Commitments and Contingencies (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Future minimum commitments under facility leases commitments with terms of more than one year
2016	$ 85,597
2017	87,147
2018	84,816
2019	92,745
2020	92,468
Thereafter	827,104
Total minimum lease payments	1,269,877
Future minimum sublease income
2016	(15,515)
2017	(15,515)
2018	(5,172)
2019	0
2020	0
Thereafter	0
Total minimum lease payments	(36,202)
Rental expense	18,100	$ 38,900	$ 57,700
Fan Pier Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2016	67,206
2017	67,206
2018	67,206
2019	72,589
2020	72,589
Thereafter	607,621
Total minimum lease payments	$ 954,417
Kendall Square Lease
Operating lease
Office space used for operation (in square feet) | ft²	120
Future minimum commitments under facility leases commitments with terms of more than one year
2016	$ 19,984
2017	19,984
2018	6,661
2019	0
2020	0
Thereafter	0
Total minimum lease payments	46,629
Other Leases
Future minimum commitments under facility leases commitments with terms of more than one year
2016	13,922
2017	15,472
2018	16,121
2019	20,156
2020	19,879
Thereafter	219,483
Total minimum lease payments	$ 305,033