CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net income	$ 50.2	$ 62.7
Pension Plan and Restoration of Retirement Income Plan:
Amortization of prior service cost, net of tax of $0.1 and $0.1, respectively	0.0	0.0
Amortization of deferred net loss, net of tax of $0.0 and $0.0, respectively	0.1	0.1
Postretirement benefit plans:
Amortization of deferred net gain, net of tax of $(0.0) and $(0.1), respectively	(0.1)	0.0
Other comprehensive income, net of tax	0.0	0.1
Comprehensive income	$ 50.2	$ 62.8