Quarterly report pursuant to Section 13 or 15(d)

Revenue from contracts with customers - Narrative (Details)

v3.19.2
Revenue from contracts with customers - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Revenue from Contract with Customer [Abstract]        
Recognized revenue related to contract liabilities $ 0.3 $ 0.2 $ 0.7 $ 0.5