Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Land	$ 4,707	$ 4,712
Buildings and improvements	55,734	54,448
Machinery and equipment	197,648	190,316
Construction in progress	1,348	1,437
Property, Plant and Equipment, Gross	259,437	250,913
Less: accumulated depreciation	(182,208)	(178,093)
Total property, plant and equipment, net	$ 77,229	$ 72,820
Building and Improvements [Member] \| Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Building and Improvements [Member] \| Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Machinery and Equipment [Member] \| Minimum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Machinery and Equipment [Member] \| Maximum [Member]
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

+ References

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- Definition

Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

+ References

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-Publisher FASB
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- Definition

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.

+ References

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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.

+ References

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- Definition

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.

+ References

No definition available.

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