Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Preferred Stock [Member]
Balance, value at Dec. 31, 2013	$ 1,053,249	$ 860,562	$ 202,514	$ (12,044)	$ 2,217
Balance, shares at Dec. 31, 2013		51,265			9
Net Income	19,844		19,844
Other comprehensive income	7,001			7,001
Issuance of common stock - cashless exercise of warrants, shares		1,140
Issuance of common stock - cashless exercise of warrants, value	0	0
Issuance of common stock - stock option and other plans, value	405	405
Issuance of common stock - stock option and other plans, shares		19
Issuance of common stock - restricted stock awards, net of cancelled awards, value	680	680
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		197
Stock Repurchased During Period, Shares		(21)
Stock Repurchased and Retired During Period, Value	(522)	(522)
Dividends, Preferred Stock, Cash	(12)
Cash dividends paid on common stock	(6,154)		(6,154)
Balance, value at Mar. 31, 2014	1,074,491	861,125	216,192	(5,043)	2,217
Balance, shares at Mar. 31, 2014		52,600			9
Balance, value at Dec. 31, 2014	1,228,175	985,839	234,498	5,621	2,217
Balance, shares at Dec. 31, 2014		57,437			9
Net Income	24,361		24,361
Other comprehensive income	8,665			8,665
Issuance of common stock - stock option and other plans, value	428	428
Issuance of common stock - stock option and other plans, shares		17
Issuance of common stock - restricted stock awards, net of cancelled awards, value	862	862
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		273
Stock Repurchased During Period, Shares		(28)
Stock Repurchased and Retired During Period, Value	(781)	(781)
Dividends, Preferred Stock, Cash	(31)
Cash dividends paid on common stock	(17,236)		(17,236)
Balance, value at Mar. 31, 2015	$ 1,244,443	$ 986,348	$ 241,592	$ 14,286	$ 2,217
Balance, shares at Mar. 31, 2015		57,699			9