Unconsolidated Affiliates Accounted For Under The Equity Method (Summarized Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Current assets	$ 969,804	$ 883,169
Current liabilities	$ (403,616)	(381,745)
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Current assets		13,623	$ 12,353
Non-current assets		4,214	3,644
Current liabilities		(2,994)	(1,938)
Non-current liabilities		$ (161)	$ (27)