Note 13 - Segment Information - Identifiable Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Identifiable Assets	$ 113,516	$ 110,066
Corporate, Non-Segment [Member]
Identifiable Assets	6,179	4,017
Electronic Test [Member]
Identifiable Assets	31,303	31,143
Environmental Technologies [Member]
Identifiable Assets	18,362	18,040
Process Technologies [Member]
Identifiable Assets	$ 57,672	$ 56,866