Significant Accounting Policies - Summary of Accounts Receivable, Net and Activity in Allowance for Credit Loss by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net, beginning balance	$ 92,695
Allowance for credit loss, beginning balance	8,456
Credit loss expense	14,387	$ 8,100	$ 6,025
Write-offs, net of recoveries	(11,376)
Allowance for credit loss, ending balance	11,467	8,456
Accounts receivable, net, ending balance	168,783	92,695
Commercial Services (Driver Billed)
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net, beginning balance	9,793
Allowance for credit loss, beginning balance	5,272
Credit loss expense	6,554
Write-offs, net of recoveries	(8,616)
Allowance for credit loss, ending balance	3,210	5,272
Accounts receivable, net, ending balance	11,060	9,793
Commercial Services (All Other)
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net, beginning balance	51,158
Allowance for credit loss, beginning balance	1,406
Credit loss expense	4,941
Write-offs, net of recoveries	(2,074)
Allowance for credit loss, ending balance	4,273	1,406
Accounts receivable, net, ending balance	48,169	51,158
Government Solutions
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net, beginning balance	31,744
Allowance for credit loss, beginning balance	1,778
Credit loss expense	2,892
Write-offs, net of recoveries	(686)
Allowance for credit loss, ending balance	3,984	1,778
Accounts receivable, net, ending balance	$ 109,554	$ 31,744