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Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 18,926	$ 19,020
Less accumulated depreciation	(11,274)	(11,267)
Property and equipment, net	7,652	7,753
Depreciation	21,147	21,641	$ 22,605
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,290	169
Building
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	39 years
Property and equipment, gross	$ 6,116	6,856
Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	39 years
Property and equipment, gross	$ 808	794
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	5 years
Property and equipment, gross	$ 1,490	1,454
Software
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	5 years
Property and equipment, gross	$ 573	573
Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	7 years
Property and equipment, gross	$ 3,133	3,111
Vehicles
Property, Plant and Equipment [Line Items]
Useful Lives (Years)	3 years
Property and equipment, gross	$ 5,516	6,063
Property, Plant, and Equipment, Excluding Rental Equipment
Property, Plant and Equipment [Line Items]
Depreciation	$ 1,200	$ 1,400	$ 1,600

X

- Definition

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

+ References

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)
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-Section S99
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- Definition

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.

+ References

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ References

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

+ References

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