Consolidated Statements of Changes in Stockholders' Equity (USD $)	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Parent [Member]	Total
Balance at Dec. 31, 2009	$ 243,967,000	$ 677,000	$ 634,623,000	$ (875,000)	$ 551,588,000	$ (125,736,000)	$ 8,500,000	$ 1,312,744,000
Balance (in Shares) at Dec. 31, 2009	258,000	63,459,590
Common stock issuance		150,000	124,778,000					124,928,000
Common stock issuance (in Shares)		15,028,409							15,028,409
Dividend Reinvestment Plan			310,000					310,000	310,000
Dividend Reinvestment Plan (in Shares)		28,778							28,778
Restricted stock units vested (in Shares)		15,006
Tax short-fall from stock options			(539,000)					(539,000)
Stock -based compensation			3,337,000					3,337,000	3,337,000
Cash dividends of $0.04/$0.04/$0.04 per share					(3,140,000)			(3,140,000)
Discount accretion and other adjustment on preferred stock	3,488,000				(3,488,000)
Dividends on preferred stock					(12,900,000)		(610,000)	(13,510,000)	16,388,000
Redemption of noncontrolling interest							(53,000)	(53,000)
Change in other comprehensive loss				(147,000)				(147,000)
Net income					11,565,000		610,000	12,175,000	11,565,000
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 short-fall from stock options			(218,000)					(218,000)
Stock -based compensation			1,758,000					1,758,000	1,758,000
Cash dividends of $0.04/$0.04/$0.04 per share					(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	1,507,186,000
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 benefits from stock options			(620,000)					(620,000)
Stock -based compensation			2,062,000					2,062,000	2,062,000
Cash dividends of $0.04/$0.04/$0.04 per share					(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