Contract Assets and Liabilities (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Contract with customer, asset, period increase (decrease)	$ 25,800
Contract with customer, asset, impairment loss	0	$ 0
Increase (decrease) in contract with customer, liability	2,300
Contract with customer, liability, revenue recognized	$ 3,500	$ 6,100