Restructuring Liabilities - Activity Related to Restructuring Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Restructuring activities
Restructuring expense (income)	$ 8	$ 1,826	$ 1,038	$ 682
Kendall Restructuring
Restructuring activities
Liability, beginning of the period	6,388	9,924	7,944	11,596
Cash payments	(5,340)	(3,975)	(13,104)	(10,544)
Cash received from subleases	2,866	2,919	8,882	8,194
Restructuring expense (income)	30	146	222	(232)
Liability, end of the period	3,944	9,014	3,944	9,014
Fan Pier Move Restructuring
Restructuring activities
Liability, beginning of the period	4,863	9,017	5,964	33,390
Cash payments	(4,199)	(3,070)	(10,451)	(25,421)
Cash received from subleases	2,539	1,820	7,308	1,820
Restructuring expense (income)	90	51	472	(1,971)
Liability, end of the period	3,293	7,818	3,293	7,818
Other Restructuring
Restructuring activities
Liability, beginning of the period	1,233	902	1,450	869
Cash payments	(1,121)	(1,559)	(1,794)	(2,782)
Restructuring expense (income)	(112)	1,629	344	2,885
Liability, end of the period	$ 0	$ 972	$ 0	$ 972