Note 3 - Joint Venture (Details Textual) - USD ($) $ in Thousands		6 Months Ended	9 Months Ended
	Apr. 02, 2015	Jun. 30, 2018	Sep. 30, 2018
Variable Interest Entity, Initial Consolidation, Gain (Loss)	$ 0
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage		50.00%	50.00%
ACS Cable Systems LLC and Quintillion Holdings, LLC Joint Venture [Member] | Quintillion Holdings, LLC [Member]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage			50.00%