Restructuring Expenses - Fan Pier Restructuring Liability (Details) ft² in Thousands, $ in Thousands	3 Months Ended								12 Months Ended			36 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) ft²	Dec. 31, 2016 USD ($)	Sep. 30, 2014
Restructuring activities
Restructuring expenses	$ 224	$ 8	$ 343	$ 687	$ 1,524	$ 1,826	$ 2,128	$ (3,272)	$ 1,262	$ 2,206	$ 50,925
Fan Pier Move Restructuring
Restructuring Cost and Reserve [Line Items]
Discount rate, lease restructuring liability (percent)													9.00%
Area of real estate property (in square feet) | ft²											120
Restructuring activities
Liability, beginning of the period				$ 5,964				$ 33,390	5,964	33,390	$ 797	$ 797
Cash payments									(12,674)	(30,022)	(18,271)
Cash received from subleases									9,751	4,229	0
Restructuring expenses									585	(1,633)	50,864
Liability, end of the period	$ 3,626				$ 5,964				$ 3,626	$ 5,964	$ 33,390	$ 3,626