Noncontrolling Interests (Redeemable Preferred Units) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance			$ 110,876
Net Income	1,123	765	2,303	1,566
Conversion of redeemable preferred units (Series Two Preferred Units) to common units				4,115
Ending Balance	110,876		110,876
Redeemable Preferred Units [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance			110,876	55,652
Net Income			2,303	1,566
Distributions			(2,303)	(1,566)
Conversion of redeemable preferred units (Series Two Preferred Units) to common units				(4,115)
Ending Balance	$ 110,876	$ 51,537	$ 110,876	$ 51,537