Losses and Loss Expenses (Tables)

12 Months Ended

Dec. 31, 2016

Segment Reporting Information [Line Items]

Reserve roll forward

The following table represents a reconciliation of the beginning and ending balances of unpaid losses and loss expenses, including an analysis of the Company’s paid and unpaid losses and loss expenses incurred for the years indicated:

(U.S. dollars in thousands)	2016			2015			2014
Unpaid losses and loss expenses at the beginning of the year	$	25,439,744		$	19,353,243		$	20,481,065
Unpaid losses and loss expenses recoverable (1)	5,248,905			3,411,528			3,414,735
Net unpaid losses and loss expenses at the beginning of the year	$	20,190,839		$	15,941,715		$	17,066,330
Acquired reserves	101,315			5,439,876			—
Increase (decrease) in net losses and loss expenses incurred in respect of losses occurring in:
Current year	6,374,377			5,072,830			3,513,465
Prior year	(301,542		)	(306,630		)	(255,072		)
Total net incurred losses and loss expenses	6,072,835			4,766,200			3,258,393
Exchange rate effects	(571,198		)	(582,300		)	(561,673		)
Less net losses and loss expenses paid in respect of losses occurring in:
Current year	1,444,251			1,047,277			381,008
Prior year	3,890,269			4,327,375			3,440,327
Total net paid losses	$	5,334,520		$	5,374,652		$	3,821,335
Net unpaid losses and loss expenses at the end of the year	20,459,271			20,190,839			15,941,715
Unpaid losses and loss expenses recoverable (1)	5,480,300			5,248,905			3,411,528
Unpaid losses and loss expenses at the end of the year	$	25,939,571		$	25,439,744		$	19,353,243

____________

(1) Property and Casualty business only. See Note 12, "Reinsurance," for further information.

Components of reserves

Unpaid losses and loss expenses prior to reinsurance recoveries for the indicated years ended December 31 comprise the following:

(U.S. dollars in thousands)	2016		2015
Reserve for reported losses and loss expenses	$	10,343,481	$	10,293,448
Reserve for losses incurred but not reported	15,596,090		15,146,296
Unpaid losses and loss expenses	$	25,939,571	$	25,439,744

Incurred and paid claims development

Total Property and Casualty

(in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	4,632,657	$	4,806,850	$	4,718,961	$	4,684,540	$	4,689,256	$	4,569,019	$	4,541,978	$	4,519,599	$	4,432,150	$	4,390,981	$	246,827	N/A
2008			5,504,796		5,575,015		5,503,422		5,524,325		5,479,907		5,449,364		5,417,072		5,357,648		5,322,204		307,738		N/A
2009					4,622,547		4,627,569		4,542,408		4,556,902		4,550,362		4,550,542		4,422,167		4,392,904		317,583		N/A
2010							4,983,044		5,111,634		5,002,061		5,026,101		4,974,782		4,957,474		4,981,939		464,306		N/A
2011									6,236,775		6,187,474		6,111,779		5,980,635		6,116,046		6,083,796		558,008		N/A
2012											5,697,958		5,660,616		5,640,576		5,754,387		5,663,926		715,827		N/A
2013													5,558,316		5,554,791		5,523,695		5,426,144		1,082,491		N/A
2014															5,183,056		5,369,393		5,397,264		1,396,883		N/A
2015																	5,354,494		5,498,206		1,962,006		N/A
2016																			6,005,506		3,425,518		N/A
																			$	53,162,870	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	521,083	$	1,289,961	$	2,055,288	$	2,587,918	$	3,126,834	$	3,397,370	$	3,612,934	$	3,744,872	$	3,822,207	$	3,894,280
2008			788,760		1,994,235		2,857,474		3,446,415		3,947,203		4,240,640		4,450,875		4,582,409		4,700,567
2009					638,179		1,530,295		2,192,791		2,655,163		3,117,922		3,366,917		3,551,474		3,663,224
2010							840,030		1,855,407		2,645,868		3,144,278		3,521,163		3,851,827		4,084,244
2011									1,246,596		2,872,319		3,664,970		4,242,053		4,737,827		5,021,000
2012											952,158		2,256,973		3,149,842		3,802,042		4,199,766
2013													976,023		2,194,912		3,049,907		3,614,076
2014															957,525		2,250,446		3,090,343
2015																	970,277		2,152,569
2016																			1,192,137
																			$	35,612,206
	All outstanding liabilities prior to 2007, net of reinsurance																		2,501,779
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	20,052,443

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	17	%	22	%	15	%	10	%	9	%	6	%	3	%	3	%	3	%	1	%

Reconciliation of claims development to liability

Reconciliation

(U.S. dollars in thousands)	December 31, 2016
Net outstanding liabilities
Insurance Segment
EPC	$	1,235,716
Specialty	1,801,962
Professional	3,951,383
Casualty and other	6,354,077
Reinsurance Segment
Property and Other Short-Tail lines	2,201,173
Casualty and Other Long-Tail lines	4,508,132
Subtotal, disaggregated triangles	$	20,052,443
Unallocated loss expenses	482,680
Discount (1)	(413,522		)
Provision for uncollectible reinsurance	42,119
Other	295,551
Total net liability for unpaid losses and loss expenses	20,459,271
Reinsurance recoverable on unpaid losses
Insurance Segment
EPC	$	486,595
Specialty	524,545
Professional	1,195,720
Casualty	2,836,800
Reinsurance Segment
Property and Other Short-Tail lines	242,845
Casualty and Other Long-Tail lines	122,190
Other	71,605
Total recoverable on unpaid losses and loss expenses	$	5,480,300
Unpaid losses and loss expenses	$	25,939,571

____________

(1) As noted in Note 10(c), "Losses and Loss Expenses - Loss Reserve Discounting," the Company discounts only certain workers’ compensation (including long term disability) liabilities and certain bodily injury liability claims, emanating from U.K. exposures, predominantly from the U.K. motor liability portfolio.

Components of incurred losses and loss expenses

Net losses and loss expenses incurred for the years indicated are comprised of:

(U.S. dollars in thousands)	2016			2015			2014
Loss and loss expenses payments	$	6,828,012		$	6,505,075		$	4,499,642
Change in unpaid losses and loss expenses	976,401			(168,263		)	(514,406		)
Change in unpaid losses and loss expenses recoverable	(238,086		)	(440,189		)	(48,536		)
Paid loss recoveries	(1,493,492		)	(1,130,423		)	(678,307		)
Net losses and loss expenses incurred	$	6,072,835		$	4,766,200		$	3,258,393

Schedule of causes of increase (decrease) in liability for unpaid claims and claims adjustment expense [Table Text Block]

The following table presents the net (favorable) adverse prior year loss development of the Company’s loss and loss expense reserves for its property and casualty operations by operating segment for each of the years indicated:

(U.S. dollars in thousands)	2016			2015			2014
Insurance segment	$	(91,459	)	$	(65,030	)	$	(99,758	)
Reinsurance segment	(210,083		)	(241,600		)	(155,314		)
Total	$	(301,542	)	$	(306,630	)	$	(255,072	)

Asbestos and environmental related claims rollforward

A reconciliation of the opening and closing unpaid losses and loss expenses related to discontinued asbestos and run-off environmental exposure claims for the years indicated is as follows:

Year ended December 31, (U.S. dollars in thousands)	2016			2015		2014
Net unpaid losses and loss expenses at beginning of year	$	93,704		$	81,416	$	80,435
Net incurred losses and loss expenses	9,042			15,663		8,903
Less net paid losses and loss expenses	9,912			9,087		7,922
Net increase (decrease) in unpaid losses and loss expenses	$	(870	)	$	6,576	$	981
Acquired reserves	—			5,712		—
Net unpaid losses and loss expenses at end of year	92,834			93,704		81,416
Unpaid losses and loss expenses recoverable at end of year	83,430			93,688		100,537
Gross unpaid losses and loss expenses at end of year	$	176,264		$	187,392	$	181,953

Schedule of open claims files for potential asbestos and environmental claims

The development of the number of open claim files for potential discontinued asbestos and run-off environmental claims, including precautionary claims, is as follows:

	Asbestos Claims		Environmental Claims
Total number of claims outstanding at December 31, 2013	1,097		338
New claims reported in 2014	456		190
Claims resolved in 2014	(154	)	(69	)
Total number of claims outstanding at December 31, 2014	1,399		459
New claims reported in 2015	272		67
Claims resolved in 2015	(246	)	(96	)
Reserves acquired in 2015	1,166		—
Total number of claims outstanding at December 31, 2015	2,591		430
New claims reported in 2016	579		69
Claims resolved in 2016	(753	)	(41	)
Total number of claims outstanding at December 31, 2016	2,417		458

Insurance Segment

Segment Reporting Information [Line Items]

Incurred and paid claims development

Insurance Segment

(in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	3,258,668	$	3,490,955	$	3,426,696	$	3,431,600	$	3,442,331	$	3,329,848	$	3,317,676	$	3,318,423	$	3,274,775	$	3,246,355	$	158,351	45.542
2008			3,891,682		3,969,259		3,935,499		3,974,071		3,918,450		3,889,538		3,857,758		3,822,133		3,786,671		186,723		54.952
2009					3,472,222		3,499,124		3,458,320		3,480,715		3,483,027		3,500,575		3,369,614		3,346,817		190,193		54.896
2010							3,702,458		3,809,102		3,699,234		3,735,809		3,688,045		3,661,919		3,697,761		313,815		61.416
2011									4,014,389		3,986,420		4,009,166		3,921,559		4,026,511		4,001,271		379,349		65.437
2012											3,870,871		3,799,876		3,800,046		3,921,415		3,851,259		468,002		70.919
2013													3,942,360		4,003,359		3,978,956		3,924,048		802,611		78.018
2014															3,748,154		3,917,364		3,978,436		1,052,314		87.491
2015																	3,849,731		4,039,203		1,418,476		94.229
2016																			4,160,269		2,358,172		65.684
																			$	38,032,090	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	367,171	$	930,428	$	1,462,857	$	1,884,318	$	2,333,047	$	2,549,256	$	2,715,861	$	2,822,610	$	2,896,977	$	2,943,144
2008			461,606		1,339,577		1,973,577		2,427,033		2,843,188		3,069,812		3,234,869		3,337,607		3,415,212
2009					462,090		1,140,796		1,666,673		2,043,196		2,432,021		2,634,783		2,787,167		2,865,558
2010							607,658		1,377,513		1,978,027		2,370,062		2,685,015		2,914,856		3,072,546
2011									649,690		1,617,155		2,216,640		2,653,619		3,062,399		3,290,213
2012											634,043		1,471,761		2,079,400		2,578,639		2,886,674
2013													657,753		1,509,232		2,141,332		2,597,422
2014															669,745		1,597,123		2,263,643
2015																	691,253		1,563,019
2016																			861,429
																			$	25,758,860
	All outstanding liabilities prior to 2007, net of reinsurance																		1,069,908
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	13,343,138

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	16	%	21	%	16	%	11	%	10	%	6	%	4	%	3	%	3	%	1	%

Components of prior year development

The following table summarizes the net (favorable) adverse prior year development by business group relating to the Insurance segment for the indicated years ended December 31:

(U.S. dollars in thousands)	2016			2015			2014
EPC	$	(38,366	)	$	(6,447	)	$	(57,465	)
Specialty	(5,655		)	(93,043		)	(82,756		)
Professional	$	10,813		$	5,740		$	17,092
Casualty and other	(58,251		)	28,720			23,371
Total	$	(91,459	)	$	(65,030	)	$	(99,758	)

Insurance Segment | Professional lines

Segment Reporting Information [Line Items]

Incurred and paid claims development

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	3	%	13	%	16	%	16	%	15	%	9	%	6	%	4	%	4	%	1	%

Average annual percentage payout of incurred losses by age

Professional (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	911,695	$	1,130,926	$	1,106,630	$	1,061,995	$	1,070,028	$	995,364	$	993,007	$	1,000,256	$	944,024	$	928,677	$	68,144	4.371
2008			1,033,982		1,087,436		1,131,685		1,221,906		1,195,931		1,174,486		1,167,289		1,136,720		1,114,924		60,568		5.187
2009					968,336		1,036,140		1,094,824		1,158,091		1,196,078		1,202,994		1,169,232		1,164,825		77,399		5.589
2010							989,432		984,780		957,486		1,035,571		996,024		1,016,013		1,061,340		113,635		5.418
2011									967,386		960,895		1,012,458		1,027,504		1,104,107		1,111,524		162,147		5.253
2012											976,450		976,593		1,011,363		1,124,437		1,117,970		212,997		5,320
2013													965,875		963,634		942,022		922,634		339,380		5.595
2014															747,671		799,952		843,003		371,270		5.969
2015																	755,087		800,568		493,667		6.391
2016																			730,198		654,395		3.704
																			$	9,795,663	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	25,207	$	111,289	$	240,287	$	421,654	$	540,255	$	612,498	$	692,492	$	738,301	$	776,445	$	801,141
2008			17,987		185,149		346,923		516,426		697,071		782,381		853,405		911,634		969,698
2009					22,350		161,125		337,568		507,629		745,836		838,990		922,453		948,015
2010							21,803		155,845		324,580		480,475		623,975		735,626		803,916
2011									28,625		144,365		315,130		480,248		683,043		815,129
2012											44,486		195,088		378,059		591,820		713,165
2013													36,582		152,052		304,503		457,890
2014															17,042		138,832		312,548
2015																	22,521		139,345
2016																			23,462
																			$	5,984,309
	All outstanding liabilities prior to 2007, net of reinsurance																		140,029
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	3,951,383

Insurance Segment | Casualty and other

Segment Reporting Information [Line Items]

Incurred and paid claims development

Casualty and other (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	1,082,033	$	1,112,540	$	1,087,608	$	1,166,693	$	1,175,846	$	1,159,030	$	1,163,024	$	1,179,115	$	1,171,058	$	1,162,152	$	85,633	17.237
2008			1,140,247		1,112,464		1,112,589		1,106,258		1,093,984		1,105,909		1,102,780		1,085,898		1,078,619		111,716		18.669
2009					1,116,831		1,101,930		1,089,006		1,083,830		1,064,751		1,089,350		1,048,630		1,041,605		104,475		20.836
2010							1,112,521		1,250,384		1,258,380		1,253,471		1,276,555		1,233,729		1,230,374		193,273		23.029
2011									1,092,125		1,139,829		1,160,676		1,134,783		1,160,467		1,138,849		175,768		24.942
2012											1,195,390		1,212,625		1,235,541		1,258,868		1,217,096		229,162		26.613
2013													1,295,006		1,344,357		1,403,279		1,375,254		407,549		29.179
2014															1,351,268		1,417,460		1,463,809		607,888		30.254
2015																	1,335,856		1,399,039		722,174		31.862
2016																			1,395,154		1,088,868		18.283
																			$	12,501,951	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	22,680	$	142,855	$	315,942	$	470,594	$	751,437	$	855,446	$	917,798	$	961,739	$	993,114	$	1,011,066
2008			46,589		175,724		384,593		557,222		673,130		771,029		843,167		886,979		898,297
2009					43,912		237,264		414,586		535,197		638,617		727,782		771,855		818,732
2010							101,673		292,403		516,383		649,167		759,673		862,584		937,451
2011									115,807		258,861		418,204		594,047		748,537		818,838
2012											117,735		297,186		471,949		644,936		775,521
2013													124,226		307,950		533,465		710,905
2014															133,592		335,216		555,967
2015																	109,217		282,670
2016																			103,727
																			$	6,913,174
	All outstanding liabilities prior to 2007, net of reinsurance																		765,300
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	6,354,077

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	7	%	14	%	16	%	13	%	13	%	8	%	5	%	4	%	3	%	3	%

Insurance Segment | EPC

Segment Reporting Information [Line Items]

Incurred and paid claims development

EPC (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)			Number of Claims
2007	$	439,938	$	394,730	$	385,373	$	365,395	$	364,454	$	361,632	$	358,820	$	357,009	$	356,106	$	355,709	$	(213	)	5,380
2008			841,913		834,562		806,976		782,005		777,476		769,906		774,108		768,610		767,031		10,701			9.013
2009					400,045		382,644		364,526		356,069		349,819		345,668		344,108		342,072		6,549			7.596
2010							596,340		611,917		589,119		571,375		565,494		574,091		568,574		(5,681		)	8.532
2011									979,353		911,684		890,820		857,510		846,315		842,481		7,165			10.172
2012											689,032		660,128		635,712		636,896		626,132		6,086			11.131
2013													740,573		715,909		690,102		684,578		9,763			12.141
2014															703,860		735,789		723,382		6,921			14.609
2015																	791,724		812,247		64,949			16.424
2016																			969,709		228,630			15.279
																			$	6,691,915	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	69,288	$	208,210	$	298,622	$	316,321	$	329,883	$	341,442	$	347,421	$	348,059	$	350,602	$	351,151
2008			152,946		467,537		604,163		653,749		730,513		748,607		752,294		747,374		750,022
2009					84,638		190,194		254,420		287,809		311,335		313,434		328,222		331,246
2010							166,353		380,649		476,832		526,375		543,985		542,011		547,486
2011									211,176		610,086		744,330		784,418		813,298		815,694
2012											161,117		389,827		531,299		574,467		593,981
2013													165,460		452,805		586,539		636,623
2014															180,735		504,925		645,682
2015																	224,497		484,431
2016																			324,575
																			$	5,480,891
	All outstanding liabilities prior to 2007, net of reinsurance																		24,692
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	1,235,716

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	26	%	38	%	20	%	6	%	5	%	1	%	1	%	—	%	1	%	1	%

Insurance Segment | Specialty

Segment Reporting Information [Line Items]

Incurred and paid claims development

Specialty (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	825,002	$	852,759	$	847,085	$	837,517	$	832,003	$	813,822	$	802,825	$	782,043	$	803,587	$	799,817	$	4,787	18.554
2008			875,540		934,797		884,249		863,902		851,059		839,237		813,581		830,905		826,097		3,738		22.083
2009					987,010		978,410		909,964		882,725		872,379		862,563		807,644		798,315		1,770		20.875
2010							1,004,165		962,021		894,249		875,392		849,972		838,086		837,473		12,588		24.437
2011									975,525		974,012		945,212		901,762		915,622		908,417		34,269		25,070
2012											1,009,999		950,530		917,430		901,214		890,061		19,757		27.855
2013													940,906		979,459		943,553		941,582		45,919		31.103
2014															945,355		964,163		948,242		66,235		36.659
2015																	967,064		1,027,349		137,686		39.552
2016																			1,065,208		386,279		28.418
																			$	9,042,561	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	249,996	$	468,074	$	608,006	$	675,749	$	711,472	$	739,870	$	758,150	$	774,511	$	776,816	$	779,786
2008			244,084		511,167		637,898		699,636		742,474		767,795		786,003		791,620		797,195
2009					311,190		552,213		660,099		712,561		736,233		754,577		764,637		767,565
2010							317,829		548,616		660,232		714,045		757,382		774,635		783,693
2011									294,082		603,843		738,976		794,906		817,521		840,552
2012											310,705		589,660		698,093		767,416		804,007
2013													331,485		596,425		716,825		792,004
2014															338,376		618,150		749,446
2015																	335,018		656,573
2016																			409,665
																			$	7,380,486
	All outstanding liabilities prior to 2007, net of reinsurance																		139,887
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	1,801,962

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	35	%	30	%	14	%	7	%	4	%	3	%	2	%	1	%	1	%	1	%

Reinsurance Segment

Segment Reporting Information [Line Items]

Incurred and paid claims development

Reinsurance Segment

(in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	1,373,989	$	1,315,895	$	1,292,265	$	1,252,940	$	1,246,925	$	1,239,171	$	1,224,302	$	1,201,176	$	1,157,375	$	1,144,626	$	88,476	N/A
2008			1,613,114		1,605,756		1,567,923		1,550,254		1,561,457		1,559,826		1,559,314		1,535,515		1,535,533		121,015		N/A
2009					1,150,325		1,128,445		1,084,088		1,076,187		1,067,335		1,049,967		1,052,553		1,046,087		127,390		N/A
2010							1,280,586		1,302,532		1,302,827		1,290,292		1,286,737		1,295,555		1,284,178		150,491		N/A
2011									2,222,386		2,201,054		2,102,613		2,059,076		2,089,535		2,082,525		178,659		N/A
2012											1,827,087		1,860,740		1,840,530		1,832,972		1,812,667		247,825		N/A
2013													1,615,956		1,551,432		1,544,739		1,502,096		279,880		N/A
2014															1,434,902		1,452,029		1,418,828		344,569		N/A
2015																	1,504,763		1,459,003		543,530		N/A
2016																			1,845,237		1,067,346		N/A
																			$	15,130,780	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	153,912	$	359,533	$	592,431	$	703,600	$	793,787	$	848,114	$	897,073	$	922,262	$	925,230	$	951,136
2008			327,154		654,658		883,897		1,019,382		1,104,015		1,170,828		1,216,006		1,244,802		1,285,355
2009					176,089		389,499		526,118		611,967		685,901		732,134		764,307		797,666
2010							232,372		477,894		667,841		774,216		836,148		936,971		1,011,698
2011									596,906		1,255,164		1,448,330		1,588,434		1,675,428		1,730,787
2012											318,115		785,212		1,070,442		1,223,403		1,313,092
2013													318,270		685,680		908,575		1,016,654
2014															287,780		653,323		826,700
2015																	279,024		589,550
2016																			330,708
																			$	9,853,346
	All outstanding liabilities prior to 2007, net of reinsurance																		1,431,871
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	6,709,305

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	20	%	24	%	15	%	8	%	5	%	4	%	1	%	2	%	3	%	1	%

Components of prior year development

The following table summarizes the net (favorable) adverse prior year development by line of business relating to the Reinsurance segment for the indicated years ended December 31:

(U.S. dollars in thousands)	2016			2015			2014
Property and Other Short-Tail Lines	$	(134,440	)	$	(173,754	)	$	(85,324	)
Casualty and Other Long-Tail Lines	(75,643		)	(67,846		)	(69,990		)
Total	$	(210,083	)	$	(241,600	)	$	(155,314	)

Reinsurance Segment | Property and other short-tail lines

Segment Reporting Information [Line Items]

Incurred and paid claims development

Property and Other Short-tail Lines (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	655,785	$	612,847	$	591,325	$	576,823	$	556,160	$	543,586	$	542,517	$	531,757	$	505,908	$	504,777	$	9,948	N/A
2008			922,391		913,108		893,143		870,757		855,385		851,340		855,891		849,351		856,596		22,281		N/A
2009					574,748		541,926		507,488		488,419		479,539		474,526		468,240		472,758		4,958		N/A
2010							821,119		842,728		846,563		852,550		857,788		840,206		840,582		26,847		N/A
2011									1,728,879		1,697,826		1,617,499		1,589,207		1,593,064		1,585,694		42,172		N/A
2012											1,268,108		1,294,768		1,285,569		1,255,565		1,243,866		69,188		N/A
2013													1,068,975		1,011,548		975,565		939,295		45,977		N/A
2014															865,668		855,081		814,558		57,491		N/A
2015																	878,711		829,691		163,854		N/A
2016																			1,140,759		531,843		N/A
																			$	9,228,576	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	128,299	$	274,682	$	427,810	$	470,765	$	487,471	$	491,862	$	503,233	$	497,701	$	478,062	$	483,023
2008			291,995		541,613		693,174		757,091		784,005		801,027		805,951		803,919		816,877
2009					145,413		307,294		389,835		421,579		441,032		445,905		445,861		453,626
2010							215,463		429,578		577,128		639,012		665,932		734,453		783,155
2011									581,324		1,196,404		1,344,405		1,432,899		1,472,992		1,493,813
2012											293,705		713,154		933,717		1,028,319		1,068,475
2013													291,534		604,497		768,385		819,523
2014															250,708		556,548		658,511
2015																	236,009		472,543
2016																			265,695
																			$	7,315,241
	All outstanding liabilities prior to 2007, net of reinsurance																		287,838
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	2,201,173

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	29	%	34	%	17	%	7	%	3	%	4	%	2	%	1	%	(1	)%	1	%

Reinsurance Segment | Casualty and Other Long-Tail Lines

Segment Reporting Information [Line Items]

Incurred and paid claims development

Casualty and Other Long-Tail Lines (in thousands)
Incurred Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,																				As of Dec 31, 2016
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016		IBNR (1)		Number of Claims
2007	$	718,204	$	703,048	$	700,940	$	676,117	$	690,765	$	695,585	$	681,785	$	669,419	$	651,467	$	639,849	$	78,528	N/A
2008			690,723		692,648		674,780		679,497		706,072		708,486		703,423		686,164		678,937		98,734		N/A
2009					575,577		586,519		576,600		587,768		587,796		575,441		584,313		573,329		122,432		N/A
2010							459,467		459,804		456,264		437,742		428,949		455,349		443,596		123,644		N/A
2011									493,507		503,228		485,114		469,869		496,471		496,831		136,487		N/A
2012											558,979		565,972		554,961		577,407		568,801		178,637		N/A
2013													546,981		539,884		569,174		562,801		233,903		N/A
2014															569,234		596,948		604,270		287,078		N/A
2015																	626,052		629,312		379,676		N/A
2016																			704,478		535,503		N/A
																			$	5,902,204	Total
Cumulative Paid Losses and Allocated Loss Expenses, Net of Reinsurance
	For the Years Ended December 31,
	Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited		Unaudited
Accident Year	2007		2008		2009		2010		2011		2012		2013		2014		2015		2016
2007	$	25,613	$	84,851	$	164,621	$	232,835	$	306,316	$	356,252	$	393,840	$	424,561	$	447,168	$	468,113
2008			35,159		113,045		190,723		262,291		320,010		369,801		410,055		440,883		468,478
2009					30,676		82,205		136,283		190,388		244,869		286,229		318,446		344,040
2010							16,909		48,316		90,713		135,204		170,216		202,518		228,543
2011									15,582		58,760		103,925		155,535		202,436		236,974
2012											24,410		72,058		136,725		195,084		244,617
2013													26,736		81,183		140,190		197,131
2014															37,072		96,775		168,189
2015																	43,015		117,007
2016																			65,013
																			$	2,538,105
	All outstanding liabilities prior to 2007, net of reinsurance																		1,144,033
	Liabilities for unpaid losses and loss expenses, net of reinsurance																		$	4,508,132

Average annual percentage payout of incurred losses by age

Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance
	Year 1		Year 2		Year 3		Year 4		Year 5		Year 6		Year 7		Year 8		Year 9		Year 10
	5	%	9	%	10	%	10	%	9	%	7	%	7	%	6	%	6	%	4	%