Consolidated Statements of Changes in Stockholders Equity (Unaudited) (USD $) In Thousands, unless otherwise specified	Total	Preferred stock	Common stock	Retained earnings	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2008	$ 539,062	$ 50,000	$ 117,613	$ 362,477	$ 8,972
Comprehensive income:
Net income	53,863	0	0	53,863	0
Other comprehensive income (loss), net of tax	6,103	0	0	0	6,103
Total comprehensive income	59,966
Common stock transactions:
Common shares purchased and retired	(11,052)	0	(11,052)	0	0
Common shares issued	3,813	0	3,813	0	0
Non-vested common shares issued	0	0	0	0	0
Stock options exercised	144	0	144	0	0
Tax benefit of stock-based compensation	742	0	742	0	0
Stock-based compensation expense	875	0	875	0	0
Cash dividends declared:
Common	(15,694)	0	0	(15,694)	0
Preferred (6.75% per share)	(3,422)	0	0	(3,422)	0
Ending Balance at Dec. 31, 2009	574,434	50,000	112,135	397,224	15,075
Comprehensive income:
Net income	37,356	0	0	37,356	0
Other comprehensive income (loss), net of tax	(5,700)	0	0	0	(5,700)
Total comprehensive income	31,656
Common stock transactions:
Common shares purchased and retired	(3,699)	0	(3,699)	0	0
Common shares issued	153,257	0	153,257	0	0
Non-vested common shares issued	0	0	0	0	0
Non-vested common shares forfeited or canceled	0	0	0	0	0
Stock options exercised	649	0	649	0	0
Non-vested common shares vesting during period	59	0	59	0	0
Tax benefit of stock-based compensation	239	0	239	0	0
Stock-based compensation expense	1,534	0	1,534	0	0
Cash dividends declared:
Common	(17,905)	0	0	(17,905)	0
Preferred (6.75% per share)	(3,422)	0	0	(3,422)	0
Ending Balance at Dec. 31, 2010	736,802	50,000	264,174	413,253	9,375
Comprehensive income:
Net income	44,546	0	0	44,546	0
Other comprehensive income (loss), net of tax	9,659	0	0	0	9,659
Total comprehensive income	54,205
Common stock transactions:
Common shares purchased and retired	(248)	0	(248)	0	0
Common shares issued	205	0	205	0	0
Non-vested common shares issued	0	0	0	0	0
Non-vested common shares forfeited or canceled	0	0	0	0	0
Stock options exercised	385	0	385	0	0
Non-vested common shares vesting during period	216	0	216	0	0
Tax benefit of stock-based compensation	204	0	204	0	0
Stock-based compensation expense	1,906	0	1,906	0	0
Cash dividends declared:
Common	(19,233)	0	0	(19,233)	0
Preferred (6.75% per share)	(3,422)	0	0	(3,422)	0
Ending Balance at Dec. 31, 2011	$ 771,020	$ 50,000	$ 266,842	$ 435,144	$ 19,034