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Revenue Recognition - Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Disaggregation of Revenue [Line Items]    
Performance obligation, contract term 12  
Retained earnings $ 5,427,000 $ 29,549,000
ASU 2014-09 | Impact after Topic 606    
Disaggregation of Revenue [Line Items]    
Retained earnings $ 0  
Minimum    
Disaggregation of Revenue [Line Items]    
Payment period 30 days  
Maximum    
Disaggregation of Revenue [Line Items]    
Payment period 90 days