SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) segment	Jun. 30, 2023 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			2
Segment Information [Line Items]
Net premiums earned	$ 1,304,478	$ 1,265,745	$ 2,562,519	$ 2,495,944
Other insurance related income (loss)	8,526	5,524	16,867	6,100
Net losses and loss expenses	(765,988)	(736,257)	(1,494,659)	(1,456,899)
Acquisition costs	(265,091)	(253,265)	(519,345)	(483,638)
Underwriting-related general and administrative expenses and corporate expenses	(148,441)	(168,503)	(311,813)	(335,314)
Net investment income	190,975	136,829	358,358	270,601
Foreign exchange (losses) gains	7,384	(30,104)	30,936	(38,814)
Interest expense and financing costs	(17,010)	(16,738)	(34,157)	(33,632)
Reorganization expenses	(14,014)	0	(26,312)	0
Amortization of intangible assets	(2,729)	(2,729)	(5,458)	(5,458)
Income before income taxes and interest in income (loss) of equity method investments	244,611	176,132	514,249	374,332
Income tax (expense) benefit	(40,547)	(27,558)	84,107	(43,454)
Interest in income of equity method investments	7,900	2,100	9,069	(105)
Net income	211,964	150,674	607,425	330,773
Preferred share dividends	7,563	7,563	15,125	15,125
Net income available to common shareholders	204,401	143,111	592,300	315,648
Operating Segments
Segment Information [Line Items]
Gross premiums written	2,440,236	2,284,378	5,094,663	4,666,354
Net premiums written	1,573,744	1,446,357	3,295,817	3,054,713
Net premiums earned	1,304,478	1,265,745	2,562,519	2,495,944
Other insurance related income (loss)	8,526	5,524	16,867	6,100
Net losses and loss expenses	(765,988)	(736,257)	(1,494,659)	(1,456,899)
Acquisition costs	(265,091)	(253,265)	(519,345)	(483,638)
Underwriting-related general and administrative expenses and corporate expenses	(120,768)	(133,255)	(258,561)	(273,650)
Underwriting income	$ 161,157	$ 148,492	$ 306,821	$ 287,857
Net losses and loss expenses ratio (as a percent)	58.70%	58.20%	58.30%	58.40%
Acquisition cost ratio (as a percent)	20.30%	20.00%	20.30%	19.40%
General and administrative expense ratio (as a percent)	11.40%	13.30%	12.20%	13.40%
Combined ratio (as a percent)	90.40%	91.50%	90.80%	91.20%
Goodwill and intangible assets	$ 282,227	$ 293,143	$ 282,227	$ 293,143
Operating Segments \| Insurance
Segment Information [Line Items]
Gross premiums written	1,814,066	1,684,150	3,388,571	3,099,762
Net premiums written	1,194,197	1,021,021	2,216,551	1,903,597
Net premiums earned	958,212	842,751	1,876,159	1,659,206
Other insurance related income (loss)	(61)	58	(39)	112
Net losses and loss expenses	(542,591)	(457,650)	(1,039,455)	(907,117)
Acquisition costs	(188,026)	(156,972)	(364,055)	(304,030)
Underwriting-related general and administrative expenses and corporate expenses	(111,894)	(113,534)	(233,981)	(230,164)
Underwriting income	$ 115,640	$ 114,653	$ 238,629	$ 218,007
Net losses and loss expenses ratio (as a percent)	56.60%	54.30%	55.40%	54.70%
Acquisition cost ratio (as a percent)	19.60%	18.60%	19.40%	18.30%
General and administrative expense ratio (as a percent)	11.70%	13.50%	12.50%	13.90%
Combined ratio (as a percent)	87.90%	86.40%	87.30%	86.90%
Goodwill and intangible assets	$ 282,227	$ 293,143	$ 282,227	$ 293,143
Operating Segments \| Reinsurance
Segment Information [Line Items]
Gross premiums written	626,170	600,228	1,706,092	1,566,592
Net premiums written	379,547	425,336	1,079,266	1,151,116
Net premiums earned	346,266	422,994	686,360	836,738
Other insurance related income (loss)	8,587	5,466	16,906	5,988
Net losses and loss expenses	(223,397)	(278,607)	(455,204)	(549,782)
Acquisition costs	(77,065)	(96,293)	(155,290)	(179,608)
Underwriting-related general and administrative expenses and corporate expenses	(8,874)	(19,721)	(24,580)	(43,486)
Underwriting income	$ 45,517	$ 33,839	$ 68,192	$ 69,850
Net losses and loss expenses ratio (as a percent)	64.50%	65.90%	66.30%	65.70%
Acquisition cost ratio (as a percent)	22.30%	22.80%	22.60%	21.50%
General and administrative expense ratio (as a percent)	2.50%	4.60%	3.60%	5.20%
Combined ratio (as a percent)	89.30%	93.30%	92.50%	92.40%
Goodwill and intangible assets	$ 0	$ 0	$ 0	$ 0
Segment Reconciling Items
Segment Information [Line Items]
Net investment income	190,975	136,829	358,358	270,601
Net investment gains (losses)	(53,479)	(24,370)	(62,687)	(44,558)
Foreign exchange (losses) gains	7,384	(30,104)	30,936	(38,814)
Interest expense and financing costs	(17,010)	(16,738)	(34,157)	(33,632)
Reorganization expenses	(14,014)	0	(26,312)	0
Amortization of intangible assets	(2,729)	(2,729)	(5,458)	(5,458)
Corporate expenses
Segment Information [Line Items]
Underwriting-related general and administrative expenses and corporate expenses	$ (27,673)	$ (35,248)	$ (53,252)	$ (61,664)

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities, the change in fair value of investment-related derivatives not designated as hedges and any hedge ineffectiveness recognized in earnings in relation to investment portfolio-related fair value hedges.

No definition available.