Note 16 - Income Tax (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Tax Credit Carryforward Duration Limit (Year)	20 years
Undistributed Earnings of Foreign Subsidiaries	$ 628,142	$ 528,519
Unrecognized Tax Benefits, Ending Balance	148	148
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	148	148
Tax Adjustments, Settlements, and Unusual Provisions	0	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	$ 38	$ 38
Minimum [Member] \| Foreign Tax Authority [Member] \| Canada Revenue Agency [Member]
Income Tax Return Examination Period (Year)	3 years
Minimum [Member] \| Foreign Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Return Examination Period (Year)	3 years
Maximum [Member] \| Foreign Tax Authority [Member] \| Canada Revenue Agency [Member]
Income Tax Return Examination Period (Year)	4 years
Maximum [Member] \| Foreign Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Return Examination Period (Year)	5 years
Canada and United States [Member] \| Minimum [Member]
Tax Credit Carryforward Duration Limit (Year)	6 years
Canada and United States [Member] \| Maximum [Member]
Tax Credit Carryforward Duration Limit (Year)	20 years

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Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.

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