1. Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Land	$ 5,511	$ 5,511
Buildings	32,719	32,461
Machinery and equipment	143,352	129,108
Total property, plant and equipment	$ 181,582	$ 167,080
Building And Building Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives	30 years
Building And Building Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives	40 years
Machinery And Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives	3 years
Machinery And Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful lives	15 years

Amount before accumulated depreciation of building structures held for productive use including addition, improvement, or renovation to the structure, including, but not limited to, interior masonry, interior flooring, electrical, and plumbing.

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-SubTopic 10
-Section 45
-Paragraph 4
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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount before accumulated depreciation of tangible personal property used to produce goods and services, including, but is not limited to, tools, dies and molds, computer and office equipment.

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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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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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