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Significant Transactions - NSM (Details) £ in Millions, $ in Millions |  |  |  |  |  |  |  |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 06, 2021 USD ($) | Apr. 12, 2021 USD ($) | Apr. 12, 2021 GBP (£) | Apr. 07, 2020 USD ($) | Apr. 07, 2020 GBP (£) | Jun. 28, 2019 USD ($) | Apr. 01, 2019 USD ($) | Mar. 31, 2019 USD ($) | Dec. 03, 2018 USD ($) | May 18, 2018 USD ($) earnout_period | Mar. 31, 2022 USD ($) | Mar. 31, 2021 USD ($) | Mar. 31, 2020 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2021 USD ($)
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on sale |  |  |  |  |  |  |  |  |  |  |  | $ 28.7 |  |  |
Goodwill |  |  |  |  |  |  |  |  |  |  | $ 641.4 |  |  |  | $ 645.5
Change in fair value of contingent consideration earnout liabilities |  |  |  |  |  |  |  |  |  |  | 0.1 |  |  |  |
Contingent consideration payments related to acquisitions of subsidiaries |  |  |  |  |  |  |  |  |  |  | 0.0 | 6.7 |  |  |
Recognized pre-tax expense (revenue) |  |  |  |  |  |  |  |  |  |  | 0.1 |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Fresh Insurance Services Group Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of business |  | $ 1.5 | £ 1.1 |  |  |  |  |  |  |  |  |  |  |  |
Disposal Group, Held-for-sale, Not Discontinued Operations | Fresh Insurance Services Group Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on sale |  |  |  |  |  |  |  |  |  |  |  | 28.7 |  |  |
Fresh Insurance Services Group Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  |  | $ 51.0 |  |  |  |  |
Purchase price adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.7 |
Number of earnout periods | earnout_period |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  |  |  | $ 49.6 |  |  |  |  |
KBK Insurance Group, Inc. & KBK Premium Services, Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  |  |  | $ 30.1 |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  |  | 60.0 |  |  |  |  |  |
Goodwill |  |  |  |  |  |  |  | $ 32.6 |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  |  |  | 32.7 |  |  |  |  |  |  |
NSM Insurance HoldCo, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  |  | $ 29.0 |  |  |  |  |  |
Embrace Pet Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  | $ 52.2 |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  |  | $ 15.4 |  |  |  |  |  |  |  |
J.C. Taylor Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings | $ 35.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates | 49.6 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill | 28.5 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intangible assets acquired | 27.2 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Assets acquired | 60.3 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill and other intangible assets | 55.7 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Liabilities acquired | $ 10.7 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill and other intangible assets |  |  |  |  |  |  |  |  |  |  | 712.0 |  |  |  | 725.4
Contingent consideration |  |  |  |  |  |  |  |  |  |  | $ 0.0 |  |  |  | $ 6.8
Specialty Insurance Distribution (NSM) | Embrace Pet Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  |  | $ 20.4 |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  | 71.5 |  |  |  |  |  |  |  |
Stock issued during period, value, acquisitions |  |  |  |  |  |  | $ 58.2 |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) | Kingsbridge Group Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings |  |  |  | $ 52.4 | £ 42.5 |  |  |  |  |  |  |  |  |  |
Stock issued during period, value, acquisitions |  |  |  | $ 80.3 |  |  |  |  |  |  |  |  |  |  |
Percentage of voting interests acquired |  |  |  | 100.00% | 100.00% |  |  |  |  |  |  |  |  |  |
Goodwill acquired |  |  |  | $ 111.5 |  |  |  |  |  |  |  |  |  |  |
Finite-lived Intangible Assets Acquired |  |  |  | 20.2 |  |  |  |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) | Kingsbridge Group Limited | United Kingdom, Pounds |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates | £ |  |  |  |  | £ 107.2 |  |  |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) | Kingsbridge Group Limited | United States of America, Dollars |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  | $ 132.2 |  |  |  |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) | J.C. Taylor Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of voting interests acquired | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
KBK Insurance Group, Inc. & KBK Premium Services, Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Change in fair value of contingent consideration earnout liabilities |  |  |  |  |  |  |  | $ 5.9 |  |  |  |  |  |  |
Contingent consideration payments related to acquisitions of subsidiaries |  |  |  |  |  |  |  |  |  |  |  | $ 6.8 | $ 6.7 |  |
AIG Collector Car Business |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  | $ 82.5 |  |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  | 82.5 |  |  |  |  |  |  |  |  |
Stock issued during period, value, acquisitions |  |  |  |  |  | 59.1 |  |  |  |  |  |  |  |  |
AIG Collector Car Business | Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowings |  |  |  |  |  | $ 22.5 |  |  |  |  |  |  |  |  |

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