Property, Plant, and Equipment (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant & Equipment
Property, plant, and Equipment	$ 174,553,000	$ 170,881,000
Accumulated depreciation	(100,501,000)	(91,675,000)
Property, plant and equipment, net	74,052,000	79,206,000
Accounts payable	16,994,000	19,910,000
Depreciation expense	8,659,000	8,187,000	$ 7,361,000
Land and land improvements
Property, Plant & Equipment
Property, plant, and Equipment	6,009,000	6,009,000
Buildings
Property, Plant & Equipment
Property, plant, and Equipment	43,545,000	43,375,000
Machinery and equipment
Property, Plant & Equipment
Property, plant, and Equipment	121,382,000	118,366,000
Tools, dies and patterns
Property, Plant & Equipment
Property, plant, and Equipment	2,195,000	1,516,000
Additions in progress
Property, Plant & Equipment
Property, plant, and Equipment	1,422,000	1,615,000
Purchase commitments for capital expenditures in progress	677,000	336,000
Accounts payable	$ 145,000	$ 158,000

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Future cash outflow to pay for construction in progress expenditures that have occurred.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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