Contingencies Remediation Liability (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Accrued Environmental Loss Contingencies, Current	$ 9,300	$ 11,444	$ 11,274
Accrual for Environmental Loss Contingencies, Charges to Expense for New Losses	791	2,602
Accrual for Environmental Loss Contingencies Payments, Net of Reimbursements	(2,956)	(2,455)
Accrual for Environmental Loss Contingencies, Foreign Currency Translation Gain (Loss)	$ 21	$ 23