Property, Plant and Equipment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Property, Plant and Equipment
Gross property, plant, and equipment	$ 163,282,000		$ 163,282,000		$ 162,061,000
Less accumulated depreciation and amortization, including accumulated amortization of finance leases	(106,382,000)		(106,382,000)		(103,839,000)
Property, plant, and equipment - net	56,900,000		56,900,000		58,222,000
Depreciation	1,876,000	$ 2,018,000	3,814,000	$ 4,008,000
Impairments of property, plant, and equipment			0	$ 0
Land
Property, Plant and Equipment
Gross property, plant, and equipment	6,182,000		6,182,000		6,224,000
Improvements to land and leaseholds
Property, Plant and Equipment
Gross property, plant, and equipment	15,412,000		15,412,000		15,416,000
Buildings
Property, Plant and Equipment
Gross property, plant, and equipment	26,760,000		26,760,000		27,206,000
Machinery and equipment, including equipment under finance leases
Property, Plant and Equipment
Gross property, plant, and equipment	112,220,000		112,220,000		112,021,000
Construction in progress
Property, Plant and Equipment
Gross property, plant, and equipment	$ 2,708,000		$ 2,708,000		$ 1,194,000