Subsequent Event (Narrative) (Detail) (USD $)	6 Months Ended
	Jun. 30, 2012
Subsequent Event [Line Items]
Number of acquisitions the company participated	1
Cash payment from the FDIC	$ 138,700,000
Montgomery Bank & Trust
Subsequent Event [Line Items]
Number of operating branches	2
Assumed Purchase price, Customer deposits	156,600,000
Assumed Purchase price, assets	18,100,000
Assumed Purchase price,cash and cash equivalents	16,700,000
Assumed Purchase price, deposits -secured loans	$ 1,200,000