XML 51 R41.htm IDEA: XBRL DOCUMENT
v3.26.1

Investments - Narrative (Details) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2026 USD ($) security | Mar. 31, 2025 USD ($) | Dec. 31, 2025 USD ($) security
Investments [Abstract] |  |  |
Allowance for credit losses on held-to-maturity fixed-maturity securities | $ 0 |  | $ 0
Proceeds from the redemption of fixed-maturity securities | 0 | $ 0 |
Sale and maturity - fixed-maturity securities available-for-sale | 6,108,053 | 6,669,556 |
Sale - equity securities | $ 0 | $ 0 |
Fixed-maturity securities accounted for gross unrealized losses | security | 244 |  | 125

X
- Definition Fixed-Maturity Securities Accounted for Gross Unrealized Losses + References No definition available. + Details
Name: | king_FixedMaturitySecuritiesAccountedForGrossUnrealizedLosses
Namespace Prefix: | king_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- 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 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 Reference 2: 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 3: 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 4: 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 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Amount of cash inflow from sale, maturity, prepayment and call 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/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481830/320-10-45-11 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-11 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 12 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-12 + Details
Name: | us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash inflow from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as investing activity. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 19 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-19 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 45 -Paragraph 1 -SubTopic 10 -Topic 321 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479567/321-10-45-1 + Details
Name: | us-gaap_ProceedsFromSaleOfEquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Equity impact of the value of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 + Details
Name: | us-gaap_StockRedeemedOrCalledDuringPeriodValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration