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Note 1 - Summary of Significant Accounting Policies - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
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Fair Value, Inputs, Level 1 [Member] |  |
Total Assets | $ 3,949 | $ 2,132
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member] |  |
Investments | 1,586 | 1,294
Fair Value, Inputs, Level 1 [Member] | Money Market and Mutual Funds [Member] |  |
Other Assets | 2,363 | 838
Fair Value, Inputs, Level 2 [Member] |  |
Total Assets | 8,184 | 7,484
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] |  |
Investments | 2,124 | 5,898
Fair Value, Inputs, Level 2 [Member] | Government-backed and Government-sponsored Enterprises' Debt Securities [Member] |  |
Investments | $ 6,060 | $ 1,586

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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- Definition Fair value portion of other assets. + References No definition available. + Details
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