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, 2010	$ 736,802	$ 50,000	$ 264,174	$ 413,253	$ 9,375
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts	216	0	216	0	0
Non-vested liability awards vesting during period	204	0	204	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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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 shares called for redemption, value	50,000	50,000	0	0	0
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	86,136	0	0		0
Other comprehensive loss, net of tax	(32,032)	0	0	0	(32,032)
Common stock transactions:
Common shares purchased and retired	(448)	0	(448)	0	0
Common shares issued	543	0	543	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	9,271	0	9,271	0	0
Tax benefit of stock-based compensation	1,898	0	1,898	0	0
Stock-based compensation expense	2,936	0	2,936	0	0
Cash dividends declared:
Common (per share)	(17,909)	0		(17,909)	0
Ending Balance at Dec. 31, 2013	$ 801,581	$ 0	$ 285,535	$ 532,087	$ (16,041)