Revenue (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Revenue from Contracts with Customer [Line Items]
Accounts receivable, net	$ 347,902	$ 341,104
Contract assets	8,900	6,900
Contract liabilities	1,700	$ 1,500
Revenue recognized from contract liability during the period	$ 1,500
Average transit time	3 days