Income taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 7,455	$ 881	$ 7,533	$ (6,416)
Increase in valuation allowance for deferred tax assets			$ 1,000