Contract Assets and Contract Liabilities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Amounts billed but not yet paid pursuant to retention provisions	$ 2.8	$ 2.2
Contract liability billings in excess of costs and estimated earnings on uncompleted contracts	$ 1.0