XML 83 R72.htm IDEA: XBRL DOCUMENT
v3.21.2

Fair Value Measurements (Fair Value of Assets Measured on Recurring Basis) (Detail) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | $ 9,095,806 |  | $ 6,354,822
Equity securities, estimated fair value | 760,758 |  | 464,126
Debt and Equity securities, estimated fair value | 9,856,564 |  | 6,818,948
Level 1 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Equity securities, estimated fair value | 760,758 |  | 464,126
Debt and Equity securities, estimated fair value | 760,758 |  | 464,126
Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 9,095,806 |  | 6,354,822
Debt and Equity securities, estimated fair value | 9,095,806 |  | 6,354,822
U.S. Treasury bonds |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 171,743 |  | 80,846
U.S. Treasury bonds | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 171,743 |  | 80,846
Municipal bonds |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 1,613,801 |  | 1,248,808
Municipal bonds | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 1,613,801 |  | 1,248,808
Foreign government bonds |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 231,375 |  | 199,530
Foreign government bonds | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 231,375 |  | 199,530
Governmental agency bonds |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 211,507 |  | 263,922
Governmental agency bonds | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 211,507 |  | 263,922
Governmental agency mortgage-backed securities |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 5,373,158 |  | 3,474,618
Governmental agency mortgage-backed securities | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 5,373,158 |  | 3,474,618
U.S. corporate debt securities |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 1,022,389 |  | 680,697
U.S. corporate debt securities | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 1,022,389 |  | 680,697
Foreign corporate debt securities |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 471,833 |  | 406,401
Foreign corporate debt securities | Level 2 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Debt securities, estimated fair value | 471,833 |  | 406,401
Preferred stocks |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Equity securities, estimated fair value | 16,944 |  | 19,479
Preferred stocks | Level 1 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Equity securities, estimated fair value | 16,944 |  | 19,479
Common stock |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Equity securities, estimated fair value | 743,814 | [1] | 444,647
Common stock | Level 1 |  |  |
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract] |  |  |
Equity securities, estimated fair value | $ 743,814 |  | $ 444,647
[1] | Includes Offerpad Solutions Inc. with a cost of $85.0 million and estimated fair value of $280.3 million. See below for further discussion about the Company’s investment in Offerpad Solutions Inc.

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=123594786&loc=SL75136599-209740 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USTreasuryBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_DomesticCorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_ForeignCorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |