Note 16 - Segment Information - Identifiable Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Identifiable Assets	$ 106,025	$ 103,905
Corporate, Non-Segment [Member]
Identifiable Assets	6,090	10,123
Electronic Test [Member]
Identifiable Assets	28,735	26,251
Environmental Technologies [Member]
Identifiable Assets	16,900	15,411
Process Technologies [Member]
Identifiable Assets	$ 54,300	$ 52,120