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, 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						113,723
Other comprehensive income	4,271					4,271
Comprehensive income	117,994					4,271	113,723
Cash dividends - Preferred Stock	(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
Adjustments to Additional Paid in Capital, Warrant Issued				(3,000)
Adjustments to Additional Paid in Capital, Other					(9,150)
Repurchase of common stock warrant	(12,150)
Ending Balance at Jun. 30, 2015	2,887,957	100,000	127,937	0	1,379,194	(67,621)	1,462,859	(114,412)
Beginning Balance at Dec. 31, 2015	2,940,095	100,000	127,937	0	1,386,677	(79,274)	1,519,438	(114,683)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	112,445			0		0	112,445
Other comprehensive income	49,801					49,801
Comprehensive income	162,246	0	0	0	0	49,801	112,445	0
Cash dividends - Preferred Stock	(2,938)	0	0	0	0	0	(2,938)	0
Cash dividends - common stock	(56,264)			0			(56,264)
Nonvested (restricted) shares granted	0			0	(12,900)			12,900
Restricted Stock Activity	(4,177)			0	701			(4,878)
Deferred compensation trust	0			0	591			(591)
Share-based compensation	8,197			0	8,197			0
Adjustments to Additional Paid in Capital, Other	(9,200)
Repurchase of common stock warrant	0
Ending Balance at Jun. 30, 2016	$ 3,047,159	$ 100,000	$ 127,937	$ 0	$ 1,383,266	$ (29,473)	$ 1,572,681	$ (107,252)