Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Series B Preferred Stock [Member]
Balance, value at Dec. 31, 2011	$ 759,338	$ 579,136	$ 155,069	$ 25,133	$ 0
Balance, shares at Dec. 31, 2011		39,506,000			0
Net Income	32,681		32,681
Other comprehensive income	3,345			3,345
Issuance of common stock - stock option and other plans, value	713	713
Issuance of common stock - stock option and other plans, shares		40,000
Issuance of common stock - restricted stock awards, net of cancelled awards, value	1,152	1,152
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		143,000
Cash dividends paid on common stock	(35,252)		(35,252)
Balance, value at Sep. 30, 2012	761,977	581,001	152,498	28,478	0
Balance, shares at Sep. 30, 2012		39,689,000			0
Balance, value at Dec. 31, 2012	764,008	581,471	162,388	20,149	0
Balance, shares at Dec. 31, 2012		39,686,000			0
Net Income	40,043		40,043
Other comprehensive income	(23,357)			(23,357)
Stock Issued During Period, Shares, New Issues		11,380,000			9,000
Stock Issued During Period, Value, New Issues	276,181	273,964			2,217
Stock Adjustment Deferred Compensation - Shares	0
Stock Adjustment Value Deferred Compensation	517
Issuance of common stock - stock option and other plans, value	1,154	1,154
Issuance of common stock - stock option and other plans, shares		68,000
Issuance of common stock - restricted stock awards, net of cancelled awards, value	1,881	1,881
Issuance of common stock - restricted stock awards, net of cancelled awards, shares		153,000
Cash dividends paid on common stock	(14,219)		(14,219)
Stock Repurchased During Period, Shares		(16,000)
Stock Repurchased During Period, Value	(391)	(391)
Dividends, Preferred Stock, Cash	(20)
Balance, value at Sep. 30, 2013	$ 1,045,797	$ 858,596	$ 188,192	$ (3,208)	$ 2,217
Balance, shares at Sep. 30, 2013		51,271,000			9,000