Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net income attributable to common shareholders	$ (72,699)	$ (750)	$ (119,090)	$ 19,320
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	254	(213)	(1,400)	(914)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	(20,802)	(14,719)	(35,292)	(18,088)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Amortization of bond premium and discount			(127)	(168)
Share-based compensation			16,932	1,820
Unearned premiums, net			1,332	5,902
Losses and loss expenses, net			(35,349)	3,399
Ceded premiums payable			37,555	52,127
Premium receivables			(32,231)	(39,109)
Amortization of Intangible Assets	9,301	1,139	18,064	2,278
Net investment gains (losses), including impairments	(2)	(4,535)	1	(4,536)
Other, net			12,535	10,789
Net Cash Provided by (Used in) Operating Activities, Total			(10,463)	27,481
Proceeds from Sale of Debt Securities, Available-for-Sale			0	20,639
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Proceeds from matured bonds			21,816	12,320
Purchases of bonds			(22,747)	(28,489)
Purchases of other investments			(66)	(15,802)
Change in short-term investments			24,966	(8,345)
Other, net			(5,939)	(149)
Net cash provided by (used in) investing activities from continuing operations			18,030	(19,826)
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Tax payments related to shares withheld for share-based compensation plans			(1,516)	(682)
Proceeds from (Payments to) Noncontrolling Interests			(894)	(1,050)
Net cash provided by (used in) financing activities from continuing operations			(9,747)	(1,732)
Effect of foreign exchange on cash and cash equivalents - discontinued operations			1,288	0
Treasury Stock, Value, Acquired, Cost Method	(179)		(3,301)	0	$ 11,698	$ 4,510
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation			(9,747)	(1,732)
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation			18,030	(19,826)
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation			(10,463)	27,481
Corporate costs reallocated to continuing operations	2,502	3,636	5,265	7,581
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Discontinued Operation	64,216	71,727	64,216	71,727	66,077	255,183
Cash Provided by (Used in) Continuing Operation			(892)	5,923
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	46,383	25,146	46,383	25,146	$ 47,275	$ 19,223
Cash Provided by (Used in) Operating Activity, Discontinued Operation			34,851	4,126
Cash Provided by (Used in) Investing Activity, Discontinued Operation			57,667	(100,025)
Cash Provided by (Used in) Financing Activity, Discontinued Operation			(94,854)	(87,492)
Cash Provided by (Used in) Discontinued Operation			(1,861)	(183,456)
Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Discontinued Operation			475	(65)
Effect of foreign exchange on cash and cash equivalents - discontinued operations			1,288	0
Depreciation, Depletion and Amortization	9,741	1,614	18,917	3,228
Net income attributable to common shareholders	(72,699)	(750)	(119,090)	19,320
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(52,151)	14,182	(82,398)	38,322
Payments to Noncontrolling Interests	2,967		(4,036)
Net Income (Loss) Attributable to Noncontrolling Interest	$ (72,953)	$ (537)	$ (117,690)	$ 20,234