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Variable Interest Entity and Noncontrolling Interests - Variable interest entity (Details) - USD ($) $ in Thousands | 1 Months Ended |
--- | --- | ---
Mar. 31, 2014 | Jul. 01, 2021
Greysbridge Holdings Ltd |  |
Variable Interest Entity [Line Items] |  |
Percentage ownership |  | 40.00%
Greysbridge Holdings Ltd | Kelso And Company |  |
Variable Interest Entity [Line Items] |  |
Percentage ownership |  | 30.00%
Greysbridge Holdings Ltd | Warburg Pincus LLC |  |
Variable Interest Entity [Line Items] |  |
Percentage ownership |  | 30.00%
Variable Interest Entity, Primary Beneficiary | Somers Holdings Ltd. |  |
Variable Interest Entity [Line Items] |  |
Initial investment contribution amount | $ 100,000 |
Variable Interest Entity, Primary Beneficiary | Common shares | Somers Holdings Ltd. |  |
Variable Interest Entity [Line Items] |  |
Number of shares acquired | 2,500,000 |

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