Construction Contracts - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract cost, amortization	$ 0.2	$ 0.7
Construction receivables retentions	7.1		$ 17.1
Construction
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Retentions	6.5		17.7
Portion Attributable To Pending Contracts
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred pre-contract costs	$ 2.6		$ 1.7