Restructuring Charges - Changes to Restructuring Liability by Major Restructuring Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Restructuring Cost And Reserve [Line Items]
Beginning balance			$ 3,439
Restructuring charges	$ 480	$ 1,387	1,125	$ 3,467
Cash payments			(1,197)
Adjustment to liability			12
Ending balance	3,379		3,379
GES | Severance & Employee Benefits
Restructuring Cost And Reserve [Line Items]
Beginning balance			1,609
Restructuring charges			460
Cash payments			(426)
Adjustment to liability			0
Ending balance	1,643		1,643
GES | Facilities
Restructuring Cost And Reserve [Line Items]
Beginning balance			1,818
Restructuring charges			456
Cash payments			(548)
Adjustment to liability			10
Ending balance	1,736		1,736
Other Restructuring | Severance & Employee Benefits
Restructuring Cost And Reserve [Line Items]
Beginning balance			12
Restructuring charges			209
Cash payments			(223)
Adjustment to liability			2
Ending balance	$ 0		$ 0