Accrued Liabilities and Other Liabilities - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities
Accrued product-related costs	$ 5,297	$ 5,556
Accrued income taxes	5,475	9,826
Accrued property and other taxes	997	1,917
Dividends payable	1,318	1,309
Remediation reserves	17,067	18,176	$ 20,603	$ 3,918
Other accrued liabilities	11,190	8,924
Total accrued expenses and other liabilities	$ 41,344	$ 45,708