STATEMENTS OF CONSOLIDATED STOCKHOLDERS' EQUITY - USD ($) $ in Millions		Total	Common Stock	Additional Paid In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2020		$ 732.4	$ 0.2	$ 1,068.6	$ 158.2	$ (475.9)	$ (18.7)
Beginning balance (shares) at Dec. 31, 2020			15,812,169
Net income (loss)		(18.5)			(18.5)
Other comprehensive income, net of tax		15.0					15.0
Common shares issued (including impacts from Long-Term Incentive programs)		0.3		0.3
Common shares issued (including impacts from Long-Term Incentive programs) (shares)			75,748
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(2.6)		(2.6)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(22,799)
Cash dividends declared	[1]	(46.7)			(46.7)
Amortization of unearned equity compensation		12.6		12.6
Ending balance at Dec. 31, 2021		692.5	$ 0.2	1,078.9	93.0	(475.9)	(3.7)
Ending balance (shares) at Dec. 31, 2021			15,865,118
Net income (loss)		(29.6)			(29.6)
Other comprehensive income, net of tax		6.9					6.9
Common shares issued (including impacts from Long-Term Incentive programs)		0.6		0.6
Common shares issued (including impacts from Long-Term Incentive programs) (shares)			107,494
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(2.8)		(2.8)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(31,856)
Cash dividends declared	[1]	(50.1)			(50.1)
Amortization of unearned equity compensation		13.7		13.7
Ending balance at Dec. 31, 2022		$ 631.2	$ 0.2	1,090.4	13.3	(475.9)	3.2
Ending balance (shares) at Dec. 31, 2022		15,940,756	15,940,756
Net income (loss)		$ 47.2			47.2
Other comprehensive income, net of tax		9.9					9.9
Common shares issued (including impacts from Long-Term Incentive programs)		0.7		0.7
Common shares issued (including impacts from Long-Term Incentive programs) (shares)			98,292
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(1.8)		(1.8)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares (shares)			(23,257)
Cash dividends declared	[1]	(50.4)			(50.4)
Amortization of unearned equity compensation		15.4		15.4
Ending balance at Dec. 31, 2023		$ 652.2	$ 0.2	$ 1,104.7	$ 10.1	$ (475.9)	$ 13.1
Ending balance (shares) at Dec. 31, 2023		16,015,791	16,015,791

[1] Dividends declared per common share were $3.08, $3.08 and $2.88 during 2023, 2022, and 2021, respectively.