Liabilities - Restructuring Accruals (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)	Dec. 31, 2019 employee
Liabilities
Number of employees impacted | employee		60
Changes in restructuring accrual
Balance at the beginning of the period	$ 2,841
Provision	1,097
Payments	(2,705)
Balance at the end of the period	$ 1,233