Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning 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
Other comprehensive loss, net of tax	(5,700)	0	0	0	(5,700)
Common stock transactions:
Common shares purchased and retired	3,699	0	(3,699)	0
Common shares issued	153,257	0	153,257	0
Non-vested common shares issued	0	0	0	0
Non-vested common shares forfeited or canceled	0	0	0	0	0
Non-vested liability awards vesting during period	59	0	59	0	0
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts	649	0	649	0
Tax benefit of stock-based compensation	239	0	239	0
Stock-based compensation expense	1,534	0	1,534	0
Cash dividends declared:
Common (per share)	(17,905)	0	0	(17,905)
Preferred (per share)	(3,422)	0	0	(3,422)
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 loss, net of tax	9,659	0	0	0	9,659
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
Non-vested liability awards vesting during period	204	0	204	0	0
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts	216	0	216	0	0
Tax benefit of stock-based compensation	385	0	385	0	0
Stock-based compensation expense	1,906	0	1,906	0	0
Cash dividends declared:
Common (per share)	(19,233)	0	0	(19,233)	0
Preferred (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
Comprehensive income:
Net income	58,224	0	0	58,224	0
Other comprehensive loss, net of tax	(3,043)	0	0	0	(3,043)
Common stock transactions:
Common shares purchased and retired	(263)	0	(263)	0	0
Common shares issued	299	0	299	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, net of shares tendered in payment of option price and income tax withholding amounts	1,612	0	1,612	0	0
Tax benefit of stock-based compensation	360	0	360	0	0
Stock-based compensation expense	2,485	0	2,485	0	0
Preferred shars called for redemption, shares		(50,000)
Preferred shares called for redemption, value	(50,000)
Cash dividends declared:
Common (per share)	(26,208)	0	0	(26,208)	0
Preferred (per share)	(3,300)	0	0	(3,300)	0
Ending Balance at Dec. 31, 2012	$ 751,186	$ 0	$ 271,335	$ 463,860	$ 15,991