XML 71 R58.htm IDEA: XBRL DOCUMENT v3.19.2
Revenue Recognition (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Performance Obligation, Description of Timing     The expected duration of the performance obligation is less than one year.  
Impairment losses on receivables $ 0      
Maximum [Member]        
Contracts and contract liabilities duration period     1 year  
Opening [Member]        
Contract liability $ 214 $ 212 $ 219 $ 235