Dispositions - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Contract estimated forward loss provision		$ 33.4
Network Rail
Business Acquisition [Line Items]
Contract estimated forward loss provision	$ 24.2
Percentage complete	45.00%
Deutsche Bahn
Business Acquisition [Line Items]
Contract estimated forward loss provision	$ 7.4
Percentage complete	22.00%
Contract 2 [Member] | SBB
Business Acquisition [Line Items]
Contract estimated forward loss provision	$ 3.5
Percentage complete	79.00%