Revenue and Related Contract Costs and Contract Liabilities - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Revenue recognition description of capitalized contract costs			Capitalized contract costs are expensed upon the transfer of the related goods or services and are included in cost of services or cost of products, as applicable
Capitalized contract costs to obtain contracts	$ 2,100,000		$ 2,100,000
Capitalized contract costs to fulfill contracts	22,100,000		22,100,000
Impairment loss on capitalized contract costs	$ 0	$ 0	$ 0	$ 0
GES
Disaggregation Of Revenue [Line Items]
Performance obligation description of payment terms			Payment terms are generally within 30-60 days and contain no significant financing components
GES | Minimum
Disaggregation Of Revenue [Line Items]
Performance obligation payment terms			30 days
GES | Maximum
Disaggregation Of Revenue [Line Items]
Performance obligation payment terms			60 days
Pursuit
Disaggregation Of Revenue [Line Items]
Performance obligation description of payment terms			When credit is extended, payment terms are generally within 30 days and contain no significant financing components
Performance obligation payment terms			30 days