XML 59 R48.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Fair Values of Financial Instruments (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2024
Fair Value Disclosures [Abstract] |
Summary of Carrying or Reported Values and Corresponding Fair Values for Financial Instruments | The following table summarizes th e carrying or reported values and corresponding fair values for financial instruments:
|  | December 31, |
|  | 2024 |  |  | 2023 |
|  | Carrying Amount |  |  | Fair Value |  |  | Carrying Amount |  |  | Fair Value |
|  | (in thousands) |
Assets: |  |  |  |  |  |  |  |  |  |  |  |
Fixed maturity securities—held-to-maturity |  | $ | 413,061 |  |  | $ | 399,721 |  |  | $ | 483,575 |  |  | $ | 473,092 |
Fixed maturity securities—available-for-sale |  |  | 307,750 |  |  |  | 307,750 |  |  |  | 317,064 |  |  |  | 317,064 |
Equity securities |  |  | 58,629 |  |  |  | 58,629 |  |  |  | 57,147 |  |  |  | 57,147 |
Short-term investments |  |  | 9,338 |  |  |  | 9,338 |  |  |  | — |  |  |  | — |
Cash and cash equivalents |  |  | 44,045 |  |  |  | 44,045 |  |  |  | 38,682 |  |  |  | 38,682 |
Schedule of Assets Measured at Fair Value on Recurring Basis | Assets measured at fair value on a recurring basis as of December 31, 2024 and 2023 are as follows:
|  | December 31, 2024 |
|  | Level 1 Inputs |  |  | Level 2 Inputs |  |  | Level 3 Inputs |  |  | Total Fair Value |
|  | (in thousands) |
Financial instruments carried at fair value, classified as part of: |  |  |  |  |  |  |  |  |  |  |  |
Securities available-for-sale—fixed maturity: |  |  |  |  |  |  |  |  |  |  |  |
States and political subdivisions |  | $ | — |  |  | $ | 148,206 |  |  | $ | — |  |  | $ | 148,206 |
Corporate bonds |  |  | — |  |  |  | 141,535 |  |  |  | — |  |  |  | 141,535 |
U.S. agency-based mortgage-backed securities |  |  | — |  |  |  | 4,059 |  |  |  | — |  |  |  | 4,059 |
U.S. Treasury securities |  |  | 13,950 |  |  |  | — |  |  |  | — |  |  |  | 13,950 |
Total securities available-for-sale—fixed maturity |  |  | 13,950 |  |  |  | 293,800 |  |  |  | — |  |  |  | 307,750 |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |
Domestic common stock |  |  | 58,629 |  |  |  | — |  |  |  | — |  |  |  | 58,629 |
Total |  | $ | 72,579 |  |  | $ | 293,800 |  |  | $ | — |  |  | $ | 366,379 |
|  | December 31, 2023 |
|  | Level 1 Inputs |  |  | Level 2 Inputs |  |  | Level 3 Inputs |  |  | Total Fair Value |
|  | (in thousands) |
Financial instruments carried at fair value, classified as part of: |  |  |  |  |  |  |  |  |  |  |  |
Securities available-for-sale—fixed maturity: |  |  |  |  |  |  |  |  |  |  |  |
States and political subdivisions |  | $ | — |  |  | $ | 131,895 |  |  | $ | — |  |  | $ | 131,895 |
Corporate bonds |  |  | — |  |  |  | 166,753 |  |  |  | — |  |  |  | 166,753 |
U.S. agency-based mortgage-backed securities |  |  | — |  |  |  | 4,745 |  |  |  | — |  |  |  | 4,745 |
U.S. Treasury securities |  |  | 13,671 |  |  |  | — |  |  |  | — |  |  |  | 13,671 |
Total securities available-for-sale—fixed maturity |  |  | 13,671 |  |  |  | 303,393 |  |  |  | — |  |  |  | 317,064 |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |
Domestic common stock |  |  | 57,147 |  |  |  | — |  |  |  | — |  |  |  | 57,147 |
Total |  | $ | 70,818 |  |  | $ | 303,393 |  |  | $ | — |  |  | $ | 374,211 |
Schedule of Assets Measured at Amortized Cost | Assets measured at amortized cost net of allowance for credit losses as of December 31, 2024 and 2023 are as follows:
|  | December 31, 2024 |
|  | Level 1 Inputs |  |  | Level 2 Inputs |  |  | Level 3 Inputs |  |  | Total Fair Value |
|  | (in thousands) |
Securities held-to-maturity—fixed maturity: |  |  |  |  |  |  |  |  |  |  |  |
States and political subdivisions |  | $ | — |  |  | $ | 356,268 |  |  | $ | — |  |  | $ | 356,268 |
Corporate bonds |  |  | — |  |  |  | 32,670 |  |  |  | — |  |  |  | 32,670 |
U.S. agency-based mortgage-backed securities |  |  | — |  |  |  | 2,643 |  |  |  | — |  |  |  | 2,643 |
U.S. Treasury securities |  |  | 8,127 |  |  |  | — |  |  |  | — |  |  |  | 8,127 |
Asset-backed securities |  |  | — |  |  |  | 13 |  |  |  | — |  |  |  | 13 |
Total held-to-maturity |  | $ | 8,127 |  |  | $ | 391,594 |  |  | $ | — |  |  | $ | 399,721 |
|  | December 31, 2023 |
|  | Level 1 Inputs |  |  | Level 2 Inputs |  |  | Level 3 Inputs |  |  | Total Fair Value |
|  | (in thousands) |
Securities held-to-maturity—fixed maturity: |  |  |  |  |  |  |  |  |  |  |  |
States and political subdivisions |  | $ | — |  |  | $ | 408,970 |  |  | $ | — |  |  | $ | 408,970 |
Corporate bonds |  |  | — |  |  |  | 49,948 |  |  |  | — |  |  |  | 49,948 |
U.S. agency-based mortgage-backed securities |  |  | — |  |  |  | 3,199 |  |  |  | — |  |  |  | 3,199 |
U.S. Treasury securities |  |  | 10,939 |  |  |  | — |  |  |  | — |  |  |  | 10,939 |
Obligations of U.S. government agencies |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Asset-backed securities |  |  | — |  |  |  | 36 |  |  |  | — |  |  |  | 36 |
Total held-to-maturity |  | $ | 10,939 |  |  | $ | 462,153 |  |  | $ | — |  |  | $ | 473,092 |

X
- Definition Fair value schedule of assets carried at amortized cost. + References No definition available. + Details
Name: | amsf_HeldToMaturitySecuritiesTableTextBlock
Namespace Prefix: | amsf_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the fair value of financial instruments, including financial assets and financial liabilities, and the measurements of those instruments, assets, and liabilities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 + Details
Name: | us-gaap_FairValueByBalanceSheetGroupingTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration