Note 3 - Segment Reporting Information - Intersegment Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Revenue from Contract with Customer, Including Assessed Tax	$ 315,612	$ 305,558
Lighting Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	189,000	206,199
Display Solutions Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	126,612	99,359
Intersegment Eliminations [Member] | Lighting Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	28,449	3,718
Intersegment Eliminations [Member] | Display Solutions Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 219	$ 552