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Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables) | 12 Months Ended
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Dec. 31, 2022
Accounting Policies [Abstract] |
Summary of Deferred Policy Acquisition Cost Amortization and Net Advertising Expense | The table below presents a summary of deferred policy acquisition cost amortization and net advertising expense:
| Year Ended December 31,
| 2022 |  | 2021 |  | 2020
| (Amounts in millions)
Deferred policy acquisition cost amortization | $ | 654.6 |  |  | $ | 633.4 |  |  | $ | 627.8 |
Net advertising expense | 11.8 |  |  | 50.1 |  |  | 37.7 |
Effects of Reinsurance | The effect of reinsurance on property and casualty premiums written and earned was as follows:
| Year Ended December 31,
| 2022 |  | 2021 |  | 2020
| (Amounts in thousands)
Premiums Written |  |  |  |  |
Direct | $ | 4,018,057 |  |  | $ | 3,877,476 |  |  | $ | 3,624,965 |
Ceded | (81,256) |  |  | (65,521) |  |  | (50,630) |
Assumed | 10,743 |  |  | 13,361 |  |  | 8,012 |
Net | $ | 3,947,544 |  |  | $ | 3,825,316 |  |  | $ | 3,582,347 |
Premiums Earned |  |  |  |  |
Direct | $ | 3,993,771 |  |  | $ | 3,764,626 |  |  | $ | 3,574,898 |
Ceded | (80,950) |  |  | (65,017) |  |  | (56,212) |
Assumed | 10,821 |  |  | 13,301 |  |  | 8,067 |
Net | $ | 3,923,642 |  |  | $ | 3,712,910 |  |  | $ | 3,526,753 |
Premium Receivable, Allowance for Credit Loss | The following table presents a summary of changes in allowance for credit losses on premiums receivable:
|  | Year Ended December 31,
|  | 2022 |  | 2021 |  | 2020
Beginning balance |  | $ | 6,000 |  |  | $ | 10,000 |  |  | $ | 1,445 |
Cumulative effect of adopting ASU 2016-13 |  | — |  |  | — |  |  | 1,855 |
Beginning balance, as adjusted |  | 6,000 |  |  | 10,000 |  |  | 3,300 |
Provision during the period for expected credit losses |  | 4,213 |  |  | (893) |  |  | 10,294 |
Write-off amounts during the period |  | (5,027) |  |  | (3,693) |  |  | (4,406) |
Recoveries during the period of amounts previously written off |  | 614 |  |  | 586 |  |  | 812 |
Ending balance |  | $ | 5,800 |  |  | $ | 6,000 |  |  | $ | 10,000 |

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- Definition Tabular disclosure of the effects of reinsurance, for example, but not limited to, disclosure of direct, assumed, and ceded insurance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 + Details
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