Permanent and Temporary Equity (Redeemable OP Unitholder and Noncontrolling Interest) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance as of December 31, 2014	$ 172,016
New issuances	87,245
Change in valuation	(8,914)
Distributions and other	15,586
Redemptions	38,231
Balance as of December 31, 2015	196,529
Redeemable Noncontrolling Interests
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance as of December 31, 2014	12,880
New issuances	0
Change in valuation	(1,082)
Distributions and other	491
Redemptions	3,324
Balance as of December 31, 2015	7,983
Redeemable OP Unitholder Interests
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance as of December 31, 2014	159,135
New issuances	87,245
Change in valuation	(7,832)
Distributions and other	15,095
Redemptions	34,907
Balance as of December 31, 2015	$ 188,546