Revenue - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Percentage of revenues derived from services provided			90.00%
Percentage of revenues derived from other sources			10.00%
Net increase to revenue for adjustments to fixed price contracts	$ 300,000	$ (400,000)	$ (200,000)	$ (500,000)
Remaining performance obligations	316,200,000		316,200,000
Remaining performance obligation expected to be recognized in next 12 months, percentage	0.85		$ 0.85
Revenue recognition period			12 months
Revenue recognized related to contract liabilities	$ 3,800,000	$ 3,200,000	$ 8,200,000	$ 11,400,000
Minimum
Disaggregation of Revenue [Line Items]
Bill and collection period			60 days
Maximum
Disaggregation of Revenue [Line Items]
Bill and collection period			120 days
Typical collection period			12 months