XML 66 R38.htm IDEA: XBRL DOCUMENT
v3.25.4

Fair Value Measurements (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2025
Fair Value Disclosures [Abstract] |
Schedule of Financial Assets Measured at Fair Value on Recurring Basis | The tables below presents information about the Company’s financial assets measured at fair value on a recurring basis:
| December 31, 2025
Total |  | Level 1 |  | Level 2 |  | Level 3
U.S. Treasury and U.S. government agencies | $30,722 |  | $30,722 |  | $— |  | $—
Corporate debt securities | 206,799 |  | — |  | 206,799 |  | —
Asset-backed securities | 92,968 |  | — |  | 92,968 |  | —
Short-term investments | 18,121 |  | — |  | 18,121 |  | —
Total | $348,610 |  | $30,722 |  | $317,888 |  | $—
| December 31, 2024
Total |  | Level 1 |  | Level 2 |  | Level 3
U.S. Treasury and U.S. government agencies | $75,234 |  | $75,234 |  | $— |  | $—
Corporate debt securities | 108,790 |  | 28,222 |  | 80,568 |  | —
Asset-backed securities | 30,021 |  | — |  | 30,021 |  | —
Total | $214,045 |  | $103,456 |  | $110,589 |  | $—
Summary of Carrying Value and Estimated Fair Value of Company's Financial Instruments Not Carried at Fait Value | The following table summarizes the carrying value and estimated fair value of the Company’s financial instruments not carried at fair value as of the date presented:
| December 31, 2025 |  | December 31, 2024
Carrying Value |  | Estimated Fair Value |  | Carrying Value |  | Estimated Fair Value
Long-term debt: |  |  |  |  |  |  |
Surplus note | $618 |  | $499 |  | $1,029 |  | $885

X
- Definition Disclosure of carrying value and estimated fair valueof company financial instrument not at carried value. + References No definition available. + Details
Name: | aii_DisclosureOfCarryingValueAndEstimatedFairValueOfCompanyFinancialInstrumentNotAtCarriedValueTableTextBlock
Namespace Prefix: | aii_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class 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_FairValueAssetsMeasuredOnRecurringBasisTextBlock
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