proceeds from issuance of common stock			21,085
Net cash used by financing activities			18,085
Net change in cash and cash equivalents			4,633	(296)
Beginning cash and cash equivalents			560	745
Ending cash and cash equivalents	$ 5,193	$ 449	$ 5,193	$ 449