Note 7 - Stockholders' Equity (Details Textual) - USD ($)	3 Months Ended
Jun. 29, 2019	Mar. 31, 2019	Jun. 30, 2018
Treasury Stock, Shares, Ending Balance	2,864,133
Treasury Stock, Value, Ending Balance	$ 78,484,000	$ 75,740,000	$ 69,556,000
Common Class A [Member]
Treasury Stock, Value, Acquired, Cost Method	$ 2,744,000

The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 4
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02.29,30)
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

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