Contracts in Progress - Remaining Performance Obligation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Performance obligations expected to be satisfied	$ 439.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Performance obligations expected to be satisfied	$ 401.9
Performance obligations expected to be satisfied, percentage	91.00%
Performance obligations expected to be satisfied, expected timing	12 months