Revenue and Related Contract Costs and Contract Liabilities - Disaggregate Revenue of GES and Pursuit by Major Product Line Timing of Revenue Recognition and Markets Served (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	$ 267,706
Total services revenue	245,548	$ 290,643
Total products revenue	31,880	35,164
Total revenue	277,428	$ 325,807
Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	(3,348)
GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	203,868
GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	67,186
Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	7,755
Total products revenue	1,967
Total revenue	9,722
Pursuit | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Total services revenue	(206)
Services Transferred Over Time
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	241,140
Services Transferred Over Time | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	188,486
Services Transferred Over Time | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	52,654
Services Transferred Over Time | Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	7,755
Products Transferred Over Time
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	14,699
Products Transferred Over Time | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	10,592
Products Transferred Over Time | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	4,107
Products Transferred at a Point in Time
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	15,215
Products Transferred at a Point in Time | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	4,790
Products Transferred at a Point in Time | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	10,425
Products Transferred at a Point in Time | Pursuit
Disaggregation Of Revenue [Line Items]
Total products revenue	1,967
Core Services
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	209,580
Core Services | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	163,367
Core Services | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	46,213
Audio Visual
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	20,252
Audio Visual | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	17,084
Audio Visual | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	3,168
Event Technology
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	11,309
Event Technology | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	8,035
Event Technology | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	3,274
Total Services
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	237,793
Total Services | Intersegment Eliminations
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	(3,348)
Total Services | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	188,486
Total Services | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	52,655
Core Products
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	29,913
Core Products | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	15,382
Core Products | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	14,531
Exhibitions
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	185,824
Exhibitions | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	130,494
Exhibitions | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	55,330
Conferences
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	44,477
Conferences | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	37,816
Conferences | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	6,661
Corporate Events
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	34,304
Corporate Events | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	29,444
Corporate Events | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	4,860
Consumer Events
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	6,449
Consumer Events | GES U.S.
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	6,114
Consumer Events | GES International
Disaggregation Of Revenue [Line Items]
Disaggregate revenue	335
Accommodations | Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	1,705
Admissions | Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	3,579
Transportation | Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	2,369
Travel Planning | Pursuit
Disaggregation Of Revenue [Line Items]
Total services revenue	308
Food and Beverage | Pursuit
Disaggregation Of Revenue [Line Items]
Total products revenue	1,219
Retail Operations | Pursuit
Disaggregation Of Revenue [Line Items]
Total products revenue	748
Banff Jasper Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue	7,089
Alaska Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue	213
Glacier Park Collection | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue	626
FlyOver | Pursuit
Disaggregation Of Revenue [Line Items]
Total revenue	$ 1,794