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Restructuring and Related Charges - Restructuring liability (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Schedule of restructuring liability
Beginning balance		$ 8,781
Restructuring and other charges	$ 3,400	13,088	$ 3,400
Payments		(2,508)
Adjustments		107
Ending balance		19,468
Accounts payable and accrued expenses
Schedule of restructuring liability
Restructuring liabilities		7,900		$ 3,100
Lease and Related Costs, Net
Schedule of restructuring liability
Beginning balance		8,781
Payments		(2,069)
Adjustments		107
Ending balance		6,819
Severance And Other Employee Separation Costs
Schedule of restructuring liability
Restructuring and other charges		13,088
Payments		(439)
Ending balance		$ 12,649