Stockholders' Equity and Partners' Capital (Details) (USD $)	12 Months Ended												12 Months Ended		0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Restricted Common Stock and Units	Dec. 31, 2012 Restricted Common Stock and Units	Dec. 31, 2011 Restricted Common Stock and Units	Dec. 31, 2013 General and Administrative Expense Restricted Common Stock and Units	Dec. 31, 2012 General and Administrative Expense Restricted Common Stock and Units	Dec. 31, 2013 Listing Expenses Restricted Common Stock and Units	Dec. 31, 2012 Listing Expenses Restricted Common Stock and Units	Dec. 31, 2012 Non Traded REIT Expenses Restricted Common Stock and Units	Dec. 31, 2011 Non Traded REIT Expenses Restricted Common Stock and Units	Dec. 31, 2013 2006 Incentive Plan	Dec. 31, 2013 2006 Incentive Plan Minimum	Dec. 31, 2013 2006 Incentive Plan Maximum	Jan. 07, 2013 Common Stock Offering	Dec. 31, 2013 Common Stock Offering	Nov. 01, 2013 Common Stock Offering Maximum	Dec. 31, 2013 LTIP	Dec. 31, 2012 LTIP	Dec. 31, 2013 LTIP Listing Expenses	Dec. 31, 2012 LTIP Listing Expenses	Dec. 31, 2011 LTIP Listing Expenses	Dec. 31, 2013 LTIP Change in Control of Company
Common Stock Offerings
Maximum amount of common stock authorized															$ 250,000,000		$ 300,000,000.0
Issuance of common stock (in shares)																21,873,013
Average share price (usd per share)																$ 11.22
Stock Repurchase Plan
Aggregate amount of repurchased shares		100,000,000.0
Stock repurchase program, remaining authorized repurchase amount	100,000,000.0
Incentive Plan
Number of shares authorized												10,000,000
Number of shares available for grant												5,101,800
Contractual term of awards																		4 years
Fair value of units with restrictions lapsed																		13,200,000
Weighted average grant date fair value (usd per share)																			$ 6.25
Allocated share-based compensation expense			2,500,000	7,000,000		1,900,000	800,000	600,000	4,700,000	1,500,000	3,200,000									3,200,000	10,400,000	0
Nonvested awards, total compensation cost not yet recognized			3,700,000																				4,500,000
Contingent units																							450,000
Weighted average fair value of stock and units granted (usd per share)			$ 10.49	$ 9.98	$ 10.00
Fair value of restricted common stock and restricted common stock units for which the restriction lapsed			$ 1,400,000	$ 8,700,000	$ 1,600,000
Service period													3 years	4 years
Period for recognition			2 years 1 month 6 days