Annual report pursuant to Section 13 and 15(d)

Revenue Recognition - Narrative (Details)

v3.10.0.1
Revenue Recognition - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Jan. 01, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]        
Unbilled receivables, net $ 41,255 $ 42,577   $ 45,961
Contract with customer, liability 5,000     $ 9,800
Contract with customer, liability, revenue recognized $ 7,900      
Concentration risk, percentage 100.00% 100.00% 100.00%  
Revenue, remaining performance obligation $ 290,000      
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%