Restructuring Liabilities - Activity Related to Restructuring Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring activities
Restructuring expense (income)	$ 343	$ 2,128	$ 1,030	$ (1,144)
Kendall Restructuring
Restructuring activities
Liability, beginning of the period	7,224	9,506	7,944	11,596
Cash payments	(3,833)	(2,584)	(7,764)	(6,569)
Cash received from subleases	3,008	2,799	6,016	5,275
Restructuring expense (income)	(11)	203	192	(378)
Liability, end of the period	6,388	9,924	6,388	9,924
Fan Pier Move Restructuring
Restructuring activities
Liability, beginning of the period	5,449	11,137	5,964	33,390
Cash payments	(3,096)	(3,095)	(6,252)	(22,351)
Cash received from subleases	2,361	0	4,769	0
Restructuring expense (income)	149	975	382	(2,022)
Liability, end of the period	4,863	9,017	4,863	9,017
Other Restructuring
Restructuring activities
Liability, beginning of the period	1,262	845	1,450	869
Cash payments	(234)	(893)	(673)	(1,223)
Restructuring expense (income)	205	950	456	1,256
Liability, end of the period	$ 1,233	$ 902	$ 1,233	$ 902