Construction Contracts - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract cost, amortization	$ 0.1	$ 0.2
Construction receivables retentions	14.7		$ 17.1
Construction
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Retentions	15.3		17.7
Portion Attributable To Pending Contracts
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred pre-contract costs	$ 2.0		$ 1.7