Accrued Liabilities - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued product related costs	$ 3,661	$ 2,950
Accrued income taxes	5,564	7,903
Accrued property and other taxes	1,914	1,574
Accrued professional fees	1,242	1,599
Accrued customer related liabilities	4,144	4,391
Dividends payable	1,291	1,299
Remediation reserves	9,337	11,444	$ 11,274
Derivative liabilities	1,287
Other accrued liabilities	4,354	5,218
Total accrued expenses and other liabilities	$ 32,794	$ 36,378