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Restructuring Expenses - Components of Restructuring Expenses (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Reserve [Roll Forward]
Balance accrued at December 31, 2019				$ 797
Restructuring charges	$ 8,197	$ 0	$ 7,400	8,197	$ 7,420
Balance accrued at June 30, 2020	5,915			5,915
2019 Restructuring
Restructuring Reserve [Roll Forward]
Balance accrued at December 31, 2019				797
Restructuring charges				0
Balance accrued at June 30, 2020	299			299
2020 Restructuring
Restructuring Reserve [Roll Forward]
Balance accrued at December 31, 2019				0
Restructuring charges				8,197
Balance accrued at June 30, 2020	$ 5,616			5,616
Workforce Reduction Payments
Restructuring Reserve [Roll Forward]
Payments for restructuring				(3,010)
Workforce Reduction Payments \| 2019 Restructuring
Restructuring Reserve [Roll Forward]
Payments for restructuring				(498)
Workforce Reduction Payments \| 2020 Restructuring
Restructuring Reserve [Roll Forward]
Payments for restructuring				(2,512)
Other Payments
Restructuring Reserve [Roll Forward]
Payments for restructuring				(69)
Other Payments \| 2019 Restructuring
Restructuring Reserve [Roll Forward]
Payments for restructuring				0
Other Payments \| 2020 Restructuring
Restructuring Reserve [Roll Forward]
Payments for restructuring				$ (69)