Note 3 - Segment Reporting Information - Intersegment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Inter-segment Revenues	$ 72,204	$ 71,010	$ 218,597	$ 242,088
Lighting Segment [Member]
Inter-segment Revenues	45,740	49,013	136,271	165,640
Graphics Segment [Member]
Inter-segment Revenues	26,464	21,997	82,326	76,448
Intersegment Eliminations [Member] | Lighting Segment [Member]
Inter-segment Revenues	6,880	744	15,998	2,415
Intersegment Eliminations [Member] | Graphics Segment [Member]
Inter-segment Revenues	$ 46	$ 153	$ 159	$ 251