Summary of Information about Incurred Claims Development and Cumulative Paid Claims and Allocated Loss Adjustment Expense (ALAE), Net of Reinsurance (Detail) $ in Thousands	Dec. 31, 2018 USD ($) Claim	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)
Claims Development [Line Items]
Total Net reserves	$ 1,835,135
U.S.Insurance | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	566,448
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	439,454
Net reserves lesser than 2009	1,327
Total Net reserves	$ 128,321
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	5.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	29.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	26.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	13.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	8.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	10.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	3.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	0.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	0.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	0.00%
U.S.Insurance | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 534,837
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	452,549
Net reserves lesser than 2009	7,740
Total Net reserves	$ 90,028
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	29.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	29.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	16.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	8.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	7.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	3.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	2.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	1.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	0.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	0.60%
U.S.Insurance | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 1,883,354
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	937,253
Net reserves lesser than 2009	31,867
Total Net reserves	$ 977,968
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	4.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	10.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	16.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	19.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	16.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	10.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	6.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	5.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	1.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	2.90%
U.S.Insurance | 2009 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 60,067	$ 61,083	$ 58,143	$ 58,660	$ 58,487	$ 60,789	$ 58,600	$ 61,023	$ 53,273	$ 47,473
Total IBNR	$ 716
Number of Reported Claims | Claim	1,370
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 58,161	58,150	58,095	57,744	53,859	55,378	51,642	41,675	21,742	3,837
U.S.Insurance | 2009 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	50,625	50,545	49,870	50,694	48,488	47,204	49,650	55,277	58,500	62,044
Total IBNR	$ 105
Number of Reported Claims | Claim	2,334
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 49,543	49,252	48,634	45,952	45,106	42,528	40,763	34,769	28,714	12,857
U.S.Insurance | 2009 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	152,609	150,614	151,298	148,126	147,405	142,348	136,835	131,636	130,391	127,749
Total IBNR	$ 4,699
Number of Reported Claims | Claim	8,603
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 144,224	139,768	137,576	130,402	124,908	111,571	87,622	56,453	33,601	$ 11,335
U.S.Insurance | 2010 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	87,687	86,164	85,348	86,787	74,535	75,619	68,375	64,020	52,302
Total IBNR	$ 477
Number of Reported Claims | Claim	1,430
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 85,158	84,529	84,511	82,013	59,765	54,019	46,868	23,147	2,981
U.S.Insurance | 2010 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	55,687	55,316	55,478	55,974	51,791	53,684	59,219	63,221	64,212
Total IBNR	$ 67
Number of Reported Claims | Claim	2,011
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 54,612	54,321	54,163	50,963	47,173	42,017	39,081	31,769	16,258
U.S.Insurance | 2010 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	110,940	111,136	108,894	105,989	104,094	101,134	95,133	97,037	97,426
Total IBNR	$ 5,939
Number of Reported Claims | Claim	7,981
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 100,698	98,053	91,559	86,665	78,243	65,972	47,222	27,036	$ 12,310
U.S.Insurance | 2011 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	82,754	82,558	79,136	79,181	73,028	70,240	62,087	58,116
Total IBNR	$ 715
Number of Reported Claims | Claim	1,726
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 78,382	78,258	75,641	65,710	59,576	43,551	23,878	3,204
U.S.Insurance | 2011 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	58,237	59,151	59,709	61,258	62,464	66,900	68,967	69,652
Total IBNR	$ (95)
Number of Reported Claims | Claim	1,916
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 57,879	57,992	57,350	56,405	51,897	48,443	39,707	14,925
U.S.Insurance | 2011 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	102,403	101,061	98,857	91,267	90,301	87,297	78,420	80,399
Total IBNR	$ 9,172
Number of Reported Claims | Claim	6,623
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 85,885	80,248	71,065	59,038	47,150	30,766	14,694	$ 3,660
U.S.Insurance | 2012 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	58,040	58,563	58,344	55,917	57,097	54,480	61,196
Total IBNR	$ 1,657
Number of Reported Claims | Claim	2,175
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 55,215	54,728	49,675	44,028	35,681	22,635	3,855
U.S.Insurance | 2012 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	72,896	70,573	70,057	68,546	71,941	87,253	84,927
Total IBNR	$ 1,774
Number of Reported Claims | Claim	1,863
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 69,007	68,750	66,950	60,486	54,470	46,215	27,254
U.S.Insurance | 2012 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	118,647	111,459	107,526	99,502	91,780	90,111	103,437
Total IBNR	$ 14,122
Number of Reported Claims | Claim	4,664
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 91,557	83,215	67,772	47,253	27,717	17,404	4,761
U.S.Insurance | 2013 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	58,855	54,228	48,298	49,104	54,982	60,899
Total IBNR	$ 3,230
Number of Reported Claims | Claim	1,984
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 50,909	47,062	38,876	32,904	22,167	4,677
U.S.Insurance | 2013 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	54,033	55,886	53,987	51,464	57,598	60,887
Total IBNR	$ (882)
Number of Reported Claims | Claim	1,818
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 51,245	51,041	46,782	41,281	35,350	17,789
U.S.Insurance | 2013 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	156,793	149,841	137,692	129,385	126,220	139,986
Total IBNR	$ 14,770
Number of Reported Claims | Claim	4,040
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 136,446	118,932	84,874	48,923	21,035	7,188
U.S.Insurance | 2014 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	43,585	41,936	39,699	35,749	49,899
Total IBNR	$ 4,590
Number of Reported Claims | Claim	2,016
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 37,780	35,008	29,309	14,319	2,304
U.S.Insurance | 2014 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	49,366	44,985	40,211	41,454	58,009
Total IBNR	$ 603
Number of Reported Claims | Claim	1,951
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 44,852	40,487	34,453	23,162	10,677
U.S.Insurance | 2014 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	167,782	156,149	149,462	160,828	192,897
Total IBNR	$ 36,292
Number of Reported Claims | Claim	4,154
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 113,585	75,618	44,999	13,569	5,269
U.S.Insurance | 2015 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	35,186	30,802	30,486	31,375
Total IBNR	$ 4,712
Number of Reported Claims | Claim	1,680
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 23,321	18,303	11,173	2,256
U.S.Insurance | 2015 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	48,027	49,341	50,837	59,296
Total IBNR	$ 338
Number of Reported Claims | Claim	2,257
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 43,897	39,927	30,565	16,801
U.S.Insurance | 2015 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	235,390	215,822	220,278	246,404
Total IBNR	$ 39,530
Number of Reported Claims | Claim	4,115
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 142,655	79,639	24,579	3,719
U.S.Insurance | 2016 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	41,299	36,036	41,053
Total IBNR	$ 5,266
Number of Reported Claims | Claim	1,813
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 31,563	18,283	2,351
U.S.Insurance | 2016 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	46,817	47,254	51,289
Total IBNR	$ 2,187
Number of Reported Claims | Claim	2,534
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 38,163	24,566	11,587
U.S.Insurance | 2016 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	242,986	245,905	273,693
Total IBNR	$ 133,717
Number of Reported Claims | Claim	3,772
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 65,439	30,124	5,885
U.S.Insurance | 2017 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	44,346	50,825
Total IBNR	$ 22,367
Number of Reported Claims | Claim	1,980
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 16,246	2,613
U.S.Insurance | 2017 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	49,961	52,135
Total IBNR	$ 10,634
Number of Reported Claims | Claim	2,389
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 32,341	18,861
U.S.Insurance | 2017 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	259,919	298,195
Total IBNR	$ 183,018
Number of Reported Claims | Claim	3,851
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 40,012	13,014
U.S.Insurance | 2018 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	54,629
Total IBNR	$ 46,916
Number of Reported Claims | Claim	2,017
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 2,719
U.S.Insurance | 2018 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	49,188
Total IBNR	$ 28,204
Number of Reported Claims | Claim	1,735
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 11,010
U.S.Insurance | 2018 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	335,885
Total IBNR	$ 301,480
Number of Reported Claims | Claim	3,514
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 16,752
International Insurance | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	292,082
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	129,747
Net reserves lesser than 2009	265
Total Net reserves	$ 162,600
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	5.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	9.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	16.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	21.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	27.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	2.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	39.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	0.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	2.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	1.20%
International Insurance | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 967,713
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	759,286
Net reserves lesser than 2009	6,028
Total Net reserves	$ 214,455
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	24.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	34.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	18.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	6.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	6.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	1.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	1.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	0.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	0.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	0.00%
International Insurance | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 442,448
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	359,630
Net reserves lesser than 2009	4,550
Total Net reserves	$ 87,368
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	25.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	34.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	24.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	10.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	4.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	3.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	(0.40%)
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	4.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	0.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	3.90%
International Insurance | 2009 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 14,496	15,711	15,752	16,785	17,143	17,061	16,528
Total IBNR	$ 118
Number of Reported Claims | Claim	624
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 14,842	14,674	14,136	13,842	12,857	10,804	8,879
International Insurance | 2009 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	82,896	80,930	81,296	82,730	89,667	90,880	95,612
Total IBNR	$ 2,065
Number of Reported Claims | Claim	4,908
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 78,044	78,007	76,752	76,050	72,605	69,853	65,715
International Insurance | 2009 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	34,679	34,305	34,049	40,488	40,776	40,687	38,479
Total IBNR	$ (100)
Number of Reported Claims | Claim	1,038
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 34,711	33,359	33,276	33,180	33,538	33,079	28,790
International Insurance | 2010 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	16,245	14,376	15,611	14,066	14,076	13,935	14,388
Total IBNR	$ 13
Number of Reported Claims | Claim	746
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 13,566	13,419	13,412	12,688	10,556	7,256	5,861
International Insurance | 2010 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	107,443	107,400	111,165	113,877	118,028	128,878	130,924
Total IBNR	$ 330
Number of Reported Claims | Claim	5,231
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 102,841	102,597	102,161	99,875	95,906	89,896	77,626
International Insurance | 2010 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	40,594	42,285	42,528	41,911	41,628	42,234	42,807
Total IBNR	$ (240)
Number of Reported Claims | Claim	1,026
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 41,505	41,405	40,935	40,818	43,112	40,576	34,935
International Insurance | 2011 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	10,704	12,622	6,872	8,817	19,213	17,971	15,310
Total IBNR	$ 3
Number of Reported Claims | Claim	666
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 16,430	16,367	4,613	4,038	2,965	2,020	1,211
International Insurance | 2011 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	72,008	73,508	73,181	77,099	81,617	84,959	99,374
Total IBNR	$ 107
Number of Reported Claims | Claim	4,855
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 69,962	69,287	68,951	67,988	63,084	58,695	45,400
International Insurance | 2011 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	59,050	54,798	59,238	59,237	59,128	61,290	71,160
Total IBNR	$ (215)
Number of Reported Claims | Claim	1,030
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 58,422	51,940	53,963	53,034	50,480	47,594	38,362
International Insurance | 2012 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	21,691	17,886	16,970	13,302	12,665	11,433	6,810
Total IBNR	$ 2
Number of Reported Claims | Claim	1,107
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 7,675	6,818	7,423	5,533	4,251	3,207	2,123
International Insurance | 2012 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	93,931	91,844	91,991	98,960	106,553	131,234	109,784
Total IBNR	$ 272
Number of Reported Claims | Claim	5,368
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 84,744	82,370	80,449	77,847	69,811	54,300	23,088
International Insurance | 2012 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	32,069	32,830	32,376	32,242	36,167	37,168	45,287
Total IBNR	$ (251)
Number of Reported Claims | Claim	921
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 32,041	31,389	31,136	29,937	26,904	21,436	13,171
International Insurance | 2013 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	15,529	16,575	15,546	14,469	4,232	10,250
Total IBNR	$ 0
Number of Reported Claims | Claim	1,181
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 14,334	13,676	9,349	3,042	2,263	726
International Insurance | 2013 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	79,832	83,094	81,072	81,807	93,736	87,215
Total IBNR	$ 669
Number of Reported Claims | Claim	5,052
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 68,443	66,900	64,075	57,973	45,992	23,455
International Insurance | 2013 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	34,656	35,185	34,221	36,307	37,182	35,862
Total IBNR	$ 154
Number of Reported Claims | Claim	1,298
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 32,715	30,067	28,484	25,649	18,294	7,093
International Insurance | 2014 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	25,411	21,438	23,663	24,419	20,607
Total IBNR	$ 6,564
Number of Reported Claims | Claim	1,775
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 20,192	8,799	5,158	2,464	1,373
International Insurance | 2014 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	112,498	118,195	115,909	117,228	104,464
Total IBNR	$ (6,412)
Number of Reported Claims | Claim	5,125
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 104,801	89,506	80,943	56,964	29,625
International Insurance | 2014 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	17,517	16,363	20,417	22,200	26,741
Total IBNR	$ (497)
Number of Reported Claims | Claim	1,273
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 17,626	16,709	13,150	8,948	3,864
International Insurance | 2015 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	40,182	35,144	30,322	28,132
Total IBNR	$ 5,923
Number of Reported Claims | Claim	2,483
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 21,128	17,242	5,864	3,417
International Insurance | 2015 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	99,103	95,449	94,055	98,245
Total IBNR	$ (1,843)
Number of Reported Claims | Claim	7,664
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 80,684	75,185	53,995	22,651
International Insurance | 2015 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	32,566	33,703	36,391	34,678
Total IBNR	$ (86)
Number of Reported Claims | Claim	2,045
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 30,659	29,420	18,293	6,780
International Insurance | 2016 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	35,873	34,074	36,103
Total IBNR	$ 15,285
Number of Reported Claims | Claim	3,212
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 10,931	6,857	2,051
International Insurance | 2016 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	89,992	94,464	87,690
Total IBNR	$ 1,561
Number of Reported Claims | Claim	10,085
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 66,912	54,708	23,357
International Insurance | 2016 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	74,382	91,431	78,827
Total IBNR	$ 987
Number of Reported Claims | Claim	3,800
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 66,743	55,287	25,971
International Insurance | 2017 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	45,128	47,610
Total IBNR	$ 32,642
Number of Reported Claims | Claim	3,642
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 5,881	1,992
International Insurance | 2017 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	135,759	107,151
Total IBNR	$ 15,783
Number of Reported Claims | Claim	12,028
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 77,451	28,774
International Insurance | 2017 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	70,448	56,376
Total IBNR	$ 15,782
Number of Reported Claims | Claim	3,209
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 35,628	14,875
International Insurance | 2018 | Professional Liability
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	66,823
Total IBNR	$ 55,207
Number of Reported Claims | Claim	2,031
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 4,768
International Insurance | 2018 | Marine
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	94,251
Total IBNR	$ 16,778
Number of Reported Claims | Claim	7,603
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 25,404
International Insurance | 2018 | Property Casualty
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	46,487
Total IBNR	$ 15,981
Number of Reported Claims | Claim	1,053
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 9,580
Global Reinsurance
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	905,235
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	732,710
Net reserves lesser than 2009	1,870
Total Net reserves	$ 174,395
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 1	28.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 2	34.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 3	6.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 4	5.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 5	9.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 6	2.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 7	0.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 8	0.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 9	0.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance 10	0.70%
Global Reinsurance | 2009
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	$ 10,610	10,307	10,466	10,426	11,171	11,290	11,158
Total IBNR	$ 338
Number of Reported Claims | Claim	201
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 10,118	10,049	10,049	9,939	8,992	8,865	8,635
Global Reinsurance | 2010
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	13,073	13,012	12,476	11,796	14,012	12,997	13,036
Total IBNR	$ 21
Number of Reported Claims | Claim	202
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 11,203	11,170	11,105	11,058	10,439	10,263	9,927
Global Reinsurance | 2011
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	73,474	73,428	72,782	73,528	76,054	76,261	53,778
Total IBNR	$ (586)
Number of Reported Claims | Claim	740
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 72,743	72,345	72,177	72,038	71,754	71,086	43,412
Global Reinsurance | 2012
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	118,477	119,565	114,856	88,203	92,584	99,019	107,134
Total IBNR	$ (1,218)
Number of Reported Claims | Claim	1,395
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 118,006	117,631	111,816	84,668	83,287	77,147	$ 37,709
Global Reinsurance | 2013
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	101,705	102,323	105,049	102,514	118,688	114,785
Total IBNR	$ (561)
Number of Reported Claims | Claim	1,271
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 100,981	99,965	98,393	90,649	82,641	$ 53,445
Global Reinsurance | 2014
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	114,981	118,131	121,591	141,968	119,351
Total IBNR	$ 860
Number of Reported Claims | Claim	1,172
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 111,712	108,693	105,574	119,195	$ 66,271
Global Reinsurance | 2015
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	93,693	94,187	91,526	101,626
Total IBNR	$ 5,777
Number of Reported Claims | Claim	1,033
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 82,942	76,837	64,425	$ 41,623
Global Reinsurance | 2016
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	97,921	90,567	88,401
Total IBNR	$ 5,781
Number of Reported Claims | Claim	1,022
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 84,245	66,141	$ 36,312
Global Reinsurance | 2017
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	153,017	129,001
Total IBNR	$ 19,356
Number of Reported Claims | Claim	1,018
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 115,743	$ 43,639
Global Reinsurance | 2018
Claims Development [Line Items]
Loss and ALAE, Net of Reinsurance	128,284
Total IBNR	$ 83,977
Number of Reported Claims | Claim	435
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 25,017