Note 16 - Subsequent Events (Details Textual) $ / shares in Units, $ in Millions					6 Months Ended
	Jul. 27, 2023 USD ($) $ / shares shares	Jul. 26, 2023 shares	Jul. 17, 2023 USD ($)	Mar. 02, 2020 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jul. 12, 2023 USD ($) a
Proceeds from Issuance of Common Stock					$ 75.0	$ 30.0
Rio Bravo [Member]
Proceeds from Divestiture of Businesses				$ 15.0
Contingent Interest Rate Swaps [Member]
Derivative Liability					$ 110.9
Subsequent Event [Member] | Private Placement, Tranche 2 [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares	22,072,103
Shares Issued, Price Per Share (in dollars per share) | $ / shares	$ 4.9837
Proceeds from Issuance of Common Stock	$ 110.0
Subsequent Event [Member] | Conversion of Preferred Stock Into Common Stock [Member]
Conversion of Stock, Shares Issued (in shares) | shares		59,500,000
Subsequent Event [Member] | Rio Bravo [Member]
Proceeds from Divestiture of Businesses			$ 4.4
Subsequent Event [Member] | Site Lease with the Brownsville Navigation District [Member]
Area of Land (Acre) | a							984
Subsequent Event [Member] | Rio Grande [Member] | CD Credit Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity							$ 500.0
Subsequent Event [Member] | Rio Grande [Member] | CD Credit Agreement [Member] | Construction Loans [Member]
Debt Instrument, Face Amount							10,300.0
Subsequent Event [Member] | Rio Grande [Member] | TCF Credit Agreement [Member] | Construction Loans [Member]
Debt Instrument, Face Amount							800.0
Subsequent Event [Member] | Rio Grande [Member] | Secured Senior Notes Due 2033 [Member]
Debt Instrument, Face Amount							$ 700.0
Debt Instrument, Interest Rate, Stated Percentage							6.67%
Subsequent Event [Member] | JV Agreement [Member]
Commitment to Fund							$ 283.0
Commitment to Fund, Cash							125.0
Remaining Equity Commitment							69.4
Subsequent Event [Member] | JV Agreement [Member] | Intermediate Holdings [Member]
Commitment to Fund							$ 6,200.0