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v3.23.2

Investments - Changes in Allowance for Credit Losses by Major Security Type of Investments Classified as Held-to-Maturity (Detail) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2023 USD ($) | Jun. 30, 2023 USD ($)
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Balance | $ 220 | $ 239
Provision for credit loss expense (benefit) | (16) | 35
Balance | 204 | 204
Amortized cost | 476,605 | 476,605
AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 446,635 | 446,635
Baa/BBB Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 29,970 | 29,970
States and Political Subdivisions [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Balance | 40 | 40
Provision for credit loss expense (benefit) | 1 | (1)
Balance | 41 | 41
Amortized cost | 408,779 | 408,779
States and Political Subdivisions [Member] | AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 405,819 | 405,819
States and Political Subdivisions [Member] | Baa/BBB Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 2,960 | 2,960
Corporate Bonds [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Balance | 178 | 196
Provision for credit loss expense (benefit) | (17) | 35
Balance | 161 | 161
Amortized cost | 53,130 | 53,130
Corporate Bonds [Member] | AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 26,137 | 26,137
Corporate Bonds [Member] | Baa/BBB Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 26,993 | 26,993
U.S. Agency-Based Mortgage-Backed Securities [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 3,499 | 3,499
U.S. Agency-Based Mortgage-Backed Securities [Member] | AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 3,499 | 3,499
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 11,143 | 11,143
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member] | AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 11,143 | 11,143
Asset-Backed Securities [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Balance | 2 | 3
Provision for credit loss expense (benefit) |  | (1)
Balance | 2 | 2
Amortized cost | 54 | 54
Asset-Backed Securities [Member] | AAA/AA/A Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | 37 | 37
Asset-Backed Securities [Member] | Baa/BBB Ratings [Member] |  |
Debt Securities Held To Maturity Credit Quality Indicator [Line Items] |  |
Amortized cost | $ 17 | $ 17

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- Definition Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (aaa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
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- Definition Amount of expense (reversal of expense) for expected credit loss on investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
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