The following development tables provide the incurred and paid losses and allocated loss adjustment expenses, net of reinsurance, for workers’ compensation and general liability for accident years 2011 through 2020. The incurred but not reported (“IBNR”) losses and claims frequency is included for each accident year presented.

	Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance																				As of
	For the Years Ended December 31,																				December 31, 2020
	(Dollars in thousands)																				Total IBNR
																					Plus
																					Expected		Cumulative
																					Development		Number of
Accident	Unaudited (1)																				on Reported		Claims
Year	2011		2012		2013		2014		2015		2016		2017		2018		2019		2020		Claims		Reported
2011	$	196,384	$	199,522	$	199,163	$	198,213	$	195,262	$	192,988	$	191,126	$	189,327	$	188,226	$	188,264	$	5,198		6,044
2012		—		222,549		222,075		212,738		193,515		184,460		182,859		180,387		178,586		177,547		6,419		5,749
2013		—		—		241,810		241,811		233,656		220,457		214,701		210,588		209,184		207,304		7,762		5,766
2014		—		—		—		268,846		268,846		249,097		235,058		226,933		218,386		212,417		5,468		5,839
2015		—		—		—		—		262,573		262,573		252,514		235,471		220,965		211,758		6,717		5,516
2016		—		—		—		—		—		250,491		250,491		241,406		218,005		209,214		6,843		5,393
2017		—		—		—		—		—		—		244,094		244,098		234,587		220,096		8,066		5,211
2018		—		—		—		—		—		—		—		250,487		250,487		235,641		16,057		5,467
2019		—		—		—		—		—		—		—		—		241,344		241,344		16,609		5,199
2020		—		—		—		—		—		—		—		—		—		220,710		8,491		4,170
																	Total		$	2,124,295	$	87,630

	Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance
	For the Years Ended December 31,
	(Dollars in thousands)

Accident	Unaudited (1)																				Claim
Year	2011		2012		2013		2014		2015		2016		2017		2018		2019		2020		Frequency (2)
2011	$	53,329	$	111,029	$	140,831	$	153,968	$	161,639	$	165,967	$	167,757	$	169,994	$	170,785	$	171,583		22.82
2012		—		50,579		107,467		133,658		149,161		154,553		157,207		159,807		161,014		162,588		18.73
2013		—		—		51,396		119,507		150,304		165,994		172,479		177,724		180,614		182,465		16.55
2014		—		—		—		53,060		119,820		153,320		169,736		180,683		186,129		191,394		14.99
2015		—		—		—		—		54,141		121,599		151,818		170,461		182,053		185,657		14.25
2016		—		—		—		—		—		52,238		115,713		143,016		156,861		166,887		14.23
2017		—		—		—		—		—		—		56,951		122,552		151,427		166,448		14.68
2018		—		—		—		—		—		—		—		62,061		126,057		152,328		15.20
2019		—		—		—		—		—		—		—		—		58,883		120,512		15.21
2020		—		—		—		—		—		—		—		—		—		50,113		13.25
																	Total			1,549,975
All outstanding liabilities before 2011, net of reinsurance																				80,533
Liabilities for loss and loss adjustment expenses, net of reinsurance																				654,854

(1) Data presented for these calendar years is required supplementary information, which is unaudited.
(2) Frequency, as calculated above, refers to reported claims divided by gross premium earned.

The average annual percentage payout of incurred losses by age, net of reinsurance, for workers’ compensation and general liability as of December 31, 2020 is summarized below. Since workers’ compensation has long payout periods, the table below shows less than 100% in the years disclosed. This is required supplementary information, which is unaudited.

The following table provides a reconciliation of the beginning and ending reserve balances, net of related amounts recoverable from reinsurers, for 2020, 2019 and 2018:

	Year Ended December 31,
	2020			2019			2018
	(in thousands)
Balance, beginning of period	$	772,887		$	798,409		$	771,845
Less amounts recoverable from reinsurers on unpaid loss and loss adjustment expenses		95,343			107,216			84,889
Net balance, beginning of period		677,544			691,193			686,956
Add incurred related to:
Current accident year		220,710			241,344			250,487
Prior accident years		(63,484	)		(65,002	)		(45,596	)
Total incurred		157,226			176,342			204,891
Less paid related to:
Current accident year		50,113			58,883			62,061
Prior accident years		129,803			131,108			138,593
Total paid		179,916			189,991			200,654
Net balance, end of period		654,854			677,544			691,193
Add amounts recoverable from reinsurers on unpaid loss and loss adjustment expenses		105,707			95,343			107,216
Balance, end of period	$	760,561		$	772,887		$	798,409

The final resolution of the estimated loss reserve liability may be different from that anticipated at the reporting date because of the inherent uncertainty in loss reserve estimates, including, but not limited to, the future settlement environment. Consequently, actual paid losses in the future may result in a significantly different amount than currently reserved, favorable or unfavorable.

The difference between currently estimated losses and losses estimated for a prior period at a prior valuation date is known as development. Development is unfavorable when the losses ultimately settle for more than they were reserved for or future estimates suggest that reserves should be increased on unresolved claims. Development is favorable when the losses ultimately settle for less than they were reserved for or future estimates suggest that reserves should be decreased on unresolved claims. Favorable or unfavorable development of loss reserves are reflected in our results of operations in the period the estimates are changed.

The foregoing reconciliation reflects favorable development of the net reserves at December 31, 2020, 2019 and 2018. The favorable development reduced loss and loss adjustment expenses incurred by $63.5 million in 2020, driven primarily by accident years 2018 and 2017 of $14.8 million and $14.5 million, respectively. In 2019 and 2018, the Company recorded favorable development of $65.0 million and $45.6 million, respectively. The revisions to the Company’s reserves reflect new information gained by claims adjusters in the normal course of adjusting claims and is reflected in the financial statements when the information becomes available. It is typical for more serious claims to take several years or longer to settle and the Company continually revises estimates as more information about claimants’ medical conditions and potential disability becomes known and the claims get closer to being settled. Multiple factors can cause loss development both unfavorable and favorable. The favorable loss development we experienced across accident years was largely due to favorable case reserve development and continued favorable severity trends compared to those originally estimated.

Reserves established for workers’ compensation insurance includes the exposure to occupational disease or accidents related to asbestos or environmental claims. The exposure to asbestos claims emanate from the direct sale of workers’ compensation insurance. These claims resulted from industry workers who were exposed to tremolite asbestos dust and electricians and carpenters who were exposed to products that contained asbestos. There has been no known exposure to asbestos claims arising from assumed business. The emergence of these claims is slow and highly unpredictable. The Company estimates full impact of the asbestos exposure by establishing full case basis reserves on all known losses. Reserves for losses incurred but not reported (IBNR) include a provision for development of reserves on reported losses. Reserves are established for loss adjustment expenses (LAE) associated with these case and IBNR loss reserves.

The Company has historically written general liability coverages that are reported in other liability lines of business. These coverages may be associated with the property and casualty industry’s exposure to environmental claims. However, the Company has not been notified by any insured for which exposure exists due to these types of claims. Company management believes potential exposure to environmental claims to be remote. Therefore, the Company has no loss or loss adjustment expense reserves for such liabilities.

The anticipated effect of inflation is implicitly considered when estimating liabilities for loss and loss adjustment expenses. In establishing our reserves for loss and loss adjustment expenses, we review the results of analyses using individual case-base valuations and statistical and actuarial methods that utilize historical loss data from our more than 35 years of underwriting workers’ compensation insurance. The actuarial analysis of our historical data provides some of the factors we use in estimating our loss reserves. These factors are primarily measures over time of the number of claims paid and reported, average paid and incurred claim amounts, claim closure rates and claim payment patterns. In evaluating the results of our analyses, management also uses substantial judgment in considering other factors that are not considered in these actuarial analyses, including changes in business mix, claims management, regulatory issues, medical trends, employment and wage patterns, insurance policy coverage interpretations, judicial determinations and other subjective factors. Due to the inherent uncertainty associated with these estimates, and the cost of incurred but unreported claims, our actual liabilities may vary significantly from our original estimates. These anticipated trends are monitored based on actual development and are modified if necessary.