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Short Duration Contracts - Claims development - Insurance (Details) $ in Thousands	Dec. 31, 2021 USD ($) claims	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liabilities for losses and loss adjustment expenses, net of reinsurance	$ 11,886,330
Insurance | Property, energy, marine and aviation
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	1,947,000
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	1,377,632
All outstanding liabilities before 2012, net of reinsurance	17,517
Insurance | Property, energy, marine and aviation | 2012
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	178,343	$ 178,250	$ 178,616	$ 190,770	$ 192,993	$ 197,005	$ 199,469	$ 205,776	$ 232,498	$ 233,149
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	174,384	174,032	173,184	181,307	179,945	167,540	161,831	138,977	93,394	20,638
Total of IBNR liabilities plus expected development on reported claims	$ 627
Cumulative number of reported claims | claims	4,245
Insurance | Property, energy, marine and aviation | 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 126,276	127,290	128,624	133,869	134,952	143,400	149,199	156,785	159,102
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	124,841	124,688	123,356	125,475	122,244	120,111	110,808	84,936	32,292
Total of IBNR liabilities plus expected development on reported claims	$ 25
Cumulative number of reported claims | claims	4,243
Insurance | Property, energy, marine and aviation | 2014
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 134,942	135,032	134,329	132,307	136,201	147,465	145,957	148,368
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	122,296	115,383	98,553	87,812	84,195	77,892	53,751	25,881
Total of IBNR liabilities plus expected development on reported claims	$ 3,098
Cumulative number of reported claims | claims	3,884
Insurance | Property, energy, marine and aviation | 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 91,892	91,830	97,852	102,515	103,995	109,865	112,409
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	87,316	86,246	87,926	86,253	76,338	64,953	23,580
Total of IBNR liabilities plus expected development on reported claims	$ 3,804
Cumulative number of reported claims | claims	4,536
Insurance | Property, energy, marine and aviation | 2016
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 92,553	96,437	100,471	105,657	101,306	104,449
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	91,241	95,002	97,506	98,683	83,552	24,828
Total of IBNR liabilities plus expected development on reported claims	$ 874
Cumulative number of reported claims | claims	6,160
Insurance | Property, energy, marine and aviation | 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 231,228	230,439	235,951	246,291	280,715
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	215,895	211,708	195,532	139,867	30,228
Total of IBNR liabilities plus expected development on reported claims	$ 8,248
Cumulative number of reported claims | claims	6,426
Insurance | Property, energy, marine and aviation | 2018
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 170,057	173,693	186,030	180,981
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	142,838	134,858	102,285	30,026
Total of IBNR liabilities plus expected development on reported claims	$ 9,136
Cumulative number of reported claims | claims	5,020
Insurance | Property, energy, marine and aviation | 2019
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 165,477	178,564	179,056
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	133,911	105,380	26,130
Total of IBNR liabilities plus expected development on reported claims	$ 6,667
Cumulative number of reported claims | claims	5,080
Insurance | Property, energy, marine and aviation | 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 329,362	359,394
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	194,487	55,619
Total of IBNR liabilities plus expected development on reported claims	$ 66,698
Cumulative number of reported claims | claims	4,186
Insurance | Property, energy, marine and aviation | 2021
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 426,870
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	90,423
Total of IBNR liabilities plus expected development on reported claims	$ 158,163
Cumulative number of reported claims | claims	2,951
Insurance | Third party occurrence business
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 4,187,063
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	1,544,247
All outstanding liabilities before 2012, net of reinsurance	242,741
Insurance | Third party occurrence business | 2012
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	239,075	242,332	244,448	243,863	253,758	258,371	272,004	269,204	263,451	241,368
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	168,119	163,016	155,085	143,885	130,098	108,660	83,637	58,650	30,915	6,984
Total of IBNR liabilities plus expected development on reported claims	$ 43,924
Cumulative number of reported claims | claims	65,731
Insurance | Third party occurrence business | 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 270,558	269,754	272,849	274,717	282,122	302,165	307,152	297,225	283,228
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	184,800	174,946	164,403	149,292	122,288	101,293	71,449	29,265	6,857
Total of IBNR liabilities plus expected development on reported claims	$ 54,640
Cumulative number of reported claims | claims	67,113
Insurance | Third party occurrence business | 2014
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 343,569	342,934	344,197	339,701	343,113	338,890	336,019	330,015
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	224,101	211,643	191,305	162,123	112,702	71,624	40,346	9,228
Total of IBNR liabilities plus expected development on reported claims	$ 66,498
Cumulative number of reported claims | claims	75,904
Insurance | Third party occurrence business | 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 386,801	382,722	391,455	392,143	398,908	391,884	359,058
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	227,697	211,715	181,704	139,492	88,515	44,605	11,139
Total of IBNR liabilities plus expected development on reported claims	$ 91,081
Cumulative number of reported claims | claims	78,785
Insurance | Third party occurrence business | 2016
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 367,818	374,896	399,571	406,082	394,485	389,832
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	194,773	164,662	136,870	87,616	41,979	11,709
Total of IBNR liabilities plus expected development on reported claims	$ 115,303
Cumulative number of reported claims | claims	79,005
Insurance | Third party occurrence business | 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 407,115	412,512	422,624	417,941	417,377
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	165,606	135,111	99,874	52,356	13,408
Total of IBNR liabilities plus expected development on reported claims	$ 145,130
Cumulative number of reported claims | claims	84,692
Insurance | Third party occurrence business | 2018
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 451,459	450,937	453,190	430,415
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	154,248	115,137	63,848	17,025
Total of IBNR liabilities plus expected development on reported claims	$ 189,965
Cumulative number of reported claims | claims	77,700
Insurance | Third party occurrence business | 2019
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 481,045	487,547	456,353
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	121,859	73,222	18,431
Total of IBNR liabilities plus expected development on reported claims	$ 253,849
Cumulative number of reported claims | claims	84,895
Insurance | Third party occurrence business | 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 616,910	607,249
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	76,743	24,509
Total of IBNR liabilities plus expected development on reported claims	$ 428,750
Cumulative number of reported claims | claims	89,560
Insurance | Third party occurrence business | 2021
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 622,713
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	26,301
Total of IBNR liabilities plus expected development on reported claims	$ 543,386
Cumulative number of reported claims | claims	65,477
Insurance | Third party claims-made business
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 3,353,974
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	1,804,720
All outstanding liabilities before 2012, net of reinsurance	64,171
Insurance | Third party claims-made business | 2012
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	286,118	285,527	285,163	277,683	275,665	291,316	313,907	318,453	320,207	317,654
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	260,173	255,337	251,313	227,389	209,295	190,395	164,724	121,211	69,069	17,718
Total of IBNR liabilities plus expected development on reported claims	$ 11,570
Cumulative number of reported claims | claims	15,576
Insurance | Third party claims-made business | 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 273,948	271,501	281,996	291,205	294,674	320,524	324,442	320,659	301,956
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	247,078	245,687	238,951	217,132	198,008	179,395	137,963	87,458	19,032
Total of IBNR liabilities plus expected development on reported claims	$ 11,739
Cumulative number of reported claims | claims	15,696
Insurance | Third party claims-made business | 2014
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 288,318	292,247	298,017	282,058	279,043	299,104	279,846	264,537
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	249,960	243,791	229,958	208,074	173,089	129,712	63,312	13,817
Total of IBNR liabilities plus expected development on reported claims	$ 22,336
Cumulative number of reported claims | claims	15,676
Insurance | Third party claims-made business | 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 267,925	252,478	255,432	260,063	276,492	277,615	258,989
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	216,986	193,186	174,161	126,499	100,089	52,046	9,066
Total of IBNR liabilities plus expected development on reported claims	$ 20,617
Cumulative number of reported claims | claims	14,724
Insurance | Third party claims-made business | 2016
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 327,230	322,042	314,747	308,453	291,645	275,394
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	242,431	205,596	158,230	127,286	68,226	10,568
Total of IBNR liabilities plus expected development on reported claims	$ 42,509
Cumulative number of reported claims | claims	15,749
Insurance | Third party claims-made business | 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 323,854	308,917	312,554	286,565	271,088
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	196,125	143,340	113,208	67,669	9,306
Total of IBNR liabilities plus expected development on reported claims	$ 60,718
Cumulative number of reported claims | claims	16,404
Insurance | Third party claims-made business | 2018
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 337,083	320,653	315,085	273,521
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	158,709	118,361	68,424	12,287
Total of IBNR liabilities plus expected development on reported claims	$ 85,411
Cumulative number of reported claims | claims	15,854
Insurance | Third party claims-made business | 2019
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 318,498	318,469	290,217
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	122,362	65,477	12,418
Total of IBNR liabilities plus expected development on reported claims	$ 119,673
Cumulative number of reported claims | claims	12,982
Insurance | Third party claims-made business | 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 414,580	384,852
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	87,547	17,161
Total of IBNR liabilities plus expected development on reported claims	$ 240,888
Cumulative number of reported claims | claims	10,049
Insurance | Third party claims-made business | 2021
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 516,420
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	23,349
Total of IBNR liabilities plus expected development on reported claims	$ 435,910
Cumulative number of reported claims | claims	8,550
Insurance | Multi-line and other specialty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 4,479,691
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	3,376,225
All outstanding liabilities before 2012, net of reinsurance	22,375
Insurance | Multi-line and other specialty | 2012
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	243,849	245,260	245,205	248,310	248,066	256,379	257,240	259,582	265,479	254,684
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	239,928	240,191	237,221	233,862	232,640	223,798	209,916	190,754	166,414	$ 78,523
Total of IBNR liabilities plus expected development on reported claims	$ 2,057
Cumulative number of reported claims | claims	55,219
Insurance | Multi-line and other specialty | 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 246,682	247,443	250,252	254,916	253,554	265,672	265,594	274,285	266,089
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	239,831	238,792	237,863	235,801	226,769	214,941	181,721	151,897	$ 86,911
Total of IBNR liabilities plus expected development on reported claims	$ 3,461
Cumulative number of reported claims | claims	71,613
Insurance | Multi-line and other specialty | 2014
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 310,097	311,097	314,300	318,297	319,418	319,706	327,098	303,053
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	295,551	294,049	292,638	282,104	267,959	235,079	197,609	$ 108,003
Total of IBNR liabilities plus expected development on reported claims	$ 5,770
Cumulative number of reported claims | claims	109,575
Insurance | Multi-line and other specialty | 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 347,669	349,895	357,123	365,362	357,364	358,587	335,250
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	330,872	327,082	321,395	306,313	278,265	236,516	$ 138,393
Total of IBNR liabilities plus expected development on reported claims	$ 7,201
Cumulative number of reported claims | claims	148,924
Insurance | Multi-line and other specialty | 2016
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 408,621	410,610	416,724	428,579	431,760	409,367
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	385,890	379,885	363,392	342,345	305,250	$ 176,238
Total of IBNR liabilities plus expected development on reported claims	$ 11,032
Cumulative number of reported claims | claims	175,261
Insurance | Multi-line and other specialty | 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 505,135	501,753	492,166	502,068	483,414
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	446,749	424,219	381,419	343,049	$ 181,454
Total of IBNR liabilities plus expected development on reported claims	$ 16,867
Cumulative number of reported claims | claims	219,810
Insurance | Multi-line and other specialty | 2018
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 566,283	563,969	565,717	513,466
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	480,852	443,644	390,009	$ 212,316
Total of IBNR liabilities plus expected development on reported claims	$ 32,467
Cumulative number of reported claims | claims	247,052
Insurance | Multi-line and other specialty | 2019
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 641,832	613,673	568,337
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	488,094	386,894	$ 212,629
Total of IBNR liabilities plus expected development on reported claims	$ 63,880
Cumulative number of reported claims | claims	235,824
Insurance | Multi-line and other specialty | 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 572,265	622,241
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	311,112	$ 173,123
Total of IBNR liabilities plus expected development on reported claims	$ 192,056
Cumulative number of reported claims | claims	149,004
Insurance | Multi-line and other specialty | 2021
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Incurred losses and allocated loss adjustment expenses, net of reinsurance	$ 637,258
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance	157,346
Total of IBNR liabilities plus expected development on reported claims	$ 361,237
Cumulative number of reported claims | claims	75,250

X

- Definition

Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense.

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Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts for accident years not separately presented in claim development information. Excludes unallocated claim adjustment expense.

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Cumulative number of reported claims for short-duration insurance contracts.

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