Summary of Significant Accounting Policies - Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Values of Financial Instruments
Carrying value, before deducting unamortized discount or premiums	$ 1,151.1	$ 1,151.4
Senior Unsecured Notes - Publicly Traded
Fair Values of Financial Instruments
Carrying value, before deducting unamortized discount or premiums	1,150.0	1,150.0
Carrying value	1,140.0	1,140.0
Senior Unsecured Notes - Publicly Traded | Level 2
Fair Values of Financial Instruments
Fair value	$ 1,090.0	$ 1,070.0