EPS Calculation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator:
Net income	$ 78,141	$ 83,699	$ 237,620	$ 245,850
Dividends declared on preferred stock	(2,040)	(2,040)	(6,120)	(6,120)
Dividends, DERs and undistributed earnings allocated to participating securities	(360)	(446)	(1,168)	(1,195)
Net income allocable to common stockholders - basic and diluted	$ 75,741	$ 81,213	$ 230,332	$ 238,535
Denominator:
Weighted average common shares for basic and diluted earnings per share	356,921,000	355,964,000	356,563,000	336,756,000
Basic and diluted earnings per share	$ 0.21	$ 0.23	$ 0.65	$ 0.71
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)	2,000,000		2,000,000
Stock options
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			432,000
Weighted average exercise price (in dollars per share)	$ 10.11		$ 10.11
Weighted average remaining contractual life			1 year 1 month 6 days
Restricted common stock
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			536,000
Weighted average grant date fair value (in dollars per share)	$ 7.42		$ 7.42
Restricted Stock Units
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			995,000
Weighted average grant date fair value (in dollars per share)	$ 7.04		$ 7.04