Summary of Significant Accounting Policies - PP&E, ARO and Other (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment
Construction in progress	$ 6,308	$ 16,813
Interest costs capitalized	0	0
Capitalized cost in accounts payable and accrued expenses	380	1,303
Impairment of long-lived assets	1,550	930
Asset Retirement Obligations
ARO included in other liabilities and accrued expenses	1,520	1,482
Amount of assets associated with AROs not fully depreciated	775
Amount spent on AROs	52	93
Accretion expense recognized on AROs	90	86	$ 84
Accrued Expenses
Personnel related expenses	2,340	1,925
Income taxes	990
Other taxes	985	914
Other	1,494	896
Total accrued expenses	5,809	3,735
Environmental Expenditures
Capital expenditures related to environmental matters	730	$ 1,156	$ 1,152
Minimum
Asset Retirement Obligations
Estimated annual expenditures in years 2018 through 2022 relating to AROs	100
Maximum
Asset Retirement Obligations
Estimated annual expenditures in years 2018 through 2022 relating to AROs	$ 200
Buildings and building and leasehold improvements. | Minimum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	3 years
Buildings and building and leasehold improvements. | Maximum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	25 years
Machinery and equipment | Minimum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	2 years
Machinery and equipment | Maximum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	30 years
Furniture and fixtures | Minimum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	10 years
Automotive equipment. | Minimum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	3 years
Automotive equipment. | Maximum
Property, Plant and Equipment
Estimated useful lives of property, plant and equipment	10 years