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	80,178						80,178
Other comprehensive income (loss), net of tax	16,326										16,326
Dividends paid on common stock of $0.25 and $0.15 per share during during 6 months ended June 30, 2013 and 2012, respectively	(13,148)						(13,148)
Dividends paid on preferred stock $42.50 per share on Series A for both 6 months ended June 30, 2013 and 2012 and $848.89 per share on Series E for 6 months ended June 30, 2013		(1,230)						(1,230)
Common stock warrants repurchased	(337)					(337)
Exercise of stock options	422					(858)				1,280
Net shares acquired related to employee share-based compensation plans	(1,677)									(1,677)
Stock-based compensation, net of tax effects	4,990					1,891	(2,704)			5,803
Issuance of common stock	250					250	0			0
Ending Balance at Jun. 30, 2012	1,931,548			28,939	907	1,146,292	928,523			(129,235)	(43,878)
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	88,490						88,490
Other comprehensive income (loss), net of tax	(32,873)										(32,873)
Dividends paid on common stock of $0.25 and $0.15 per share during during 6 months ended June 30, 2013 and 2012, respectively	(21,868)						(21,868)
Dividends paid on preferred stock $42.50 per share on Series A for both 6 months ended June 30, 2013 and 2012 and $848.89 per share on Series E for 6 months ended June 30, 2013		(1,230)	(4,295)					(1,230)	(4,295)
Common stock warrants repurchased	(30)					(30)
Exercise of stock options	377					(182)				559
Net shares acquired related to employee share-based compensation plans	(169)									(169)
Stock-based compensation, net of tax effects	5,374					1,752	(2,026)			5,648
Issuance of common stock	169				26	(21,299)	(36,255)			57,697
Ending Balance at Jun. 30, 2013	$ 2,127,475			$ 151,649	$ 933	$ 1,125,861	$ 1,023,243			$ (109,072)	$ (65,139)