Note 3 - Acquisitions of Swire Pacific Offshore Holdings LTD (Details Textual)		3 Months Ended
	Apr. 22, 2022 USD ($) $ / shares shares	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Warrants Issued to Acquire Swire Pacific Offshore Holdings Ltd. [Member]
Class of Warrant or Right, Issued During Period, Exercise Price (in dollars per share) | $ / shares	$ 0.001
Swire Pacific Offshore Holdings Ltd. [Member]
Number of Vessels, Offshore Support	50
Payments to Acquire Businesses, Gross	$ 42,000,000.0
Payments to Acquire Businesses, Preclosing Working Capital Adjustments	19,600,000
Proceeds From Previous Acquisition, Post-closing Working Capital Refund	8,800,000
Business Combination, Consideration Transferred, Total	$ 215,500,000
Goodwill, Ending Balance		$ 0
Business Combination, Acquisition Related Costs		$ 0.7	$ 2.2
Swire Pacific Offshore Holdings Ltd. [Member] | Warrants Issued to Acquire Swire Pacific Offshore Holdings Ltd. [Member]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares) | shares	8,100,000