PENSION AND POST-RETIREMENT PLANS - AMOUNTS INCLUDED IN FINANCIAL STATEMENTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Employee benefit plans
Non-current assets	$ 59.8	$ 49.0
Non-current liabilities	(16.1)	(21.3)
Pension Benefits
Employee benefit plans
Projected benefit obligations	199.1	192.2	$ 193.1
Fair value of plan assets at end of year	258.9	241.2	227.9
Pension Benefits | Qualified Plan
Employee benefit plans
Non-current assets	59.8	49.0
Total	59.8	49.0
Net (loss) gain, net of taxes	(8.6)	(14.0)
Total	(8.6)	(14.0)
Pension Benefits | Nonqualified Plan
Employee benefit plans
Current liabilities	(1.2)	(0.4)
Non-current liabilities	(4.1)	(4.0)
Total	(5.3)	(4.4)
Net (loss) gain, net of taxes	(0.7)	(0.4)
Total	(0.7)	(0.4)
Post-retirement benefits
Employee benefit plans
Projected benefit obligations	$ 12.7	18.4	$ 19.5
Amortization period of unrecognized gains and losses	5 years
Post-retirement benefits | Qualified Plan
Employee benefit plans
Current liabilities	$ (0.7)	(1.1)
Non-current liabilities	(12.0)	(17.3)
Total	(12.7)	(18.4)
Net (loss) gain, net of taxes	6.0	2.5
Prior service credit, net of taxes	2.9	5.6
Total	$ 8.9	$ 8.1