Summary of Significant Accounting Policies (Details Textual) (USD $)	9 Months Ended
	Sep. 30, 2012 Segment Room Property	Dec. 31, 2011	Jan. 19, 2011 Employee Property
Summary of Significant Accounting Policies (Textual) [Abstract]
Number of common stock sold, shares			31,625,000
Common stock price per share			$ 20.50
Shares of common stock issued to accredited prior investors			7,030,084
Common units of limited partnership interests issued to accredited prior investors			18,145,039
Aggregate value of common units of limited partnership interests issued to accredited prior investors			$ 516,100,000
Cash paid to non-accredited prior investors from IPO			6,100,000
Revolving credit facility			250,000,000
Maximum revolving credit facility available under specified circumstances	219,400,000		400,000,000
Indebtedness	964,068,000	943,479,000	342,000,000
Defeasance costs			24,300,000
Loan transfer and consent and credit facility origination fees			10,800,000
Loan transfer and consent and credit facility origination fees prepaid by predecessor			700,000
Net proceeds from IPO			594,600,000
IPO offering costs paid by predecessor			$ 1,900,000
Properties of entities with controlling ownership interests			17
Properties of entities with non-controlling ownership interests			4
Percent ownership of predecessor			25.00%
Number of employees			130
Office, retail, multifamily, and mixed-use Operating properties	23
Properties held for development	5
Number of operating segments	4
Room in mixed-use segment all-suite hotel	369