EPS Calculation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Numerator:
Net income	$ 83,699	$ 77,214	$ 245,850	$ 208,181
Dividends declared on preferred stock	(2,040)	(2,040)	(6,120)	(6,120)
Dividends, DERs and undistributed earnings allocated to participating securities	(446)	(172)	(1,196)	(388)
Net income allocable to common stockholders - basic and diluted	$ 81,213	$ 75,002	$ 238,535	$ 201,673
Denominator:
Weighted average common shares for basic earnings per share (in shares)	355,510,000	280,278,000	336,485,000	280,190,000
Add: Weighted average dilutive equity instruments (in shares)	454,000	302,000	271,000	286,000
Denominator for diluted earnings per share (in shares)	355,964,000	280,580,000	336,756,000	280,476,000
Basic and diluted EPS (in dollars per share)	$ 0.23	$ 0.27	$ 0.71	$ 0.72
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			671,000
Stock options
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			477,000
Weighted average exercise price (in dollars per share)	$ 10.15		$ 10.15
Weighted average remaining contractual life (in years)	2.0		2.0
Restricted common stock
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			179,000
Weighted average grant date fair value (in dollars per share)	$ 8.18		$ 8.18
Restricted Stock Units
Anti-dilutive securities
Anti-dilutive securities excluded from diluted earnings per share calculations (in shares)			15,000
Weighted average grant date fair value (in dollars per share)	$ 5.63		$ 5.63