Revenue and Related Contract Costs and Contract Liabilities - Disaggregate GES and Pursuit Revenue by Major Product Line Timing of Revenue Recognition and Markets Served (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation Of Revenue [Line Items]
Total revenue		$ 363,677	$ 364,774	$ 641,105	$ 690,581
GES
Disaggregation Of Revenue [Line Items]
Total revenue		315,322		583,028
GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		315,322	320,109	583,028	637,980
GES | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total revenue		(6,346)	(7,205)	(9,694)	(10,444)
Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		48,355		58,077
Pursuit | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		48,355	44,665	58,077	52,601
Pursuit | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total revenue		(500)		(706)
U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		241,239	242,031	445,107	499,242
International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		80,429	85,283	147,615	149,182
Services Transferred Over Time | GES
Disaggregation Of Revenue [Line Items]
Total revenue		277,901		515,694
Services Transferred Over Time | GES | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total revenue		(6,346)		(9,694)
Services Transferred Over Time | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		36,822		44,577
Services Transferred Over Time | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		224,590		413,076
Services Transferred Over Time | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		59,657		112,312
Products Transferred Over Time | GES
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	15,794		30,493
Products Transferred Over Time | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	10,084		20,676
Products Transferred Over Time | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	5,710		9,817
Products Transferred at a Point in Time | GES
Disaggregation Of Revenue [Line Items]
Total revenue		21,627		36,841
Products Transferred at a Point in Time | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		11,533		13,500
Products Transferred at a Point in Time | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		6,565		11,355
Products Transferred at a Point in Time | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		15,062		25,486
Core Services | GES
Disaggregation Of Revenue [Line Items]
Total revenue		243,572		453,152
Core Services | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		193,315		356,682
Core Services | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		50,257		96,470
Audio Visual | GES
Disaggregation Of Revenue [Line Items]
Total revenue		27,294		47,546
Audio Visual | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		20,741		37,825
Audio Visual | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		6,553		9,721
Event Technology | GES
Disaggregation Of Revenue [Line Items]
Total revenue		13,381		24,690
Event Technology | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		10,534		18,569
Event Technology | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		2,847		6,121
Total Services | GES
Disaggregation Of Revenue [Line Items]
Total revenue		277,901		515,694
Total Services | GES | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total revenue		(6,346)		(9,694)
Total Services | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		36,822		44,577
Total Services | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		224,590		413,076
Total Services | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		59,657		112,312
Core Products | GES
Disaggregation Of Revenue [Line Items]
Total revenue		37,421		67,334
Core Products | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		16,649		32,031
Core Products | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		20,772		35,303
Exhibitions | GES
Disaggregation Of Revenue [Line Items]
Total revenue		178,542		364,366
Exhibitions | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		125,174		255,668
Exhibitions | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		53,368		108,698
Conferences | GES
Disaggregation Of Revenue [Line Items]
Total revenue		101,825		146,302
Conferences | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		84,599		122,415
Conferences | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		17,226		23,887
Corporate Events | GES
Disaggregation Of Revenue [Line Items]
Total revenue		34,380		68,684
Corporate Events | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		25,810		55,254
Corporate Events | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		8,570		13,430
Consumer Events | GES
Disaggregation Of Revenue [Line Items]
Total revenue		6,921		13,370
Consumer Events | U.S. | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		5,656		11,770
Consumer Events | International | GES | Operating Segments
Disaggregation Of Revenue [Line Items]
Total revenue		1,265		1,600
Accommodations | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		9,030		10,735
Admissions | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		23,480		27,059
Transportation | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		4,321		6,690
Travel Planning | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		491		799
Food and Beverage | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		6,705		7,924
Retail Operations | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		4,828		5,576
Products
Disaggregation Of Revenue [Line Items]
Total revenue		48,954	$ 45,595	80,834	$ 80,759
Products | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		11,533		13,500
Banff Jasper Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		28,519		35,608
Alaska Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		10,614		10,827
Glacier Park Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		6,640		7,266
FlyOver | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue		$ 2,582		$ 4,376

[1] GES’ graphics product revenue is recognized over time as it is considered a part of the single performance obligation satisfied over time.