Note 3 - Segment Reporting Information - Intersegment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Inter-segment Revenues	$ 71,010	$ 72,832	$ 242,088	$ 247,330
Lighting Segment [Member]
Inter-segment Revenues	49,013	52,785	165,640	177,871
Graphics Segment [Member]
Inter-segment Revenues	21,997	20,047	76,448	69,459
Intersegment Eliminations [Member] | Lighting Segment [Member]
Inter-segment Revenues	744	479	2,415	1,758
Intersegment Eliminations [Member] | Graphics Segment [Member]
Inter-segment Revenues	$ 153	$ 96	$ 251	$ 171