Acquisition Activity (Detail) (USD $)	3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Location	Dec. 31, 2012 Subsequent Event [Member]	Sep. 30, 2012 Subsequent Event [Member]	Jun. 30, 2012 Florida Gulf Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Date of acquisition agreement					Mar. 19, 2012
Number of branches of acquiree			8	2	8
Total assets					$ 357,000,000
Total loans					249,000,000
Total deposits					288,000,000
Common stock outstanding per share					23.00
Contingent consideration for acquisition					4,400,000
Redeemed preferred stock during acquisition					4,100,000
Number of branches announced to close		10
Asset impairment loss	$ 2,743,000	$ 2,743,000