Note 2 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Restricted Cash, Total	$ 9,200	$ 200
Letters of Credit Outstanding, Amount	6,500
Tax Increment Revenue Bonds [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Ending Balance	$ 0
Guaranty for Payment of Debt Service Shortfalls, Threshold, Coverage Rate	53.7
Guarantor Obligations, Current Carrying Value	$ 5,000
Investment Cash Held as Collateral for Letters of Credit [Member]
Restricted Cash, Total	$ 6,500