Note 12 - Dispositions (Details Textual) - Certain Assets from Test and Measurement business segment Sold Under an Asset Purchase Agreement to Hickock Waekon, LLC [Member] $ in Millions	Jun. 01, 2018 USD ($) shares
Disposal Group, Including Discontinued Operation, Consideration	$ 1.6
Disposal Group, Excluding Discontinued Operation, Net Assets Sold	2.7
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	$ (1.2)
Director and His Affiliate [Member] | Common Class A [Member]
Disposal Group, Excluding Discontinued Operation, Consideration, Shares | shares	21,413
Director and His Affiliate [Member] | Common Class B [Member]
Disposal Group, Excluding Discontinued Operation, Consideration, Shares | shares	176,768