Acquisition Activity (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2011	May 31, 2011	Mar. 31, 2011
Omni Bancshares, Inc [Member]
Goodwill	$ 63,518,000
Business acquisition, contingent consideration	46,407,000	46,407,000
Revenue from assets acquired	2,318,000
Net income	704,000
Number of branch offices of acquiree	14
Operational days subsequent to acquisition	30
Business acquisition, amount paid	4,841,000
Acquisition date	5/31/2011
Cameron Bancshares, Inc [Member]
Goodwill	51,315,000
Business acquisition, contingent consideration	143,241,000	143,241,000
Revenue from assets acquired	3,304,000
Net income	1,740,000
Number of branch offices of acquiree	22
Operational days subsequent to acquisition	30
Number of ATMs			48
Business acquisition, amount paid	3,154,000
Acquisition date	5/31/2011
Florida Corporation [Member]
Goodwill	52,000
Business acquisition, amount paid	700,000
Contingent payment for the acquisition of assets	700,000
Resulted additional intangible assets included in company's consolidated balance sheet	$ 1,400,000