Note 13 - Income Tax - Earning Before Income Tax by Jurisdiction (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Earnings before income tax	$ 115,202	$ 96,615
Canada Revenue Agency [Member] \| Foreign Tax Authority [Member]
Earnings before income tax	6,854	4,375
Internal Revenue Service (IRS) [Member] \| Domestic Tax Authority [Member]
Earnings before income tax	$ 108,348	$ 92,240

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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