Derivative instruments - Additional information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2017	May 31, 2016
Derivative [Line Items]
Receivable derivative settlements			$ 3,814
Predecessor
Derivative [Line Items]
Receivable derivative settlements				$ 119,303
Amount utilized to offset outstanding borrowings under credit facility	$ 103,560	$ 103,560