RESERVES FOR LOSSES AND LOSS SETTLEMENT EXPENSES (Tables)

12 Months Ended

Dec. 31, 2017

Insurance Loss Reserves [Abstract]

Schedule of Liability for Unpaid Claims and Claims Adjustment Expense

The following table provides an analysis of changes in our property and casualty losses and loss settlement expense reserves for 2017, 2016 and 2015 (net of reinsurance amounts):

Years Ended December 31,	2017			2016			2015
Gross liability for losses and loss settlement expenses at beginning of year	$	1,123,896		$	1,003,895		$	969,437
Ceded losses and loss settlement expenses	(59,794		)	(54,653		)	(63,757		)
Net liability for losses and loss settlement expenses at beginning of year	$	1,064,102		$	949,242		$	905,680
Losses and loss settlement expenses incurred for claims occurring during
Current year	$	779,966		$	683,662		$	560,482
Prior years	(54,253		)	(31,229		)	(40,395		)
Total incurred	$	725,713		$	652,433		$	520,087
Losses and loss settlement expense payments for claims occurring during
Current year	$	311,972		$	277,053		$	225,022
Prior years	313,531			260,520			251,503
Total paid	$	625,503		$	537,573		$	476,525
Net liability for losses and loss settlement expenses at end of year	$	1,164,312		$	1,064,102		$	949,242
Ceded loss and loss settlement expenses	59,871			59,794			54,653
Gross liability for losses and loss settlement expenses at end of year	$	1,224,183		$	1,123,896		$	1,003,895

Short-duration Insurance Contracts, Claims Development

The following tables provide information about incurred and paid losses and loss settlement expense development as of December 31, 2017, net of reinsurance, as well as cumulative development, cumulative claim frequency and IBNR liabilities. Claim data for Mercer Insurance Group, which was acquired on March 28, 2011, is presented retrospectively.

The cumulative number of reported claims, for calendar year 2017 and 2016, are counted for all lines of business on a per claimant per coverage basis and a single event may result in multiple claims due to the involvement of multiple individual claimants and / or multiple independent coverages. Claim counts for calendar years 2015 and prior are counted on a per claim and per coverage basis. Claim counts include open claims, claims that have been paid and closed, and reported claims that have been closed without the need for any payment.

Line of business: Commercial other liability
	Incurred losses and allocated loss settlement expenses, net of reinsurance																				As of December 31, 2017
	For the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported claims		Cumulative development		Cumulative number of reported claims
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	79,455	$	84,944	$	81,963	$	73,892	$	63,231	$	78,152	$	75,178	$	74,115	$	74,915	$	75,364	$	12,636	(4,091	)	6,734
2009			88,298		85,991		73,545		65,831		84,286		83,660		85,761		86,757		86,543		11,268		(1,755	)	6,123
2010					88,987		69,533		65,299		82,865		78,564		77,948		78,291		78,498		14,468		(10,489	)	5,174
2011							81,522		64,738		88,371		88,200		79,591		80,801		81,463		15,016		(59	)	5,328
2012									100,389		96,158		94,195		91,980		92,537		91,346		18,407		(9,043	)	5,540
2013											104,982		91,460		90,502		86,119		85,399		9,697		(19,583	)	6,007
2014													118,928		117,958		106,486		97,809		13,583		(21,119	)	6,109
2015															137,386		125,307		120,005		25,634		(17,381	)	7,083
2016																	139,144		130,041		35,760		(9,103	)	7,512
2017																			139,602		68,465				5,833
																	Total		$	986,070

Line of business: Commercial other liability
	Cumulative paid losses and allocated loss settlement expenses, net of reinsurance
	For the years ended December 31,
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	9,220	$	24,096	$	34,482	$	42,545	$	47,112	$	50,143	$	52,659	$	55,843	$	59,052	$	60,698
2009			8,375		21,151		32,073		41,696		50,098		56,789		63,149		67,733		70,814
2010					7,103		15,230		24,577		35,043		51,336		56,761		60,116		62,070
2011							6,236		13,670		26,260		40,595		50,146		56,150		62,165
2012									6,875		24,620		39,948		55,316		64,574		69,800
2013											9,835		25,228		39,953		54,559		65,773
2014													10,207		29,679		50,211		70,363
2015															11,185		27,182		53,901
2016																	13,782		38,184
2017																			17,716
																	Total		$	571,484
					All outstanding liabilities for unpaid losses and loss settlement expenses before 2008, net of reinsurance														29,167
					Liabilities for unpaid losses and loss settlement expenses, net of reinsurance														$	443,753

Line of business: Commercial fire and allied
	Incurred losses and allocated loss settlement expenses, net of reinsurance																				As of December 31, 2017
	For the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported claims		Cumulative development		Cumulative number of reported claims
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	157,303	$	141,384	$	138,602	$	140,321	$	134,821	$	116,940	$	118,115	$	118,376	$	118,329	$	118,308	$	44	(38,995	)	21,101
2009			113,754		106,085		105,031		105,614		87,751		87,845		87,932		88,891		89,027		154		(24,727	)	18,038
2010					113,139		106,152		108,246		83,836		83,932		83,767		83,981		84,213		229		(28,926	)	16,671
2011							148,220		142,330		117,082		120,492		119,820		120,219		121,434		611		(26,786	)	16,026
2012									138,602		110,448		108,774		108,047		107,958		108,623		970		(29,979	)	6,408
2013											91,521		88,550		91,498		92,212		93,826		1,139		2,305		6,598
2014													126,216		131,198		128,762		128,185		1,397		1,969		7,827
2015															103,177		108,293		110,633		3,370		7,456		7,465
2016																	147,473		144,208		3,597		(3,265	)	9,496
2017																			155,139		16,178				11,574
																	Total		$	1,153,596

Line of business: Commercial fire and allied
	Cumulative paid losses and allocated loss settlement expenses, net of reinsurance
	For the years ended December 31,
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	80,005	$	102,804	$	107,480	$	112,678	$	115,804	$	115,897	$	117,553	$	117,690	$	118,003	$	118,059
2009			53,219		72,181		77,732		82,809		86,930		87,544		87,721		88,037		88,159
2010					52,660		72,271		78,284		80,352		82,037		83,000		83,374		83,915
2011							85,585		104,800		109,429		112,497		116,614		118,183		120,178
2012									71,008		94,380		100,078		103,197		105,250		106,521
2013											59,331		78,226		82,853		86,115		89,200
2014													84,456		113,663		116,750		122,370
2015															67,217		90,454		95,515
2016																	92,895		125,962
2017																			99,484
																	Total		$	1,049,363
					All outstanding liabilities for unpaid losses and loss settlement expenses before 2008, net of reinsurance														573
					Liabilities for unpaid losses and loss settlement expenses, net of reinsurance														$	104,806

Line of business: Commercial automobile
	Incurred losses and allocated loss settlement expenses, net of reinsurance																				As of December 31, 2017
	For the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported claims		Cumulative development		Cumulative number of reported claims
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	80,461	$	78,391	$	76,051	$	76,527	$	75,070	$	75,021	$	73,506	$	73,431	$	73,463	$	73,487	$	12	(6,974	)	18,114
2009			80,021		69,328		68,569		64,121		64,516		63,605		63,560		63,567		63,509		—		(16,512	)	15,019
2010					75,781		68,068		65,860		67,015		67,563		67,296		68,086		67,910		17		(7,871	)	16,245
2011							84,887		87,299		90,750		92,519		92,379		91,336		90,766		311		5,879		15,246
2012									100,039		90,848		94,755		95,321		96,594		96,389		488		(3,650	)	14,353
2013											104,356		98,037		102,943		103,726		104,980		1,310		624		15,504
2014													107,723		106,076		113,720		118,869		3,634		11,146		17,222
2015															125,506		129,816		132,206		7,874		6,700		19,875
2016																	174,018		175,357		21,439		1,339		26,662
2017																			227,919		58,850				28,858
																	Total		$	1,151,392

Line of business: Commercial automobile
	Cumulative paid losses and allocated loss settlement expenses, net of reinsurance
	For the years ended December 31,
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	30,527	$	47,271	$	58,926	$	68,629	$	70,459	$	72,122	$	72,984	$	72,990	$	73,018	$	73,394
2009			27,674		44,867		53,451		58,087		61,398		62,732		63,495		63,503		63,508
2010					29,329		41,141		52,953		57,947		62,231		65,169		67,622		67,852
2011							34,332		50,931		65,021		79,383		85,348		87,475		88,609
2012									39,247		57,201		71,469		82,944		90,292		93,179
2013											43,592		67,630		79,663		90,780		96,375
2014													45,704		68,033		87,590		99,922
2015															50,782		78,225		99,201
2016																	66,013		103,528
2017																			81,311
																	Total		$	866,879
					All outstanding liabilities for unpaid losses and loss settlement expenses before 2008, net of reinsurance														39
					Liabilities for unpaid losses and loss settlement expenses, net of reinsurance														$	284,552

Line of business: Workers' compensation
	Incurred losses and allocated loss settlement expenses, net of reinsurance																				As of December 31, 2017
	For the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported claims		Cumulative development		Cumulative number of reported claims
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	42,739	$	42,301	$	39,895	$	41,278	$	40,474	$	40,010	$	39,386	$	39,680	$	39,768	$	38,664	$	499	(4,075	)	5,057
2009			43,560		39,009		36,294		36,837		36,823		36,158		36,014		35,026		35,012		489		(8,548	)	4,264
2010					38,210		42,531		41,180		41,167		40,647		41,422		41,468		42,617		596		4,407		3,978
2011							39,967		38,481		35,352		34,309		33,585		33,314		33,352		747		(6,615	)	3,930
2012									48,848		46,279		42,158		38,423		38,553		39,015		754		(9,833	)	3,813
2013											64,048		62,579		56,369		54,584		52,761		975		(11,287	)	4,173
2014													64,051		60,729		58,284		56,630		1,409		(7,421	)	4,593
2015															53,788		55,578		51,003		1,753		(2,785	)	5,311
2016																	70,419		66,575		3,392		(3,844	)	6,732
2017																			76,184		7,317				5,460
																	Total		$	491,813

Line of business: Workers' compensation
	Cumulative paid losses and allocated loss settlement expenses, net of reinsurance
	For the years ended December 31,
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	10,082	$	21,227	$	25,736	$	30,123	$	31,980	$	33,770	$	34,319	$	34,862	$	35,292	$	36,010
2009			10,478		20,292		24,189		27,747		29,898		31,003		31,886		32,911		33,117
2010					11,821		22,606		28,765		31,887		33,119		34,143		35,052		38,973
2011							10,322		21,678		26,033		27,497		28,247		29,022		29,453
2012									11,802		23,023		28,397		30,933		33,063		34,330
2013											14,136		30,209		38,023		42,941		45,078
2014													13,965		30,289		38,441		42,964
2015															12,063		27,304		35,229
2016																	14,413		32,345
2017																			14,647
																	Total		$	342,146
					All outstanding liabilities for unpaid losses and loss settlement expenses before 2008, net of reinsurance														18,973
					Liabilities for unpaid losses and loss settlement expenses, net of reinsurance														$	168,640

Line of business: Personal
	Incurred losses and allocated loss settlement expenses, net of reinsurance																				As of December 31, 2017
	For the years ended December 31,																				Total of incurred but not reported liabilities plus expected development on reported claims		Cumulative development		Cumulative number of reported claims
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	49,961	$	44,686	$	43,408	$	43,672	$	43,577	$	43,535	$	43,515	$	43,482	$	42,882	$	42,881	$	—	(7,080	)	15,821
2009			34,597		33,519		31,945		32,026		32,134		32,029		32,085		32,070		31,867		2		(2,730	)	13,502
2010					36,686		34,347		33,928		33,865		33,403		33,413		33,432		33,213		29		(3,473	)	13,325
2011							50,014		48,534		47,090		47,035		46,968		47,013		46,733		74		(3,281	)	14,843
2012									47,924		46,199		46,403		46,150		44,715		44,352		108		(3,572	)	10,769
2013											39,232		38,525		37,262		37,086		36,729		172		(2,503	)	9,232
2014													53,910		52,661		52,944		52,782		236		(1,128	)	10,899
2015															42,848		41,088		40,336		396		(2,512	)	9,490
2016																	48,072		45,840		733		(2,232	)	11,674
2017																			60,330		3,310				13,049
																	Total		$	435,063

Line of business: Personal
	Cumulative paid losses and allocated loss settlement expenses, net of reinsurance
	For the years ended December 31,
Accident Year	2008		2009		2010		2011		2012		2013		2014		2015		2016		2017
	(Unaudited)
2008	$	32,032	$	40,114	$	41,735	$	42,414	$	42,613	$	42,627	$	42,748	$	42,748	$	42,787	$	42,881
2009			22,086		27,926		29,801		30,829		31,564		31,644		31,718		31,804		31,837
2010					24,499		29,867		31,340		32,076		32,771		32,997		33,165		33,158
2011							36,489		43,801		45,306		45,949		46,487		46,573		46,575
2012									30,415		41,979		43,375		44,448		43,569		44,139
2013											25,505		32,788		34,297		35,306		36,155
2014													37,055		47,912		49,710		51,837
2015															29,551		37,431		39,027
2016																	32,999		40,910
2017																			42,135
																	Total		$	408,654
					All outstanding liabilities for unpaid losses and loss settlement expenses before 2008, net of reinsurance														1,326
					Liabilities for unpaid losses and loss settlement expenses, net of reinsurance														$	27,735

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability

The reconciliation of the net incurred and loss development tables to the liability for unpaid losses and loss settlement expenses in the consolidated statement of financial position is as follows.

	December 31, 2017
Net outstanding liabilities for unpaid losses and allocated loss settlement expenses:
Commercial other liability	$	443,753
Commercial fire and allied	104,806
Commercial automobile	284,552
Commercial workers' compensation	168,640
Personal	27,735
All other lines	43,709
Net outstanding liabilities for unpaid losses and allocated loss settlement expenses	1,073,195
Net outstanding liabilities for unpaid unallocated loss settlement expenses	88,193
Fair value adjustment (purchase accounting adjustment for Mercer acquisition)	2,924
Liabilities for unpaid losses and loss settlement expenses, net of reinsurance	1,164,312
Reinsurance recoverable on unpaid losses and allocated loss settlement expenses:
Commercial other liability	20,367
Commercial fire and allied	10,806
Commercial automobile	1,994
Commercial workers' compensation	26,799
Personal	26
All other lines	2,675
Reinsurance recoverable on unpaid losses and allocated loss settlement expenses	62,667
Reinsurance fair value amortization (purchase accounting adjustment for Mercer acquisition)	(2,796		)
Total reinsurance recoverable on unpaid losses and loss settlement expenses	59,871
Total gross liability for unpaid losses and loss settlement expenses	$	1,224,183

Short-duration Insurance Contracts, Schedule of Historical Claims Duration

The following is supplementary information about average historical claims duration as of December 31, 2017.

	Average annual percentage payout of incurred claims 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
	(Unaudited)
Commercial other liability	10.1	%	15.9	%	16.4	%	15.3	%	11.9	%	6.4	%	5.6	%	4.0	%	3.9	%	2.2	%
Commercial fire and allied	64.4	%	20.9	%	4.8	%	3.7	%	3.0	%	0.9	%	0.9	%	0.4	%	0.2	%	—	%
Commercial automobile	39.9	%	20.9	%	15.1	%	10.9	%	5.6	%	2.8	%	1.8	%	0.1	%	—	%	0.5	%
Commercial workers' compensation	26.1	%	29.0	%	13.6	%	8.1	%	4.3	%	3.2	%	1.8	%	4.5	%	0.8	%	1.9	%
Personal	71.9	%	19.1	%	4.0	%	2.5	%	1.1	%	0.5	%	0.3	%	0.1	%	0.1	%	0.2	%