Note 3 - Joint Venture - Certain Financial Information About the Joint Venture Included On the Company's Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Property, plant and equipment, net of accumulated depreciation of $433 and $408	$ 380,344	$ 382,358
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member]
Cash	270		$ 270
Property, plant and equipment, net of accumulated depreciation of $433 and $408	$ 1,708		$ 1,733

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.

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