Note 6 - Property and Equipment - Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Property and equipment, at cost	$ 403,785	$ 376,710
Accumulated depreciation	(244,176)	(229,062)
Net property and equipment	$ 159,609	147,648
Minimum [Member]
Depreciable lives (Year)	2 years
Maximum [Member]
Depreciable lives (Year)	30 years
Land [Member]
Property and equipment, at cost	$ 15,881	15,881
Land Improvements [Member]
Property and equipment, at cost	$ 3,547	3,270
Land Improvements [Member] \| Minimum [Member]
Depreciable lives (Year)	5 years
Land Improvements [Member] \| Maximum [Member]
Depreciable lives (Year)	10 years
Building and Building Improvements [Member]
Property and equipment, at cost	$ 133,386	131,655
Building and Building Improvements [Member] \| Minimum [Member]
Depreciable lives (Year)	7 years
Building and Building Improvements [Member] \| Maximum [Member]
Depreciable lives (Year)	30 years
Machinery and Equipment [Member]
Property and equipment, at cost	$ 205,826	184,683
Machinery and Equipment [Member] \| Minimum [Member]
Depreciable lives (Year)	2 years
Machinery and Equipment [Member] \| Maximum [Member]
Depreciable lives (Year)	15 years
Furniture and Fixtures [Member]
Property and equipment, at cost	$ 6,374	6,298
Furniture and Fixtures [Member] \| Minimum [Member]
Depreciable lives (Year)	3 years
Furniture and Fixtures [Member] \| Maximum [Member]
Depreciable lives (Year)	7 years
Software and Software Development Costs [Member]
Property and equipment, at cost	$ 28,638	28,677
Depreciable lives (Year)	5 years
Software and Software Development Costs [Member] \| Minimum [Member]
Depreciable lives (Year)	2 years
Software and Software Development Costs [Member] \| Maximum [Member]
Depreciable lives (Year)	5 years
Vehicles [Member]
Property and equipment, at cost	$ 1,876	1,746
Vehicles [Member] \| Minimum [Member]
Depreciable lives (Year)	2 years
Vehicles [Member] \| Maximum [Member]
Depreciable lives (Year)	5 years
Assets Held under Capital Leases [Member]
Property and equipment, at cost	$ 86
Construction in Progress [Member]
Property and equipment, at cost	$ 8,171	$ 4,500

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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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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