Permanent and Temporary Equity (Redeemable OP Unitholder and Noncontrolling Interest) (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Temporary Equity [Line Items]
Balance as of December 31, 2012	$ 174,555
New issuances	11,053
Change in valuation	3,178
Distributions and other	(6,191)
Redemptions	(25,935)
Balance as of December 31, 2013	156,660
Redeemable Noncontrolling Interests
Temporary Equity [Line Items]
Balance as of December 31, 2012	59,622
New issuances	0
Change in valuation	11,861
Distributions and other	(1,052)
Redemptions	(25,378)
Balance as of December 31, 2013	45,053
Redeemable OP Unitholder Interests
Temporary Equity [Line Items]
Balance as of December 31, 2012	114,933
New issuances	11,053
Change in valuation	(8,683)
Distributions and other	(5,139)
Redemptions	(557)
Balance as of December 31, 2013	$ 111,607