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Debt - Narrative (Details) - USD ($) |  |  | 1 Months Ended | 3 Months Ended | 6 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 10, 2022 | Jun. 04, 2019 | Mar. 31, 2021 | Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022 | Feb. 15, 2022 | Sep. 22, 2020 | Jun. 08, 2018 | Feb. 28, 2015
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | $ 1,388,100,000 |  | $ 1,388,100,000 |  | $ 1,386,900,000 |  |  |  |
Interest and other expenses |  |  |  | 14,000,000 | $ 14,000,000 | 28,100,000 | $ 26,700,000 |  |  |  |  |
Interest paid, including capitalized interest, operating and investing activities |  |  |  | 2,500,000 | $ 2,400,000 | 27,300,000 | $ 24,400,000 |  |  |  |  |
Derivative, Gain on Derivative |  |  |  |  |  | 5,900,000 |  |  |  |  |  |
2.400% Senior Notes due September 30, 2030 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  |  |  |  |  |  |  | $ 395,800,000 |  |
Senior Notes, 3.800 Percent Due February 23, 2033 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  |  |  |  |  |  | $ 395,100,000 |  |  |
5.875% Fixed-Rate Reset Junior Subordinated Debentures due 2062 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt | $ 144,700,000 |  |  |  |  |  |  |  |  |  |  |
Senior Notes | 4.350% Senior Notes due February 15, 2025 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | $ 449,500,000 |  | $ 449,500,000 |  | 449,300,000 |  |  |  |
Stated interest rate |  |  |  | 4.35% |  | 4.35% |  |  |  |  |  |
Long-term debt, gross |  |  |  | $ 450,000,000 |  | $ 450,000,000 |  |  |  |  |  |
Face amount of debt |  |  |  |  |  |  |  |  |  |  |  | $ 250,000,000
Increase in senior notes |  |  | $ 200,000,000 |  |  |  |  |  |  |  |  |
Senior Notes | 2.400% Senior Notes due September 30, 2030 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | 396,800,000 |  | 396,800,000 |  | 396,600,000 |  |  |  |
Stated interest rate |  |  |  |  |  |  |  |  |  | 2.40% |  |
Long-term debt, gross |  |  |  | 400,000,000 |  | 400,000,000 |  |  |  |  |  |
Effective interest rate |  |  |  |  |  |  |  |  |  | 2.52% |  |
Senior Notes | Senior Notes, 3.800 Percent Due February 23, 2033 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | 395,700,000 |  | 395,700,000 |  | 395,500,000 |  |  |  |
Stated interest rate |  |  |  |  |  |  |  |  | 3.80% |  |  |
Long-term debt, gross |  |  |  | 400,000,000 |  | 400,000,000 |  |  |  |  |  |
Effective interest rate |  |  |  |  |  |  |  |  |  | 3.95% |  |
Senior Notes | 5.875% Fixed-Rate Reset Junior Subordinated Debentures due 2062 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt, gross |  |  |  | 150,000,000 |  | 150,000,000 |  |  |  |  |  |
Senior Notes | Senior Notes, 5.875 Percent Due March 15, 2062 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  |  | 146,100,000 |  | 146,100,000 |  | $ 145,500,000 |  |  |  |
Junior Debt | Senior Notes, 5.875 Percent Due March 15, 2062 |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate | 5.875% |  |  |  |  |  |  |  |  |  |  |
Junior Debt | Senior Notes, 5.875 Percent Due March 15, 2062 | Five-Year Treasury Rate |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 4.14% |  |  |  |  |  |  |  |  |  |  |
Revolving Credit Facility | Notes Payable under Revolving Credit Agreement | Second Amended and Restated Credit Agreement |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 800,000,000 |  | 460,000,000 |  | 460,000,000 |  |  |  |  | $ 600,000,000 |
Increase in revolving credit borrowing capacity |  | $ 200,000,000 |  |  |  |  |  |  |  |  |  |
Line of credit facility, amount outstanding |  |  |  | $ 0 |  | $ 0 |  |  |  |  |  |

X
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