Condensed Consolidated Balance Sheets Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Preferred Unit, Liquidation Preference	$ 16.62	$ 16.62
Stock issued	1,560,360	1,560,360
Tenant and other receivables allowance	$ 1,520	$ 1,427
Deferred rent receivables allowance	$ 437	$ 420
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Capital Units, Outstanding	1,560,360	1,560,360
Common Class A [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	110,612,438	106,044,560
Common stock, shares outstanding	110,598,327	106,030,449
Common Class B [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	1,149,014	1,161,438
Common stock, shares outstanding	1,149,014	1,161,438