Income taxes Income Taxes (Details) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Loss before income taxes	$ (75,083)	$ (25,309)	$ (110,962)	$ (141,001)
Income tax (benefit) expense	$ 273	$ (1,780)	$ 500	$ 296
Effective Income Tax Rate Reconciliation, Percent	0.40%	(7.00%)	0.50%	0.20%