| Segment Reporting [Table Text Block] |
| (In thousands) | | Three Months Ended | | | Nine Months Ended | |
| | | March 31, 2026 | | | March 31, 2026 | |
| | | | | | | | | | | Segment | | | | | | | | | | | Segment | |
| | | Lighting | | | Display | | | Total | | | Lighting | | | Display | | | Total | |
| Total sales | | $ | 62,860 | | | $ | 90,630 | | | $ | 153,490 | | | $ | 205,080 | | | $ | 259,698 | | | $ | 464,778 | |
| Inter-segment sales | | | (2,822 | ) | | | (143 | ) | | | (2,965 | ) | | | (9,316 | ) | | | (686 | ) | | | (10,002 | ) |
| Net sales | | | 60,038 | | | | 90,487 | | | | 150,525 | | | | 195,764 | | | | 259,012 | | | | 454,776 | |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Other segment items * | | | (53,637 | ) | | | (82,922 | ) | | | (136,559 | ) | | | (175,802 | ) | | | (238,388 | ) | | | (414,190 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Adjusted net income | | | 6,401 | | | | 7,565 | | | | 13,966 | | | | 19,962 | | | | 20,624 | | | | 40,586 | |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Unallocated corporate expenses | | | | | | | | | | | (3,893 | ) | | | | | | | | | | | (11,025 | ) |
| Interest expense | | | | | | | | | | | (474 | ) | | | | | | | | | | | (1,794 | ) |
| Long-term performance based compensation | | | | | | | | | | | (597 | ) | | | | | | | | | | | (2,264 | ) |
| Amortization expense on acquired intangible assets | | | | | | | | | | | (1,377 | ) | | | | | | | | | | | (3,653 | ) |
| Restructuring / severance costs | | | | | | | | | | | (19 | ) | | | | | | | | | | | 35 | |
| Acquisition costs | | | | | | | | | | | (4,898 | ) | | | | | | | | | | | (5,205 | ) |
| Lease expense on the step-up basis of acquired leases | | | | | | | | | | | (241 | ) | | | | | | | | | | | (340 | ) |
| Foreign currency transaction loss on intercompany loan | | | | | | | | | | | 147 | | | | | | | | | | | | (207 | ) |
| Tax rate difference between reported and adjusted net income | | | | | | | | | | | (523 | ) | | | | | | | | | | | (430 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Net income | | | | | | | | | | $ | 2,091 | | | | | | | | | | | $ | 15,703 | |
| (In thousands) | | Three Months Ended | | | Nine Months Ended | |
| | | March 31, 2025 | | | March 31, 2025 | |
| | | | | | | | | | | Segment | | | | | | | | | | | Segment | |
| | | Lighting | | | Display | | | Total | | | Lighting | | | Display | | | Total | |
| Total sales | | $ | 62,302 | | | $ | 73,796 | | | $ | 136,098 | | | $ | 190,984 | | | $ | 243,284 | | | $ | 434,268 | |
| Inter-segment sales | | | (3,334 | ) | | | (283 | ) | | | (3,617 | ) | | | (15,371 | ) | | | (587 | ) | | | (15,958 | ) |
| Net sales | | | 58,968 | | | | 73,513 | | | | 132,481 | | | | 175,613 | | | | 242,697 | | | | 418,310 | |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Other segment items * | | | (53,196 | ) | | | (67,466 | ) | | | (120,662 | ) | | | (159,677 | ) | | | (224,475 | ) | | | (384,152 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Adjusted net income | | | 5,772 | | | | 6,047 | | | | 11,819 | | | | 15,936 | | | | 18,222 | | | | 34,158 | |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Unallocated corporate expenses | | | | | | | | | | | (4,827 | ) | | | | | | | | | | | (9,587 | ) |
| Interest expense | | | | | | | | | | | (661 | ) | | | | | | | | | | | (2,264 | ) |
| Long-term performance based compensation | | | | | | | | | | | (879 | ) | | | | | | | | | | | (3,039 | ) |
| Amortization expense on acquired intangible assets | | | | | | | | | | | (1,128 | ) | | | | | | | | | | | (3,260 | ) |
| Restructuring / severance costs | | | | | | | | | | | - | | | | | | | | | | | | (45 | ) |
| Acquisition costs | | | | | | | | | | | (577 | ) | | | | | | | | | | | (627 | ) |
| Lease expense on the step-up basis of acquired leases | | | | | | | | | | | (52 | ) | | | | | | | | | | | (155 | ) |
| Consulting expense: commercial growth initiatives | | | | | | | | | | | - | | | | | | | | | | | | (62 | ) |
| Tax rate difference between reported and adjusted net income | | | | | | | | | | | 188 | | | | | | | | | | | | 1,093 | |
| | | | | | | | | | | | | | | | | | | | | | | | | |
| Net income | | | | | | | | | | $ | 3,883 | | | | | | | | | | | $ | 16,212 | |
| (In thousands) | | Three Months Ended | | | Nine Months Ended | |
| | | March 31, | | | March 31, | |
| | | 2026 | | | 2025 | | | 2026 | | | 2025 | |
| Capital Expenditures: | | | | | | | | | | | | | | | | |
| Lighting Segment | | $ | 490 | | | $ | 246 | | | $ | 1,228 | | | $ | 1,467 | |
| Display Solutions Segment | | | 251 | | | | 358 | | | | 2,062 | | | | 934 | |
| | | $ | 741 | | | $ | 604 | | | $ | 3,290 | | | $ | 2,401 | |
| | | | | | | | | | | | | | | | | |
| Total segment capital expenditures | | $ | 741 | | | $ | 604 | | | $ | 3,290 | | | $ | 2,401 | |
| Other unallocated capital expenditures | | | (34 | ) | | | 86 | | | | 68 | | | | 114 | |
| Consolidated capital expenditures | | $ | 707 | | | $ | 690 | | | $ | 3,358 | | | $ | 2,515 | |
| | | | | | | | | | | | | | | | | |
| Income Tax Expense: | | | | | | | | | | | | | | | | |
| Lighting Segment | | $ | 1,201 | | | $ | 2,063 | | | $ | 5,147 | | | $ | 5,103 | |
| Display Solutions Segment | | | 2,245 | | | | 992 | | | | 5,700 | | | | 5,298 | |
| | | $ | 3,446 | | | $ | 3,055 | | | $ | 10,847 | | | $ | 10,401 | |
| | | | | | | | | | | | | | | | | |
| Total segment income tax expense | | $ | 3,446 | | | $ | 3,055 | | | $ | 10,847 | | | $ | 10,401 | |
| Other unallocated income tax (credit) | | | (2,179 | ) | | | (1,342 | ) | | | (5,102 | ) | | | (5,352 | ) |
| Consolidated income tax expense | | $ | 1,267 | | | $ | 1,713 | | | $ | 5,745 | | | $ | 5,049 | |
| | | | | | | | | | | | | | | | | |
| Depreciation and Amortization: | | | | | | | | | | | | | | | | |
| Lighting Segment | | $ | 1,279 | | | $ | 1,284 | | | $ | 3,816 | | | $ | 3,778 | |
| Display Solutions Segment | | | 2,012 | | | | 1,693 | | | | 5,703 | | | | 4,984 | |
| | | $ | 3,291 | | | $ | 2,977 | | | $ | 9,519 | | | $ | 8,762 | |
| | | | | | | | | | | | | | | | | |
| Total segment depreciation and amortization | | $ | 3,291 | | | $ | 2,977 | | | $ | 9,519 | | | $ | 8,762 | |
| Other unallocated depreciation and amortization | | | 101 | | | | 84 | | | | 301 | | | | 258 | |
| Consolidated depreciation and amortization | | $ | 3,392 | | | $ | 3,061 | | | $ | 9,820 | | | $ | 9,020 | |
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