Consolidated Statements of Changes in Stockholders' Equity - USD ($)	Restricted Stock Units (RSUs) [Member] Additional Paid-in Capital [Member]	Restricted Stock Units (RSUs) [Member] Parent [Member]	Series B Preferred Stock [Member] Preferred Stock [Member]	Series B Preferred Stock [Member] Additional Paid-in Capital [Member]	Series B Preferred Stock [Member] Parent [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Parent [Member]	Total
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
Balance, shares (in Shares) at Dec. 31, 2012						258,000	78,778,288
Dividend Reinvestment Plan								605,000					605,000	$ 605,000
Dividend Reinvestment Plan, shares (in Shares)							25,984							25,984
Redemption of Series B Preferred Stock			$ (258,000,000)	$ (302,000)	$ (258,302,000)
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							$ 1,000						1,000
Restricted stock units vested, shares (in Shares)							138,220
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, shares (in Shares)							594,946							594,946
Tax short-fall from stock options								(2,509,000)					(2,509,000)
Stock -based compensation								2,106,000					2,106,000
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	123,735,000
Balance at Dec. 31, 2013							$ 838,000	784,489,000	(29,729,000)	829,109,000	(125,736,000)		1,458,971,000
Balance, shares (in Shares) at Dec. 31, 2013							79,589,869
Dividend Reinvestment Plan							$ 1,000	2,847,000					2,848,000	$ 2,800,000
Dividend Reinvestment Plan, shares (in Shares)							116,957							116,957
Restricted stock units vested							$ 1,000						1,000
Restricted stock units vested, shares (in Shares)							88,537
Shares withheld related to net share settlement of RSUs	$ (850,000)	$ (850,000)
Stock issued to directors								350,000					350,000
Stock issued to directors, shares (in Shares)							13,690
Stock options exercised								128,000					128,000
Stock options exercised, shares (in Shares)							5,500							5,500
Tax short-fall from stock options								(1,285,000)					(1,285,000)
Stock -based compensation								3,840,000					3,840,000
Cash dividends										(23,105,000)			(23,105,000)
Change in other comprehensive loss									24,160,000				24,160,000
Net income										137,830,000			137,830,000	$ 137,830,000
Balance at Dec. 31, 2014							$ 840,000	789,519,000	(5,569,000)	943,834,000	(125,736,000)		1,602,888,000	1,602,888,000
Balance, shares (in Shares) at Dec. 31, 2014							79,814,553
Dividend Reinvestment Plan							$ 2,000	4,173,000					4,175,000	$ 4,200,000
Dividend Reinvestment Plan, shares (in Shares)							148,582							148,582
Restricted stock units vested, shares (in Shares)							18,955
Warrant exercised (in Shares)							369
Shares withheld related to net share settlement of RSUs	$ (227,000)	$ (227,000)
Stock issued to directors								495,000					495,000
Stock issued to directors, shares (in Shares)							17,974
Stock options exercised							$ 2,000	5,012,000					5,014,000
Stock options exercised, shares (in Shares)							214,580							214,580
Equity consideration for acquisition							$ 26,000	82,743,000					82,769,000
Equity consideration for acquisition (in Shares)							2,580,353
Purchases of treasury stock											(59,412,000)		(59,412,000)	$ (59,400,000)
Purchases of treasury stock (in Shares)							(1,989,250)
Tax short-fall from stock options								(5,348,000)					(5,348,000)
Stock -based compensation								4,455,000					4,455,000
Cash dividends										(45,283,000)			(45,283,000)	(45,300,000)
Change in other comprehensive loss									(2,857,000)				(2,857,000)
Net income										161,109,000			161,109,000	161,109,000
Balance at Dec. 31, 2015							$ 870,000	$ 880,822,000	$ (8,426,000)	$ 1,059,660,000	$ (185,148,000)		$ 1,747,778,000	$ 1,747,778,000
Balance, shares (in Shares) at Dec. 31, 2015							80,806,116