Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ 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	41,071		41,071
Other comprehensive income	15,604			15,604
Issuance of common stock - cashless exercise of warrants, shares		1,140
Issuance of common stock - cashless exercise of warrants, value	0	$ 0
Stock Adjustment Value Deferred Compensation	(1)	$ (1)
Stock Adjustment Deferred Compensation - Shares		0
Issuance of common stock - stock option and other plans, value	425	$ 425
Issuance of common stock - stock option and other plans, shares		21
Issuance of common stock - restricted stock awards, net of cancelled awards, value	1,224	$ 1,224
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		233
Stock Repurchased and Retired During Period, Value	(601)	$ (601)
Stock Repurchased During Period, Shares		(24)
Dividends, Preferred Stock, Cash	(37)		(37)
Cash dividends paid on common stock	(18,783)		(18,783)
Balance, value at Jun. 30, 2014	1,092,151	$ 861,609	224,765	3,560	$ 2,217
Balance, shares at Jun. 30, 2014		52,635			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	46,307		46,307
Other comprehensive income	(2,832)			(2,832)
Issuance of common stock - stock option and other plans, value	519	$ 519
Issuance of common stock - stock option and other plans, shares		21
Issuance of common stock - restricted stock awards, net of cancelled awards, value	1,836	$ 1,836
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		282
Stock Repurchased and Retired During Period, Value	(874)	$ (874)
Stock Repurchased During Period, Shares		(31)
Dividends, Preferred Stock, Cash	(66)		(66)
Cash dividends paid on common stock	(36,851)		(36,851)
Balance, value at Jun. 30, 2015	$ 1,236,214	$ 987,320	$ 243,888	$ 2,789	$ 2,217
Balance, shares at Jun. 30, 2015		57,709			9