Condensed Consolidated Statements Of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Series A Preferred Stock [Member]	Series E Preferred Stock [Member]	Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Series A Preferred Stock [Member]	Retained Earnings [Member] Series E Preferred Stock [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2011	$ 1,845,774			$ 28,939	$ 907	$ 1,145,346	$ 865,427			$ (134,641)	$ (60,204)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	125,171						125,171
Other comprehensive income (loss), net of tax	30,927										30,927
Dividends paid on common stock of $0.40 and $0.25 per share during 9 months ended September 30, 2013 and 2012, respectively	(21,906)						(21,906)
Dividends paid on preferred stock $63.75 per share on Series A for both 9 months ended Sept. 30, 2013 and 2012 and $1,248.89 per share on Series E for 9 months ended Sept. 30, 2013		(1,845)						(1,845)
Common stock warrants repurchased	(385)					(385)
Exercise of stock options	856					(1,711)				2,567
Net shares acquired related to employee share-based compensation plans	(2,008)									(2,008)
Stock-based compensation, net of tax effects	6,687					1,735	(4,253)			9,205
Issuance of common stock	407					407	0			0
Ending Balance at Sep. 30, 2012	1,983,678			28,939	907	1,145,392	962,594			(124,877)	(29,277)
Beginning Balance at Dec. 31, 2012	2,093,530			151,649	907	1,145,620	1,000,427			(172,807)	(32,266)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	135,795						135,795
Other comprehensive income (loss), net of tax	(26,675)										(26,675)
Dividends paid on common stock of $0.40 and $0.25 per share during 9 months ended September 30, 2013 and 2012, respectively	(35,176)						(35,176)
Dividends paid on preferred stock $63.75 per share on Series A for both 9 months ended Sept. 30, 2013 and 2012 and $1,248.89 per share on Series E for 9 months ended Sept. 30, 2013		(1,845)	(6,319)					(1,845)	(6,319)
Common stock warrants repurchased	(30)					(30)
Exercise of stock options	984					(729)				1,713
Net shares acquired related to employee share-based compensation plans	(381)									(381)
Stock-based compensation, net of tax effects	7,581					2,757	(2,511)			7,335
Issuance of common stock	195				26	(21,274)	(36,254)			57,697
Ending Balance at Sep. 30, 2013	$ 2,167,659			$ 151,649	$ 933	$ 1,126,344	$ 1,054,117			$ (106,443)	$ (58,941)