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Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 USD ($) | Dec. 31, 2020 USD ($) shares | Dec. 31, 2019 USD ($) shares | Dec. 31, 2018 USD ($) shares
Revenue from Contract with Customer, Including Assessed Tax |  | $ 285,907 | $ 279,317 | $ 172,149
Workers' Compensation Liability |  | 1,700 | 1,700 |
Workers' Compensation Liability, Current |  | 237 | 269 |
Foreign Currency Transaction Gain (Loss), Realized |  | $ (1,100) | $ 500 | $ (400)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares |  | 0 | 0 | 63,000
Restricted Stock Units and Performance Share Award Target Level, Percentage |  |  | 100.00% |
Number of Customers with Receivable Balance in Excess of Ten Percent of Receivables |  | 1 | 1 |
Performance Shares [Member] |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares |  |  |  | 39,000
Restricted Stock Units and Performance Share Award Target Level, Percentage |  | 100.00% |  |
Accrued Liability [Member] |  |  |  |
Workers' Compensation Liability, Current |  | $ 200 | $ 300 |
Other Long-term Liabilities [Member] |  |  |  |
Workers' Compensation Liability, Noncurrent |  | $ 1,500 | $ 1,400 |
Minimum [Member] |  |  |  |
Finite-Lived Intangible Asset, Useful Life (Year) |  | 3 years |  |
Maximum [Member] |  |  |  |
Finite-Lived Intangible Asset, Useful Life (Year) |  | 15 years |  |
Land Improvements [Member] | Minimum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 15 years |  |
Land Improvements [Member] | Maximum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 30 years |  |
Building [Member] | Minimum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 20 years |  |
Building [Member] | Maximum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 40 years |  |
Machinery and Equipment [Member] | Minimum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 3 years |  |
Machinery and Equipment [Member] | Maximum [Member] |  |  |  |
Property, Plant and Equipment, Useful Life (Year) |  | 30 years |  |
Out of Period Adjustment [Member] |  |  |  |
Revenue from Contract with Customer, Including Assessed Tax | $ (1,200) |  |  |

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