Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Amounts due from/to related parties
Due from joint ventures	$ 1,727		$ 1,727		$ 1,334
Other	13,113		13,113		9,316
Related party receivables	14,840		14,840		$ 10,650
Alliance Building Services
Related Party Transactions
Profit participation from related party	800	$ 900	2,600	$ 2,900
Payments made for services	5,300	5,700	16,100	14,300
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party	$ 100	$ 100	$ 300	$ 400