SEGMENT INFORMATION (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) segment	Sep. 30, 2021 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			2
Segment Information [Line Items]
Net premiums earned	$ 1,284,866	$ 1,211,427	$ 3,820,163	$ 3,472,090
Other insurance related income	1,092	7,665	9,998	16,262
Net losses and loss expenses	941,911	911,369	2,444,196	2,292,559
Acquisition costs	(240,511)	(231,712)	(746,443)	(669,654)
Underwriting-related general and administrative expenses and corporate expenses	(158,245)	(157,960)	(492,872)	(478,820)
Net investment income	88,177	107,339	271,744	326,174
Foreign exchange gains	135,660	28,032	236,934	4,316
Interest expense and financing costs	(15,915)	(15,954)	(46,720)	(46,759)
Reorganization expenses	(6,213)	0	(21,941)	0
Amortization of value of business acquired	0	(1,028)	0	(3,083)
Amortization of intangible assets	(2,729)	(3,149)	(8,188)	(9,163)
Income (loss) before income taxes and interest in income (loss) of equity method investments	(2,187)	44,223	164,248	432,672
Income tax (expense) benefit	363	(1,186)	5,304	(49,827)
Interest in income (loss) of equity method investments	(7,560)	11,911	5,040	30,871
Net income (loss)	(9,384)	54,948	174,592	413,716
Preferred share dividends	7,563	7,563	22,688	22,688
Net income (loss) available (attributable) to common shareholders	(16,947)	47,385	151,904	391,028
Operating Segments
Segment Information [Line Items]
Gross premiums written	1,707,808	1,646,489	6,455,899	6,123,156
Net premiums written	1,036,784	996,471	4,166,502	3,979,215
Net premiums earned	1,284,866	1,211,427	3,820,163	3,472,090
Other insurance related income	1,092	7,665	9,998	16,262
Net losses and loss expenses	941,911	911,369	2,444,196	2,292,559
Acquisition costs	(240,511)	(231,712)	(746,443)	(669,654)
Underwriting-related general and administrative expenses and corporate expenses	(132,570)	(134,826)	(413,069)	(396,455)
Underwriting income (loss)	$ (29,034)	$ (58,815)	$ 226,453	$ 129,684
Net losses and loss expenses ratio (as a percent)	73.30%	75.20%	64.00%	66.00%
Acquisition cost ratio (as a percent)	18.70%	19.10%	19.50%	19.30%
General and administrative expense ratio (as a percent)	12.30%	13.10%	12.90%	13.80%
Combined ratio (as a percent)	104.30%	107.40%	96.40%	99.10%
Goodwill and intangible assets	$ 301,330	$ 312,358	$ 301,330	$ 312,358
Operating Segments \| Insurance
Segment Information [Line Items]
Gross premiums written	1,317,890	1,176,500	4,114,776	3,548,169
Net premiums written	777,789	707,492	2,491,120	2,128,190
Net premiums earned	782,101	681,008	2,303,640	1,928,970
Other insurance related income	151	468	470	1,435
Net losses and loss expenses	519,006	442,681	1,346,585	1,131,753
Acquisition costs	(139,436)	(123,529)	(422,979)	(348,172)
Underwriting-related general and administrative expenses and corporate expenses	(108,072)	(104,905)	(330,598)	(307,777)
Underwriting income (loss)	$ 15,738	$ 10,361	$ 203,948	$ 142,703
Net losses and loss expenses ratio (as a percent)	66.40%	65.00%	58.50%	58.70%
Acquisition cost ratio (as a percent)	17.80%	18.10%	18.40%	18.00%
General and administrative expense ratio (as a percent)	13.80%	15.40%	14.30%	16.00%
Combined ratio (as a percent)	98.00%	98.50%	91.20%	92.70%
Goodwill and intangible assets	$ 301,330	$ 312,358	$ 301,330	$ 312,358
Operating Segments \| Reinsurance
Segment Information [Line Items]
Gross premiums written	389,918	469,989	2,341,123	2,574,987
Net premiums written	258,995	288,979	1,675,382	1,851,025
Net premiums earned	502,765	530,419	1,516,523	1,543,120
Other insurance related income	941	7,197	9,528	14,827
Net losses and loss expenses	422,905	468,688	1,097,611	1,160,806
Acquisition costs	(101,075)	(108,183)	(323,464)	(321,482)
Underwriting-related general and administrative expenses and corporate expenses	(24,498)	(29,921)	(82,471)	(88,678)
Underwriting income (loss)	$ (44,772)	$ (69,176)	$ 22,505	$ (13,019)
Net losses and loss expenses ratio (as a percent)	84.10%	88.40%	72.40%	75.20%
Acquisition cost ratio (as a percent)	20.10%	20.40%	21.30%	20.80%
General and administrative expense ratio (as a percent)	4.90%	5.60%	5.40%	5.80%
Combined ratio (as a percent)	109.10%	114.40%	99.10%	101.80%
Goodwill and intangible assets	$ 0	$ 0	$ 0	$ 0
Segment Reconciling Items
Segment Information [Line Items]
Net investment income	88,177	107,339	271,744	326,174
Net investment gains (losses)	(146,458)	10,932	(414,231)	113,868
Foreign exchange gains	135,660	28,032	236,934	4,316
Interest expense and financing costs	(15,915)	(15,954)	(46,720)	(46,759)
Reorganization expenses	(6,213)	0	(21,941)	0
Amortization of value of business acquired	0	(1,028)	0	(3,083)
Amortization of intangible assets	(2,729)	(3,149)	(8,188)	(9,163)
Corporate Expenses
Segment Information [Line Items]
Underwriting-related general and administrative expenses and corporate expenses	$ (25,675)	$ (23,134)	$ (79,803)	$ (82,365)

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.