Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Amounts due from/to related parties
Due from joint ventures	$ 1,343		$ 1,343		$ 1,254
Other	9,746		9,746		10,481
Related party receivables	11,089		11,089		$ 11,735
Alliance Building Services
Related Party Transactions
Profit participation from related party	900	$ 900	2,900	$ 2,800
Payments made for services	5,700	5,900	14,300	14,700
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party	$ 100	$ 100	$ 400	$ 300