v3.26.1
Note 9 - Pension and Postretirement Benefits - Components of Net Periodic Benefit Cost and Amounts Recognized in Other Comprehensive Income (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pension Plan and SERP Plan [Member]        
Interest cost $ 3.8 $ 3.8 $ 7.6 $ 7.5
Expected return on plan assets (7.3) (6.3) (14.0) (12.5)
Amortization of prior service cost 0.2 0.0 0.3 0.1
Amortization of net actuarial loss 0.9 1.0 1.8 1.9
Net periodic (benefit) cost (2.4) (1.5) (4.3) (3.0)
Employer contributions/(reimbursement), net 0.2 0.1 1.0 0.2
Other Postretirement Benefits Plan [Member]        
Interest cost 0.0 0.0 0.0 0.1
Expected return on plan assets 0.0 0.0 0.0 (0.1)
Amortization of prior service cost 0.0 0.0 0.0 0.0
Amortization of net actuarial loss 0.1 0.1 0.2 0.2
Net periodic (benefit) cost 0.1 0.1 0.2 0.2
Employer contributions/(reimbursement), net $ 0.3 $ (0.3) $ 0.4 $ (2.7)