Accrued Liabilities - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities
Accrued product related costs	$ 3,090	$ 2,950
Accrued income taxes	6,921	7,903
Accrued property and other taxes	1,948	1,574
Accrued professional fees	903	1,599
Contract with Customer, Liability	3,673	4,391
Dividends payable	1,291	1,299
Remediation reserves	9,300	11,444	$ 11,274
Derivative Liability	2,220	0
Other accrued liabilities	3,829	5,218
Total accrued expenses and other liabilities	$ 33,175	$ 36,378