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Reserve for Known and Incurred but Not Reported Claims (Narrative) (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Insurance [Abstract] |  |  |
Provision for title loss, percentage of title premiums and escrow fees | 3.25% | 4.00% | 4.00%
Ultimate loss rate | 3.75% | 4.00% | 4.00%
Estimated increase in loss reserve for prior policy years |  | $ 0.0 | $ 0.0
Percentage reserve release for prior policy years | 0.50% |  |
Reserve release for prior policy years | $ 21.6 |  |

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- Definition Increase in loss reserve estimates for prior policy years. + References No definition available. + Details
Name: | faf_IncreaseInLossReserveEstimatesForPriorPolicyYears
Namespace Prefix: | faf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition The provision for title losses expressed as a percentage of title premiums and escrow fees. + References No definition available. + Details
Name: | faf_LossProvisionPercentageOfTitlePremiumsAndEscrowFees
Namespace Prefix: | faf_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Percentage reserve releases for prior policy years. + References No definition available. + Details
Name: | faf_PercentageReserveReleasesForPriorPolicyYears
Namespace Prefix: | faf_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition Reserve releases for prior policy years. + References No definition available. + Details
Name: | faf_ReserveReleasesForPriorPolicyYears
Namespace Prefix: | faf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Ultimate loss rate percentage. + References No definition available. + Details
Name: | faf_UltimateLossRatePercentage
Namespace Prefix: | faf_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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