Note 5 - Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, plant and equipment, gross	$ 290,347	$ 288,477
Less accumulated depreciation	(178,119)	(174,984)
Property, plant and equipment, net	112,228	113,493
Land [Member]
Property, plant and equipment, gross	3,863	3,869
Building [Member]
Property, plant and equipment, gross	107,283	106,940
Machinery and Equipment [Member]
Property, plant and equipment, gross	$ 179,201	$ 177,668

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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