Stockholders' Equity and Partners' Capital (Details) (USD $)	3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended					0 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended			0 Months Ended
	Sep. 30, 2012 Restricted Stock	Sep. 30, 2013 Restricted Stock	Sep. 30, 2012 Restricted Stock	Sep. 30, 2013 2006 Incentive Plan	Sep. 30, 2013 General and Administrative Expense Restricted Stock	Sep. 30, 2013 General and Administrative Expense Restricted Stock	Sep. 30, 2012 General and Administrative Expense Restricted Stock	Sep. 30, 2013 Listing Expenses Restricted Stock	Sep. 30, 2012 Listing Expenses Restricted Stock	Sep. 30, 2012 Non Traded REIT Expenses Restricted Stock	Jan. 07, 2013 Common Stock Offering	Sep. 30, 2013 Common Stock Offering	Sep. 30, 2013 Long Term Incentive Program Listing Expenses	Sep. 30, 2012 Long Term Incentive Program Listing Expenses	Sep. 30, 2013 Long Term Incentive Program Listing Expenses	Sep. 30, 2012 Long Term Incentive Program Listing Expenses	Sep. 30, 2013 Long Term Incentive Program Change in Control of Company	Nov. 01, 2013 Subsequent Event Maximum Common Stock Offering
Common Stock Offerings [Abstract]
Maximum amount of common stock authorized											$ 250,000,000							$ 300,000,000.0
Issuance of common stock (in shares)												20,707,113
Average share price												$ 11.24
Long-Term Incentive Program [Abstract]
Number of shares authorized (in shares)				10,000,000
Number of shares available for grant (in shares)				5,096,100
Allocated share-based compensation expense	200,000	2,000,000	6,400,000		500,000	1,400,000	200,000	600,000	4,700,000	1,500,000			0	4,500,000	3,100,000	5,900,000
Nonvested awards, total compensation cost not yet recognized		$ 4,200,000															$ 4,500,000
Contingent units																	450,000
Period for recognition		2 years 3 months 18 days