Note 8 - Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands	9 Months Ended		21 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020
Pension Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer			$ 0
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 1,200	$ 1,200
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	400		400
Defined Benefit Plan, Benefit Obligation, Ending Balance	$ 22,800		$ 22,800	$ 22,800