Note 3 - Segment Reporting Information - Intersegment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Inter-segment Revenues	$ 78,843	$ 78,156	$ 258,614	$ 247,973
Lighting Segment [Member]
Inter-segment Revenues	61,554	61,693	199,156	192,034
Graphics Segment [Member]
Inter-segment Revenues	17,289	16,463	59,458	55,939
Intersegment Eliminations [Member] | Lighting Segment [Member]
Inter-segment Revenues	443	433	2,150	1,886
Intersegment Eliminations [Member] | Graphics Segment [Member]
Inter-segment Revenues	$ 133	$ 216	$ 1,204	$ 1,028