XML 89 R77.htm IDEA: XBRL DOCUMENT
v3.25.3

Stockholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Millions |  |  | 2 Months Ended | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Oct. 13, 2025 | Aug. 14, 2025 | Oct. 13, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Aug. 13, 2025 | Aug. 05, 2025 | May 06, 2020 | Aug. 06, 2014
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Value of additional shares authorized to be repurchased |  |  |  |  |  |  |  |  |  | $ 200.0 |
Remaining authorized repurchase amount |  |  |  |  |  |  |  |  |  | $ 333.3 | $ 133.3
Payment for share repurchase |  |  |  |  |  |  |  | $ 150.0 |  |  |
Shares repurchased (in shares) |  | 2,279,000 |  |  |  |  |  |  |  |  |
Shares repurchased as percentage of total to be repurchased |  | 80.00% |  |  |  |  |  |  |  |  |
Initial price per share (in dollars per share) |  | $ 52.65 |  |  |  |  |  |  |  |  |
Stock repurchased and retired during period (in shares) |  |  |  |  | 400,000 |  | 400,000 |  |  |  |
Stock repurchased and retired during period, value |  |  |  | $ 218.8 | $ 25.0 | $ 251.3 | $ 25.0 |  |  |  |
Average cost per share (in dollars per share) |  |  |  |  | $ 61.21 |  | $ 61.21 |  |  |  |
Repurchase Program 2025 |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Remaining authorized repurchase amount |  |  |  | $ 383.8 |  | $ 383.8 |  |  |  |  |
Authorized repurchase amount |  |  |  |  |  |  |  |  | $ 500.0 |  |
Open Market Transactions |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Stock repurchased and retired during period (in shares) |  |  |  | 1,126,000 |  | 1,636,000 |  |  |  |  |
Stock repurchased and retired during period, value |  |  |  | $ 66.5 |  | $ 99.0 |  |  |  |  |
Average cost per share (in dollars per share) |  |  |  | $ 59.00 |  | $ 60.52 |  |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Shares repurchased (in shares) | 615,000 |  | 2,894,000 |  |  |  |  |  |  |  |
Price per share (in dollars per share) |  |  | $ 51.84 |  |  |  |  |  |  |  |
Employee Stock Purchase Plan | Share-based Payment Arrangement |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Shares issued under employee stock purchase plan (in shares) |  |  |  | 17,000 | 14,000 | 45,000 | 47,000 |  |  |  |
Price per share (in dollars per share) |  |  |  | $ 51.17 | $ 51.61 | $ 51.17 | $ 51.61 |  |  |  |
Employee Stock Purchase Plan | Employee Stock Option |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |
Price per share (in dollars per share) |  |  |  | $ 43.82 | $ 52.06 | $ 43.82 | $ 52.06 |  |  |  |
Compensation costs |  |  |  | $ 0.1 | $ 0.1 | $ 0.4 | $ 0.4 |  |  |  |

X
- Definition Stock Repurchase Program, Additional Authorized Amount + References No definition available. + Details
Name: | kmpr_StockRepurchaseProgramAdditionalAuthorizedAmount
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Treasury Stock, Shares, Acquired, Percentage Expected To Be Repurchased + References No definition available. + Details
Name: | kmpr_TreasuryStockSharesAcquiredPercentageExpectedToBeRepurchased
Namespace Prefix: | kmpr_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 505 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481520/505-30-50-4 + Details
Name: | srt_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | srt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Final price paid per share for the purchase of the targeted number of shares, determined by an average market price over a fixed period of time. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 30 -Name Accounting Standards Codification -Section 25 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481138/505-30-25-5 + Details
Name: | us-gaap_AcceleratedShareRepurchasesFinalPricePaidPerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The price paid per share to immediately purchase the targeted number of shares on the date of executing the accelerated share repurchase agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 30 -Name Accounting Standards Codification -Section 25 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481138/505-30-25-5 + Details
Name: | us-gaap_AcceleratedShareRepurchasesInitialPricePaidPerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cash receipt from (payment to) bank; or stock received from (issuance to) bank in the settlement of the accelerated share repurchase agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 30 -Name Accounting Standards Codification -Section 25 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481138/505-30-25-5 + Details
Name: | us-gaap_AcceleratedShareRepurchasesSettlementPaymentOrReceipt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479983/718-10-S45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479830/718-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 8A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 480 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479857/480-10-S50-1 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-13 Reference 6: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 272 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483014/272-10-45-3 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 272 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482987/272-10-50-1 Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(d)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-13 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-13 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-13 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-13 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-14 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 18 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-18 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(27)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.6-03(i)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.6-03(i)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.6-03(i)(2)(i)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.6-03(i)(2)(ii)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479886/946-10-S99-3 + Details
Name: | us-gaap_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Per share or per unit amount of equity securities issued. + References No definition available. + Details
Name: | us-gaap_SharesIssuedPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares issued during the period as a result of an employee stock purchase plan. + 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount remaining authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number of shares that have been repurchased and retired during the period. + 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital). + 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockRepurchasedAndRetiredDuringPeriodValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481549/505-30-45-1 + Details
Name: | us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares that have been repurchased during the period and are being held in treasury. + 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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_TreasuryStockSharesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ShareRepurchaseProgramAxis=kmpr_RepurchaseProgram2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ShareRepurchaseProgramAxis=kmpr_OpenMarketTransactionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=kmpr_EmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_StockCompensationPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |