Related party transactions (Details) - Affiliated Entities - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CP&P Joint Venture
Related Party Transaction [Line Items]
Sales of products to related party	$ 900	$ 33
Purchased goods and services from related party	$ 600	$ 176
Lone Star
Related Party Transaction [Line Items]
Payment of certain covered tax benefits buy the Company, percentage	85.00%