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v3.22.2.2

Debt - Narrative (Details) - USD ($) |  | 1 Months Ended | 3 Months Ended | 9 Months Ended |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 04, 2019 | Mar. 31, 2021 | Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021 | Mar. 10, 2022 | Feb. 15, 2022 | Dec. 31, 2021 | Sep. 22, 2020 | Jul. 02, 2018 | Jun. 08, 2018 | Feb. 28, 2015
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  | $ 1,386,400,000 |  | $ 1,386,400,000 |  |  |  | $ 1,121,900,000 |  |  |  |
Interest and other expenses |  |  | 14,300,000 | $ 10,700,000 | 41,000,000 | $ 33,000,000 |  |  |  |  |  |  |
Interest paid, including capitalized interest, operating and investing activities |  |  | 25,000,000 | $ 21,600,000 | 49,400,000 | $ 43,700,000 |  |  |  |  |  |  |
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 | 5.000% Senior Notes due September 19, 2022 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  | 0 |  | 0 |  |  |  | 276,700,000 |  |  |  |
Stated interest rate |  |  |  |  |  |  |  |  |  |  | 5.00% |  |
Senior Notes | 5.000% Senior Notes due September 19, 2022 | Infinity Property and Casualty Corporation |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Face amount of debt |  |  |  |  |  |  |  |  |  |  | $ 275,000,000 |  |
Business combination, liabilities assumed, long-term debt |  |  |  |  |  |  |  |  |  |  | 282,100,000 |  |
Unamortized premium |  |  |  |  |  |  |  |  |  |  | $ 7,100,000 |  |
Effective interest rate |  |  |  |  |  |  |  |  |  |  | 4.36% |  |
Senior Notes | 4.350% Senior Notes due February 15, 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term Debt |  |  | $ 449,300,000 |  | $ 449,300,000 |  |  |  | 449,000,000.0 |  |  |  |
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 |  |  | 396,500,000 |  | 396,500,000 |  |  |  | 396,200,000 |  |  |  |
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 |  |  | 395,300,000 |  | 395,300,000 |  |  |  | $ 0 |  |  |  |
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 |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  | $ 600,000,000 |
Increase in revolving credit borrowing capacity | 200,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Debt issuance costs | 2,200,000 |  |  |  |  |  |  |  |  |  |  |  |
Remaining unamortized costs | $ 2,300,000 |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, amount outstanding |  |  | $ 0 |  | $ 0 |  |  |  |  |  |  |  |

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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 + Details
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