Note 5 - Employee Benefit Plans - Accumulated Benefit Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 0	$ 195,862
Accumulated benefit obligation	0	191,597
Fair value of plan assets	0	$ 189,874
Plan Assets Exceed ABO [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	148,143
Accumulated benefit obligation	144,816
Fair value of plan assets	$ 175,159