Fee and Other Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fee And Other Income
BMS cleaning fees	$ 78,920	$ 82,113	$ 85,658
Management and leasing fees	20,891	16,831	19,905
Lease termination fees	9,516	27,233	16,362
Other income	32,480	38,528	33,281
Fee and other income	$ 141,807	164,705	$ 155,206
20 Broad Street
Fee And Other Income
Lease termination income		$ 15,000