Property and Casualty Insurance Activity - Average Historical Claims (Details)	Dec. 31, 2024
Property and Casualty Insurance Activity
1	55.30%
2	19.00%
3	6.60%
4	5.50%
5	4.20%
6	3.00%
7	2.00%
8	1.10%
9	0.00%
10	0.10%

Property and Casualty Insurance Activity

No definition available.

Name:	kins_PropertyAndCasualtyInsuranceActivityAbstract
Namespace Prefix:	kins_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of average annual payout, after reinsurance, in the eighth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 9F
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480046/944-40-55-9F

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 4G
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480081/944-40-50-4G

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the fifth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the fourth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the ninth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the first year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the seventh year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the sixth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the tenth year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the third year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of average annual payout, after reinsurance, in the second year after a claim is incurred, beginning with the earliest accident year disclosed for short-duration insurance contracts.

+ References

+ Details

Name:	us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant