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v3.20.2

Significant Transactions (Details) |  |  |  |  |  |  |  |  |  | 3 Months Ended | 9 Months Ended |  |  |  |
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May 07, 2020 USD ($) | Apr. 07, 2020 GBP (£) | Apr. 07, 2020 USD ($) | Jun. 28, 2019 USD ($) | Apr. 04, 2019 USD ($) | Apr. 01, 2019 USD ($) | Feb. 26, 2019 USD ($) | Dec. 03, 2018 USD ($) | May 18, 2018 USD ($) earnout_period | May 11, 2018 USD ($) | Sep. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Sep. 30, 2019 USD ($) | Mar. 31, 2019 USD ($) | Sep. 30, 2020 USD ($) | Sep. 30, 2019 USD ($) | May 31, 2019 USD ($) | Apr. 03, 2019 USD ($) | Dec. 31, 2018 | Feb. 05, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to fund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 125,000,000.0
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 129,400,000 | $ 243,400,000 |  |  |  |
Goodwill |  |  |  |  |  |  |  |  |  |  | $ 540,100,000 |  | $ 394,700,000 |  |  | 540,100,000 |  |  |  |  |
Change in fair value of contingent consideration earnout liabilities |  |  |  |  |  |  |  |  |  |  | 700,000 |  |  | $ (2,000,000.0) |  | (1,600,000) | 5,600,000 |  |  |  |
Payments to acquire business, net |  |  |  |  | $ 81,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total commitment under revolving credit facility |  |  | $ 291,400,000 |  |  |  |  |  |  |  |  | $ 234,000,000.0 |  |  |  |  |  |  |  |  |
Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contingent consideration earnout liabilities |  |  |  |  |  |  |  |  |  |  | 11,800,000 |  | 20,600,000 |  |  | 11,800,000 |  |  |  |  |
Payment for contingent consideration liability |  |  |  |  |  |  |  |  |  |  | 600,000 | 6,400,000 |  | 2,600,000 |  | 7,000,000.0 | 2,600,000 |  |  |  |
Change in fair value of contingent consideration earnout liabilities |  |  |  |  |  |  |  |  |  |  | $ 700,000 |  |  | (2,000,000.0) |  | $ (1,600,000) | 5,600,000 |  |  |  |
Marketing Technology (MediaAlpha) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  | 48.30% |  |  |  |  |  |  |  |  |  |  |  |  | 61.00% |
Fully diluted ownership interest (as a percent) |  |  |  |  |  |  | 42.00% |  |  |  |  |  |  |  |  |  |  |  |  | 58.90% |
Unrealized gain (loss) on investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 114,700,000 |  |  |  |
Proceeds from dividends received |  |  |  |  |  |  | $ 89,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net gain from sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 67,500,000 |  |  |  |  |  |
Assets, fair value |  |  |  |  |  |  | $ 114,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unrealized investment gain |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 114,700,000 |  |  |  |  |  |
Total realized and unrealized gain on sale of minority stake |  |  |  |  |  |  |  |  |  |  |  | $ 182,200,000 |  |  |  |  |  |  |  |  |
Passport/DavidShield |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  | 53.80% | 50.00% |  |  |  | 53.80% |  |  |  |  |
Stock issued during period, value, acquisitions | $ 15,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
NSM Bank Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount borrowed |  |  |  |  |  |  |  |  |  | $ 100,000,000.0 |  |  |  |  |  |  |  |  |  |  |
NSM Bank Facility | Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount borrowed |  |  |  |  |  |  |  |  |  |  | $ 275,000,000.0 |  |  |  |  | $ 275,000,000.0 |  |  |  |  |
NSM Bank Facility | Specialty Insurance Distribution (NSM) | Revolving credit loan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  |  |  |  |  |  |  |  |  |  | 0 |  |  | $ 0 |  | 0 | 6,500,000 |  |  |  |
Total commitment under revolving credit facility |  |  | 15,000,000.0 |  |  |  |  |  |  |  |  | $ 10,000,000.0 |  |  |  |  |  |  |  |  |
Kudu Debt | Kudu | Revolving credit loan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total commitment under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  | 125,000,000.0 |  |  |  |  |  |  |  |
Remaining borrowing capacity under revolving credit facility |  |  |  |  |  |  |  |  |  |  | 51,000,000.0 |  | $ 68,000,000.0 |  |  | 51,000,000.0 |  |  |  |  |
NSM Insurance HoldCo, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  | 95.00% |  |  |  |  |  |  |  |  |  |  |
Fully diluted ownership interest (as a percent) |  |  |  |  |  |  |  |  |  | 83.60% |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  | $ 29,000,000.0 |  | $ 274,200,000 |  |  |  |  |  |  |  |  |  |  |
Fresh Insurance Services Group Limited |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, aggregate cost |  |  |  |  |  |  |  |  | $ 49,600,000 |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  |  |  |  |  |  |  |  | $ 51,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |
Purchase price adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 700,000 |  |  |  |
Number of earnout periods | earnout_period |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |
KBK Insurance Group, Inc. & KBK Premium Services, Inc. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  |  |  | 60,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  |  |  |  |  |  |  | 30,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill and intangible assets acquired |  |  |  |  |  |  |  | $ 59,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 32,600,000 |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 32,700,000 |  |  |  |  |  |
Contingent consideration earnout liabilities |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 5,900,000 |  |  |  |  |  |
Embrace Pet Insurance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  | $ 52,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  |  | 15,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Embrace Pet Insurance | Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  |  |  | 58,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  |  |  |  |  | $ 20,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of voting interests acquired |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to acquire businesses, gross |  |  |  |  |  | $ 71,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Kingsbridge Group Limited | Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  | £ 107,200,000 | 132,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  | £ 42,500,000 | $ 52,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill and intangible assets acquired |  |  |  |  |  |  |  |  |  |  | $ 125,100,000 |  |  |  |  | $ 125,100,000 |  |  |  |  |
Percentage of voting interests acquired |  |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Kingsbridge Group Limited | White Mountains |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  | $ 80,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Elementum Holdings, L.P. |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  | 30.00% |  | 30.00% |  |  | 30.00% |  | 30.00% |  |  |
Other investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 55,100,000 |  |  |
Insurance-Linked Securities Funds |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitment to fund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 50,000,000.0 |  |  |
Elementum Funds |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, aggregate cost |  |  |  |  |  |  |  |  |  |  | $ 52,700,000 |  |  |  |  | $ 52,700,000 |  |  |  |  |
NSM Insurance HoldCo, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  | 96.60% |  | 96.40% |  |  | 96.60% |  |  |  |  |
Fully diluted ownership interest (as a percent) |  |  |  |  |  |  |  |  |  |  | 89.60% |  | 88.40% |  |  | 89.60% |  |  |  |  |
AIG Collector Car Business |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  | $ 82,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to acquire intangible assets |  |  |  | 82,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
AIG Collector Car Business | Specialty Insurance Distribution (NSM) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from borrowings |  |  |  | 22,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
AIG Collector Car Business | White Mountains |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash consideration to acquire businesses and interest in affiliates |  |  |  | $ 59,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asset Management (Kudu) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership interest (as a percent) |  |  |  |  | 99.10% |  |  |  |  |  |  |  |  |  |  |  |  |  | 49.50% |  | 49.50%
Fully diluted ownership interest (as a percent) |  |  |  |  | 85.40% |  |  |  |  |  |  |  |  |  |  |  |  |  | 42.70% |  | 42.70%
Goodwill |  |  |  |  | $ 7,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intangible assets acquired |  |  |  |  | 2,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unfunded capital commitment |  |  |  |  | 250,000,000.0 |  |  |  |  |  | $ 94,500,000 |  | $ 129,000,000.0 |  |  | $ 94,500,000 |  |  | $ 250,000,000.0 |  |
Assets acquired |  |  |  |  | 155,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Liabilities acquired |  |  |  |  | 800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Noncontrolling interest acquired |  |  |  |  | $ 1,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in capital commitment |  |  |  |  |  |  |  |  |  |  |  |  | 100,000,000.0 |  |  |  |  |  |  |  |
Funded capital commitment |  |  |  |  |  |  |  |  |  |  |  |  | $ 350,000,000.0 |  |  |  |  |  |  |  |

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