Note 7 - Goodwill and Other Intangible Assets (Details Textual) $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($)	Mar. 01, 2021 USD ($)
Number of Reporting Units	2
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 0
Intangible Assets, Indefinite-lived, Amount of Fair Value in Excess of Carrying Amount	$ 15,700
Intangible Assets, Indefinite-lived, Percentage of Fair Value in Excess of Carrying Amount	358.00%
Lighting Segment [Member]
Number of Reporting Units	1
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount		$ 28,200
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		26.00%
Graphics Segment [Member]
Number of Reporting Units	1
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount		$ 11,400
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount		2065.00%

Amount of fair value of indefinite lived intangible assets in excess of carrying amount.

No definition available.

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- Definition

Percentage of fair value of indefinite lives intangible assets in excess of carrying amount.

+ References

No definition available.

+ Details

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- Definition

Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

+ References

No definition available.

+ Details

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- Definition

Amount of fair value of reporting unit in excess of carrying amount.

+ References

No definition available.

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- Definition

Percentage of fair value of reporting unit in excess of carrying amount.

+ References

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