Property, Plant & Equipment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property, plant and equipment	$ 205,016,000		$ 205,016,000		$ 200,525,000
Accumulated depreciation	(122,837,000)		(122,837,000)		(117,258,000)
Property, plant and equipment — net	82,179,000		82,179,000		83,267,000
Depreciation expense	2,521,000	$ 2,485,000	5,499,000	$ 5,002,000
Capital additions in progress	$ 5,280,000		5,280,000		$ 7,396,000
Purchase commitments for capital expenditures in progress			$ 2,761,000	$ 2,812,000