Stock-based compensation composition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 5,779	$ 5,405	$ 17,294	$ 17,441
Stock-based Compensation - G&A
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	5,479	5,171	16,420	16,632
Stock-based Compensation - LOE
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expense	$ 300	$ 234	$ 874	$ 809