Stockholders' Equity (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Class of Stock [Line Items]
Common Stock, Shares, Outstanding, Beginning Balance	68,841,296	61,845,214	44,652,182
Issuance of Common Stock including Issuance of Restricted Stock Units	17,646,586	6,518,736	16,874,884
Issuance of Restricted Stock Shares	292,339	573,198	35,145
Repurchase and Retirement of Restricted Stock Shares	(98,603)	(123,438)	(132,463)
Common Stock, Shares, Outstanding, Ending Balance	86,807,402	68,841,296	61,845,214
Convertible Common Stock [Member]
Class of Stock [Line Items]
Conversion of Operating Partnership Units	125,784	27,586	415,466