Capital Stock (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Total Shares Authorized	210,000,000
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Par Value	$ 0.01	$ 0.01
Phantom Stock Value Per Share	$ 3.33
SERP units	0	16,023	16,023
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 925.0
Common Stock, Voting Rights	one vote per share
Stock Repurchased and Retired During Period, Shares	0
Proceeds from Issuance of Common Stock	$ 220.7	$ 0.0	$ 0.0
Company recognized total stock compensation expense, net of forfeitures	$ 29.2	$ 36.6	$ 25.8
Union ratification stock awards
Class Of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	22,594	93,565
Share-based Payment Arrangement, Expense	$ 0.6	$ 3.0
Restricted Stock Units (RSUs) [Member] | LTIP
Class Of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	553,578
Share-based Payment Arrangement | LTIP
Class Of Stock [Line Items]
Fair Value Of Shares Granted	$ 24.0
Performance Shares | LTIP
Class Of Stock [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	284,653
Fair Value Of Shares Granted	$ 22.0
Class A [Member]
Class Of Stock [Line Items]
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Par Value	$ 0.01	$ 0.01
Class B [Member]
Class Of Stock [Line Items]
Common Stock, Shares Authorized	0	0
Common Stock, Par Value	$ 0	$ 0