Repositioning and Other Changes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Repositioning costs incurred	$ 0	$ 0	$ 6,043	$ 0
Total Amount Expected to be Incurred in the Repositioning Plan	8,068		8,068
Cumulative Amount Incurred through September 30, 2021	7,318		7,318
Severance and termination benefits
Restructuring Cost and Reserve [Line Items]
Repositioning costs incurred	0		185
Total Amount Expected to be Incurred in the Repositioning Plan	185		185
Cumulative Amount Incurred through September 30, 2021	185		185
Office space consolidation
Restructuring Cost and Reserve [Line Items]
Repositioning costs incurred	0		2,071
Total Amount Expected to be Incurred in the Repositioning Plan	2,321		2,321
Cumulative Amount Incurred through September 30, 2021	2,071		2,071
Professional services
Restructuring Cost and Reserve [Line Items]
Repositioning costs incurred	0		3,787
Total Amount Expected to be Incurred in the Repositioning Plan	5,562		5,562
Cumulative Amount Incurred through September 30, 2021	$ 5,062		$ 5,062