Segment Information - Reconciliation of Assets from Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of assets from segment
Total Assets	$ 853,224	$ 1,318,691	$ 922,541
Total Depreciation and Amortization	56,565	58,964	56,842
Capital expenditures	53,567	76,147	83,345
GES | North America
Reconciliation of assets from segment
Total Assets	134,162	475,279	406,484
Total Depreciation and Amortization	24,022	29,321	30,855
Capital expenditures	9,003	19,099	19,263
GES | EMEA
Reconciliation of assets from segment
Total Assets	50,644	132,975	111,798
Total Depreciation and Amortization	4,053	6,260	7,071
Capital expenditures	1,388	7,098	7,065
Pursuit
Reconciliation of assets from segment
Total Assets	620,413	589,205	357,630
Total Depreciation and Amortization	28,393	23,154	18,690
Capital expenditures	43,176	49,934	56,865
Corporate and other
Reconciliation of assets from segment
Total Assets	48,005	121,232	46,629
Total Depreciation and Amortization	$ 97	229	226
Capital expenditures		$ 16	$ 152