EPS Calculation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Numerator:
Net income	$ 71,328		$ 78,141		$ 224,152		$ 237,620
Dividends declared on preferred stock	(3,750)		(2,040)		(10,000)		(6,120)
Dividends, DERs and undistributed earnings allocated to participating securities	(230)		(360)		(880)		(1,168)
Issuance costs of redeemed preferred stock	0	[1]	0	[1]	(3,947)	[1]	0	[1]
Net income to common stockholders - basic and diluted	$ 67,348		$ 75,741		$ 209,325		$ 230,332
Denominator:
Weighted average common shares for basic and diluted earnings per share	363,918,000	[2]	356,921,000	[2]	361,181,000	[2]	356,563,000	[2]
Basic and diluted EPS (in dollars per share)	$ 0.19		$ 0.21		$ 0.58		$ 0.65
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)					1,600,000
Stock options
Denominator:
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)					407,000
Weighted average exercise price (in dollars per share)	$ 10.23				$ 10.23
Weighted average remaining contractual life					4 days
Restricted common stock
Denominator:
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)					379,000
Weighted average grant date fair value (in dollars per share)	$ 7.73				$ 7.73
Restricted Stock Units
Denominator:
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)					787,000
Weighted average grant date fair value (in dollars per share)	$ 6.50				$ 6.50

[1] Issuance costs of redeemed preferred stock represent the original offering costs related to the Series A Preferred Stock, which was redeemed on May 16, 2013. (See Note 11)

[2] At September 30, 2013, the Company had an aggregate of 1.6 million equity instruments outstanding that were not included in the calculation of diluted EPS for the three and nine months ended September 30, 2013, as their inclusion would have been anti-dilutive. These equity instruments were comprised of 407,000 stock options with a weighted average exercise price of $10.23 and a weighted average remaining contractual life of 0.01 years, approximately 379,000 shares of restricted common stock with a weighted average grant date fair value of $7.73 and approximately 787,000 RSUs with a weighted average grant date fair value of $6.50. These equity instruments may have a dilutive impact on future EPS.