Annual report pursuant to Section 13 and 15(d)

Subsequent Events (Details)

v2.4.0.6
Subsequent Events (Details) (USD $)
 3 Months Ended 12 Months Ended 0 Months Ended
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Jul. 15, 2011
May 25, 2011
Mar. 16, 2011
Feb. 24, 2012
Issuance of Equity [Member]
Jan. 17, 2012
Issuance of Equity [Member]
Subsequent Event [Line Items]                      
Common Stock, Shares, Issued       140,596,708 40,501,212   42,000,000 20,000,000 25,000,000 30,000,000 34,000,000
Common Stock, Shares, Issued Pursuant to the Underwriters' Over-allotments             6,300,000 3,000,000 3,750,000 4,500,000 5,100,000
Equity Issuance, Amount Per Share                   $ 9.90 $ 9.17
Proceeds from Issuance of Common Stock $ 490,200,000 $ 239,200,000 $ 294,700,000 $ 1,006,847,000 $ 235,275,000 $ 1,000       $ 341,600,000 $ 358,500,000
Proceeds from Issuance of Common Stock, Net       1,000,000,000           337,400,000 354,500,000
Payments of Stock Issuance Costs       $ 17,600,000           $ 4,200,000 $ 4,000,000