Note 3 - Income Taxes (Details Textual) $ in Millions	Sep. 30, 2020 USD ($)
Deferred Tax Liabilities, Net, Total	$ 126.1
Domestic Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Deferred Tax Liabilities, Net, Total	34.9
Foreign Tax Authority [Member] \| Canada Revenue Agency [Member]
Deferred Tax Liabilities, Net, Total	94.6
Foreign Tax Authority [Member] \| Mexican Tax Authority [Member]
Deferred Tax Assets, Net of Valuation Allowance, Total	$ 3.4

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=120406818&loc=d3e31931-109318

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

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