PENSION AND POST-RETIREMENT PLANS - FAIR VALUE (Details) - Pension Benefits - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension and Post-retirement Plans
Total	$ 227.9	$ 206.3	$ 238.9
Fair Value Measurement
Pension and Post-retirement Plans
Total	186.3	166.4
Total plan assets	227.9	206.4
Fair Value Measurement | Cash
Pension and Post-retirement Plans
Total	6.1	8.8
Fair Value Measurement | U S large-cap
Pension and Post-retirement Plans
Total	82.8	69.1
Fair Value Measurement | U S mid and small-cap
Pension and Post-retirement Plans
Total	46.0	41.5
Fair Value Measurement | International large-cap
Pension and Post-retirement Plans
Total	7.1	6.2
Fair Value Measurement | U S Treasuries
Pension and Post-retirement Plans
Total	19.2	17.4
Fair Value Measurement | Municipal bonds
Pension and Post-retirement Plans
Total	0.2	0.2
Fair Value Measurement | Investment grade U S corporate bonds
Pension and Post-retirement Plans
Total	24.7	22.8
Fair Value Measurement | Convertible Bonds
Pension and Post-retirement Plans
Total	0.1	0.3
Fair Value Measurement | International Fixed Income
Pension and Post-retirement Plans
Total	0.1	0.1
Fair Value Measurement | Quoted Prices in Active Markets (Level 1)
Pension and Post-retirement Plans
Total	142.0	125.6
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | Cash
Pension and Post-retirement Plans
Total	6.1	8.8
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | U S large-cap
Pension and Post-retirement Plans
Total	82.8	69.1
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | U S mid and small-cap
Pension and Post-retirement Plans
Total	46.0	41.5
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | International large-cap
Pension and Post-retirement Plans
Total	7.1	6.2
Fair Value Measurement | Significant Observable Inputs (Level 2)
Pension and Post-retirement Plans
Total	44.3	40.8
Fair Value Measurement | Significant Observable Inputs (Level 2) | U S Treasuries
Pension and Post-retirement Plans
Total	19.2	17.4
Fair Value Measurement | Significant Observable Inputs (Level 2) | Municipal bonds
Pension and Post-retirement Plans
Total	0.2	0.2
Fair Value Measurement | Significant Observable Inputs (Level 2) | Investment grade U S corporate bonds
Pension and Post-retirement Plans
Total	24.7	22.8
Fair Value Measurement | Significant Observable Inputs (Level 2) | Convertible Bonds
Pension and Post-retirement Plans
Total	0.1	0.3
Fair Value Measurement | Significant Observable Inputs (Level 2) | International Fixed Income
Pension and Post-retirement Plans
Total	0.1	0.1
Fair Value Measurement | Investment measured at NAV
Pension and Post-retirement Plans
Total	$ 41.6	$ 40.0