Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019
Operating Loss Carryforwards [Line Items]
CARES Act, reduction in tax payments			$ 7,000
Income tax payments			$ 465	$ 55,785
Federal
Operating Loss Carryforwards [Line Items]
Income tax payments		$ 0
Federal | Forecast
Operating Loss Carryforwards [Line Items]
Income tax payments	$ 33,000