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Revenue (Narrative) (Details) - customer
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Revenue Benchmark [Member]      
Disaggregation of Revenue [Line Items]      
Number Of Major Customers     0
Concentration Risk Percentage Benchmark     10.00%
Revenue Benchmark [Member] | Customer A [Member]      
Disaggregation of Revenue [Line Items]      
Concentration Risk, Percentage 16.00% 11.00%  
Minimum [Member]      
Disaggregation of Revenue [Line Items]      
Revenue, Performance Obligation, Payment Terms 10 days    
Maximum [Member]      
Disaggregation of Revenue [Line Items]      
Revenue, Performance Obligation, Payment Terms 30 days