Note 1 - Description of Business and Basis of Presentation (Restated) (Details Textual) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Defined Benefit Plan, Termination Charge	$ 0		$ 0	$ 6,945	$ 0
Income Tax Expense (Benefit), Total	1,780		$ 2,140	3,690	$ 7,090
Deferred Income Tax Assets, Net, Total	352			352		$ 0
Deferred Income Tax Liabilities, Net, Total	0			0		$ 450
Revision of Prior Period, Error Correction, Adjustment [Member]
Income Tax Expense (Benefit), Total				(1,800)
Deferred Income Tax Assets, Net, Total	352			352
Deferred Income Tax Liabilities, Net, Total	$ (1,448)			(1,448)
Noncontributory Qualified Defined Pension Plans [Member]
Defined Benefit Plan, Termination Charge		$ 6,900		$ 6,900