Revenue (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contracts with Customer [Line Items]
Accounts receivable, net	$ 337,897	$ 322,846
Contract assets	7,800	5,900
Contract liabilities	1,000	$ 1,300
Revenue recognized from contract liability during the period	$ 1,300
Average transit time	3 days