XML 66 R53.htm IDEA: XBRL DOCUMENT v3.21.1
Fair Value Measurements And Derivative Instruments Reporting (Narrative) (Details) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Transfers between levels $ 0 $ 0  
Impairment - intangible and tangible assets   33,964,000  
Cash equivalents $ 0   $ 0
Fair Value, Nonrecurring [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Impairment - intangible and tangible assets   1,000,000.0  
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   $ 33,000,000.0