Consolidated Statements of Changes in Stockholders' Equity (USD $)	Preferred Stock [Member] Series B Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Series B Preferred Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Parent [Member] Series B Preferred Stock [Member]	Parent [Member]	Series B Preferred Stock [Member]	Total
Balance at Dec. 31, 2010		$ 247,455,000	$ 827,000		$ 762,509,000	$ (1,022,000)	$ 543,625,000	$ (125,736,000)	$ 8,447,000		$ 1,436,105,000
Balance (in Shares) at Dec. 31, 2010		258,000	78,531,783
Dividend Reinvestment Plan			1,000		286,000						287,000		287,000
Dividend Reinvestment Plan (in Shares)			21,281										21,281
Restricted stock units vested (in Shares)			12,633
Stock options exercised			1,000		1,306,000						1,307,000
Stock options exercised (in Shares)			86,860										86,860
Tax effect from stock options					(218,000)						(218,000)
Stock -based compensation					1,758,000						1,758,000		1,758,000
Cash dividends							(3,146,000)				(3,146,000)
Discount accretion and other adjustment on preferred stock		3,537,000					(3,537,000)
Dividends on preferred stock							(12,900,000)		(605,000)		(13,505,000)		16,437,000
Change in other comprehensive loss						(7,710,000)					(7,710,000)
Net income							100,150,000		605,000		100,755,000		100,150,000
Balance at Dec. 31, 2011		250,992,000	829,000		765,641,000	(8,732,000)	624,192,000	(125,736,000)	8,447,000		1,515,633,000
Balance (in Shares) at Dec. 31, 2011		258,000	78,652,557
Dividend Reinvestment Plan					291,000						291,000		291,000
Dividend Reinvestment Plan (in Shares)			17,956										17,956
Restricted stock units vested (in Shares)			11,814
Stock salary					788,000						788,000
Stock salary (in Shares)			45,937
Stock options exercised			1,000		763,000						764,000
Stock options exercised (in Shares)			50,024										50,024
Tax effect from stock options					(620,000)						(620,000)
Stock -based compensation					2,062,000						2,062,000		2,850,000
Cash dividends							(3,149,000)				(3,149,000)
Discount accretion and other adjustment on preferred stock		3,588,000					(3,588,000)
Dividends on preferred stock							(12,900,000)		(605,000)		(13,505,000)		16,488,000
Change in other comprehensive loss						9,197,000					9,197,000
Net income							117,438,000		605,000		118,043,000		117,438,000
Balance at Dec. 31, 2012		254,580,000	830,000		768,925,000	465,000	721,993,000	(125,736,000)	8,447,000		1,629,504,000		1,621,057,000
Balance (in Shares) at Dec. 31, 2012		258,000	78,778,288
Dividend Reinvestment Plan					605,000						605,000		605,000
Dividend Reinvestment Plan (in Shares)			25,984										25,984
Redemption of Series B Preferred Stock	(258,000,000)			(302,000)						(258,302,000)		(258,000,000)
Redemption of Series B Preferred Stock (in Shares)	(258,000)
Redemption of noncontrolling interest					(191,000)				(8,447,000)		(8,638,000)
Restricted stock units vested (in Shares)			138,220
Restricted stock units vested			1,000								1,000
Stock salary			1,000		1,106,000						1,107,000
Stock salary (in Shares)			52,431
Stock options exercised			6,000		14,749,000						14,755,000
Stock options exercised (in Shares)			594,946										594,946
Tax effect from stock options					(2,509,000)						(2,509,000)
Stock -based compensation					2,106,000						2,106,000		3,213,000
Cash dividends							(6,342,000)				(6,342,000)
Discount accretion and other adjustment on preferred stock		3,420,000					(3,420,000)
Dividends on preferred stock							(6,265,000)		(592,000)		(6,857,000)		9,685,000
Change in other comprehensive loss						(30,194,000)					(30,194,000)
Net income							123,143,000		592,000		123,735,000		123,143,000
Balance at Dec. 31, 2013			$ 838,000		$ 784,489,000	$ (29,729,000)	$ 829,109,000	$ (125,736,000)			$ 1,458,971,000		$ 1,458,971,000
Balance (in Shares) at Dec. 31, 2013			79,589,869