Contract Assets and Liabilities (Narrative) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Contract with customer, asset, period decrease	$ 26,100,000
Contract with customer, asset, impairment loss	0	$ 0
Decrease in contract with customer, liability	1,100,000
Contract with customer, liability, revenue recognized	$ 4,700,000	$ 2,100,000