Note 9 - Debt - Summary of Debt Outstanding (Details) (Parentheticals)	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
The 8.00% Senior Secured Notes due August 2022 [Member]
Interest rate	8.00%	8.00%
Maturity date	Aug. 31, 2022	Aug. 31, 2022
NOK Denominated Notes Due May 2024 [Member] | Troms Offshore [Member]
Maturity date	May 31, 2024	May 31, 2024
NOK Denominated Notes Due January 2026 [Member] | Troms Offshore [Member]
Maturity date	Jan. 31, 2026	Jan. 31, 2026
USD Denominated Notes Due January 2027 [Member] | Troms Offshore [Member]
Maturity date	Jan. 31, 2027	Jan. 31, 2027
USD Denominated Notes Due April 2027 [Member] | Troms Offshore [Member]
Maturity date	Apr. 30, 2027	Apr. 30, 2027