XML 74 R59.htm IDEA: XBRL DOCUMENT v3.19.1
Revenue Net contract assets (liabilities) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Jan. 01, 2018
Net contract assets (liabilities) [Abstract]    
Contract with Customer, Asset, Gross, Current $ 11,934 $ 14,757
Contract with Customer, Asset, Explanation of Change (2,823)  
Contract with Customer, Liability, Current (135) 143
Contract with Customer, Liability, Explanation of Change 8  
Contract with Customer, Asset, Net, Current 11,799 $ 14,614
Contract with Customer, Net, Explanation of Change $ (2,815)