Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Warrant	Capital Surplus	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Beginning Balance at Dec. 31, 2013	$ 2,702,894	$ 100,000	$ 127,937	$ 3,000	$ 1,390,643	$ (66,876)	$ 1,277,975	$ (129,785)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	112,974						112,974
Total other comprehensive gains/(losses), Net of Tax	27,369					27,369
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	140,343					27,369	112,974
Dividends, Preferred Stock, Cash	(2,938)						(2,938)
Cash dividends - common stock	(52,640)						(52,640)
Nonvested (restricted) shares granted	99				(12,993)			13,092
Restricted Stock Activity	(4,221)				802			(5,023)
Deferred compensation trust	0				600			(600)
Share-based compensation	8,201				8,201
Ending Balance at Jun. 30, 2014	2,791,738	100,000	127,937	3,000	1,387,253	(39,507)	1,335,371	(122,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Payments for Repurchase of Warrants	0
Beginning Balance at Dec. 31, 2014	2,834,281	100,000	127,937	3,000	1,393,090	(71,892)	1,404,717	(122,571)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	113,723	0	0	0	0	0	113,723	0
Total other comprehensive gains/(losses), Net of Tax	4,271					4,271
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	117,994					4,271	113,723
Dividends, Preferred Stock, Cash	(2,938)						(2,938)
Cash dividends - common stock	(52,643)						(52,643)
Nonvested (restricted) shares granted	0				(14,340)			14,340
Restricted Stock Activity	(4,253)				1,291			(5,544)
Deferred compensation trust	0				637			(637)
Share-based compensation	7,666				7,666
Ending Balance at Jun. 30, 2015	2,887,957	$ 100,000	$ 127,937	0	1,379,194	$ (67,621)	$ 1,462,859	$ (114,412)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Warrant Issued				$ (3,000)
Adjustments to Additional Paid in Capital, Warrant Issued					$ (9,150)
Payments for Repurchase of Warrants	$ (12,150)