Restructuring and Related Charges - Restructuring liability (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Liability Rollforward
Beginning balance	$ 20,887	$ 8,781	$ 11,985
Restructuring and other charges	3,920	16,319	3,414
Payments	(9,984)	(4,656)	(7,037)
Adjustments	(6,540)	443	419
Ending balance	8,283	20,887	8,781
Lease and Related Costs, Net
Restructuring Liability Rollforward
Beginning balance	6,540	8,781	11,985
Payments	0	(2,684)	(3,623)
Adjustments	(6,540)	443	419
Ending balance	0	6,540	8,781
Severance And Other Employee Separation Costs
Restructuring Liability Rollforward
Beginning balance	14,347
Restructuring and other charges	3,920	16,319	3,414
Payments	(9,984)	(1,972)	$ (3,414)
Ending balance	$ 8,283	$ 14,347

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

+ References

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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