v3.25.1
BENEFIT PLANS: (Details)
$ in Millions
3 Months Ended
Mar. 31, 2025
USD ($)
plan
Mar. 31, 2024
USD ($)
Benefit plans    
Number of noncontributory defined benefit pension plans | plan 2  
Defined contribution plan and post-retirement defined benefit plans    
Defined benefit plan, net periodic benefit costs    
Service cost $ 0.6 $ 0.7
Interest cost 0.9 0.9
Expected return on plan assets (1.8) (1.5)
Amortization of net loss/(gain) 0.1  
Net periodic (benefit) cost (0.2) 0.1
Post-retirement health care plans    
Defined benefit plan, net periodic benefit costs    
Interest cost 0.5 0.5
Net periodic (benefit) cost $ 0.5 $ 0.5