Quarterly report pursuant to Section 13 or 15(d)

Revenue - Narrative (Details)

v3.19.1
Revenue - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Unbilled receivables, net $ 44,450   $ 41,255
Contract with customer, liability 4,500   $ 5,000
Contract with customer, liability, revenue recognized 1,500 $ 6,500  
Revenue, remaining performance obligation $ 278,000    
Sales Revenue, Net | Product Concentration Risk | Transferred over Time      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Concentration risk, percentage 57.00%    
Sales Revenue, Net | Product Concentration Risk | Transferred at Point in Time      
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]      
Concentration risk, percentage 43.00%