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Commitments and Contingencies (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2019 | Dec. 31, 2019 | Jun. 28, 2019 | Dec. 31, 2018
American International Group | NSM Insurance HoldCo, LLC |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Intangible assets acquired |  |  |  | $ 82.5 |
Sirius Group | Swedish Tax Authority | Sirius Group |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Contingent liability | $ 16.6 | $ 16.6 |  |  | $ 17.3
Change in contingent liability | $ (0.7) | $ (0.7) |  |  |
Scenario, Forecast | American International Group | NSM Insurance HoldCo, LLC |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |
Purchase Obligation |  |  | $ 82.5 |  |

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