Note 8 - Loan Payable (Details Textual) $ in Thousands			12 Months Ended
	Jun. 14, 2019 USD ($)	Jan. 20, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	[1]	Dec. 31, 2017 USD ($)	Mar. 18, 2019 USD ($)
Payments of Financing Costs, Total			$ 641	$ 8		$ 620
Royal Bank, Bank of Montreal, Bank of Nova Scotia, HSBC and CIBC [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 240,000
Fees to Lenders	300
Legal Fees	200
Debt Issuance Costs, Gross	$ 400
Debt Instrument, Term	4 years
Maximum Total Funded Debt to EBITDA Ratio			3.5
Minimum Fixed Charge Coverage Ratio			3
Percentage of Forecasted Capital Expenditures, Threshold for Annual Capital Expenditures			110.00%
Total Funded Debt to EBITDA Ratio			2
Royal Bank, Bank of Montreal, Bank of Nova Scotia, HSBC and CIBC [Member] | General and Administrative Expense [Member]
Payments of Financing Costs, Total	$ 100
Royal Bank, Bank of Montreal, Bank of Nova Scotia, HSBC and CIBC [Member] | Guaranteed Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	180,000
Royal Bank, Bank of Montreal, Bank of Nova Scotia, HSBC and CIBC [Member] | Accordion Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 60,000
Bank of Montreal and Royal Bank of Canada [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 140,000
Debt Issuance Costs, Gross							$ 200
Debt Instrument, Term		4 years

[1] The Company has initially applied ASC 2014-09 (Topic 606) on January 1, 2018 and ASC 2016-02 (Topic 842) on January 1, 2019. Both accounting standards were adopted using the modified retrospective method, under this method the comparative periods were not restated.