Fair Value Measurements And Derivative Instruments Reporting (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 06, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment - intangible and tangible assets		$ 35,121	$ 16,486
Cash equivalents		0	0
Interest expense		43,104	8,250	$ 4,217
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment - intangible and tangible assets		1,000
Fair Value, Nonrecurring [Member] | COVID 19 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment - intangible and tangible assets		$ 34,100
Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest expense			$ 700	$ 1,000
Minimum [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer attrition rates and discount rates	11.00%
Maximum [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Customer attrition rates and discount rates	16.00%