Operating Expenses (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 31,330	$ 29,112	$ 29,021
Amortization expense	43,591	41,389	37,593
Software [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	199	410	494
Amortization expense	$ 29,779	$ 27,944	$ 18,996