Consolidated Statements of Changes in Equity (USD $) In Thousands	Total	Series A Preferred Stock [Member]	Series C Preferred Stock [Member]	Preferred Stock [Member] Series A Preferred Stock [Member]	Preferred Stock [Member] Series C Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Series A Preferred Stock [Member]	Additional Paid-In Capital [Member] Series C Preferred Stock [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2012	$ 3,569,431			$ 957,327		$ 113,182	$ 2,868,965			$ (114,176)	$ 4,101	$ (259,968)
Net income	120,804											120,804
Other comprehensive income (loss), net of income taxes	(33,615)										(33,615)
Cash dividends declared on Common Stock - $0.21 per share	(26,703)											(26,703)
Cash dividends paid on Preferred Stock		(33,741)						(33,741)
Accretion of discount on Series A Preferred Stock				10,543				(10,543)
Redemption of Series A Preferred Stock		(967,870)		(967,870)
Settlement of prepaid common stock purchase contracts	122,848					17,550	(17,550)
Issuance of stock, net of issuance costs	174,764		125,400		125,400	8,553	166,211
Restricted share unit activity	(3,541)					372	(3,413)					(500)
Stock options exercised	789					47	742
Share-based compensation tax benefit	371
Share-based compensation expense	5,771						5,771
Balance at Sep. 30, 2013	2,931,860			0	125,400	139,704	2,976,813			(114,176)	(29,514)	(166,367)
Balance at Dec. 31, 2013	2,948,985				125,862	139,721	2,976,348			(114,176)	(41,258)	(137,512)
Net income	142,077											142,077
Other comprehensive income (loss), net of income taxes	16,431										16,431
Cash dividends declared on Common Stock - $0.21 per share	(29,194)											(29,194)
Cash dividends paid on Preferred Stock			(7,678)						(7,678)
Settlement of prepaid common stock purchase contracts	0
Issuance of stock, net of issuance costs			118		118
Restricted share unit activity	(468)					41	(509)
Stock options exercised	1,985					116	1,869
Share-based compensation tax deficiency	(3,164)						(3,164)
Share-based compensation expense	7,453						7,453
Balance at Sep. 30, 2014	$ 3,076,545				$ 125,980	$ 139,878	$ 2,974,319			$ (114,176)	$ (24,827)	$ (24,629)