EMC Insurance (EMCI) 10-K 5 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 28, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	EMC INSURANCE GROUP INC.
Entity Central Index Key	356,130
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 265,448,151
Entity Common Stock, Shares Outstanding		21,512,806
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investments:
Fixed maturity securities available-for-sale, at fair value (amortized cost $1,253,166 and $1,189,525)	$ 1,275,016	$ 1,199,699
Equity securities available-for-sale, at fair value (cost $144,274 and $147,479)	228,115	213,839
Other long-term investments	13,648	12,506
Short-term investments	23,613	39,670
Total investments	1,540,392	1,465,714
Cash	347	307
Reinsurance receivables due from affiliate	31,650	21,326
Prepaid reinsurance premiums due from affiliate	12,789	9,309
Deferred policy acquisition costs (affiliated $40,848 and $40,660)	41,114	40,939
Prepaid pension and postretirement benefits due from affiliate	20,683	12,314
Accrued investment income	11,286	11,050
Amounts receivable under reverse repurchase agreements	16,500	20,000
Accounts receivable	1,604	2,076
Goodwill	942	942
Other assets (affiliated $4,423 and $4,632)	4,633	4,836
Total assets	1,681,940	1,588,813
LIABILITIES
Losses and settlement expenses (affiliated $726,413 and $685,533)	732,612	690,532
Unearned premiums (affiliated $256,434 and $243,682)	257,797	244,885
Other policyholders' funds (all affiliated)	10,013	13,068
Surplus notes payable to affiliate	25,000	25,000
Amounts due affiliate to settle inter-company transaction balances	367	11,222
Pension benefits payable to affiliate	4,185	4,097
Income taxes payable	544	2,359
Deferred income taxes	15,020	11,321
Other liabilities (affiliated $27,520 and $27,871)	32,556	32,987
Total liabilities	1,078,094	1,035,471
STOCKHOLDERS' EQUITY
Common stock, $1 par value, authorized 30,000,000 shares; issued and outstanding, 21,455,545 shares in 2017 and 21,222,535 shares in 2016	21,455	21,223
Additional paid-in capital	124,556	119,054
Accumulated other comprehensive income	83,384	46,081
Retained earnings	374,451	366,984
Total stockholders' equity	603,846	553,342
Total liabilities and stockholders' equity	$ 1,681,940	$ 1,588,813

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investments:
Fixed maturity securities available-for-sale, amortized cost	$ 1,253,166	$ 1,189,525
Equity securities available-for-sale, cost	144,274	147,479
Deferred policy acquisition costs from affiliates	40,848	40,660
Affiliated other assets	4,423	4,632
LIABILITIES
Affiliated losses and settlement expenses	726,413	685,533
Unearned premiums from affiliates	256,434	243,682
Affiliated other liabilities	$ 27,520	$ 27,871
STOCKHOLDERS' EQUITY
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	21,455,545	21,222,535
Common stock, shares outstanding (in shares)	21,455,545	21,222,535

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES
Premiums earned (affiliated $603,233, $586,609 and $566,103)	$ 607,158	$ 592,408	$ 570,266
Net investment income	45,479	47,490	45,582
Net realized investment gains, excluding impairment losses on securities available-for-sale	7,644	5,338	7,634
Total other-than-temporary impairment losses on securities available-for-sale	(1,088)	(1,264)	(1,481)
Portion of other-than-temporary impairment losses on fixed maturity securities available-for-sale reclassified from other comprehensive income (before taxes)	0	0	0
Net impairment losses on securities available-for-sale	(1,088)	(1,264)	(1,481)
Net realized investment gains	6,556	4,074	6,153
Other income (loss) (affiliated $143, $1,021 and $1,214)	(348)	1,011	1,725
Total revenues	658,845	644,983	623,726
LOSSES AND EXPENSES
Losses and settlement expenses (affiliated $417,259, $385,708 and $368,722)	421,969	386,897	370,736
Dividends to policyholders (all affiliated)	7,610	13,800	7,705
Amortization of deferred policy acquisition costs (affiliated $107,854, $106,931 and $101,090)	108,910	108,403	102,184
Other underwriting expenses (affiliated $76,932, $69,560 and $68,305)	76,806	69,612	68,418
Interest expense (all affiliated)	337	337	337
Other expenses (affiliated $1,825, $1,860 and $1,822)	3,397	2,727	2,690
Total losses and expenses	619,029	581,776	552,070
Income before income tax expense	39,816	63,207	71,656
INCOME TAX EXPENSE (BENEFIT)
Current	8,004	18,061	18,611
Deferred	(7,426)	(1,057)	2,883
Total income tax expense	578	17,004	21,494
Net income	$ 39,238	$ 46,203	$ 50,162
Net income per common share - basic and diluted	$ 1.84	$ 2.20	$ 2.43
Average number of common shares outstanding - basic and diluted (in shares)	21,326,358	21,006,302	20,621,919

CONSOLIDATED STATEMENTS OF INC5

CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES
Premiums earned, affiliated	$ 603,233	$ 586,609	$ 566,103
Other income, affiliated	143	1,021	1,214
LOSSES AND EXPENSES
Losses and settlement expenses, affiliated	417,259	385,708	368,722
Amortization of deferred policy acquisition costs, affiliated	107,854	106,931	101,090
Other underwriting expenses, affiliated	76,932	69,560	68,305
Other expense, affiliated	$ 1,825	$ 1,860	$ 1,822

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 26,184	$ 746	$ 5,504	$ 6,804	$ 21,292	$ 4,129	$ 6,128	$ 14,654	$ 39,238	$ 46,203	$ 50,162
OTHER COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) on investment securities, net of defered income tax expense (benefit) of $14,688, $(2,092) and $(7,021)									27,278	(3,885)	(13,037)
Reclassification adjustment for net realized investment gains included in net income, net of income tax expense of $(4,483), $(3,628) and $(2,668)									(8,326)	(6,736)	(4,956)
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income, net of deferred income tax expense of $(587), $(457) and $(693):
Net actuarial loss									958	1,549	863
Prior service credit									(2,047)	(2,399)	(2,150)
Total reclassification adjustment associated with affiliate's pension and postretirement benefit plans									(1,089)	(850)	(1,287)
Change in funded status of affiliate's pension and postretirement benefit plans, net of deferred income tax expense (benefit) of $1,507, $(474) and $(2,126):
Net actuarial gain (loss)									5,571	(542)	(3,637)
Prior service credit (cost)									96	(339)	(312)
Total change in funded status of affiliate's pension and postretirement benefit plans									5,667	(881)	(3,949)
Other comprehensive income (loss)									23,530	(12,352)	(23,229)
Total comprehensive income									$ 62,768	$ 33,851	$ 26,933

CONSOLIDATED STATEMENTS OF COM7

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OTHER COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) on investment securities, deferred income tax expense (benefit)	$ 14,688	$ (2,092)	$ (7,021)
Reclassification adjustment for net realized investment (gains) losses included in net income (loss), income tax (expense) benefit	(4,483)	(3,628)	(2,668)
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit cost (income), deferred income tax (expense) benefit	(587)	(457)	(693)
Change in funded status of affiliate's pension and postretirement benefit plans, deferred income tax expense (benefit)	$ 1,507	$ (474)	$ (2,126)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2014	$ 502,886	$ 20,344	$ 99,891	$ 81,662	$ 300,989
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through stock plans	9,078	437	8,641
Increase resulting from stock-based compensation expense	215		215
Other comprehensive income (loss)	(23,229)			(23,229)
Net income	50,162				50,162
Dividends paid to public stockholders	(6,012)				(6,012)
Dividends paid to affiliate	(8,162)				(8,162)
Balance at Dec. 31, 2015	524,938	20,781	108,747	58,433	336,977
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through stock plans	11,070	459	10,611
Repurchase of common stock	(383)	(17)	(366)
Increase resulting from stock-based compensation expense	62		62
Other comprehensive income (loss)	(12,352)			(12,352)
Net income	46,203				46,203
Dividends paid to public stockholders	(7,014)				(7,014)
Dividends paid to affiliate	(9,182)				(9,182)
Balance at Dec. 31, 2016	553,342	21,223	119,054	46,081	366,984
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock through stock plans	7,527	300	7,227
Repurchase of common stock	(1,858)	(68)	(1,790)
Increase resulting from stock-based compensation expense	65		65
Other comprehensive income (loss)	23,530			23,530
Net income	39,238				39,238
Dividends paid to public stockholders	(7,992)				(7,992)
Dividends paid to affiliate	(10,006)				(10,006)
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	0			13,773	(13,773)
Balance at Dec. 31, 2017	$ 603,846	$ 21,455	$ 124,556	$ 83,384	$ 374,451

CONSOLIDATED STATEMENTS OF STO9

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Dividends paid to public stockholders (per share)	$ 0.850	$ 0.780	$ 0.693
Dividends paid to affiliate (per share)	$ 0.850	$ 0.780	$ 0.693

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 39,238	$ 46,203	$ 50,162
Adjustments to reconcile net income to net cash provided by operating activities:
Losses and settlement expenses (affiliated $40,880, $14,364 and $20,517)	42,080	11,758	17,465
Unearned premiums (affiliated $12,752, $5,045 and $8,177)	12,912	5,450	7,342
Other policyholders' funds due to affiliate	(3,055)	4,347	(1,432)
Amounts due to/from affiliate to settle inter-company transaction balances	(10,855)	4,814	(2,151)
Net pension and postretirement benefits due from affiliate	(2,783)	(3,045)	(2,691)
Reinsurance receivables due from affiliate	(10,324)	2,910	4,367
Prepaid reinsurance premiums due from affiliate	(3,480)	(2,746)	2,302
Commissions payable (affiliated $981, $(1,662) and $3,191)	903	(1,697)	3,265
Deferred policy acquisition costs (affiliated $(188), $(125) and $(1,605))	(175)	(219)	(1,377)
Accrued investment income	(236)	(261)	(494)
Current income tax	(1,815)	8,512	(1,643)
Deferred income tax	(7,426)	(1,057)	2,883
Net realized investment gains	(6,556)	(4,074)	(6,153)
Other, net (affiliated $(1,058), $960 and $1,796)	10,474	12,539	13,767
Total adjustments to reconcile net income to net cash provided by operating activities	19,664	37,231	35,450
Net cash provided by operating activities	58,902	83,434	85,612
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of fixed maturity securities available-for-sale	(310,684)	(403,134)	(235,242)
Disposals of fixed maturity securities available-for-sale	235,626	330,239	174,971
Purchases of equity securities available-for-sale	(62,939)	(63,683)	(83,098)
Disposals of equity securities available-for-sale	83,256	71,106	70,905
Purchases of other long-term investments	(14,782)	(8,720)	(8,416)
Disposals of other long-term investments	3,433	571	2,297
Net (purchases) disposals of short-term investments	16,057	(1,071)	14,663
Net receipts (disbursements) under reverse repurchase agreements	3,500	(3,150)	(16,850)
Net cash used in investing activities	(46,533)	(77,842)	(80,770)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock through affiliate’s stock plans	7,527	11,070	9,078
Excess tax benefit associated with affiliate’s stock plans	0	0	95
Repurchase of common stock	(1,858)	(383)	0
Dividends paid to stockholders (affiliated $(10,006), $(9,182) and $(8,162))	(17,998)	(16,196)	(14,174)
Net cash used in financing activities	(12,329)	(5,509)	(5,001)
NET INCREASE (DECREASE) IN CASH	40	83	(159)
Cash at the beginning of the year	307	224	383
Cash at the end of the year	347	307	224
Income taxes paid	9,820	13,967	20,254
Interest paid to affiliate	$ 337	$ 337	$ 337

CONSOLIDATED STATEMENTS OF CA11

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Adjustments to reconcile net income to net cash provided by operating activities:
Losses and settlement expenses, affiliated	$ 40,880	$ 14,364	$ 20,517
Unearned premiums, affiliated	12,752	5,045	8,177
Commissions payable, affiliated	981	(1,662)	3,191
Deferred policy acquisition costs, affiliated	(188)	(125)	(1,605)
Other, net, affiliated	(1,058)	960	1,796
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends paid to stockholders, affiliated	$ (10,006)	$ (9,182)	$ (8,162)

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Business EMC Insurance Group Inc., a majority owned subsidiary of Employers Mutual Casualty Company (Employers Mutual), is an insurance holding company with operations in property and casualty insurance and reinsurance. The Company conducts its property and casualty insurance operations through the following subsidiaries: EMCASCO Insurance Company, Illinois EMCASCO Insurance Company and Dakota Fire Insurance Company, and its reinsurance operations through its subsidiary, EMC Reinsurance Company. The Company also has an excess and surplus lines insurance agency subsidiary, EMC Underwriters, LLC. The term “Company” is used interchangeably to describe EMC Insurance Group Inc. (Parent Company only) and EMC Insurance Group Inc. and its subsidiaries. The Company writes property and casualty insurance in both commercial and personal lines of insurance, with a focus on medium-sized commercial accounts. Approximately 37 percent of the premiums written are in Iowa and contiguous states. The Company’s reinsurance business is primarily written through a quota share reinsurance agreement with Employers Mutual. A small portion of the assumed reinsurance business is written on a direct basis, outside the quota share reinsurance agreement. Principles of Consolidation and Basis of Presentation The consolidated financial statements have been prepared on the basis of U.S. generally accepted accounting principles (GAAP), which differ in some respects from those followed in reports to insurance regulatory authorities. All significant inter-company balances and transactions have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. The Company has evaluated all subsequent events through the date the financial statements were issued. Property and Casualty Insurance and Reinsurance Operations Premiums written is the amount charged for policies issued during a reporting period. Property and casualty insurance premiums are recognized as revenue ratably over the terms of the respective policies. Unearned premiums are calculated on the daily pro rata method. Both domestic and foreign assumed reinsurance premiums are recognized as revenues ratably over the terms of the related contracts and underlying policies. Amounts paid as ceded reinsurance premiums are reported as prepaid reinsurance premiums and are amortized over the remaining contract period in proportion to the amount of reinsurance protection provided. Reinsurance reinstatement premiums are recognized in the same period as the loss event that gave rise to the reinstatement premiums. Costs related to the acquisition of insurance contracts are deferred and amortized to expense as the associated premium revenue is recognized. Only incremental costs or costs directly related to the successful acquisition of new or renewal insurance contracts are capitalized. Accordingly, acquisition costs consist of commissions, premium taxes, and salary and benefit expenses of employees directly involved in the underwriting of insurance policies that are successfully issued. The method followed in computing deferred policy acquisition costs limits the amount of such deferred costs to the estimated realizable value. In determining estimated realizable value, the computation gives effect to the premium to be earned, related investment income, anticipated losses and settlement expenses, anticipated policyholder dividends, and certain other costs expected to be incurred to administer the insurance policies as the premium is earned. The anticipated losses and settlement expenses are not discounted and are based on the Company’s projected loss and settlement expense ratios for the next twelve months, which include catastrophe loads based on historical results adjusted for recent trends. The occurrence of a significant catastrophic event, and/or the accumulation of catastrophe losses would not have a direct impact on the determination of premium deficiencies; however, such occurrences would be included in the historical results that are used to establish the catastrophe loads. A premium deficiency is first recognized by expensing the amount of unamortized deferred policy acquisition costs necessary to eliminate the deficiency. If the premium deficiency is greater than the unamortized deferred policy acquisition costs, a liability is accrued for the excess deficiency. The Company did not record a premium deficiency for the years ended December 31, 2017 , 2016 or 2015 . Certain commercial lines of business written by the property and casualty insurance subsidiaries, including workers’ compensation, are eligible for policyholder dividends in accordance with provisions of the underlying insurance policies. Net premiums written subject to policyholder dividends represented approximately 26 percent and 22 percent of the property and casualty insurance subsidiaries’ total net commercial line premiums written in 2017 and 2016 , respectively. Policyholder dividends are accrued over the terms of the underlying policy periods. Liabilities for losses reflect losses incurred through the balance sheet date and are based upon the estimated ultimate loss ratios established by line of business and accident year, and estimates of losses expected under assumed reinsurance contracts. Liabilities for settlement expenses are provided by estimating expenses expected to be incurred in settling the claims provided for in the loss reserves. Changes in reserves estimates are reflected in net income in the year such changes are recorded (see note 4). Ceded reinsurance amounts with nonaffiliated reinsurers relating to reinsurance receivables for unpaid losses and settlement expenses and prepaid reinsurance premiums are reported on the balance sheet on a gross basis. Amounts ceded to Employers Mutual under the affiliated reinsurance pooling agreement and the inter-company reinsurance programs (see note 2) have not been grossed up because the contracts provide that receivables and payables may be offset upon settlement. Based on current information, the liabilities for losses and settlement expenses are considered to be adequate. Since the provisions are necessarily based on estimates, the ultimate liabilities may be more or less than such provisions. Investments Currently, all securities are classified as available-for-sale and are carried at fair value, with unrealized holding gains and losses reported as a component of accumulated other comprehensive income in stockholders’ equity, net of deferred income taxes. Other long-term investments consist of holdings in limited partnerships that are carried under the equity method of accounting, and holdings in limited partnerships and limited liability companies that are carried at amortized cost. The Company has an investment in a limited partnership that is designed to help protect the Company from a sudden and significant decline in the value of its equity portfolio. This limited partnership is carried under the equity method of accounting. Because of the nature of this investment, which is used solely to support the equity tail-risk hedging strategy, changes in the carrying value of the limited partnership are recorded as realized investment gains (losses), rather than as a component of investment income. Short-term investments generally include money market funds, U.S. Treasury bills and commercial paper that are carried at fair value, which approximates cost. The Company participates in a reverse repurchase arrangement involving the purchase of investment securities from third-party sellers, with the agreement that the purchased securities be sold back to the third-party sellers for agreed-upon prices at specified future dates. The third-party sellers are required to pledge collateral with a value greater than the amount of cash received in the transactions. In accordance with GAAP, the investment securities purchased under the reverse repurchase agreements are not reflected in the Company's consolidated balance sheets, but instead a receivable is recorded for the principal amount lent. Net proceeds/disbursements related to the reverse repurchase transactions are reported as a component of investing activities in the consolidated statements of cash flows, and the income as a component of operating activities. The Company uses independent pricing sources to obtain the estimated fair value of securities. The fair value is based on quoted market prices, where available. In cases where quoted market prices are not available, fair values are based on a variety of valuation techniques depending on the type of investment. The fair values obtained from independent pricing sources are reviewed for reasonableness and any discrepancies are investigated for final valuation (see note 8). The Company uses a practical expedient to measure the pooled separate account investments in Employers Mutual's qualified pension plan at the net asset value per share (see note 12). Premiums and discounts on fixed maturity securities are amortized over the expected life of the security as an adjustment to yield using the effective interest method . Amortization of premiums and discounts on mortgage-backed securities incorporates prepayment assumptions to estimate expected lives. Prepayment assumptions are reviewed quarterly and adjusted as necessary. Gains and losses realized on the disposition of investments are included in net income. The cost of investments sold is determined on the specific identification method using the highest cost basis first. Included in investments at December 31, 2017 and 2016 are securities on deposit with various regulatory authorities as required by law amounting to $11.3 million and $11.0 million , respectively. The Company regularly monitors its investment portfolio for securities whose fair value is less than the carrying value for indications of “other-than-temporary” impairment. Several factors are used to determine whether the carrying value of an individual security has been “other-than-temporarily” impaired. Such factors include, but are not limited to (1) the security’s value and performance in the context of the overall markets, (2) length of time and extent the security’s fair value has been below carrying value, (3) key corporate events, (4) for fixed maturity securities, the amount of collateral available, and (5) for equity securities, the ability and intent to hold the security until recovery to its cost basis. When an equity security is deemed to be “other-than-temporarily” impaired, the carrying value is reduced to fair value and a realized loss is recognized and charged to income. For fixed maturity securities, if the present value of cash flows expected to be collected is less than the amortized cost of the security, a credit loss is deemed to exist and the security is considered “other-than-temporarily” impaired. The portion of the impairment related to a credit loss is recognized through earnings, and the portion of the impairment related to other factors, if any, is recognized through “other comprehensive income”. Alternatively, if the Company has the intent to sell a fixed maturity security that is in an unrealized loss position, or determines that it will "more likely than not" be required to sell a fixed maturity security that is in an unrealized loss position before recovery of its amortized cost basis, then the carrying value is reduced to fair value and the entire amount of the impairment is recognized through earnings. Income Taxes The Company files a consolidated Federal income tax return with its subsidiaries. Consolidated income taxes/benefits are allocated among the entities based upon separate tax liabilities. Deferred income taxes are provided for temporary differences between the tax basis of assets and liabilities and the reported amounts of those assets and liabilities for financial reporting purposes. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Income tax expense provisions increase or decrease in the same period in which a change in tax rates is enacted. A valuation allowance is established to reduce deferred tax assets to their net realizable value if it is “more likely than not” that a tax benefit will not be realized. In February 2018, the Financial Accounting Standards Board (FASB) issued updated guidance in Income Statement-Comprehensive Income Topic 220 of the Accounting Standards Codification TM (Codification or ASC). The objective of this update is to allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (TCJA), and requires certain disclosures about the stranded tax effects. The Company adopted this guidance in 2017, and elected to transfer the stranded tax effects in accumulated other comprehensive income to retained earnings as reflected in the consolidated statements of stockholders' equity. The Company releases the tax effects in accumulated other comprehensive income on an individual unit of account basis. An assessment of the Company’s current tax positions indicated no uncertainties that would warrant different recognition and valuation from that applied in the Company’s tax returns. Stock-Based Compensation The Company has a stock-based compensation plan for non-employee directors. Compensation expense under this plan is based upon grant date fair value, which is recognized as the requisite service period is rendered. The Company has no other stock-based compensation plans of its own; however, Employers Mutual has several stock plans that utilize the common stock of the Company. The Company receives the current fair value for all shares issued under Employers Mutual's plans, and a portion of the compensation expense recognized by Employers Mutual is allocated to the Company’s property and casualty insurance subsidiaries though their participation in the pooling agreement (see note 2). For granted options and restricted stock awards, the expense is based upon the grant date fair value, which is recognized as the requisite service periods are rendered. For granted restricted stock units, the expense is determined in accordance with the liability-based model, whereby Employers Mutual records a liability representing the current value of the Company's stock granted for the portion of the service period that has been rendered (both the liability and the resulting expense are allocated to the Company's property and casualty insurance subsidiaries through the pooling agreement). Excess tax benefits (deficiencies) related to non-qualified stock option activities allocated to the Company's property and casualty insurance subsidiaries through the pooling agreement are recognized through the consolidated statements of income as components of current and deferred income taxes, with the associated cash flows reflected as cash flows from operating activities. Because a portion of Employers Mutual’s stock compensation expense is reflected in the Company’s financial statements and issuances of the Company’s stock under Employers Mutual’s stock plans have an impact on the Company’s capital accounts, the disclosures required by the Compensation – Stock Compensation Topic 718 of the FASB ASC are included in the Company’s consolidated financial statements (see note 13). Employee Retirement Plans Employers Mutual has various employee benefit plans, including two defined benefit pension plans, and two postretirement benefit plans that provide retiree healthcare and life insurance benefits. Although the Company has no employees of its own, it is responsible for its share of the plans' expenses and related prepaid assets and liabilities (the "funded status") as determined under the terms of the pooling agreement. Accordingly, the Company recognizes its share of the funded status of Employers Mutual’s pension and postretirement benefit plans on its balance sheet, with changes in the funded status of the plans recognized through “other comprehensive income.” In addition, the Company is responsible for its share of costs of these plans allocated by Employers Mutual to subsidiaries that do not participate in the pooling agreement (see note 2). During 2016, Employers Mutual's management determined that an allocation of the plans' funded status to the Company's reinsurance subsidiary would no longer be made because the amounts were immaterial and significant time and cost was needed to determine the allocation. As a result, the assets and liabilities allocated to the reinsurance subsidiary as of December 31, 2015 were settled with Employers Mutual during 2016. Accounts Receivable The accounts receivable balance consists of assumed reinsurance premiums receivable (net of any commissions) on business written directly by the reinsurance subsidiary, and commission income receivable on excess and surplus lines business marketed by EMC Underwriters, LLC. These receivables are carried at their initial recognition amounts. It is the Company’s policy to reflect the impairment of receivables through a valuation allowance until ultimately collected or charged-off. No valuation allowance is currently carried, as no amounts are deemed impaired. No interest income, other fees, or deferred costs related to these receivables are assessed or recognized. Off-Balance-Sheet Credit Exposure Employers Mutual collects from agents, policyholders and ceding companies all written premiums associated with the insurance business produced by the pool participants and the assumed reinsurance business ceded to the reinsurance subsidiary. Employers Mutual also collects from its reinsurers all losses and settlement expenses recoverable under the reinsurance contracts protecting the pool participants and, starting in 2016, the reinsurance subsidiary (see note 2), as well as the fronting business ceded to the reinsurance subsidiary. Employers Mutual settles with the pool participants (monthly) and the reinsurance subsidiary (quarterly) the premiums written from these insurance policies and the paid losses and settlement expenses recoverable under the external reinsurance contracts, providing full credit for the premiums written and the paid losses and settlement expenses recoverable under the external reinsurance contracts generated during the period (not just the collected portion). Due to this arrangement, and since a significant portion of the premium balances are collected over the course of the underlying coverage periods, Employers Mutual carries a substantial receivable balance for insurance and reinsurance premiums in process of collection and, to a lesser extent, paid losses and settlement expenses recoverable from the external reinsurance companies. Any of these receivable amounts that are ultimately deemed to be uncollectible are charged-off by Employers Mutual and the expense is charged to the reinsurance subsidiary or allocated to the pool members on the basis of pool participation. As a result, the Company has off-balance sheet arrangements with an unconsolidated entity that results in credit-risk exposures (Employers Mutual’s insurance and reinsurance premium receivable balances, and paid loss and settlement expense recoverable amounts) that are not reflected in the Company’s financial statements. The average annual expense for such charge-offs allocated to the Company over the past ten years is $380,000 . Based on this historical data, this credit-risk exposure is not considered to be material to the Company’s results of operations or financial position and, accordingly, no loss contingency liability has been recorded. Foreign Currency Transactions Included in the underlying reinsurance business assumed by the reinsurance subsidiary are reinsurance transactions conducted with foreign cedants denominated in their local functional currencies. In accordance with the terms of the quota share agreement (see note 2), the reinsurance subsidiary assumes all foreign currency exchange gains/losses associated with contracts that are subject to the quota share agreement. The reinsurance subsidiary also has foreign currency exchange gains/losses associated with the business assumed outside the quota share agreement. The assets and liabilities resulting from these foreign reinsurance transactions are reported in U.S. dollars based on the foreign currency exchange rates that existed at the balance sheet dates. The foreign currency exchange rate gains/losses reported in the consolidated statements of income that resulted from these foreign reinsurance transactions are reported in U.S. dollars re-measured from the foreign currency exchange rates that existed at the inception of each reinsurance contract. The foreign currency exchange rate gains/losses resulting from these re-measurements to U.S. dollars are reported as a component of other income in the consolidated statements of income. Net Income Per Share - Basic and Diluted The Company’s basic and diluted net income per share is computed by dividing net income by the weighted average number of common shares outstanding during each period. As previously noted, the Company receives the current fair value for all shares issued under Employers Mutual’s stock plans. As a result, with the exception of the immaterial number of shares of outstanding non-vested restricted stock issued to the Company's non-employee directors, the Company had no potential common shares outstanding during 2017 , 2016 or 2015 that would have been dilutive to the calculation of net income per share. The outstanding non-vested restricted stock issued to the Company's non-employee directors is not material enough to produce a diluted net income per share different from the basic net income per share; therefore, the Company does not disclose an amount for the diluted weighted average number of common shares outstanding. Goodwill Goodwill represents the excess of cost over the fair value of net assets of acquired subsidiaries. Goodwill is not amortized, but is instead subject to impairment if the carrying value of the goodwill exceeds the estimated fair value of net assets. If the carrying amount of the reporting unit (including goodwill) exceeds the computed fair value, an impairment loss is recognized through the income statement equal to the excess amount, but not greater than the balance of the goodwill. Goodwill was not deemed to be impaired in 2017 , 2016 or 2015 . New Accounting Pronouncements Not Yet Adopted In May 2014, the FASB updated its guidance related to the Revenue from Contracts with Customers Topic 606 of the ASC. The objective of this update (and other related following updates) is to improve the reporting of revenue by providing a more robust framework for addressing revenue issues, and improved disclosure requirements. Current revenue recognition guidance in U.S. GAAP is comprised of broad revenue recognition concepts together with numerous revenue requirements for particular industries or transactions, which sometimes result in different accounting for economically similar transactions. This guidance is to be applied retrospectively to annual and interim reporting periods beginning after December 15, 2017, with early adoption permitted as of the original effective date (annual and interim reporting periods beginning after December 15, 2016). The Company has adopted this guidance as of January 1, 2018. Since premium revenue from insurance contracts is excluded, the Company has only minimal revenue items that are covered by this guidance. The largest revenue item, outside of premium income, is commission income on excess and surplus lines business marketed by EMC Underwriters, LLC, which is included in "Other income" in the consolidated statements of income. Applying this new revenue recognition guidance to commission income produces no material difference compared to that recognized under current practices, as the commission income is typically recognized in full at the time the policy is issued, which is when substantially all of the performance obligation is performed. Adoption of this guidance will have no impact on the consolidated financial condition or operating results of the Company. In January 2016, the FASB updated its guidance related to the Financial Instruments-Overall Subtopic 825-10 of the ASC. The objective of this update is to enhance the reporting model for financial instruments to provide financial statement users with more decision-useful information. The major change in reporting from this update that will impact the Company is a requirement that equity investments (excluding those accounted for under the equity method of accounting or those that are consolidated) be measured at fair value, with changes in fair value recognized in net income. While all of the Company's equity investments are already measured at fair value (with the exception of those that are consolidated and those that are accounted for under the equity method of accounting), the Company currently classifies all of its investments in equity securities as available-for-sale, and as such, the changes in fair value are currently recognized in other comprehensive income rather than net income. This guidance is to be applied to annual and interim reporting periods beginning after December 15, 2017, with recognition of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. Early adoption is not permitted. The Company adopted this guidance on January 1, 2018, and reclassified $66.2 million from accumulated other comprehensive income to retained earnings which is equal to the amount of net unrealized gains on available-for-sale equity securities as of December 31, 2017, net of deferred income tax. Adoption of this guidance is expected to introduce volatility to the Company's consolidated net income. In February 2016, the FASB issued updated guidance in Leases Topic 842 of the ASC, which supersedes the guidance in Leases Topic 840 of the ASC. The objective of this update is to increase transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet, and disclosure of key information about leasing arrangements. This guidance is effective for interim and annual periods beginning after December 15, 2018, and is to be applied using a modified retrospective approach. Early adoption is permitted. The Company will adopt this guidance during the first quarter of 2019. Management continues to research this guidance, which thus far has led management to a preliminary determination that lease costs allocated to the Company through the pooling and quota share agreements can not be attributed to a specified asset, and therefore do not meet the definition of a leased asset contained in the guidance. As a result, adoption of this guidance is not expected to have a material impact on the Company's consolidated financial condition or net income. In June 2016, the FASB issued updated guidance in Financial Instruments-Credit Losses Topic 326 of the ASC. The objective of this update is to provide information about expected credit losses on financial instruments and other commitments to extend credit. Specifically, this updated guidance replaces the current incurred loss impairment methodology, which delays recognition of a loss until it is probable a loss has been incurred, with a methodology that reflects expected credit losses considering a broader range of reasonable and supportable information. This guidance covers financial assets that are not accounted for at fair value through net income, thus will not be applicable to the Company's equity investments upon implementation of the updated guidance described above for the Financial Instruments-Overall Subtopic 825-10. This guidance is effective for interim and annual periods beginning after December 15, 2019, and is to be applied with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (modified-retrospective approach). Early adoption is permitted, but only to fiscal years beginning after December 15, 2018. The Company will adopt this guidance during the first quarter of 2020. The Company is currently evaluating the impact this guidance will have on the Company's consolidated financial condition and net income. In March 2017, the FASB issued updated guidance in Compensation-Retirement Benefits Topic 715 of the ASC. The objective of this update is to improve the presentation of net periodic pension and postretirement benefit costs by disaggregating the components of these expenses (disclosing the service cost component separately from the other components) for income statement reporting. Also included in this update is a prohibition against including components of the net periodic pension and postretirement benefit costs, other than the service cost component, in any capitalized assets. This guidance is effective for interim and annual periods beginning after December 15, 2017. The portion of the guidance related to the income statement display of net periodic pension and postretirement benefit costs is to be applied retrospectively, while the prohibition against including these costs, other than the service cost component, in capitalized assets is to be applied prospectively. Early adoption is permitted. The Company has adopted this guidance as of January 1, 2018. Adoption will not impact consolidated stockholders' equity initially; however, the prohibition against including components of the net periodic pension and postretirement benefit costs, other than the service cost component, in capitalized assets is expected to result in a relatively small change in the deferred policy acquisition cost asset starting March 31, 2018, which is expected to have an immaterial impact, net of tax, on consolidated stockholders' equity and net income from that which would otherwise have been reported.

AFFILIATION AND TRANSACTIONS WI

AFFILIATION AND TRANSACTIONS WITH AFFILIATES	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
AFFILIATION AND TRANSACTIONS WITH AFFILIATES	AFFILIATION AND TRANSACTIONS WITH AFFILIATES The operations of the Company are highly integrated with those of Employers Mutual through participation in a property and casualty reinsurance pooling agreement (the "pooling agreement"), a quota share retrocessional reinsurance agreement (the "quota share agreement") and inter-company reinsurance programs. All transactions occurring under the pooling agreement, quota share agreement and the inter-company reinsurance programs are based on statutory accounting principles. Certain adjustments are made to the statutory-basis amounts assumed by the property and casualty insurance subsidiaries and the reinsurance subsidiary to bring the amounts into compliance with GAAP. Property and Casualty Insurance Subsidiaries The Company’s three property and casualty insurance subsidiaries and two subsidiaries and an affiliate of Employers Mutual (Union Insurance Company of Providence, EMC Property & Casualty Company and Hamilton Mutual Insurance Company) are parties to a pooling agreement with Employers Mutual. Under the terms of the pooling agreement, each company cedes to Employers Mutual all of its insurance business, and assumes from Employers Mutual an amount equal to its participation in the pool. All premiums, losses, settlement expenses, and other underwriting and administrative expenses, excluding the voluntary reinsurance business assumed by Employers Mutual from nonaffiliated insurance companies, are prorated among the parties on the basis of participation in the pool. Employers Mutual negotiates reinsurance agreements that provide protection to the pool and each of its participants, including protection against losses arising from catastrophic events. The aggregate participation of the Company’s property and casualty insurance subsidiaries in the pool is 30 percent . Since 2016, the Company's property and casualty insurance subsidiaries and Employers Mutual have been parties to an inter-company reinsurance program. This reinsurance program is intended to reduce the volatility of the Company's quarterly results caused by excessive catastrophe and storm losses, and provide protection from both the frequency and severity of such losses. The reinsurance program consists of two semi-annual aggregate catastrophe excess of loss treaties. The first treaty is effective each year from January 1 through June 30, and has a retention of $20.0 million and a limit of $24.0 million . The total cost of this treaty was approximately $6.0 million in 2017 . The second treaty is effective each year from July 1 through December 31, and has a retention of $15.0 million and a limit of $12.0 million . The total cost of this treaty was approximately $1.4 million in 2017 . The terms of these treaties were the same in 2016 with the exception of the costs, which were $6.3 million during the first half of 2016 and $1.5 million during the second half of 2016 . Losses and settlement expenses ceded to Employers Mutual under the inter-company reinsurance program totaled $19.2 million , compared to $7.5 million during 2016 . All catastrophe and storm losses assumed by the property and casualty insurance subsidiaries (net of applicable reinsurance recoveries from external reinsurance protections purchased by the pool participants) are subject to the terms of these treaties, and there is no co-participation provision. In accordance with the terms of the treaties, all outstanding balances associated with the 2016 treaties were commuted at the end of 2017 . In connection with that commutation, Employers Mutual paid the property and casualty insurance subsidiaries $2.8 million to settle the outstanding loss and settlement expense reserves, with no gain or loss recognized on the commutation. Operations of the pool and the inter-company reinsurance program give rise to inter-company balances with Employers Mutual, which are generally settled during the subsequent month. The investment and income tax activities of the pool participants are not subject to the pooling agreement. The pooling agreement provides that Employers Mutual will make up any shortfall or difference resulting from an error in its systems and/or computation processes that would otherwise result in the required restatement of the pool participants’ financial statements. The purpose of the pooling agreement is to spread the risk of an exposure insured by any of the pool participants among all the companies participating in the pool. The pooling agreement produces a more uniform and stable underwriting result from year to year for the companies participating in the pool than might be experienced individually. In addition, each company benefits from the capacity of the entire pool, rather than being limited to policy exposures of a size commensurate with its own statutory surplus, and from the wide range of policy forms, lines of insurance written, rate filings and commission plans offered by each of the companies. Reinsurance Subsidiary The Company’s reinsurance subsidiary is party to a quota share agreement and an inter-company reinsurance program with Employers Mutual. Under the terms of the quota share agreement, the reinsurance subsidiary assumes 100 percent of Employers Mutual’s assumed reinsurance business, subject to certain exceptions. The inter-company reinsurance program in place with Employers Mutual covers both business assumed from Employers Mutual through the quota share agreement, as well as business obtained outside the quota share agreement. The Inter-Company Committees of the boards of directors of the Company and Employers Mutual approved a change in the inter-company reinsurance program between the Company's reinsurance subsidiary and Employers Mutual starting in 2016. This revised reinsurance program now consists of two treaties. The first is a per occurrence catastrophe excess of loss treaty with a retention of $10.0 million , a limit of $10.0 million , 20 percent co-participation, and no reinstatement. The total cost of this treaty was approximately $1.7 million in 2017 . The second is an annual aggregate catastrophe excess of loss treaty with a retention of $20.0 million , a limit of $100.0 million , and 20 percent co-participation. The total cost of this treaty was approximately $3.2 million in 2017 . Any losses recovered under the per occurrence treaty inure to the benefit of the aggregate treaty, and only catastrophic events with total losses greater than $500,000 are subject to the terms of the aggregate treaty. The terms of the program were the same in 2016 with the exception of the costs, which were $2.0 million for the per occurrence treaty and $3.2 million for the annual aggregate treaty. Prior to 2016, the reinsurance program with Employers Mutual consisted of a single excess of loss reinsurance agreement. Under the terms of that agreement, the reinsurance subsidiary retained the first $4.0 million of losses per event, and also retained 20 percent of any losses between $4.0 million and $10.0 million and 10 percent of any losses between $10.0 million and $50.0 million . The cost of the excess of loss reinsurance protection, which included reimbursement for the cost of reinsurance protection purchased by Employers Mutual to protect itself from the assumption of excessive losses in the event of a major catastrophe, was calculated as 8.0 percent of the reinsurance subsidiary’s total assumed reinsurance premiums written in 2015 , and amounted to $10.8 million . Losses and settlement expenses ceded to Employers Mutual under the inter-company reinsurance program totaled $16.8 million in 2017 , compared to a negative $467,000 during 2016 , and $622,000 during 2015 . In accordance with the terms of the treaties, the 2016 treaties were commuted at the end of 2017 , with no payment and no gain or loss recognized on the commutation. In connection with the change in the inter-company reinsurance program in 2016, the reinsurance subsidiary began purchasing additional reinsurance protection in peak exposure territories from external parties in which coverage is triggered when losses experienced by the insurance industry from a catastrophic event exceed a specified threshold. Any reinsurance recoveries received from external parties reduces the amount of losses ceded to Employers Mutual under the inter-company reinsurance program. No recoveries have been made from external parties in 2017 or 2016 . The reinsurance subsidiary does not directly reinsure any of the insurance business written by Employers Mutual or the other pool participants; however, Employers Mutual assumes reinsurance business from the Mutual Reinsurance Bureau underwriting association (MRB), which provides a small amount of reinsurance protection to the members of the EMC Insurance Companies pooling agreement. As a result, the reinsurance subsidiary’s assumed exposures include a small portion of the EMC Insurance Companies’ direct business, after ceded reinsurance protections purchased by MRB are applied. In addition, the reinsurance subsidiary does not reinsure any “involuntary” facility or pool business that Employers Mutual assumes pursuant to state law. The reinsurance subsidiary assumes all foreign currency exchange gain/loss associated with contracts incepting on January 1, 2006 and thereafter that are subject to the quota share agreement. Operations of the quota share agreement and the inter-company reinsurance program, as well as the purchase of the reinsurance protection from external parties, give rise to inter-company balances with Employers Mutual, which are generally settled during the month following the end of each quarter. The investment and income tax activities of the reinsurance subsidiary are not subject to the quota share agreement. Premiums earned assumed by the reinsurance subsidiary from Employers Mutual amounted to $135.7 million , $135.2 million and $129.6 million in 2017 , 2016 and 2015 , respectively. Losses and settlement expenses assumed by the reinsurance subsidiary from Employers Mutual amounted to $131.1 million , $90.9 million and $77.5 million in 2017 , 2016 and 2015 , respectively. It is customary in the reinsurance business for the assuming company to compensate the ceding company for the acquisition expenses incurred in the generation of the business. Commissions incurred by the reinsurance subsidiary under the quota share agreement with Employers Mutual amounted to $27.5 million , $27.4 million and $27.3 million in 2017 , 2016 and 2015 , respectively. The net foreign currency exchange gains (losses) assumed by the reinsurance subsidiary from Employers Mutual were $(978,000) in 2017 , $367,000 in 2016 and $386,000 in 2015 . The total amount of net foreign currency exchange gains (losses) assumed by the reinsurance subsidiary, including the business written on a direct basis outside the quota share agreement, were $(1.6) million in 2017 , $356,000 in 2016 and $898,000 in 2015 . Services Provided by Employers Mutual The Company does not have any employees of its own. Employers Mutual performs all operations for all of its subsidiaries and affiliate. Such services include data processing, claims, financial, actuarial, legal, auditing, marketing and underwriting. Employers Mutual allocates a portion of the cost of these services to its subsidiaries that do not participate in the pooling agreement based upon a number of criteria, including usage of the services and the number of transactions. The remaining costs are charged to the pooling agreement and each pool participant shares in the total cost in accordance with its pool participation percentage. Costs allocated to the Company by Employers Mutual for services provided to the holding company and its subsidiaries that do not participate in the pooling agreement amounted to $4.4 million , $4.7 million and $3.4 million in 2017 , 2016 and 2015 , respectively. Costs allocated to the Company through the operation of the pooling agreement amounted to $97.7 million , $92.3 million and $87.4 million in 2017 , 2016 and 2015 , respectively. Investment expenses are based on actual expenses incurred by the Company and its subsidiaries, plus an allocation of other investment expenses incurred by Employers Mutual, which is based on a weighted-average of total invested assets and number of investment transactions. Investment expenses allocated to the Company by Employers Mutual amounted to $1.6 million , $1.4 million and $1.4 million in 2017 , 2016 and 2015 , respectively.

REINSURANCE

REINSURANCE	12 Months Ended
	Dec. 31, 2017
Reinsurance Disclosures [Abstract]
REINSURANCE	REINSURANCE The parties to the pooling agreement cede insurance business to other insurers in the ordinary course of business for the purpose of limiting their maximum loss exposure through diversification of their risks. In its consolidated financial statements, the Company treats risks to the extent they are reinsured as though they were risks for which the Company is not liable. However, insurance ceded by the pool participants does not relieve their primary liability as the originating insurers. Employers Mutual evaluates the financial condition of the reinsurers of the parties to the pooling agreement and monitors concentrations of credit risk arising from similar geographic regions, activities or economic characteristics of the reinsurers to minimize exposure to significant losses from reinsurer insolvencies. As of December 31, 2017 and 2016 , amounts recoverable from nonaffiliated reinsurers ( three in 2017 and two in 2016 ) totaled $22.7 million and $10.4 million respectively, which represents a significant portion of the total prepaid reinsurance premiums and reinsurance receivables for losses and settlement expenses. Included in the 2017 balance is the property and casualty insurance subsidiaries’ aggregate pool participation percentage of amounts ceded by Employers Mutual to an organization on a mandatory basis. Credit risk associated with these amounts are minimal, as all companies participating in the organization are responsible for the liabilities of the organization on a pro rata basis. The effect of reinsurance on premiums written and earned, and losses and settlement expenses incurred, for the three years ended December 31, 2017 is presented below. The classification of the assumed and ceded reinsurance amounts between affiliates and nonaffiliates is based on the participants in the underlying reinsurance agreements, and is intended to provide an understanding of the actual source of the reinsurance activities. This presentation differs from the classifications used in the consolidated financial statements, where all amounts flowing through the pooling and quota share agreements and inter-company reinsurance programs with Employers Mutual are reported as “affiliated” balances. Year ended December 31, 2017 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 391,029 $ — $ 391,029 Assumed from nonaffiliates 4,454 147,284 151,738 Assumed from affiliates 520,932 — 520,932 Ceded to nonaffiliates (34,019 ) (10,160 ) (44,179 ) Ceded to affiliates (398,369 ) (4,850 ) (403,219 ) Net premiums written $ 484,027 $ 132,274 $ 616,301 Premiums earned Direct $ 384,993 $ — $ 384,993 Assumed from nonaffiliates 4,299 149,952 154,251 Assumed from affiliates 505,795 — 505,795 Ceded to nonaffiliates (30,385 ) (10,313 ) (40,698 ) Ceded to affiliates (392,333 ) (4,850 ) (397,183 ) Net premiums earned $ 472,369 $ 134,789 $ 607,158 Losses and settlement expenses incurred Direct $ 252,007 $ — $ 252,007 Assumed from nonaffiliates 2,879 142,687 145,566 Assumed from affiliates 334,240 1,330 335,570 Ceded to nonaffiliates (14,968 ) (8,183 ) (23,151 ) Ceded to affiliates (271,185 ) (16,838 ) (288,023 ) Net losses and settlement expenses incurred $ 302,973 $ 118,996 $ 421,969 Year ended December 31, 2016 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 383,811 $ — $ 383,811 Assumed from nonaffiliates 4,544 146,236 150,780 Assumed from affiliates 491,315 — 491,315 Ceded to nonaffiliates (24,346 ) (10,126 ) (34,472 ) Ceded to affiliates (391,651 ) (5,080 ) (396,731 ) Net premiums written $ 463,673 $ 131,030 $ 594,703 Premiums earned Direct $ 382,300 $ — $ 382,300 Assumed from nonaffiliates 4,444 148,851 153,295 Assumed from affiliates 483,759 — 483,759 Ceded to nonaffiliates (23,896 ) (7,830 ) (31,726 ) Ceded to affiliates (390,140 ) (5,080 ) (395,220 ) Net premiums earned $ 456,467 $ 135,941 $ 592,408 Losses and settlement expenses incurred Direct $ 229,859 $ — $ 229,859 Assumed from nonaffiliates 2,712 93,306 96,018 Assumed from affiliates 304,007 1,811 305,818 Ceded to nonaffiliates (4,891 ) (3,056 ) (7,947 ) Ceded to affiliates (237,318 ) 467 (236,851 ) Net losses and settlement expenses incurred $ 294,369 $ 92,528 $ 386,897 Year ended December 31, 2015 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 370,955 $ — $ 370,955 Assumed from nonaffiliates 4,392 138,700 143,092 Assumed from affiliates 474,323 — 474,323 Ceded to nonaffiliates (24,281 ) (3,369 ) (27,650 ) Ceded to affiliates (370,955 ) (10,827 ) (381,782 ) Net premiums written $ 454,434 $ 124,504 $ 578,938 Premiums earned Direct $ 366,752 $ — $ 366,752 Assumed from nonaffiliates 4,240 139,839 144,079 Assumed from affiliates 466,966 — 466,966 Ceded to nonaffiliates (24,009 ) (5,943 ) (29,952 ) Ceded to affiliates (366,752 ) (10,827 ) (377,579 ) Net premiums earned $ 447,197 $ 123,069 $ 570,266 Losses and settlement expenses incurred Direct $ 198,504 $ — $ 198,504 Assumed from nonaffiliates 2,407 83,515 85,922 Assumed from affiliates 294,324 857 295,181 Ceded to nonaffiliates (4,848 ) (4,897 ) (9,745 ) Ceded to affiliates (198,504 ) (622 ) (199,126 ) Net losses and settlement expenses incurred $ 291,883 $ 78,853 $ 370,736 Individual lines in the above tables are defined as follows: • “Direct” represents business produced by the property and casualty insurance subsidiaries. • “Assumed from nonaffiliates” for the property and casualty insurance subsidiaries represents their aggregate 30 percent pool participation percentage of involuntary business assumed by the pool participants pursuant to state law. For the reinsurance subsidiary, this line represents the reinsurance business assumed through the quota share agreement (including “fronting” activities initiated by Employers Mutual) and the business assumed outside the quota share agreement. • “Assumed from affiliates” for the property and casualty insurance subsidiaries represents their aggregate 30 percent pool participation percentage of all the pool members’ direct business. The amounts reported under the caption “Losses and settlement expenses incurred” also include claim-related services provided by Employers Mutual that are allocated to the property and casualty insurance subsidiaries and the reinsurance subsidiary. • “Ceded to nonaffiliates” for the property and casualty insurance subsidiaries represents their aggregate 30 percent pool participation percentage of 1) the amounts ceded to nonaffiliated reinsurance companies in accordance with the terms of the reinsurance agreements providing protection to the pool and each of its participants, and 2) the amounts ceded on a mandatory basis to state organizations in connection with various programs. For the reinsurance subsidiary, this line includes 1) reinsurance business that is ceded to other insurance companies in connection with “fronting” activities initiated by Employers Mutual, and 2) starting in 2016, amounts ceded to purchase additional reinsurance protection in peak exposure territories from external parties. • “Ceded to affiliates” for the property and casualty insurance subsidiaries represents the cession of their direct business to Employers Mutual under the terms of the pooling agreement and, beginning in 2016, amounts ceded to Employers Mutual under the terms of the inter-company reinsurance program. For the reinsurance subsidiary this line represents amounts ceded to Employers Mutual under the terms of the inter-company reinsurance program.

LIABILITY FOR LOSSES AND SETTLE

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES	12 Months Ended
	Dec. 31, 2017
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES	LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES The following table sets forth a reconciliation of beginning and ending reserves for losses and settlement expenses of the Company. Amounts presented are on a net basis, with a reconciliation of beginning and ending reserves to the gross amounts presented in the consolidated financial statements. Year ended December 31, ($ in thousands) 2017 2016 2015 Gross reserves at beginning of year $ 690,532 $ 678,774 $ 661,309 Re-valuation due to foreign currency exchange rates (1,913 ) (2,475 ) (2,061 ) Less ceded reserves at beginning of year 20,664 23,477 28,253 Net reserves at beginning of year 671,781 657,772 635,117 Incurred losses and settlement expenses related to: Current year 441,588 427,838 405,850 Prior years (19,619 ) (40,941 ) (35,114 ) Total incurred losses and settlement expenses 421,969 386,897 370,736 Paid losses and settlement expenses related to: Current year 179,354 172,652 154,958 Prior years 213,232 200,236 193,123 Total paid losses and settlement expenses 392,586 372,888 348,081 Net reserves at end of year 701,164 671,781 657,772 Plus ceded reserves at end of year 30,923 20,664 23,477 Re-valuation due to foreign currency exchange rates 525 (1,913 ) (2,475 ) Gross reserves at end of year $ 732,612 $ 690,532 $ 678,774 There is an inherent amount of uncertainty involved in the establishment of insurance liabilities. This uncertainty is greatest in the current and more recent accident years because a smaller percentage of the expected ultimate claims have been reported, adjusted and settled compared to more mature accident years. For this reason, carried reserves for these accident years reflect prudently conservative assumptions. As the carried reserves for these accident years run off, the overall expectation is that, more often than not, favorable development will occur. However, there is also the possibility that the ultimate settlement of liabilities associated with these accident years will show adverse development, and such adverse development could be substantial. Changes in reserve estimates are reflected in net income in the year such changes are recorded. Following is an analysis of the reserve development the Company experienced during the past three years. Care should be exercised when attempting to analyze the financial impact of the reported development amounts because, as noted above, the overall expectation is that, more often than not, favorable development will occur as the prior accident years’ reserves run off. 2017 Development For the property and casualty insurance segment, the December 31, 2017 estimate of loss and settlement expense reserves for accident years 2016 and prior decreased $15.7 million from the estimate at December 31, 2016 . This decrease represents 3.2 percent of the December 31, 2016 gross carried reserves and is primarily attributed to reductions in prior year ultimate loss ratios for every line of business except commercial auto liability and surety bonds (included in "other" lines of business). Commercial auto liability experienced adverse development as ultimate loss and settlement expense ratios were increased for accident years 2013-2016 due to increases in projected severity and/or frequency. The adverse development from surety bonds was due to two large accident year 2015 losses. The two lines of business contributing the majority of favorable development were other liability and workers' compensation. Other liability’s ultimate loss ratios were decreased for most accident years from 2001 through 2016 mainly in response to decreases in expected ultimate severity. Workers' compensation’s favorable development reflects a reduction in the accident year 2016 ultimate ratio as reported losses to date are materially more favorable than anticipated in frequency and severity assumptions underlying the December 31, 2016 selection. Included in the development amount is adverse development experienced in the other liability line of business stemming from the settlement of claims for past and future legal fees and losses on a multi-year asbestos exposure associated with a former insured, and a slight strengthening of remaining reserves. For the reinsurance segment, the December 31, 2017 estimate of loss and settlement expense reserves for accident years 2016 and prior decreased $3.9 million from the estimate at December 31, 2016 . This decrease represents 1.9 percent of the December 31, 2016 gross carried reserves and primarily reflects favorable development in the property/casualty global pro rata and excess contracts, and the per risk excess contracts. For the property/casualty global pro rata contracts, the favorable development was related to a change in ultimate loss assumptions for several prior years due to the use of company experience in place of Reinsurance Association of America data for calculating development factors to ultimate. 2016 Development During the third quarter of 2016, management implemented a new reserving methodology for the determination of direct bulk reserves in the property and casualty insurance segment. The new methodology, which is referred to as the accident year ultimate estimate approach, better conforms to industry practices and provides increased transparency of the drivers of the property and casualty insurance segment's performance. In connection with this change in reserving methodology, there was a reallocation of IBNR loss reserves and allocated settlement expense reserves from prior accident years to the current accident year in multiple lines of business. This change resulted in the movement of approximately $5.6 million of reserves from prior accident years to the current accident year that was reported as favorable development; however, this development is "mechanical in nature", and did not have an impact on earnings because the total amount of carried reserves did not change. For the property and casualty insurance segment, the December 31, 2016 estimate of loss and settlement expense reserves for accident years 2015 and prior decreased $30.0 million from the estimate at December 31, 2015 . Excluding the $5.6 million of "mechanical" favorable development that resulted from the change in reserving methodology noted above, the implied amount of favorable development that had an impact on earnings was approximately $24.4 million . This decrease represented 5.1 percent of the December 31, 2015 gross carried reserves and was primarily attributed to a significant amount of favorable reserve development experienced in the workers' compensation and other liability lines of business. The favorable development in the workers' compensation line of business was generated from a change in assumptions due to better than expected loss frequency for accident year 2015 and loss severity for the most recent accident years. The favorable development in the other liability line of business was generated from a change in assumptions due to better than expected loss severity. For the reinsurance segment, the December 31, 2016 estimate of loss and settlement expense reserves for accident years 2015 and prior decreased $10.9 million from the estimate at December 31, 2015 . This decrease represented 5.5 percent of the December 31, 2015 gross carried reserves and was attributed to favorable development in the 2015 accident year in the HORAD pro rata line of business, and an increase in the amount of negative bulk IBNR loss reserve carried on prior years' reserves in the MRB book of business. During 2016, the expected loss ratios utilized for prior contract years remained unchanged, except for ocean marine pro rata business. The expected loss ratios associated with this contract type were decreased in contract years 2012, 2014 and 2015 from the ratios utilized during 2015. Additionally, the expected loss ratio for contract year 2013 was increased slightly relative to the 2015 value. These changes were made in response to reserving information supplied by the ceding company, a large writer of ocean marine pro rata business. 2015 Development For the property and casualty insurance segment, the December 31, 2015 estimate of loss and settlement expense reserves for accident years 2014 and prior decreased $13.8 million from the estimate at December 31, 2014 . No changes were made in the key actuarial assumptions utilized to estimate loss and settlement expense reserves during 2015 ; however, the accident year allocation factors applied to IBNR loss reserves, bulk case loss reserves and the defense and cost containment portion of settlement expense reserves were revised at December 31, 2015 as part of the annual review. This change resulted in the movement of $423,000 of reserves from prior accident years to the current accident year, and hence, was reported as favorable development on prior years' reserves. Development on prior years’ reserves resulting solely from changes in the allocation of bulk reserves between the current and prior accident years is also "mechanical in nature", and does not have an impact on earnings. Excluding this $423,000 of "mechanical" favorable development, the implied amount of favorable development that had an impact on earnings was approximately $13.4 million . This decrease represented 2.9 percent of the December 31, 2014 gross carried reserves and was primarily attributed to better than expected outcomes on claims reported in prior years and favorable development on prior years' settlement expenses. For the reinsurance segment, the December 31, 2015 estimate of loss and settlement expense reserves for accident years 2014 and prior decreased $21.3 million from the estimate at December 31, 2014 . No changes were made in the key actuarial assumptions utilized to estimate loss and settlement expense reserves during 2015; however, the accident year allocation factors applied to IBNR loss reserves were revised during 2015, resulting in $1.0 million of "mechanical" adverse development. Excluding this $1.0 million of adverse development, the implied amount of favorable development that had an impact on earnings was approximately $22.3 million . This decrease represented 11.3 percent of the December 31, 2014 gross carried reserves and was attributed to several factors, including adjustments made in the offshore energy and liability proportional account, a reduction in carried IBNR loss reserves that was no longer necessary and a negative bulk IBNR loss reserve established for the MRB book of business. Following is information about reported incurred and paid claims development as of December 31, 2017 , net of reinsurance, as well as cumulative claim frequency and the amount of IBNR loss reserves carried (representing both IBNR liabilities and expected loss reserve development on reported claims). The information displayed for assumed reinsurance is restated to reflect all foreign currency denominated transactions on the basis of current (December 31, 2017 ) exchange rates. The number of reported claims (cumulative claim frequency) for the Company’s direct insurance business represents the total number of claims reported by the participants in the pooling agreement, and is determined on the basis of each unique combination of claimant, specific policy coverage, and type of loss. This is in contrast to all other reported amounts that are stated at the aggregate 30 percent pool participation percentage of the Company's property and casualty insurance subsidiaries. The cumulative claim frequency for the Company’s assumed reinsurance business is not readily available. Consistent with industry practices, bordereauxs on pro rata accounts often exclude claim frequency information, and if it is included, the level of detail provided by the ceding companies can vary significantly. Excess of loss contracts customarily report total losses subject to the treaty without detailed loss listings. ($ in thousands) Commercial auto liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 29,898 $ 30,082 $ 29,433 $ 27,968 $ 26,886 $ 26,923 $ 26,878 $ 26,741 $ 26,768 $ 26,764 $ (1 ) 11,511 2009 28,973 27,923 26,667 25,370 24,986 24,874 24,730 24,655 24,697 15 10,482 2010 30,377 27,480 26,478 26,401 26,252 26,479 26,166 26,166 — 11,393 2011 32,775 29,790 31,098 31,961 31,914 31,635 31,638 275 11,767 2012 32,768 34,235 37,098 37,681 37,693 37,753 (203 ) 11,941 2013 37,265 40,382 42,086 42,336 43,159 (52 ) 13,640 2014 50,342 49,998 51,455 51,933 1,225 15,059 2015 53,883 57,824 58,627 1,664 16,494 2016 59,468 61,188 6,307 16,829 2017 63,909 16,652 15,220 Total $ 425,834 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 6,551 $ 13,437 $ 19,204 $ 23,144 $ 25,215 $ 26,306 $ 26,527 $ 26,648 $ 26,750 $ 26,756 2009 6,952 12,957 17,359 21,532 24,001 24,495 24,593 24,608 24,628 2010 7,025 13,278 19,274 23,547 24,674 25,558 26,039 26,088 2011 6,801 14,875 22,206 26,598 29,121 30,293 30,878 2012 8,830 19,398 26,023 32,636 35,406 36,541 2013 8,729 19,975 29,997 36,232 40,807 2014 12,069 25,746 37,433 44,783 2015 13,336 27,424 39,478 2016 13,583 30,233 2017 14,474 Total $ 314,666 All outstanding liabilities before 2008, net of reinsurance (34 ) Liability for losses and settlement expenses, net of reinsurance $ 111,134 ($ in thousands) Commercial property insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 48,559 $ 42,870 $ 42,645 $ 42,422 $ 42,562 $ 42,649 $ 42,784 $ 42,765 $ 42,707 $ 42,786 $ 23 15,799 2009 39,511 36,003 35,985 35,881 35,622 35,926 36,056 36,020 36,292 (71 ) 14,654 2010 40,422 38,650 38,770 39,071 39,154 39,379 39,428 39,347 (75 ) 16,276 2011 58,930 57,614 57,271 57,629 57,703 58,375 58,148 22 19,509 2012 41,535 44,157 45,313 46,273 46,566 46,750 22 16,054 2013 50,266 50,976 52,511 53,070 52,966 268 16,005 2014 60,018 60,990 60,662 60,867 456 16,735 2015 55,508 56,798 55,659 99 14,366 2016 59,708 58,343 (176 ) 14,866 2017 55,459 65 13,818 Total $ 506,617 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 31,514 $ 40,603 $ 41,868 $ 41,991 $ 42,071 $ 42,607 $ 42,691 $ 42,755 $ 42,755 $ 42,761 2009 25,321 32,602 34,624 35,422 35,803 35,803 35,849 35,893 36,224 2010 28,032 35,730 36,931 37,926 38,901 39,314 39,318 39,323 2011 41,524 53,226 54,803 56,249 57,065 57,607 58,106 2012 32,879 41,862 43,628 44,543 46,270 46,562 2013 36,555 47,683 50,460 51,457 52,182 2014 43,022 55,679 58,045 59,255 2015 37,208 50,068 52,444 2016 41,652 51,103 2017 38,114 Total $ 476,074 All outstanding liabilities before 2008, net of reinsurance (1 ) Liability for losses and settlement expenses, net of reinsurance $ 30,542 ($ in thousands) Workers' compensation insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 49,577 $ 46,240 $ 44,113 $ 43,156 $ 43,766 $ 43,338 $ 43,301 $ 43,737 $ 42,943 $ 43,272 $ 1,540 21,622 2009 46,130 43,335 44,098 44,041 44,093 43,590 43,724 42,774 43,417 1,642 19,236 2010 46,328 49,336 50,057 49,906 49,851 50,069 49,145 49,435 2,032 19,624 2011 47,836 46,724 44,709 44,506 44,427 43,695 44,056 1,831 19,569 2012 51,099 50,094 47,756 46,928 45,088 45,276 2,335 19,380 2013 52,141 51,637 48,946 46,102 45,949 2,509 19,843 2014 51,515 50,973 47,472 47,836 2,902 19,457 2015 54,960 48,919 47,227 1,777 19,177 2016 57,832 48,276 3,084 20,147 2017 52,409 6,721 19,181 Total $ 467,153 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 12,432 $ 25,214 $ 31,110 $ 34,302 $ 36,024 $ 37,270 $ 37,938 $ 38,654 $ 39,099 $ 39,496 2009 11,879 25,157 31,802 35,363 37,409 38,329 39,167 39,583 39,908 2010 14,237 28,074 35,029 39,001 41,437 42,651 43,614 44,175 2011 13,291 26,291 32,237 35,295 37,027 38,437 39,167 2012 14,015 28,109 33,943 37,307 39,456 40,292 2013 14,917 29,219 35,061 37,907 39,254 2014 14,692 28,894 35,883 39,046 2015 14,956 29,023 35,458 2016 15,473 29,592 2017 16,863 Total $ 363,251 All outstanding liabilities before 2008, net of reinsurance 34,420 Liability for losses and settlement expenses, net of reinsurance $ 138,322 ($ in thousands) Other liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 46,327 $ 40,005 $ 38,877 $ 34,689 $ 38,755 $ 37,005 $ 36,305 $ 35,528 $ 35,491 $ 34,941 $ 538 10,957 2009 44,497 39,908 37,650 34,263 35,614 32,827 32,384 32,521 32,063 647 9,844 2010 41,624 36,213 34,655 38,829 36,137 34,655 34,556 33,736 639 10,144 2011 44,490 42,982 35,125 35,177 33,649 32,452 31,711 992 9,994 2012 42,661 42,081 41,139 40,275 37,093 37,180 38 10,043 2013 47,974 43,837 42,544 42,187 39,175 3,666 10,580 2014 61,382 54,403 52,601 51,047 1,662 10,878 2015 54,221 47,553 43,379 9,566 10,496 2016 59,052 56,384 12,913 10,262 2017 59,420 25,293 8,407 Total $ 419,036 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 4,299 $ 10,443 $ 16,525 $ 24,139 $ 28,476 $ 31,270 $ 32,514 $ 32,863 $ 33,162 $ 33,451 2009 3,294 10,707 16,718 22,276 26,255 28,172 29,722 30,176 30,488 2010 3,403 8,315 15,041 21,732 27,612 29,688 30,711 31,776 2011 4,730 10,572 17,308 22,154 25,647 28,228 29,060 2012 4,720 12,851 19,661 25,095 29,651 32,753 2013 4,414 11,894 21,122 27,642 31,752 2014 5,630 17,267 27,506 35,318 2015 4,331 11,588 19,022 2016 6,403 18,784 2017 6,322 Total $ 268,726 All outstanding liabilities before 2008, net of reinsurance 13,369 Liability for losses and settlement expenses, net of reinsurance $ 163,679 ($ in thousands) Personal auto liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 9,024 $ 8,221 $ 8,121 $ 8,098 $ 8,094 $ 7,909 $ 7,876 $ 7,833 $ 7,862 $ 7,804 $ — 6,783 2009 10,168 9,653 9,452 9,386 9,353 9,382 9,339 9,325 9,312 (2 ) 7,523 2010 9,815 9,851 9,736 9,698 9,700 9,656 9,676 9,649 2 7,431 2011 9,741 9,388 9,331 9,432 9,460 9,311 9,413 10 8,051 2012 10,917 10,756 11,023 10,731 10,537 10,626 7 7,872 2013 10,492 10,384 10,376 10,085 10,085 22 7,235 2014 10,573 9,631 9,331 9,204 27 6,312 2015 9,119 8,638 8,378 181 5,666 2016 7,404 6,584 108 4,693 2017 7,043 553 4,427 Total $ 88,098 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 3,096 $ 5,798 $ 6,743 $ 7,291 $ 7,558 $ 7,794 $ 7,810 $ 7,809 $ 7,805 $ 7,804 2009 3,564 6,393 7,966 8,905 9,049 9,194 9,204 9,278 9,314 2010 3,988 6,666 8,250 9,108 9,401 9,562 9,632 9,631 2011 3,950 6,842 8,129 8,883 9,038 9,153 9,335 2012 4,779 7,439 9,091 9,871 10,244 10,415 2013 4,377 7,521 8,985 9,648 9,932 2014 3,970 6,392 7,755 8,598 2015 3,800 6,229 7,535 2016 3,505 5,427 2017 3,467 Total $ 81,458 All outstanding liabilities before 2008, net of reinsurance 71 Liability for losses and settlement expenses, net of reinsurance $ 6,711 ($ in thousands) Homeowners insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 22,736 $ 20,222 $ 19,894 $ 19,924 $ 19,905 $ 19,886 $ 19,886 $ 19,901 $ 19,908 $ 19,911 $ — 12,999 2009 18,109 16,606 16,467 16,379 16,352 16,394 16,465 16,464 16,467 — 11,486 2010 17,875 17,523 17,074 17,053 17,093 17,129 17,146 17,139 7 12,146 2011 24,530 23,389 22,975 23,309 23,448 23,415 23,350 (19 ) 14,287 2012 16,057 16,496 16,836 16,929 16,892 16,879 (24 ) 10,113 2013 14,844 14,833 14,685 14,784 14,737 (14 ) 8,688 2014 13,228 13,328 13,447 13,427 18 7,423 2015 11,233 11,153 11,041 (25 ) 5,940 2016 11,801 11,377 87 7,281 2017 9,926 (221 ) 7,359 Total $ 154,254 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 15,642 $ 19,385 $ 19,550 $ 19,787 $ 19,891 $ 19,902 $ 19,903 $ 19,902 $ 19,908 $ 19,911 2009 12,645 15,885 16,135 16,246 16,288 16,315 16,421 16,464 16,467 2010 13,457 16,633 16,909 17,011 17,128 17,128 17,130 17,132 2011 19,828 22,421 22,737 23,136 23,403 23,370 23,368 2012 13,759 16,283 16,582 16,793 16,859 16,905 2013 11,735 14,285 14,621 14,681 14,703 2014 11,065 13,025 13,215 13,269 2015 8,650 10,456 10,730 2016 10,573 10,869 2017 8,760 Total $ 152,114 All outstanding liabilities before 2008, net of reinsurance 91 Liability for losses and settlement expenses, net of reinsurance $ 2,231 ($ in thousands) Auto physical damage insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 19,589 $ 17,743 $ 17,598 $ 17,584 $ 17,578 $ 17,567 $ 17,562 $ 17,558 $ 17,540 $ 17,541 $ (9 ) 28,635 2009 18,077 16,744 16,720 16,639 16,593 16,605 16,602 16,587 16,590 (11 ) 29,424 2010 19,249 18,657 18,538 18,549 18,527 18,532 18,488 18,494 (28 ) 31,518 2011 21,965 21,003 20,919 20,917 20,915 20,877 20,867 (27 ) 34,394 2012 21,389 21,342 21,263 21,233 21,161 21,184 (30 ) 31,099 2013 22,847 22,553 22,486 22,371 22,408 (4 ) 31,041 2014 24,897 24,115 23,904 23,946 (51 ) 31,580 2015 27,950 26,612 26,331 (10 ) 30,665 2016 28,070 27,629 (310 ) 30,715 2017 28,523 (1,868 ) 29,755 Total $ 223,513 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 16,491 $ 17,662 $ 17,577 $ 17,570 $ 17,577 $ 17,564 $ 17,560 $ 17,557 $ 17,555 $ 17,550 2009 15,566 16,661 16,687 16,636 16,592 16,603 16,602 16,601 16,599 2010 17,113 18,557 18,529 18,540 18,523 18,528 18,521 18,521 2011 19,849 20,984 20,912 20,904 20,912 20,900 20,892 2012 19,719 21,328 21,256 21,227 21,216 21,216 2013 20,774 22,512 22,463 22,417 22,408 2014 22,743 24,110 23,987 23,978 2015 24,483 26,538 26,327 2016 26,871 27,883 2017 27,452 Total $ 222,826 All outstanding liabilities before 2008, net of reinsurance (33 ) Liability for losses and settlement expenses, net of reinsurance $ 654 ($ in thousands) Assumed pro rata reinsurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 29,931 $ 25,463 $ 24,129 $ 24,473 $ 23,972 $ 24,103 $ 23,914 $ 24,068 $ 24,126 $ 24,084 $ 261 Unavailable 2009 23,812 19,364 18,442 17,626 17,447 17,274 17,212 17,204 17,183 225 2010 19,629 17,279 16,658 15,993 15,807 15,589 15,539 15,533 135 2011 30,231 30,316 29,848 29,075 28,459 28,440 28,339 182 2012 22,113 21,580 21,110 18,429 17,855 17,644 349 2013 23,306 30,174 27,545 26,936 25,442 1,883 2014 31,516 27,776 28,007 26,419 753 2015 38,442 35,356 35,148 1,704 2016 35,830 39,412 7,664 2017 29,989 14,704 Total $ 259,193 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 9,263 $ 18,268 $ 20,525 $ 21,744 $ 22,284 $ 22,700 $ 22,950 $ 23,253 $ 23,395 $ 23,476 2009 6,105 13,004 14,644 15,481 16,024 16,283 16,463 16,651 16,748 2010 5,059 12,057 14,081 14,499 15,172 15,212 15,254 15,299 2011 10,220 23,008 26,733 27,477 27,901 27,973 28,037 2012 4,478 12,826 15,159 16,403 16,772 16,852 2013 3,886 12,639 17,963 21,123 21,864 2014 6,052 16,185 20,745 23,567 2015 9,569 22,042 30,356 2016 9,673 22,280 2017 7,674 Total $ 206,153 All outstanding liabilities before 2008, net of reinsurance 2,599 Liability for losses and settlement expenses, net of reinsurance $ 55,639 ($ in thousands) Assumed excess of loss reinsurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 43,963 $ 39,939 $ 41,427 $ 40,162 $ 39,019 $ 39,606 $ 37,519 $ 37,063 $ 36,928 $ 37,786 $ 1,384 Unavailable 2009 38,903 30,552 29,987 30,518 30,167 28,233 27,913 27,142 26,922 1,496 2010 47,426 41,011 40,820 40,307 39,675 40,432 39,628 39,166 1,857 2011 72,124 61,787 60,948 59,345 59,090 58,700 58,279 1,977 2012 58,852 56,119 54,494 53,247 52,896 52,003 2,898 2013 52,699 47,705 45,103 44,947 44,829 3,188 2014 65,573 59,108 60,454 62,009 5,061 2015 60,183 55,190 51,924 6,372 2016 66,995 67,206 9,099 2017 91,994 29,426 Total $ 532,118 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 14,314 $ 25,556 $ 28,756 $ 30,690 $ 31,320 $ 32,634 $ 32,784 $ 33,216 $ 33,660 $ 33,837 2009 8,554 15,896 18,803 21,011 21,882 22,231 22,854 23,032 23,264 2010 9,282 24,759 28,037 30,858 32,700 33,709 35,387 35,646 2011 25,309 42,214 47,965 50,613 52,611 53,906 54,628 2012 21,320 36,266 40,641 43,637 45,174 46,735 2013 11,732 27,635 33,422 37,717 39,520 2014 22,172 39,361 46,163 50,242 2015 13,434 30,495 36,918 2016 18,408 38,913 2017 27,881 Total $ 387,584 All outstanding liabilities before 2008, net of reinsurance 18,772 Liability for losses and settlement expenses, net of reinsurance $ 163,306 The following table sets forth a reconciliation of the incurred and paid claims development tables to the liability for losses and settlement expenses: ($ in thousands) December 31, 2017 Net outstanding liabilities for losses and allocated settlement expenses: Commercial auto liability insurance $ 111,134 Commercial property insurance 30,542 Workers' compensation insurance 138,322 Other liability insurance 163,679 Personal auto liability insurance 6,711 Homeowners insurance 2,231 Auto physical damage insurance 654 Assumed pro rata reinsurance 55,639 Assumed excess of loss reinsurance 163,306 Other lines of insurance 2,283 Liability for losses and allocated settlement expenses, net of reinsurance 674,501 Ceded reserves for losses and allocated settlement expenses: Commercial auto liability insurance 768 Commercial property insurance 4,624 Workers' compensation insurance 10,005 Other liability insurance 3,938 Personal auto liability insurance 1,337 Homeowners insurance 573 Auto physical damage insurance 228 Assumed pro rata reinsurance 7,167 Assumed excess of loss reinsurance 1,444 Other lines of insurance 839 Total ceded reserves for losses and allocated settlement expenses 30,923 Unallocated settlement expenses 27,188 Gross reserve for losses and settlement expenses $ 732,612 Average annual percentage payout of incurred claims by age, net of reinsurance Supplementary unaudited information Years 1 2 3 4 5 6 7 8 9 10 Commercial auto liability insurance 23.5 % 25.7 % 21.2 % 15.4 % 8.0 % 3.2 % 1.2 % 0.3 % 0.3 % 0.0 % Commercial property insurance 70.3 % 20.1 % 4.0 % 1.9 % 1.7 % 0.8 % 0.3 % 0.1 % 0.5 % 0.0 % Workers' compensation insurance 30.5 % 29.8 % 13.8 % 7.2 % 4.2 % 2.5 % 1.8 % 1.3 % 0.9 % 0.9 % Other liability insurance 11.5 % 19.6 % 19.5 % 17.2 % 12.7 % 7.3 % 3.5 % 1.9 % 1.0 % 0.8 % Personal auto liability insurance 44.1 % 29.4 % 14.9 % 8.2 % 2.6 % 1.8 % 0.7 % 0.3 % 0.2 % 0.0 % Homeowners insurance 82.2 % 14.9 % 1.7 % 0.9 % 0.5 % 0.1 % 0.2 % 0.1 % 0.0 % 0.0 % Auto physical damage insurance 94.3 % 6.6 % (0.3 )% (0.1 )% (0.1 )% 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % Assumed pro rata reinsurance 28.4 % 39.5 % 15.0 % 6.5 % 2.7 % 0.9 % 0.6 % 0.9 % 0.6 % 0.3 % Assumed excess of loss reinsurance 32.3 % 31.2 % 10.3 % 6.7 % 3.3 % 2.5 % 2.1 % 0.8 % 1.1 % 0.5 %

ASBESTOS AND ENVIRONMENTAL CLAI

ASBESTOS AND ENVIRONMENTAL CLAIMS	12 Months Ended
	Dec. 31, 2017
Liability for Asbestos and Environmental Claims [Abstract]
ASBESTOS AND ENVIRONMENTAL CLAIMS	ASBESTOS AND ENVIRONMENTAL CLAIMS The Company has exposure to asbestos and environmental related claims associated with the insurance business written by the parties to the pooling agreement and the reinsurance business assumed from Employers Mutual by the reinsurance subsidiary. Asbestos and environmental losses paid by the Company have averaged $2.9 million per year over the past five years. Reserves for asbestos and environmental related claims for direct insurance and assumed reinsurance business totaled $11.7 million and $13.3 million ( $11.4 million and $13.0 million net of reinsurance) at December 31, 2017 and 2016 , respectively. Estimating loss and settlement expense reserves for asbestos and environmental claims is very difficult due to the many uncertainties surrounding these types of claims. These uncertainties exist because the assignment of responsibility varies widely by state and claims often emerge long after a policy has expired, which makes assignment of damages to the appropriate party and to the time period covered by a particular policy difficult. In establishing reserves for these types of claims, management monitors the relevant facts concerning each claim, the current status of the legal environment, social and political conditions, and claim history and trends within the Company and the industry. At present, the pool participants are defending approximately 1,872 asbestos bodily injury lawsuits, some of which involve multiple plaintiffs. Most of the lawsuits are subject to express reservation of rights based upon the lack of an injury within the applicable policy periods, because many asbestos lawsuits do not specifically allege dates of asbestos exposure or dates of injury. The pool participants’ policyholders named as defendants in these asbestos lawsuits are typically peripheral defendants who have little or no exposure and are often dismissed from asbestos litigation with nominal or no payment (i.e., small contractors, supply companies, and a furnace manufacturer). Prior to 2008, actual losses paid for asbestos-related claims had been minimal due to the plaintiffs’ failure to identify an exposure to any asbestos-containing products associated with the pool participants’ current and former policyholders. However, paid losses and settlement expenses have increased significantly since 2008 as a result of claims attributed to one former policyholder. During the period 2009 through 2017 , the Company's share of paid losses and settlement expenses attributed to this former policyholder, a furnace manufacturer, was $12.5 million (mostly settlement expenses). A coverage-in-place agreement was executed with this former policyholder in 2009 and a national coordinating counsel was retained to address the multi-state litigation issues. The asbestos exposure associated with this former policyholder has increased in recent years, and this trend may possibly continue into the future with increased per plaintiff settlements. Approximately 692 asbestos exposure claims associated with this former policyholder remain open. During 2017 a settlement was reached with another former insured, resulting in the Company recognizing $4.5 million (its share) of settlement expenses to remove all past and future asbestos liability exposure related to that policyholder. While the Company does not have a significant amount of exposure to asbestos claims, management has been strengthening the reserves carried for these exposures each year to the amount believed to be management's best estimate. In 2017 , the settlement expense reserves for asbestos claims were strengthened by $900,000 .

STATUTORY INFORMATION AND DIVID

STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS	12 Months Ended
	Dec. 31, 2017
STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS [Abstract]
STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS	STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS The Company’s insurance subsidiaries are required to file financial statements with state regulatory authorities. The accounting principles used to prepare these statutory financial statements follow prescribed or permitted accounting practices that differ from GAAP. Prescribed statutory accounting principles include state laws, regulations and general administrative rules issued by the state of domicile, as well as a variety of publications and manuals of the National Association of Insurance Commissioners (NAIC). Permitted accounting practices encompass all accounting practices not prescribed, but allowed by the state of domicile. The Company’s insurance subsidiaries had no permitted accounting practices during 2017 , 2016 or 2015 . Statutory surplus of the Company’s insurance subsidiaries was $560.1 million and $526.8 million at December 31, 2017 and 2016 , respectively. Statutory net income of the Company’s insurance subsidiaries was $30.1 million , $48.3 million and $48.8 million for 2017 , 2016 and 2015 , respectively. The NAIC utilizes a risk-based capital model to help state regulators assess the capital adequacy of insurance companies and identify insurers that are in, or are perceived as approaching, financial difficulty. This model establishes minimum capital needs based on the risks applicable to the operations of the individual insurer. The risk-based capital requirements for property and casualty insurance companies measure three major areas of risk: asset risk, credit risk and underwriting risk. Companies having less statutory surplus than required by the risk-based capital requirements are subject to varying degrees of regulatory scrutiny and intervention, depending on the severity of the inadequacy. At December 31, 2017 , the Company’s insurance subsidiaries had total adjusted statutory capital of $560.1 million , which exceeds the minimum risk-based capital requirement of $94.4 million . The amount of dividends available for distribution to the Company by its insurance subsidiaries is limited by law to a percentage of the statutory unassigned surplus of each of the subsidiaries as of the previous December 31, as determined in accordance with accounting practices prescribed by insurance regulatory authorities of the state of domicile of each subsidiary. Under Iowa law, the maximum dividend that may be paid within a 12 month period without prior regulatory approval is restricted to the greater of 10 percent of statutory surplus as regards policyholders as of the preceding December 31, or net income of the preceding calendar year on a statutory basis, not greater than earned statutory surplus (North Dakota, the state of domicile of Dakota Fire Insurance Company, imposes similar restrictions, except that it is limited to the lesser of 10 percent of statutory surplus as regards policyholders as of the preceding December 31, or net income excluding capital gains of the preceding calendar year on a statutory basis, not greater than earned statutory surplus). At December 31, 2017 , $54.2 million was available for distribution to the Company in 2018 without prior approval.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company’s operations consist of a property and casualty insurance segment and a reinsurance segment. The property and casualty insurance segment writes both commercial and personal lines of insurance, with a focus on medium-sized commercial accounts. The reinsurance segment provides reinsurance for other insurers and reinsurers. The segments are managed separately due to differences in the insurance products sold and the business environments in which they operate. Management evaluates the performance of its insurance segments using financial measurements based on Statutory Accounting Principles (SAP) instead of GAAP. Such measures include premiums written, premiums earned, statutory underwriting profit (loss), and investment results, as well as loss and loss adjustment expense ratios, trade underwriting expense ratios, and combined ratios. The GAAP accounting policies of the segments are described in note 1, Summary of Significant Accounting Policies. Summarized financial information for the Company’s segments is as follows: Year ended December 31, 2017 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 472,369 $ 134,789 $ — $ 607,158 Underwriting profit (loss): SAP underwriting profit (loss) 2,702 (15,386 ) — (12,684 ) GAAP adjustments 5,217 (670 ) — 4,547 GAAP underwriting profit (loss) 7,919 (16,056 ) — (8,137 ) Net investment income (loss) 32,670 12,771 38 45,479 Net realized investment gains (losses) 4,896 1,660 — 6,556 Other income (loss) 1,171 (1,519 ) — (348 ) Interest expense 337 — — 337 Other expenses 1,128 — 2,269 3,397 Income (loss) before income tax expense (benefit) $ 45,191 $ (3,144 ) $ (2,231 ) $ 39,816 Assets $ 1,200,636 $ 484,678 $ 604,105 $ 2,289,419 Eliminations — — (599,036 ) (599,036 ) Reclassifications (1,393 ) (6,273 ) (777 ) (8,443 ) Total assets $ 1,199,243 $ 478,405 $ 4,292 $ 1,681,940 Year ended December 31, 2016 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 456,467 $ 135,941 $ — $ 592,408 Underwriting profit (loss): SAP underwriting profit (loss) 4,276 11,377 — 15,653 GAAP adjustments (934 ) (1,023 ) — (1,957 ) GAAP underwriting profit (loss) 3,342 10,354 — 13,696 Net investment income (loss) 33,886 13,591 13 47,490 Net realized investment gains (losses) 4,082 (8 ) — 4,074 Other income (loss) 594 417 — 1,011 Interest expense 337 — — 337 Other expenses 721 — 2,006 2,727 Income (loss) before income tax expense (benefit) $ 40,846 $ 24,354 $ (1,993 ) $ 63,207 Assets $ 1,122,037 $ 455,493 $ 554,164 $ 2,131,694 Eliminations — — (540,249 ) (540,249 ) Reclassifications — (1,932 ) (700 ) (2,632 ) Total assets $ 1,122,037 $ 453,561 $ 13,215 $ 1,588,813 Year ended December 31, 2015 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 447,197 $ 123,069 $ — $ 570,266 Underwriting profit (loss): SAP underwriting profit (loss) 2,494 13,228 — 15,722 GAAP adjustments 5,460 41 — 5,501 GAAP underwriting profit (loss) 7,954 13,269 — 21,223 Net investment income (loss) 32,668 12,923 (9 ) 45,582 Net realized investment gains (losses) 4,163 1,990 — 6,153 Other income (loss) 771 954 — 1,725 Interest expense 337 — — 337 Other expenses 748 — 1,942 2,690 Income (loss) before income tax expense (benefit) $ 44,471 $ 29,136 $ (1,951 ) $ 71,656 The following table displays the premiums earned for the property and casualty insurance segment and the reinsurance segment for the three years ended December 31, 2017 , by line of insurance. Year ended December 31, ($ in thousands) 2017 2016 2015 Property and casualty insurance segment Commercial lines: Automobile $ 118,224 $ 110,941 $ 105,904 Property 108,162 105,012 104,303 Workers' compensation 100,552 96,517 92,828 Other liability 98,674 96,630 92,665 Other 8,719 8,374 8,079 Total commercial lines 434,331 417,474 403,779 Personal lines 38,038 38,993 43,418 Total property and casualty insurance $ 472,369 $ 456,467 $ 447,197 Reinsurance segment Pro rata reinsurance $ 44,636 $ 56,317 $ 47,421 Excess of loss reinsurance 90,153 79,624 75,648 Total reinsurance $ 134,789 $ 135,941 $ 123,069 Consolidated $ 607,158 $ 592,408 $ 570,266

DISCLOSURES ABOUT THE FAIR VALU

DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS	DISCLOSURES ABOUT THE FAIR VALUES OF FINANCIAL INSTRUMENTS The carrying amounts and the estimated fair values of the Company’s financial instruments as of December 31, 2017 and 2016 are summarized in the tables below. December 31, 2017 Carrying Estimated ($ in thousands) Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 8,078 $ 8,078 U.S. government-sponsored agencies 297,949 297,949 Obligations of states and political subdivisions 307,536 307,536 Commercial mortgage-backed 83,980 83,980 Residential mortgage-backed 119,799 119,799 Other asset-backed 24,114 24,114 Corporate 433,560 433,560 Total fixed maturity securities available-for-sale 1,275,016 1,275,016 Equity securities available-for-sale: Common stocks: Financial services 43,522 43,522 Information technology 35,810 35,810 Healthcare 30,595 30,595 Consumer staples 14,127 14,127 Consumer discretionary 20,538 20,538 Energy 16,905 16,905 Industrials 28,489 28,489 Other 16,421 16,421 Non-redeemable preferred stocks 21,708 21,708 Total equity securities available-for-sale 228,115 228,115 Short-term investments 23,613 23,613 Liabilities: Surplus notes 25,000 16,689 December 31, 2016 Carrying Estimated ($ in thousands) Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 7,830 $ 7,830 U.S. government-sponsored agencies 239,197 239,197 Obligations of states and political subdivisions 335,757 335,757 Commercial mortgage-backed 37,572 37,572 Residential mortgage-backed 96,434 96,434 Other asset-backed 26,393 26,393 Corporate 456,516 456,516 Total fixed maturity securities available-for-sale 1,199,699 1,199,699 Equity securities available-for-sale: Common stocks: Financial services 35,122 35,122 Information technology 30,542 30,542 Healthcare 24,707 24,707 Consumer staples 19,100 19,100 Consumer discretionary 22,321 22,321 Energy 19,071 19,071 Industrials 24,245 24,245 Other 18,384 18,384 Non-redeemable preferred stocks 20,347 20,347 Total equity securities available-for-sale 213,839 213,839 Short-term investments 39,670 39,670 Liabilities: Surplus notes 25,000 11,228 The estimated fair values of fixed maturity and equity securities is based on quoted market prices, where available. In cases where quoted market prices are not available, fair values are based on a variety of valuation techniques depending on the type of security. Short-term investments generally include money market funds, U.S. Treasury bills and commercial paper. Short-term investments are carried at fair value, which approximates cost, due to the highly liquid nature of the securities. Short-term securities are classified as Level 1 fair value measurements when the fair values can be validated by recent trades. When recent trades are not available, fair value is deemed to be the cost basis and the securities are classified as Level 2 fair value measurements. The estimated fair value of the surplus notes is derived by discounting future expected cash flows at a rate deemed appropriate. The discount rate was set at the average of current yields-to-maturity on several insurance company surplus notes that are traded in observable markets, adjusted upward by 50 basis points to reflect illiquidity and perceived risk premium differences. Other assumptions include a 25 -year term (the surplus notes have no stated maturity date) and an interest rate that continues at the current 1.35 percent interest rate. The rate is typically adjusted every five years (next review due in 2018) and is based upon the then-current Federal Home Loan Bank borrowing rate for 5-year funds available to Employers Mutual. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The following fair value hierarchy prioritizes inputs to valuation techniques used to measure fair value. Level 1 - Unadjusted quoted prices for identical assets or liabilities in active markets that the Company has the ability to access. Level 2 - Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in inactive markets; or valuations based on models where the significant inputs are observable (e.g., interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. Level 3 - Prices or valuation techniques that require significant unobservable inputs because observable inputs are not available. The unobservable inputs may reflect the Company’s own judgments about the assumptions that market participants would use. The Company uses an independent pricing source to obtain the estimated fair values of a majority of its securities, subject to an internal validation. The fair values are based on quoted market prices, where available. This is typically the case for equity securities and money market funds, which are accordingly classified as Level 1 fair value measurements. In cases where quoted market prices are not available, fair values are based on a variety of valuation techniques depending on the type of security. Fixed maturity securities, non-redeemable preferred stocks and various short-term investments in the Company’s portfolio may not trade on a daily basis; however, observable inputs are utilized in their valuations, and these securities are therefore classified as Level 2 fair value measurements. Following is a brief description of the various pricing techniques used by the independent pricing source for different asset classes. • U.S. Treasury securities (including bonds, notes, and bills) are priced according to a number of live data sources, including active market makers and inter-dealer brokers. Prices from these sources are reviewed based on the sources’ historical accuracy for individual issues and maturity ranges. • U.S. government-sponsored agencies and corporate securities (including fixed-rate corporate bonds and medium-term notes) are priced by determining a bullet (non-call) spread scale for each issuer for maturities going out to forty years. These spreads represent credit risk and are obtained from the new issue market, secondary trading, and dealer quotes. An option adjusted spread model is incorporated to adjust spreads of issues that have early redemption features. The final spread is then added to the U.S. Treasury curve. • Obligations of states and political subdivisions are priced by tracking and analyzing actively quoted issues and reported trades, material event notices and benchmark yields. Municipal bonds with similar characteristics are grouped together into market sectors, and internal yield curves are constructed daily for these sectors. Individual bond evaluations are extrapolated from these sectors, with the ability to make individual spread adjustments for attributes such as discounts, premiums, alternative minimum tax, and/or whether or not the bond is callable. • Mortgage-backed and asset-backed securities are first reviewed for the appropriate pricing speed (if prepayable), spread, yield and volatility. The securities are priced with models using spreads and other information solicited from market buy- and sell-side sources, including primary and secondary dealers, portfolio managers, and research analysts. To determine a tranche’s price, first the benchmark yield is determined and adjusted for collateral performance, tranche level attributes and market conditions. Then the cash flow for each tranche is generated (using consensus prepayment speed assumptions including, as appropriate, a prepayment projection based on historical statistics of the underlying collateral). The tranche-level yield is used to discount the cash flows and generate the price. Depending on the characteristics of the tranche, a volatility-driven, multi-dimensional single cash flow stream model or an option-adjusted spread model may be used. When cash flows or other security structure or market information is not available, broker quotes may be used. On a quarterly basis, the Company receives from its independent pricing service a list of fixed maturity securities, if any, that were priced solely from broker quotes. For these securities, fair value may be determined using the broker quotes, or by the Company using similar pricing techniques as the Company’s independent pricing service. Depending on the level of observable inputs, these securities would be classified as Level 2 or Level 3 fair value measurements. At December 31, 2017 and 2016 , the Company had no securities priced solely from broker quotes. A small number of the Company’s securities are not priced by the independent pricing service. Two of these are equity securities that are reported as Level 3 fair value measurements since no observable inputs are used in their valuations. The largest of these equity security holdings is in a privately placed non-redeemable convertible preferred stock investment in a start-up technology company that Employers Mutual is working closely with in its data analytics activities. This security is carried at its cost, which is presumed to approximate fair value. The other equity security, a much smaller holding, continues to be reported at the fair value obtained from the Securities Valuation Office (SVO) of the NAIC. The SVO establishes a per share price for this security based on an annual review of that company’s financial statements, typically performed during the second quarter. The other securities not priced by the Company’s independent pricing service consist of eight fixed maturity securities ( nine at December 31, 2016 ). Two of these fixed maturity securities, classified as Level 3 fair value measurements, are corporate securities that convey premium tax benefits and are not publicly traded. The fair values for these securities are based on discounted cash flow analyses. The other fixed maturity securities are classified as Level 2 fair value measurements. The fair values for these fixed maturity securities were obtained from either the SVO, the Company’s investment custodian, or the Company's investment department using similar pricing techniques as the Company's independent pricing service. Presented in the tables below are the estimated fair values of the Company’s financial instruments as of December 31, 2017 and 2016 . December 31, 2017 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Financial instruments reported at fair value on recurring basis: Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 8,078 $ — $ 8,078 $ — U.S. government-sponsored agencies 297,949 — 297,949 — Obligations of states and political subdivisions 307,536 — 307,536 — Commercial mortgage-backed 83,980 — 83,980 — Residential mortgage-backed 119,799 — 119,799 — Other asset-backed 24,114 — 24,114 — Corporate 433,560 — 432,940 620 Total fixed maturity securities available-for-sale 1,275,016 — 1,274,396 620 Equity securities available-for-sale: Common stocks: Financial services 43,522 43,519 — 3 Information technology 35,810 35,810 — — Healthcare 30,595 30,595 — — Consumer staples 14,127 14,127 — — Consumer discretionary 20,538 20,538 — — Energy 16,905 16,905 — — Industrials 28,489 28,489 — — Other 16,421 16,421 — — Non-redeemable preferred stocks 21,708 9,512 10,196 2,000 Total equity securities available-for-sale 228,115 215,916 10,196 2,003 Short-term investments 23,613 23,613 — — Financial instruments not reported at fair value: Liabilities: Surplus notes 16,689 — — 16,689 December 31, 2016 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Financial instruments reported at fair value on recurring basis: Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 7,830 $ — $ 7,830 $ — U.S. government-sponsored agencies 239,197 — 239,197 — Obligations of states and political subdivisions 335,757 — 335,757 — Commercial mortgage-backed 37,572 — 37,572 — Residential mortgage-backed 96,434 — 96,434 — Other asset-backed 26,393 — 26,393 — Corporate 456,516 — 455,534 982 Total fixed maturity securities available-for-sale 1,199,699 — 1,198,717 982 Equity securities available-for-sale: Common stocks: Financial services 35,122 35,119 — 3 Information technology 30,542 30,542 — — Healthcare 24,707 24,707 — — Consumer staples 19,100 19,100 — — Consumer discretionary 22,321 22,321 — — Energy 19,071 19,071 — — Industrials 24,245 24,245 — — Other 18,384 18,384 — — Non-redeemable preferred stocks 20,347 11,074 7,273 2,000 Total equity securities available-for-sale 213,839 204,563 7,273 2,003 Short-term investments 39,670 39,670 — — Financial instruments not reported at fair value: Liabilities: Surplus notes 11,228 — — 11,228 Presented in the table below is a reconciliation of the assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2017 and 2016 . Any unrealized gains or losses on these securities are recognized in other comprehensive income (loss). Any gains or losses from settlements, disposals or impairments of these securities are reported as realized investment gains or losses in net income. Fair value measurements using significant unobservable (Level 3) inputs ($ in thousands) Fixed maturity securities available-for-sale, corporate Equity securities Equity securities available-for-sale, non-redeemable preferred stocks Total Balance at December 31, 2015 $ 1,329 $ 3 $ — $ 1,332 Purchases — — 2,000 2,000 Settlements (345 ) — — (345 ) Unrealized losses included in other comprehensive income (loss) (2 ) — — (2 ) Balance at December 31, 2016 982 3 2,000 2,985 Settlements (356 ) — — (356 ) Unrealized losses included in other comprehensive income (loss) (6 ) — — (6 ) Balance at December 31, 2017 $ 620 $ 3 $ 2,000 $ 2,623 There were no transfers into or out of Levels 1 or 2 during 2017 or 2016 . It is the Company’s policy to recognize transfers between levels at the beginning of the reporting period.

INVESTMENTS

INVESTMENTS	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
INVESTMENTS	INVESTMENTS Investments of the Company’s insurance subsidiaries are subject to the insurance laws of the state of their incorporation. These laws prescribe the kind, quality and concentration of investments that may be made by insurance companies. In general, these laws permit investments, within specified limits and subject to certain qualifications, in federal, state and municipal obligations, corporate bonds, preferred and common stocks and real estate mortgages. The Company believes that it is in compliance with these laws. The amortized cost and estimated fair value of securities available-for-sale as of December 31, 2017 and 2016 are as follows. All securities are classified as available-for-sale and are carried at fair value. December 31, 2017 Amortized Gross Gross Estimated ($ in thousands) Securities available-for-sale: Fixed maturity securities: U.S. treasury $ 8,115 $ — $ 37 $ 8,078 U.S. government-sponsored agencies 303,932 122 6,105 297,949 Obligations of states and political subdivisions 290,038 17,729 231 307,536 Commercial mortgage-backed 84,058 591 669 83,980 Residential mortgage-backed 120,554 2,479 3,234 119,799 Other asset-backed 23,934 625 445 24,114 Corporate 422,535 11,490 465 433,560 Total fixed maturity securities 1,253,166 33,036 11,186 1,275,016 Equity securities: Common stocks: Financial services 30,103 13,594 175 43,522 Information technology 18,308 17,504 2 35,810 Healthcare 18,877 11,876 158 30,595 Consumer staples 9,275 4,917 65 14,127 Consumer discretionary 10,935 9,640 37 20,538 Energy 12,441 5,381 917 16,905 Industrials 12,746 15,757 14 28,489 Other 11,058 5,363 — 16,421 Non-redeemable preferred stocks 20,531 1,216 39 21,708 Total equity securities 144,274 85,248 1,407 228,115 Total securities available-for-sale $ 1,397,440 $ 118,284 $ 12,593 $ 1,503,131 December 31, 2016 Amortized Gross Gross Estimated ($ in thousands) Securities available-for-sale: Fixed maturity securities: U.S. treasury $ 7,841 $ — $ 11 $ 7,830 U.S. government-sponsored agencies 249,495 311 10,609 239,197 Obligations of states and political subdivisions 319,663 17,034 940 335,757 Commercial mortgage-backed 37,964 741 1,133 37,572 Residential mortgage-backed 102,307 1,435 7,308 96,434 Other asset-backed 26,592 732 931 26,393 Corporate 445,663 12,232 1,379 456,516 Total fixed maturity securities 1,189,525 32,485 22,311 1,199,699 Equity securities: Common stocks: Financial services 22,922 12,410 210 35,122 Information technology 19,832 10,739 29 30,542 Healthcare 16,092 8,700 85 24,707 Consumer staples 13,438 5,787 125 19,100 Consumer discretionary 14,812 7,672 163 22,321 Energy 14,276 4,873 78 19,071 Industrials 13,005 11,258 18 24,245 Other 13,071 5,345 32 18,384 Non-redeemable preferred stocks 20,031 483 167 20,347 Total equity securities 147,479 67,267 907 213,839 Total securities available-for-sale $ 1,337,004 $ 99,752 $ 23,218 $ 1,413,538 The following tables set forth the estimated fair values and gross unrealized losses associated with investment securities that were in an unrealized loss position as of December 31, 2017 and 2016 , listed by length of time the securities were consistently in an unrealized loss position. December 31, 2017 Less than twelve months Twelve months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. treasury $ 8,078 $ 37 $ — $ — $ 8,078 $ 37 U.S. government-sponsored agencies 134,284 1,491 127,604 4,614 261,888 6,105 Obligations of states and political subdivisions — — 14,416 231 14,416 231 Commercial mortgage-backed 32,155 221 8,530 448 40,685 669 Residential mortgage-backed 30,003 394 22,948 2,840 52,951 3,234 Other asset-backed — — 13,440 445 13,440 445 Corporate 28,314 329 4,047 136 32,361 465 Total fixed maturity securities 232,834 2,472 190,985 8,714 423,819 11,186 Equity securities: Common stocks: Financial services 4,391 175 — — 4,391 175 Information technology 344 2 — — 344 2 Healthcare 2,532 158 — — 2,532 158 Consumer staples 575 65 — — 575 65 Consumer discretionary 992 37 — — 992 37 Energy 3,181 917 — — 3,181 917 Industrials 3,016 14 — — 3,016 14 Non-redeemable preferred stocks — — 1,961 39 1,961 39 Total equity securities 15,031 1,368 1,961 39 16,992 1,407 Total temporarily impaired securities $ 247,865 $ 3,840 $ 192,946 $ 8,753 $ 440,811 $ 12,593 December 31, 2016 Less than twelve months Twelve months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. treasury $ 7,830 $ 11 $ — $ — $ 7,830 $ 11 U.S. government-sponsored agencies 202,900 10,609 — — 202,900 10,609 Obligations of states and political subdivisions 43,777 940 — — 43,777 940 Commercial mortgage-backed 21,695 1,133 — — 21,695 1,133 Residential mortgage-backed 26,217 1,232 23,625 6,076 49,842 7,308 Other asset-backed 19,091 931 — — 19,091 931 Corporate 82,657 1,273 8,625 106 91,282 1,379 Total fixed maturity securities 404,167 16,129 32,250 6,182 436,417 22,311 Equity securities: Common stocks: Financial services 1,462 12 908 198 2,370 210 Information technology 1,947 29 — — 1,947 29 Healthcare 3,585 85 — — 3,585 85 Consumer staples 2,427 125 — — 2,427 125 Consumer discretionary 1,637 163 — — 1,637 163 Energy 1,621 33 1,188 45 2,809 78 Industrials 779 18 — — 779 18 Other 1,472 32 — — 1,472 32 Non-redeemable preferred stocks 3,356 44 1,877 123 5,233 167 Total equity securities 18,286 541 3,973 366 22,259 907 Total temporarily impaired securities $ 422,453 $ 16,670 $ 36,223 $ 6,548 $ 458,676 $ 23,218 All of the fixed maturity securities that are in an unrealized loss position are considered investment grade by credit rating agencies. Because management does not intend to sell these securities, does not believe it will be required to sell these securities before recovery, and believes it will collect the amounts due on these securities, it was determined that these securities were not “other-than-temporarily” impaired at December 31, 2017 . No individual equity security accounted for a material amount of unrealized losses. Because the Company has the ability and intent to hold these securities for a reasonable amount of time to allow for recovery, it was determined that these securities were not “other-than-temporarily” impaired at December 31, 2017 . All of the Company’s preferred stock holdings that are in an unrealized loss position are perpetual preferred stocks. The Company evaluates these perpetual preferred stocks with unrealized losses for “other-than-temporary” impairment similar to fixed maturity securities since they have debt-like characteristics such as periodic cash flows in the form of dividends and call features, are rated by rating agencies and are priced like other long-term callable fixed maturity securities. There was no evidence of any credit deterioration in the issuers of the preferred stocks and the Company does not intend to sell these securities before recovery, nor does it believe it will be required to sell these securities before recovery; therefore, it was determined that these securities were not “other-than-temporarily” impaired at December 31, 2017 . The amortized cost and estimated fair values of fixed maturity securities at December 31, 2017 , by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations, with or without call or prepayment penalties. ($ in thousands) Amortized Estimated Securities available-for-sale: Due in one year or less $ 40,543 $ 41,094 Due after one year through five years 173,741 177,883 Due after five years through ten years 368,782 376,119 Due after ten years 463,572 474,251 Securities not due at a single maturity date 206,528 205,669 Totals $ 1,253,166 $ 1,275,016 A summary of realized investment gains and (losses) is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Fixed maturity securities available-for-sale: Gross realized investment gains $ 545 $ 2,054 $ 725 Gross realized investment losses (4,849 ) (2,829 ) (251 ) Equity securities available-for-sale: Gross realized investment gains 19,792 15,078 12,741 Gross realized investment losses (1,592 ) (2,675 ) (4,110 ) "Other-than-temporary" impairments (1,088 ) (1,055 ) (1,481 ) Other long-term investments, net (6,252 ) (6,499 ) (1,471 ) Totals $ 6,556 $ 4,074 $ 6,153 Gains and losses realized on the disposition of investments are included in net income. The cost of investments sold is determined on the specific identification method using the highest cost basis first. The Company did not have any outstanding cumulative credit losses on fixed maturity securities that have been recognized in earnings from “other-than-temporary” impairments during any of the reported periods. The amounts reported as “other-than-temporary” impairments on equity securities do not include any individually significant items. The net realized investment losses recognized on other long-term investments primarily represent changes in the carrying value of a limited partnership that is used solely to support an equity tail-risk hedging strategy, but for 2016 also included an "other-than-temporary" impairment loss of $209,000 on an investment that conveys investment tax credits. A summary of net investment income is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Interest on fixed maturity securities $ 39,992 $ 41,499 $ 42,261 Dividends on equity securities 6,032 6,922 5,617 Income on reverse repurchase agreements 306 236 117 Interest on short-term investments 273 121 2 Return on long-term investments 1,126 514 (461 ) Total investment income 47,729 49,292 47,536 Securities litigation income 12 111 32 Investment expenses (2,262 ) (1,913 ) (1,986 ) Net investment income $ 45,479 $ 47,490 $ 45,582 A summary of net changes in unrealized holding gains (losses) on securities available-for-sale is included in the table below. Year ended December 31, ($ in thousands) 2017 2016 2015 Fixed maturity securities $ 11,676 $ (20,634 ) $ (16,685 ) Deferred income tax expense (benefit) 4,086 (7,222 ) (5,840 ) Total fixed maturity securities 7,590 (13,412 ) (10,845 ) Equity securities 17,481 4,293 (10,997 ) Deferred income tax expense (benefit) 6,119 1,502 (3,849 ) Total equity securities 11,362 2,791 (7,148 ) Total available-for-sale securities $ 18,952 $ (10,621 ) $ (17,993 )

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES On December 22, 2017 the TCJA was signed into law. Among other provisions, the TCJA lowered the federal corporate tax rate from 35 percent to 21 percent , effective January 1, 2018. Since the change in tax rate is not effective until 2018, current tax expense in 2017 is unaffected; however, the temporary tax differences that comprised the net deferred income tax liability at the enactment date are now projected to reverse at the lower 21 percent tax rate. The re-measurement of deferred income tax assets and liabilities resulted in the recognition of a $9.1 million deferred income tax benefit. On December 22, 2017, the Securities Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118), which allows a company to record a provisional amount for certain income tax effects of the TCJA that are based on reasonable estimates in circumstances in which the accounting is incomplete. Pursuant to SAB 118, the Company made reasonable estimates of the effects the TCJA had on the deferred income tax assets and liabilities. For other items where the Company could not make a reasonable estimate, primarily loss reserve discounting, the Company is using existing accounting guidance and the provisions of the tax laws that were in place prior to the enactment until further guidance is released by the Internal Revenue Service (IRS) with updated discount factors. The Company will continue to gather information to provide a more precise re-measurement of deferred income tax assets and liabilities, and expects to complete its analysis of the effects of the TCJA within a year of the enactment date. Temporary differences between the consolidated financial statement carrying amount and tax basis of assets and liabilities that give rise to significant portions of the deferred income tax asset (liability) at December 31, 2017 and 2016 are as follows: December 31, ($ in thousands) 2017 2016 Loss reserve discounting $ 7,507 $ 13,442 Unearned premium reserve limitation 10,284 16,497 Other policyholders' funds payable 2,103 4,574 Other, net 2,202 2,561 Total deferred income tax asset 22,096 37,074 Net unrealized holding gains on investment securities (22,195 ) (26,786 ) Deferred policy acquisition costs (8,634 ) (14,328 ) Retirement benefits (3,714 ) (3,510 ) Other, net (2,573 ) (3,771 ) Total deferred income tax liability (37,116 ) (48,395 ) Net deferred income tax liability $ (15,020 ) $ (11,321 ) Based upon anticipated future taxable income and consideration of all other available evidence, management believes that it is “more likely than not” that the Company’s deferred income tax assets will be realized. The actual income tax expense for the years ended December 31, 2017 , 2016 and 2015 differed from the “expected” income tax expense for those years (computed by applying the United States federal corporate tax rate of 35 percent to income before income tax expense) as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Computed "expected" income tax expense $ 13,936 $ 22,123 $ 25,079 Increases (decreases) in tax resulting from: Deferred income tax benefit from enactment of the TCJA (9,056 ) — — Tax-exempt interest income (2,715 ) (2,803 ) (2,805 ) Dividends received deduction (1,291 ) (1,429 ) (1,136 ) Proration of tax-exempt interest and dividends received deduction 601 635 591 Investment tax credits (672 ) (1,392 ) — Other, net (225 ) (130 ) (235 ) Total income tax expense $ 578 $ 17,004 $ 21,494 Comprehensive income tax expense included in the consolidated financial statements for the years ended December 31, 2017 , 2016 and 2015 is as follows. The deferred income tax benefit that resulted from the enactment of the TCJA in 2017 is included in the "operations" line. Year ended December 31, ($ in thousands) 2017 2016 2015 Income tax expense (benefit) on: Operations $ 578 $ 17,004 $ 21,494 Change in unrealized holding gains on investment securities 10,205 (5,720 ) (9,689 ) Change in funded status of retirement benefit plans: Pension plans 1,694 414 (1,748 ) Postretirement benefit plans (774 ) (1,345 ) (1,071 ) Comprehensive income tax expense $ 11,703 $ 10,353 $ 8,986 The Company had no provision for uncertain income tax positions at December 31, 2017 or 2016 . The Company recognized no interest expense or other penalties related to U.S. federal or state income taxes during 2017 , 2016 or 2015 . It is the Company’s accounting policy to reflect income tax penalties as other expense, and interest as interest expense. The Company files a U.S. federal income tax return, along with various state income tax returns. The Company is no longer subject to U.S. federal and state income tax examinations by tax authorities for years before 2014.

SURPLUS NOTES

SURPLUS NOTES	12 Months Ended
	Dec. 31, 2017
SURPLUS NOTES [Abstract]
SURPLUS NOTES	SURPLUS NOTES The Company’s property and casualty insurance subsidiaries have $25.0 million of surplus notes issued to Employers Mutual at an interest rate of 1.35 percent . The Inter-Company Committees of the boards of directors of the Company and Employers Mutual approved a change in the interest rate on the surplus notes to 2.73 percent effective February 1, 2018, subject to regulatory approval. Reviews of the interest rate are conducted every five years , with the next review due in 2023. Payments of interest and repayments of principal can only be made out of the applicable subsidiary’s statutory surplus and are subject to prior approval by the insurance commissioner of the respective states of domicile. The surplus notes are subordinate and junior in right of payment to all obligations or liabilities of the applicable insurance subsidiaries. Total interest expense on these surplus notes was $337,000 in 2017 , 2016 and 2015 . At December 31, 2017 , the Company’s property and casualty insurance subsidiaries had received approval for the payment of the 2017 interest expense on the surplus notes.

EMPLOYEE RETIREMENT PLANS

EMPLOYEE RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
EMPLOYEE RETIREMENT PLANS	EMPLOYEE RETIREMENT PLANS Employers Mutual has various employee benefit plans, including a qualified defined benefit pension plan, a non-qualified defined benefit supplemental pension plan, a retiree life insurance benefit and a retiree health reimbursement arrangement (HRA) benefit. The qualified defined benefit plan covers substantially all of its employees. This plan is funded by employer contributions and provides a benefit under a cash balance formula for most employees; however, benefits are provided to a few long-term employees based on a traditional benefit formula. On December 18, 2017, Employers Mutual notified its employees that effective January 1, 2019, the benefits provided under the cash balance formula will be based on a combination of age and years of service, rather than just age. This change did not have a material impact on the pension benefit obligation. Benefits generally vest after three years of service or the attainment of 55 years of age. It is Employers Mutual’s funding policy to make contributions sufficient to be in compliance with minimum regulatory funding requirements, plus additional amounts as determined by management. Employers Mutual’s non-qualified defined benefit supplemental retirement plan provides additional retirement benefits for a select group of management and highly-compensated employees. This plan enables select employees to receive retirement benefits without the limit on compensation imposed on qualified defined benefit pension plans by the Internal Revenue Service (IRS) and to recognize compensation that has been deferred in the non-qualified deferred compensation plan. The plan is unfunded and benefits generally vest after three years of service. Employers Mutual also offers postretirement benefit plans which provide an HRA and life insurance benefits for eligible retired employees. Substantially all of its employees may become eligible for those benefits if they reach age 55 and have attained the required length of service while working for Employers Mutual. Under the HRA, Employers Mutual reimburses eligible participants, up to a pre-determined maximum, for amounts expended to enroll in publicly available individual health care plans and/or pay for qualifying out-of-pocket health care costs. The obligations of the HRA are based on the total amount of reimbursements expected to be made by Employers Mutual over the lives of the participants, rather than the total amount of medical benefits expected to be paid over the participants’ lives. Therefore, the obligations of the HRA are not directly impacted by changes in the cost of health care. However, the maximum amount Employers Mutual will reimburse eligible participants is adjusted periodically based on an analysis of the change in health care costs. Such adjustments are reflected as plan amendments and increased the postretirement benefit plans' benefit obligation $2.7 million in 2017 and $2.2 million in 2016. During December 2017, Employers Mutual notified its employees that the life insurance benefit will be eliminated for employees retiring after 2018. As a result, the postretirement benefit plans' benefit obligation as of December 31, 2017 decreased $3.8 million . This change is also reflected as a plan amendment. The life insurance plan is noncontributory. The benefits provided under both plans are subject to change. Employers Mutual maintains a Voluntary Employee Beneficiary Association (VEBA) trust that has historically been used to accumulate funds for the payment of postretirement benefits. Given the overfunded position of the postretirement benefit plans, contributions to the VEBA trust are not anticipated for the foreseeable future. The following table sets forth the funded status of Employers Mutual’s pension and postretirement benefit plans as of December 31, 2017 and 2016 , based upon measurement dates of December 31, 2017 and 2016 , respectively. Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Change in projected benefit obligation: Benefit obligation at beginning of year $ 284,194 $ 269,904 $ 55,651 $ 51,449 Service cost 15,135 14,432 1,362 1,273 Interest cost 11,190 10,161 2,281 2,215 Actuarial loss 12,577 5,361 3,278 357 Benefits paid (14,852 ) (15,664 ) (2,455 ) (2,377 ) Medicare subsidy reimbursements — — — 553 Plan amendments — — (1,113 ) 2,181 Projected benefit obligation at end of year 308,244 284,194 59,004 55,651 Change in plan assets: Fair value of plan assets at beginning of year 300,915 283,231 67,809 66,320 Actual return on plan assets 54,255 23,081 10,304 3,866 Employer contributions 8,686 10,267 — — Benefits paid (14,852 ) (15,664 ) (2,455 ) (2,377 ) Fair value of plan assets at end of year 349,004 300,915 75,658 67,809 Funded status $ 40,760 $ 16,721 $ 16,654 $ 12,158 The following tables set forth the amounts recognized in the Company’s financial statements as a result of the property and casualty insurance subsidiaries’ aggregate 30 percent participation in the pooling agreement. Amounts recognized in the Company’s consolidated balance sheets: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Assets: Prepaid pension and postretirement benefits $ 16,327 $ 9,065 $ 4,356 $ 3,249 Liability: Pension and postretirement benefits (4,185 ) (4,097 ) — — Net amount recognized $ 12,142 $ 4,968 $ 4,356 $ 3,249 Amounts recognized in the Company’s consolidated balance sheets under the caption “accumulated other comprehensive income”, before deferred income taxes: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Net actuarial loss $ (11,598 ) $ (18,927 ) $ (4,950 ) $ (6,147 ) Prior service (cost) credit — (6 ) 16,407 19,441 Net amount recognized $ (11,598 ) $ (18,933 ) $ 11,457 $ 13,294 During 2018 , the Company will amortize $150,000 of net actuarial loss and no prior service cost associated with the pension plans into net periodic benefit cost. In addition, the Company will amortize $260,000 of net actuarial loss and $3.2 million of prior service credit associated with the postretirement benefit plans into net periodic postretirement benefit income in 2018 . Amounts recognized in the Company’s consolidated statements of comprehensive income, before deferred income taxes: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Net actuarial gain (loss) $ 7,329 $ 1,174 $ 1,197 $ 376 Prior service (cost) credit 6 9 (3,034 ) (4,221 ) Net amount recognized $ 7,335 $ 1,183 $ (1,837 ) $ (3,845 ) The following table sets forth the projected benefit obligation, accumulated benefit obligation and fair value of plan assets of Employers Mutual’s non-qualified pension plan. The amounts related to the qualified pension plan are not included since the plan assets exceeded the accumulated benefit obligation. Year ended December 31, ($ in thousands) 2017 2016 Projected benefit obligation $ 13,950 $ 13,656 Accumulated benefit obligation 12,272 12,182 Fair value of plan assets — — The components of net periodic benefit cost (income) for Employers Mutual’s pension and postretirement benefit plans is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Pension plans: Service cost $ 15,135 $ 14,432 $ 13,962 Interest cost 11,190 10,161 9,311 Expected return on plan assets (20,765 ) (19,361 ) (20,298 ) Amortization of net actuarial loss 3,643 4,311 2,710 Amortization of prior service cost 20 31 31 Net periodic pension benefit cost $ 9,223 $ 9,574 $ 5,716 Postretirement benefit plans: Service cost $ 1,362 $ 1,273 $ 1,411 Interest cost 2,281 2,215 2,148 Expected return on plan assets (4,311 ) (4,224 ) (4,416 ) Amortization of net actuarial loss 1,371 1,494 1,745 Amortization of prior service credit (11,154 ) (11,338 ) (11,466 ) Net periodic postretirement benefit income $ (10,451 ) $ (10,580 ) $ (10,578 ) The net periodic postretirement benefit income recognized on Employers Mutual's postretirement benefit plans is due to a plan amendment that was announced in the fourth quarter of 2013. This plan amendment generated a prior service credit that is being amortized into net periodic benefit cost over a period of 10 years . Net periodic pension benefit cost allocated to the Company amounted to $2.8 million , $2.9 million and $1.8 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Net periodic postretirement benefit income allocated to the Company for the years ended December 31, 2017 , 2016 and 2015 amounted to $2.9 million , $3.0 million , and $3.0 million , respectively. The weighted-average assumptions used to measure the benefit obligations are as follows: Year ended December 31, 2017 2016 Pension plans: Discount rate 3.60 % 4.07 % Rate of compensation increase: Qualified pension plan 5.09 % 5.07 % Non-qualified pension plan 4.45 % 4.53 % Postretirement benefit plans: Discount rate 3.63 % 4.21 % The weighted-average assumptions used to measure the net periodic benefit costs are as follows: Year ended December 31, 2017 2016 2015 Pension plans: Discount rate 4.07 % 3.90 % 3.57 % Expected long-term rate of return on plan assets 7.00 % 7.00 % 7.00 % Rate of compensation increase: Qualified pension plan 5.08 % 5.07 % 4.73 % Non-qualified pension plan 4.47 % 4.56 % 4.68 % Postretirement benefit plans: Discount rate 4.21 % 4.42 % 4.04 % Expected long-term rate of return on plan assets 6.50 % 6.50 % 6.50 % The expected long-term rates of return on plan assets were developed considering actual historical results, current and expected market conditions, plan asset mix and management’s investment strategy. The following benefit payments, which reflect expected future service, are expected to be paid from the plans over the next ten years: ($ in thousands) Pension benefits Postretirement benefits 2018 $ 20,276 $ 3,175 2019 22,628 3,383 2020 23,050 3,560 2021 19,841 3,636 2022 22,655 3,690 2023 - 2027 119,538 18,679 Employers Mutual manages its VEBA trust assets internally. The VEBA trust assets are reviewed relative to liabilities to determine the optimum allocation focusing on both asset accumulation and income generation. Assets contained in the VEBA trust are invested in fixed income, international equity and domestic equity mutual funds, an emerging markets exchange traded fund (ETF) and universal life insurance policies issued by EMC National Life Company, an affiliate of Employers Mutual, that carry a guaranteed interest rate of 4.5 percent . See note 8 for a discussion on fair value measurement. Following is a description of the valuation techniques and inputs used for each major class of assets measured at fair value in Employers Mutual’s VEBA trust. • Money Market Fund: Valued at amortized cost, which approximates fair value. Under this method, investments purchased at a discount or premium are valued by accreting or amortizing the difference between the original purchase price and maturity value of the issue over the period to maturity. The net asset value of each share held by the trust at year-end was $1.00 . • Mutual Funds: Valued at the net asset value of shares held by the trust at year-end. For purposes of calculating the net asset value, portfolio securities and other assets for which market quotes are readily available are valued at fair value. Fair value is generally determined on the basis of last reported sales prices, or if no sales are reported, based on quotes obtained from a quotation reporting system, established market makers, or independent pricing services. • ETF: Valued at the closing price from the applicable exchange. • Life Insurance Contract: Valued at the cash surrender value, which approximates fair value. The fair values of the assets held in Employers Mutual’s VEBA trust are as follows: December 31, 2017 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Money market fund $ 1,254 $ 1,254 $ — $ — Emerging markets ETF 4,803 4,803 — — Mutual funds 54,180 54,180 — — Life insurance contracts 14,524 — — 14,524 Cash 897 897 — — Total benefit plan assets $ 75,658 $ 61,134 $ — $ 14,524 December 31, 2016 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Money market fund $ 1,485 $ 1,485 $ — $ — Emerging markets ETF 3,743 3,743 — — Mutual funds 47,916 47,916 — — Life insurance contracts 14,159 — — 14,159 Cash 506 506 — — Total benefit plan assets $ 67,809 $ 53,650 $ — $ 14,159 Presented below is a reconciliation of the assets measured at fair value using significant unobservable inputs (Level 3) for the years ended December 31, 2017 and 2016 . Fair value measurements Life insurance contracts ($ in thousands) 2017 2016 Balance at beginning of year $ 14,159 $ 13,792 Actual return on plan assets: Increase in cash surrender value of life insurance contracts 365 367 Balance at end of year $ 14,524 $ 14,159 Employers Mutual uses Global Portfolio Strategies, Inc. to advise on the asset allocation strategy for its qualified pension plan. The asset allocation strategy and process of Global Portfolio Strategies, Inc. uses a diversified allocation of equity, debt and real estate exposures that is customized to the plan’s payment risk and return targets. Global Portfolio Strategies, Inc. reviews the plan’s assets and liabilities in relation to expectations of long-term market performance and liability development to determine the appropriate asset allocation. The data for the contributions and emerging liabilities is provided from the plan’s actuarial valuation, while the current asset and monthly benefit payment data is provided by the plan record keeper. Following is a description of the valuation techniques and inputs used for pooled separate accounts, the only major class of assets measured at fair value in Employers Mutual’s qualified pension plan. • Pooled Separate Accounts: Each of the funds held by the Plan is in a pooled or commingled investment vehicle that is maintained by the fund sponsor, each with many investors. The Plan asset is represented by a “unit of account” and a per unit value, whose value is the accumulated value of the underlying investments less liabilities. The net asset value is determined by the issuer of the fund by taking the fair value of the underlying investments less any liabilities divided by the number of units outstanding. Sponsors of the funds specify the source(s) used for the underlying investment asset prices and the protocol used to value each fund. In accordance with ASU 2015-07, a fair value hierarchy table is not included here since all of the Plan's investments are measured at fair value using the net asset value per share (or its equivalent) practical expedient, which are not classified in the fair value hierarchy. Presented below are the fair values of assets held in Employers Mutual's defined benefit retirement plan: December 31, ($ in thousands) 2017 2016 Pooled separate accounts $ 349,004 $ 300,915 Total benefit plan assets $ 349,004 $ 300,915 Employers Mutual plans to contribute approximately $8.0 million to the pension plan in 2018 . No contributions are expected to be made to the VEBA trust in 2018 . The Company participates in other benefit plans sponsored by Employers Mutual, including its 401(k) Plan, Board and Executive Non-Qualified Excess Plans and Defined Contribution Supplemental Executive Retirement Plan. The Company’s share of expenses for these plans amounted to $2.9 million , $2.7 million and $2.5 million in 2017 , 2016 and 2015 , respectively.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION The Company has a stock-based compensation plan for non-employee directors. Employers Mutual also has several stock plans which utilize the common stock of the Company. Employers Mutual can provide the common stock required under its plans by: 1) using shares of common stock that it currently owns; 2) purchasing common stock in the open market; or 3) directly purchasing common stock from the Company at the current fair value. Employers Mutual's current practice is to purchase common stock from the Company for use in all of its stock plans (including its non-employee director stock purchase plan and its employee stock purchase plan). A portion of the compensation expense recognized by Employers Mutual (as the requisite service period for granted options and restricted stock awards/units is rendered) is allocated to the Company’s property and casualty insurance subsidiaries though their participation in the pooling agreement. Stock Plans On May 26, 2017, the Company registered 150,000 shares of its common stock for use in the EMC Insurance Group Inc. 2017 Non-Employee Director Stock Plan (the "2017 Director Plan"). The 2017 Director Plan provides for the awarding of non-qualified stock options, restricted stock, restricted stock units and other stock-based awards to the Company's non-employee directors. During 2017 , 2,000 shares of restricted stock were granted to non-employee directors of the Company under this plan. These shares of restricted stock vest over a one year period. Dividends on the unvested restricted stock are accrued and will be paid to the directors at the time of vesting. Employers Mutual currently maintains two separate stock plans for the benefit of officers and key employees of Employers Mutual and its subsidiaries. A total of 3,000,000 shares of the Company’s common stock have been reserved for issuance under the 2007 Employers Mutual Casualty Company Stock Incentive Plan (2007 Plan), and a total of 1,000,000 shares have been reserved for issuance under the Employers Mutual Casualty Company 2017 Stock Incentive Plan (2017 Plan). Both of Employers Mutual's plans permit the issuance of performance shares, performance units, and other stock-based awards, in addition to qualified (incentive) and non-qualified stock options, stock appreciation rights, restricted stock and restricted stock units. Both plans provide for a ten -year time limit for granting awards. No additional grants can be made under the 2007 Plan due to the expiration of the term of the plan. The Senior Executive Compensation Committee of Employers Mutual’s Board of Directors grants the awards and is the administrator of the plans. The Company’s Compensation Committee must consider and approve all awards granted to the Company’s executive officers. Awards granted to directors are approved by the Company's Corporate Governance and Nominating Committee. Options granted under the 2007 Plan generally had a vesting period of five years , with options becoming exercisable in equal annual cumulative increments commencing on the first anniversary of the option grant. Option prices cannot be less than the fair value of the common stock on the date of grant. Restricted stock awards granted under the 2007 Plan generally have a vesting period of four years , with shares vesting in equal annual cumulative increments commencing on the first anniversary of the grant. With the exception of death, permanent disability or a change in control, any unvested shares of restricted stock are forfeited on termination of employment, including retirement. Holders of unvested shares of restricted stock receive compensation income equal to the amount of any dividends declared on the common stock. During 2017, Employers Mutual began issuing restricted stock unit awards rather than restricted stock awards. In connection with this change, Employers Mutual will now acquire stock to fulfill its obligations to the recipients of the restricted stock unit awards on the date they vest, rather than on the grant date of the awards. Because of this change, an account Employers Mutual established to hold previously granted restricted stock awards until they vest will contain excess shares of the Company's stock stemming from forfeitures and surrenders. During 2017 , the Company repurchased 67,974 shares of stock from this unvested restricted stock account at an average cost of $27.34 . Like restricted stock awards, restricted stock unit awards generally have a vesting period of four years , with shares vesting in equal annual cumulative increments commencing on the first anniversary of the grant. Upon death, disability or change in control, any granted but unvested restricted stock units become fully vested and settled. Upon qualifying for "Approved Retirement" [attaining 70 points (combined age plus whole years of continuous service) with a minimum age of 55 years , or reaching age 65 ], restricted stock units will generally become non-forfeitable on a pro-rated basis over the 12 months following the grant date. Settlement of non-forfeitable restricted stock units is deferred until the date on which the restricted stock units otherwise vest and settle pursuant to the normal four-year vesting schedule. Holders of unvested restricted stock units do not receive compensation income equal to the amount of dividends declared on the common stock. During 2016 , 2,000 shares of restricted stock were granted to non-employee directors of the Company under the 2007 Plan. These shares of restricted stock vest over a period of three years , or upon a director reaching 75 years of age while an active director. The directors are entitled to receive compensation income (equal to the amount of dividends paid on the Company's common stock) earned on unvested shares of restricted stock. The Company recognized compensation expense from these plans of $801,000 ( $521,000 net of tax), $788,000 ( $512,000 net of tax) and $500,000 ( $325,000 net of tax) in 2017 , 2016 and 2015 , respectively. Due to the historically small number of forfeitures, the Company has elected to recognize the reduction to compensation expense from forfeitures as they occur. A summary of the stock option activity under Employers Mutual’s stock plans for 2017 , 2016 and 2015 is as follows: Year ended December 31, 2017 2016 2015 Number Weighted- Number Weighted- Number Weighted- Outstanding, beginning of year 649,012 $ 14.65 1,006,171 $ 14.92 1,351,802 $ 14.89 Exercised (222,921 ) 14.88 (321,312 ) 15.31 (323,486 ) 14.86 Expired (18,805 ) 15.16 (34,947 ) 16.32 (20,850 ) 14.11 Forfeited (975 ) 13.99 (900 ) 13.99 (1,295 ) 14.68 Outstanding, end of year 406,311 $ 14.51 649,012 $ 14.65 1,006,171 $ 14.92 Exercisable, end of year 406,311 $ 14.51 593,224 $ 14.72 824,365 $ 14.95 As discussed above, during 2017 Employers Mutual began issuing restricted stock unit awards to eligible employees. These awards are accounted for as liability-based awards, whereby the liability is remeasured at each reporting date as the average of the high and low trading prices of the Company's common stock on that date. Upon settlement, the Company will receive the full fair value for all shares issued. The Company's share of this liability at December 31, 2017 was $543,000 . A summary of restricted stock unit awards activity for 2017 is as follows: Year ended December 31, 2017 Number of awards Non-vested, beginning of year — Granted 116,288 Vested — Forfeited 2,233 Non-vested, end of year 114,055 For restricted stock awards, the average of the high and low trading prices of the Company's common stock on the dates of grant were used to determine their fair values. The Company received in 2016 and 2015 the full fair value, as of the grant date, for all shares issued in connection with Employers Mutual's grant of restricted stock awards. At December 31, 2017 , the Company’s portion of the unrecognized compensation cost associated with restricted stock awards that are not currently vested was $640,000 with a 1.56 year weighted-average period over which the compensation expense is expected to be recognized. The Company's portion of the total fair value of restricted stock awards that vested was $545,000 , $414,000 and $233,000 in 2017 , 2016 and 2015 , respectively. A summary of restricted stock awards activity for 2017 , 2016 and 2015 is as follows: Year ended December 31, 2017 2016 2015 Number Weighted- Number Weighted- Number Weighted- Non-vested, beginning of year 234,281 $ 22.31 216,944 $ 20.40 155,864 $ 19.21 Granted 2,000 26.95 118,588 24.56 117,146 21.36 Vested (85,192 ) 21.31 (69,057 ) 19.98 (40,941 ) 18.99 Forfeited (7,039 ) 22.57 (32,194 ) 22.73 (15,125 ) 19.35 Non-vested, end of year 144,050 $ 22.96 234,281 $ 22.31 216,944 $ 20.40 The Company’s portion of the total intrinsic value of options exercised under Employers Mutual’s stock plans was $901,000 , $1.1 million and $770,000 in 2017 , 2016 and 2015 , respectively. Under the terms of the pooling and quota share agreements, these amounts were paid to Employers Mutual. The Company receives the full fair value, as of the exercise date, for all shares issued in connection with option exercises. Additional information relating to options outstanding and options vested (exercisable) at December 31, 2017 is as follows: December 31, 2017 ($ in thousands, except share and per share amounts) Number of options Weighted-average exercise price Aggregate intrinsic value Weighted-average remaining term Options outstanding 406,311 $ 14.51 $ 5,910 2.81 Options exercisable 406,311 $ 14.51 $ 5,910 2.81 Incentive stock options generally do not generate income tax deductions for the Company. The Company has recorded a deferred income tax benefit for non-qualified stock options and restricted stock awards that have been issued. The Company’s portion of the current income tax deduction realized from exercises of non-qualified stock options was $239,000 , $284,000 and $121,000 in 2017 , 2016 and 2015 , respectively. These actual deductions are generally in excess of the deferred tax benefits recorded in conjunction with the compensation expense (referred to as excess tax benefits), which reduce income tax expense (prior to 2016 were recorded to additional paid in capital). The income tax benefit that results from disqualifying dispositions of stock purchased through the exercise of incentive stock options is deemed immaterial. Employee Stock Purchase Plan On May 30, 2008, the Company registered 750,000 shares of its common stock for use in the Employers Mutual Casualty Company 2008 Employee Stock Purchase Plan. All employees are eligible to participate in the plan. An employee may participate in the plan by delivering, during the first twenty days of the calendar month preceding the first day of an election period, a payroll deduction authorization to the plan administrator; or making a cash contribution (employees designated as “Insiders” are required to give six months advance notice prior to participating in the plan). Participants pay 85 percent of the fair market value of the stock on the date of purchase. The plan is administered by the Board of Directors of Employers Mutual, which has the right to amend or terminate the plan at any time; however, no such amendment or termination shall adversely affect the rights and privileges of participants. Expenses allocated to the Company in connection with this plan totaled $100,000 , $78,000 and $59,000 in 2017 , 2016 and 2015 , respectively. During 2017 , shares were purchased under the plan at prices ranging from $23.64 to $25.15 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 349,404 414,883 471,459 Shares purchased under the plan (77,819 ) (65,479 ) (56,576 ) Shares available for purchase, end of year 271,585 349,404 414,883 Non-Employee Director Stock Purchase Plan On March 14, 2013, the Company registered 300,000 shares of its common stock for issuance under the 2013 Employers Mutual Casualty Company Non-Employee Director Stock Purchase Plan. All non-employee directors of Employers Mutual and its subsidiaries and affiliates, as well as non-employee directors of the Company, are eligible to participate in the plan. Each eligible director can purchase shares of common stock at 75 percent of the fair value of the stock on the exercise date in an amount equal to a minimum of 25 percent and a maximum of 100 percent of their annual cash retainer. The plan will continue through the period of the 2023 annual meetings. The plan is administered by the Corporate Governance and Nominating Committee of the Board of Directors of Employers Mutual. The Board may amend or terminate the plan at any time; however, no such amendment or termination shall adversely affect the rights and privileges of the participants. Expenses allocated to the Company in connection with this plan totaled $65,000 , $84,000 and $62,000 in 2017 , 2016 and 2015 , respectively. During 2017 , shares were purchased under the plan at prices ranging from $20.15 to $23.15 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 249,843 264,446 279,809 Shares purchased under the plan (14,470 ) (14,603 ) (15,363 ) Shares available for purchase, end of year 235,373 249,843 264,446 Dividend Reinvestment Plan The Company maintains a dividend reinvestment and common stock purchase plan (the “Plan”) which provides stockholders with the option of reinvesting cash dividends in additional shares of the Company’s common stock. Participants can also purchase additional shares of common stock without incurring broker commissions by making optional cash contributions to the plan, and sell shares of common stock through the plan. Employers Mutual did not participate in this plan in 2017 , 2016 or 2015 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 971,222 976,697 982,227 Shares purchased under the plan (5,421 ) (5,475 ) (5,530 ) Shares available for purchase, end of year 965,801 971,222 976,697 Lowest purchase price $ 26.94 $ 22.09 $ 21.02 Highest purchase price $ 31.09 $ 30.50 $ 26.43

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME	ACCUMULATED OTHER COMPREHENSIVE INCOME The Company has available-for-sale securities and receives an allocation of the actuarial losses and net prior service credits associated with Employers Mutual’s pension and postretirement benefit plans, both of which generate accumulated other comprehensive income (loss) amounts. The following table reconciles, by component, the beginning and ending balances of accumulated other comprehensive income, net of tax. Accumulated other comprehensive income by component Unrealized Unrecognized pension and postretirement benefit obligations ($ in thousands) Net actuarial loss Prior service credit Total Total Balance at December 31, 2015 $ 60,369 $ (17,306 ) $ 15,370 $ (1,936 ) $ 58,433 Other comprehensive income (loss) before reclassifications (3,885 ) (542 ) (339 ) (881 ) (4,766 ) Amounts reclassified from accumulated other comprehensive income (6,736 ) 1,549 (2,399 ) (850 ) (7,586 ) Other comprehensive income (loss) (10,621 ) 1,007 (2,738 ) (1,731 ) (12,352 ) Balance at December 31, 2016 49,748 (16,299 ) 12,632 (3,667 ) 46,081 Other comprehensive income (loss) before reclassifications 27,278 5,571 96 5,667 32,945 Amounts reclassified from accumulated other comprehensive income (8,326 ) 958 (2,047 ) (1,089 ) (9,415 ) Other comprehensive income (loss) 18,952 6,529 (1,951 ) 4,578 23,530 Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA 14,797 (3,304 ) 2,280 (1,024 ) 13,773 Balance at December 31, 2017 $ 83,497 $ (13,074 ) $ 12,961 $ (113 ) $ 83,384 The following tables display amounts reclassified out of accumulated other comprehensive income and into net income during the three years ended December 31, 2017 . ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2017 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 12,809 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (4,483 ) Total income tax expense Net reclassification adjustment 8,326 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (1,474 ) (1) Prior service credit 3,150 (1) Total before tax 1,676 Deferred income tax expense (587 ) Net reclassification adjustment 1,089 Total reclassification adjustment $ 9,415 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details). ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2016 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 10,364 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (3,628 ) Total income tax expense Net reclassification adjustment 6,736 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (2,383 ) (1) Prior service credit 3,690 (1) Total before tax 1,307 Deferred income tax expense (457 ) Net reclassification adjustment 850 Total reclassification adjustment $ 7,586 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details). ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2015 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 7,624 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (2,668 ) Total income tax expense Net reclassification adjustment 4,956 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (1,327 ) (1) Prior service credit 3,307 (1) Total before tax 1,980 Deferred income tax expense (693 ) Net reclassification adjustment 1,287 Total reclassification adjustment $ 6,243 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details).

STOCK REPURCHASE PROGRAMS

STOCK REPURCHASE PROGRAMS	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
STOCK REPURCHASE PROGRAMS	STOCK REPURCHASE PROGRAMS Stock Repurchase Plans On November 3, 2011, the Company’s Board of Directors authorized a $15.0 million stock repurchase program. This program does not have an expiration date. The timing and terms of the purchases are determined by management based on board approved parameters and market conditions, and are conducted in accordance with the applicable rules of the Securities and Exchange Commission. Common stock repurchased under this program will be retired by the Company. During 2016, the Company repurchased 17,300 shares under this program at an average cost of $22.14 . Stock Purchase Plan During the second quarter of 2005, Employers Mutual initiated a $15.0 million stock purchase program under which Employers Mutual may purchase shares of the Company’s common stock in the open market. This purchase program does not have an expiration date; however, this program is currently dormant and will remain so while the Company’s repurchase program is in effect. The timing and terms of the purchases are determined by management based on market conditions and are conducted in accordance with the applicable rules of the Securities and Exchange Commission. No purchases were made during 2017 , 2016 and 2015 . As of December 31, 2017 , $4.5 million remained available under this plan for additional purchases.

LEASES, COMMITMENTS AND CONTING

LEASES, COMMITMENTS AND CONTINGENT LIABILITIES	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
LEASES, COMMITMENTS AND CONTINGENT LIABILITIES	LEASES, COMMITMENTS AND CONTINGENT LIABILITIES One of the Company’s property and casualty insurance subsidiaries leases office facilities in Bismarck, North Dakota with lease terms expiring in 2024 . Employers Mutual has entered into various leases for branch and service office facilities with lease terms expiring through 2027 . All of these lease costs are included as expenses under the pooling agreement. The following table reflects the Company's share of lease commitments as of December 31, 2017 . Payments due by period ($ in thousands) Total Less than 1 - 3 4 - 5 More than Lease commitments Real estate operating leases $ 2,207 $ 423 $ 820 $ 530 $ 434 The participants in the pooling agreement are subject to guaranty fund assessments by states in which they write business. Guaranty fund assessments are used by states to pay policyholder liabilities of insolvent insurers domiciled in those states. Many states allow assessments to be recovered through premium tax offsets. The Company has accrued estimated guaranty fund assessments of $706,000 and $851,000 as of December 31, 2017 and 2016 , respectively. Premium tax offsets of $897,000 and $1.0 million , which are related to prior guarantee fund payments and current assessments, have been accrued as of December 31, 2017 and 2016 , respectively. The guaranty fund assessments are expected to be paid over the next two years and the premium tax offsets are expected to be realized within ten years of the payments. The participants in the pooling agreement are also subject to second-injury fund assessments, which are designed to encourage employers to employ workers with pre-existing disabilities. The Company has accrued estimated second-injury fund assessments of $2.0 million and $1.9 million as of December 31, 2017 and 2016 , respectively. The second-injury fund assessment accruals are based on projected loss payments. The periods over which the assessments will be paid is not known. The participants in the pooling agreement have purchased annuities from life insurance companies, under which the claimant is payee, to fund future payments that are fixed pursuant to specific claim settlement provisions. The Company’s share of case loss reserves eliminated by the purchase of those annuities was $110,000 at December 31, 2017 . The Company had a contingent liability for the aggregate guaranteed amount of the annuities of $183,000 at December 31, 2017 should the issuers of those annuities fail to perform. The probability of a material loss due to failure of performance by the issuers of these annuities is considered remote. The Company and Employers Mutual and its other subsidiaries are parties to numerous lawsuits arising in the normal course of the insurance business. The Company believes that the resolution of these lawsuits will not have a material adverse effect on its financial condition or its results of operations. The companies involved have established reserves which are believed adequate to cover any potential liabilities arising out of all such pending or threatened proceedings.

UNAUDITED INTERIM FINANCIAL INF

UNAUDITED INTERIM FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED INTERIM FINANCIAL INFORMATION	UNAUDITED INTERIM FINANCIAL INFORMATION Three months ended, ($ in thousands, except per share amounts) March 31 June 30 September 30 December 31 2017 Total revenues $ 154,457 $ 164,150 $ 165,918 $ 174,320 Income (loss) before income tax expense (benefit) $ 8,440 $ 7,229 $ (440 ) $ 24,587 Income tax expense (benefit) 1,636 1,725 (1,186 ) (1,597 ) Net income $ 6,804 $ 5,504 $ 746 $ 26,184 Net income per common share - basic and diluted 1 $ 0.32 $ 0.26 $ 0.03 $ 1.23 Three months ended, ($ in thousands, except per share amounts) March 31 June 30 September 30 December 31 2016 Total revenues $ 153,871 $ 160,336 $ 162,378 $ 168,398 Income (loss) before income tax expense (benefit) $ 20,877 $ 8,087 $ 5,047 $ 29,196 Income tax expense (benefit) 6,223 1,959 918 7,904 Net income $ 14,654 $ 6,128 $ 4,129 $ 21,292 Net income per common share - basic and diluted 1 $ 0.70 $ 0.29 $ 0.20 $ 1.01 1 Since the weighted-average number of shares outstanding for the quarters are calculated independently of the weighted-average number of shares outstanding for the year, quarterly net income per share may not total to annual net income per share.

Schedule I - Summary of Investm

Schedule I - Summary of Investments-Other than Investments in Related Parties	12 Months Ended
	Dec. 31, 2017
Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I - Summary of Investments-Other than Investments in Related Parties	EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule I – Summary of Investments- Other than Investment in Related Parties December 31, 2017 ($ in thousands) Type of investment Cost Fair value Amount at which shown in the balance sheet Securities available-for-sale: Fixed maturity securities: U.S. treasury $ 8,115 $ 8,078 $ 8,078 U.S. government-sponsored agencies 303,932 297,949 297,949 Obligations of states and political subdivisions 290,038 307,536 307,536 Commercial mortgage-backed 84,058 83,980 83,980 Residential mortgage-backed 120,554 119,799 119,799 Other asset-backed 23,934 24,114 24,114 Corporate 422,535 433,560 433,560 Total fixed maturity securities 1,253,166 1,275,016 1,275,016 Equity securities: Common stocks: Financial services 30,103 43,522 43,522 Information technology 18,308 35,810 35,810 Healthcare 18,877 30,595 30,595 Consumer staples 9,275 14,127 14,127 Consumer discretionary 10,935 20,538 20,538 Energy 12,441 16,905 16,905 Industrials 12,746 28,489 28,489 Other 11,058 16,421 16,421 Non-redeemable preferred stocks 20,531 21,708 21,708 Total equity securities 144,274 228,115 228,115 Other long-term investments 13,648 XXXX 13,648 Short-term investments 23,613 23,613 23,613 Total investments $ 1,434,701 XXXX $ 1,540,392

Schedule II - Condensed Financi

Schedule II - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule II - Condensed Financial Information of Registrant	EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule II – Condensed Financial Information of Registrant Condensed Balance Sheets December 31, ($ in thousands, except share and per share amounts) 2017 2016 ASSETS Investments: Common stock of subsidiaries (equity method) $ 599,036 $ 540,249 Equity securities available-for-sale, at fair value (cost $2,000 and $2,000) 2,000 2,000 Short-term investments 1,900 10,874 Total investments 602,936 553,123 Cash 255 184 Accrued investment income 1 3 Prepaid assets 136 154 Income taxes recoverable 777 700 Total assets $ 604,105 $ 554,164 LIABILITIES Accounts payable $ 80 $ 46 Amounts due affiliate to settle inter-company transaction balances 160 740 Deferred income taxes 19 36 Total liabilities 259 822 STOCKHOLDERS' EQUITY Common stock, $1 par value, authorized 30,000,000 shares; issued and outstanding, 21,455,545 shares in 2017 and 21,222,535 shares in 2016 21,455 21,223 Additional paid-in capital 124,556 119,054 Accumulated other comprehensive income 83,384 46,081 Retained earnings 374,451 366,984 Total stockholders' equity 603,846 553,342 Total liabilities and stockholders' equity $ 604,105 $ 554,164 All affiliated balances presented above are the result of related party transactions with Employers Mutual. EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule II – Condensed Financial Information of Registrant, Continued Condensed Statements of Income Year ended December 31, ($ in thousands) 2017 2016 2015 REVENUES Dividends received from subsidiaries $ 5,719 $ 9,707 $ 9,180 Investment income (loss) 38 13 (9 ) Total revenues 5,757 9,720 9,171 Operating expenses (affiliated $1,124, $1,139 and $1,074) 2,269 2,006 1,942 Income before income tax benefit and equity in undistributed net income of subsidiaries 3,488 7,714 7,229 Income tax benefit (794 ) (698 ) (682 ) Income before equity in undistributed net income of subsidiaries 4,282 8,412 7,911 Equity in undistributed net income of subsidiaries 34,956 37,791 42,251 Net income $ 39,238 $ 46,203 $ 50,162 All affiliated balances presented above are the result of related party transactions with Employers Mutual. EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule II – Condensed Financial Information of Registrant, Continued Condensed Statements of Comprehensive Income Year ended December 31, ($ in thousands) 2017 2016 2015 Net income $ 39,238 $ 46,203 $ 50,162 OTHER COMPREHENSIVE INCOME (LOSS) Unrealized holding gains (losses) on investment securities, net of deferred income taxes 27,278 (3,885 ) (13,037 ) Reclassification adjustment for realized investment gains included in net income, net of income taxes (8,326 ) (6,736 ) (4,956 ) Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income, net of deferred income taxes: Net actuarial loss 958 1,549 863 Prior service credit (2,047 ) (2,399 ) (2,150 ) Total reclassification adjustment associated with affiliate's pension and postretirement benefit plans (1,089 ) (850 ) (1,287 ) Change in funded status of affiliate's pension and postretirement benefit plans, net of deferred income taxes: Net actuarial gain (loss) 5,571 (542 ) (3,637 ) Prior service credit (cost) 96 (339 ) (312 ) Total change in funded status of affiliate's pension and postretirement benefit plans 5,667 (881 ) (3,949 ) Other comprehensive income (loss) 23,530 (12,352 ) (23,229 ) Total comprehensive income $ 62,768 $ 33,851 $ 26,933 All balances labeled with "affiliate" above are the result of related party transactions with Employers Mutual. All other comprehensive income (loss) balances presented above are from the Registrant's subsidiaries. EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule II – Condensed Financial Information of Registrant, Continued Condensed Statements of Cash Flows Year ended December 31, ($ in thousands) 2017 2016 2015 Net cash provided by operating activities $ 3,726 $ 9,170 $ 7,893 Cash flows from investing activities Capital contributions to subsidiaries (300 ) (500 ) — Purchases of equity securities available-for-sale — (2,000 ) — Net (purchases) disposals of short-term investments 8,974 (1,113 ) (3,030 ) Net cash (used in) provided by investing activities 8,674 (3,613 ) (3,030 ) Cash flows from financing activities Issuance of common stock through affiliate’s stock plans 7,527 11,070 9,078 Excess tax benefit associated with affiliate’s stock plans — — 95 Repurchase of common stock (1,858 ) (383 ) — Dividends paid to stockholders (affiliated $(10,006), $(9,182) and $(8,162)) (17,998 ) (16,196 ) (14,174 ) Net cash used in financing activities (12,329 ) (5,509 ) (5,001 ) Net increase (decrease) in cash 71 48 (138 ) Cash at the beginning of the year 184 136 274 Cash at the end of the year $ 255 $ 184 $ 136 Income taxes recovered $ 700 $ 716 $ 559 Interest paid $ — $ — $ — All affiliated balances presented above are the result of related party transactions with Employers Mutual.

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2017
Supplementary Insurance Information [Abstract]
Schedule III - Supplementary Insurance Information	EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule III – Supplementary Insurance Information For Years Ended December 31, 2017 , 2016 and 2015 ($ in thousands) Segment Deferred policy acquisition costs Loss and settlement expense reserves Unearned premiums Premium revenue Net investment income Losses and settlement expenses incurred Amortization of deferred policy acquisition costs Other underwriting expenses Premiums written Year ended December 31, 2017 Property and casualty insurance $ 37,140 $ 502,864 $ 236,030 $ 472,369 $ 32,670 $ 302,973 $ 79,734 $ 74,133 $ 484,027 Reinsurance 3,974 229,748 21,767 134,789 12,771 118,996 29,176 2,673 132,274 Parent company — — — — 38 — — — — Consolidated $ 41,114 $ 732,612 $ 257,797 $ 607,158 $ 45,479 $ 421,969 $ 108,910 $ 76,806 $ 616,301 Year ended December 31, 2016 Property and casualty insurance $ 36,295 $ 486,387 $ 220,697 $ 456,467 $ 33,886 $ 294,369 $ 78,493 $ 66,463 $ 463,673 Reinsurance 4,644 204,145 24,188 135,941 13,591 92,528 29,910 3,149 131,030 Parent company — — — — 13 — — — — Consolidated $ 40,939 $ 690,532 $ 244,885 $ 592,408 $ 47,490 $ 386,897 $ 108,403 $ 69,612 $ 594,703 Year ended December 31, 2015 Property and casualty insurance $ 35,219 $ 480,413 $ 212,652 $ 447,197 $ 32,668 $ 291,883 $ 75,701 $ 63,954 $ 454,434 Reinsurance 5,501 198,361 26,783 123,069 12,923 78,853 26,483 4,464 124,504 Parent company — — — — (9 ) — — — — Consolidated $ 40,720 $ 678,774 $ 239,435 $ 570,266 $ 45,582 $ 370,736 $ 102,184 $ 68,418 $ 578,938

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2017
Supplemental Schedule of Reinsurance Premiums for Insurance Companies [Abstract]
Schedule IV - Reinsurance	EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule IV – Reinsurance For Years Ended December 31, 2017 , 2016 and 2015 ($ in thousands) Gross amount Ceded to other companies Assumed from other companies Net amount Percentage of amount assumed to net Year ended December 31, 2017 Consolidated earned premiums $ 384,993 $ 437,881 $ 660,046 $ 607,158 108.7 % Year ended December 31, 2016 Consolidated earned premiums $ 382,300 $ 426,946 $ 637,054 $ 592,408 107.5 % Year ended December 31, 2015 Consolidated earned premiums $ 366,752 $ 407,531 $ 611,045 $ 570,266 107.2 %

Schedule VI - Supplemental Info

Schedule VI - Supplemental Information Concerning Property-Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2017
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Schedule VI - Supplemental Information Concerning Property-Casualty Insurance Operations	EMC INSURANCE GROUP INC. AND SUBSIDIARIES Schedule VI – Supplemental Information Concerning Property-Casualty Insurance Operations For Years Ended December 31, 2017 , 2016 and 2015 ($ in thousands) Deferred Reserves for Discount, if Unearned Earned Net Year ended December 31, 2017 $ 41,114 $ 732,612 $ — $ 257,797 $ 607,158 $ 45,441 Year ended December 31, 2016 $ 40,939 $ 690,532 $ — $ 244,885 $ 592,408 $ 47,477 Year ended December 31, 2015 $ 40,720 $ 678,774 $ — $ 239,435 $ 570,266 $ 45,591 Losses and settlement Amortization of Paid losses and settlement expenses Premiums ($ in thousands) Current year Prior years Year ended December 31, 2017 $ 441,588 $ (19,619 ) $ 108,910 $ 392,586 $ 616,301 Year ended December 31, 2016 $ 427,838 $ (40,941 ) $ 108,403 $ 372,888 $ 594,703 Year ended December 31, 2015 $ 405,850 $ (35,114 ) $ 102,184 $ 348,081 $ 578,938

SUMMARY OF SIGNIFICANT ACCOUN34

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Nature of operations	Description of Business EMC Insurance Group Inc., a majority owned subsidiary of Employers Mutual Casualty Company (Employers Mutual), is an insurance holding company with operations in property and casualty insurance and reinsurance. The Company conducts its property and casualty insurance operations through the following subsidiaries: EMCASCO Insurance Company, Illinois EMCASCO Insurance Company and Dakota Fire Insurance Company, and its reinsurance operations through its subsidiary, EMC Reinsurance Company. The Company also has an excess and surplus lines insurance agency subsidiary, EMC Underwriters, LLC. The term “Company” is used interchangeably to describe EMC Insurance Group Inc. (Parent Company only) and EMC Insurance Group Inc. and its subsidiaries. The Company writes property and casualty insurance in both commercial and personal lines of insurance, with a focus on medium-sized commercial accounts. Approximately 37 percent of the premiums written are in Iowa and contiguous states. The Company’s reinsurance business is primarily written through a quota share reinsurance agreement with Employers Mutual. A small portion of the assumed reinsurance business is written on a direct basis, outside the quota share reinsurance agreement.
Principles of Consolidation and Basis of Presentation	Principles of Consolidation and Basis of Presentation The consolidated financial statements have been prepared on the basis of U.S. generally accepted accounting principles (GAAP), which differ in some respects from those followed in reports to insurance regulatory authorities. All significant inter-company balances and transactions have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. The Company has evaluated all subsequent events through the date the financial statements were issued.
Property and Casualty Insurance and Reinsurance Operations	Property and Casualty Insurance and Reinsurance Operations Premiums written is the amount charged for policies issued during a reporting period. Property and casualty insurance premiums are recognized as revenue ratably over the terms of the respective policies. Unearned premiums are calculated on the daily pro rata method. Both domestic and foreign assumed reinsurance premiums are recognized as revenues ratably over the terms of the related contracts and underlying policies. Amounts paid as ceded reinsurance premiums are reported as prepaid reinsurance premiums and are amortized over the remaining contract period in proportion to the amount of reinsurance protection provided. Reinsurance reinstatement premiums are recognized in the same period as the loss event that gave rise to the reinstatement premiums. Costs related to the acquisition of insurance contracts are deferred and amortized to expense as the associated premium revenue is recognized. Only incremental costs or costs directly related to the successful acquisition of new or renewal insurance contracts are capitalized. Accordingly, acquisition costs consist of commissions, premium taxes, and salary and benefit expenses of employees directly involved in the underwriting of insurance policies that are successfully issued. The method followed in computing deferred policy acquisition costs limits the amount of such deferred costs to the estimated realizable value. In determining estimated realizable value, the computation gives effect to the premium to be earned, related investment income, anticipated losses and settlement expenses, anticipated policyholder dividends, and certain other costs expected to be incurred to administer the insurance policies as the premium is earned. The anticipated losses and settlement expenses are not discounted and are based on the Company’s projected loss and settlement expense ratios for the next twelve months, which include catastrophe loads based on historical results adjusted for recent trends. The occurrence of a significant catastrophic event, and/or the accumulation of catastrophe losses would not have a direct impact on the determination of premium deficiencies; however, such occurrences would be included in the historical results that are used to establish the catastrophe loads. A premium deficiency is first recognized by expensing the amount of unamortized deferred policy acquisition costs necessary to eliminate the deficiency. If the premium deficiency is greater than the unamortized deferred policy acquisition costs, a liability is accrued for the excess deficiency. The Company did not record a premium deficiency for the years ended December 31, 2017 , 2016 or 2015 . Certain commercial lines of business written by the property and casualty insurance subsidiaries, including workers’ compensation, are eligible for policyholder dividends in accordance with provisions of the underlying insurance policies. Net premiums written subject to policyholder dividends represented approximately 26 percent and 22 percent of the property and casualty insurance subsidiaries’ total net commercial line premiums written in 2017 and 2016 , respectively. Policyholder dividends are accrued over the terms of the underlying policy periods. Liabilities for losses reflect losses incurred through the balance sheet date and are based upon the estimated ultimate loss ratios established by line of business and accident year, and estimates of losses expected under assumed reinsurance contracts. Liabilities for settlement expenses are provided by estimating expenses expected to be incurred in settling the claims provided for in the loss reserves. Changes in reserves estimates are reflected in net income in the year such changes are recorded (see note 4). Ceded reinsurance amounts with nonaffiliated reinsurers relating to reinsurance receivables for unpaid losses and settlement expenses and prepaid reinsurance premiums are reported on the balance sheet on a gross basis. Amounts ceded to Employers Mutual under the affiliated reinsurance pooling agreement and the inter-company reinsurance programs (see note 2) have not been grossed up because the contracts provide that receivables and payables may be offset upon settlement. Based on current information, the liabilities for losses and settlement expenses are considered to be adequate. Since the provisions are necessarily based on estimates, the ultimate liabilities may be more or less than such provisions.
Investments	Investments Currently, all securities are classified as available-for-sale and are carried at fair value, with unrealized holding gains and losses reported as a component of accumulated other comprehensive income in stockholders’ equity, net of deferred income taxes. Other long-term investments consist of holdings in limited partnerships that are carried under the equity method of accounting, and holdings in limited partnerships and limited liability companies that are carried at amortized cost. The Company has an investment in a limited partnership that is designed to help protect the Company from a sudden and significant decline in the value of its equity portfolio. This limited partnership is carried under the equity method of accounting. Because of the nature of this investment, which is used solely to support the equity tail-risk hedging strategy, changes in the carrying value of the limited partnership are recorded as realized investment gains (losses), rather than as a component of investment income. Short-term investments generally include money market funds, U.S. Treasury bills and commercial paper that are carried at fair value, which approximates cost. The Company participates in a reverse repurchase arrangement involving the purchase of investment securities from third-party sellers, with the agreement that the purchased securities be sold back to the third-party sellers for agreed-upon prices at specified future dates. The third-party sellers are required to pledge collateral with a value greater than the amount of cash received in the transactions. In accordance with GAAP, the investment securities purchased under the reverse repurchase agreements are not reflected in the Company's consolidated balance sheets, but instead a receivable is recorded for the principal amount lent. Net proceeds/disbursements related to the reverse repurchase transactions are reported as a component of investing activities in the consolidated statements of cash flows, and the income as a component of operating activities. The Company uses independent pricing sources to obtain the estimated fair value of securities. The fair value is based on quoted market prices, where available. In cases where quoted market prices are not available, fair values are based on a variety of valuation techniques depending on the type of investment. The fair values obtained from independent pricing sources are reviewed for reasonableness and any discrepancies are investigated for final valuation (see note 8). The Company uses a practical expedient to measure the pooled separate account investments in Employers Mutual's qualified pension plan at the net asset value per share (see note 12). Premiums and discounts on fixed maturity securities are amortized over the expected life of the security as an adjustment to yield using the effective interest method . Amortization of premiums and discounts on mortgage-backed securities incorporates prepayment assumptions to estimate expected lives. Prepayment assumptions are reviewed quarterly and adjusted as necessary. Gains and losses realized on the disposition of investments are included in net income. The cost of investments sold is determined on the specific identification method using the highest cost basis first. Included in investments at December 31, 2017 and 2016 are securities on deposit with various regulatory authorities as required by law amounting to $11.3 million and $11.0 million , respectively. The Company regularly monitors its investment portfolio for securities whose fair value is less than the carrying value for indications of “other-than-temporary” impairment. Several factors are used to determine whether the carrying value of an individual security has been “other-than-temporarily” impaired. Such factors include, but are not limited to (1) the security’s value and performance in the context of the overall markets, (2) length of time and extent the security’s fair value has been below carrying value, (3) key corporate events, (4) for fixed maturity securities, the amount of collateral available, and (5) for equity securities, the ability and intent to hold the security until recovery to its cost basis. When an equity security is deemed to be “other-than-temporarily” impaired, the carrying value is reduced to fair value and a realized loss is recognized and charged to income. For fixed maturity securities, if the present value of cash flows expected to be collected is less than the amortized cost of the security, a credit loss is deemed to exist and the security is considered “other-than-temporarily” impaired. The portion of the impairment related to a credit loss is recognized through earnings, and the portion of the impairment related to other factors, if any, is recognized through “other comprehensive income”. Alternatively, if the Company has the intent to sell a fixed maturity security that is in an unrealized loss position, or determines that it will "more likely than not" be required to sell a fixed maturity security that is in an unrealized loss position before recovery of its amortized cost basis, then the carrying value is reduced to fair value and the entire amount of the impairment is recognized through earnings.
Income Taxes	Income Taxes The Company files a consolidated Federal income tax return with its subsidiaries. Consolidated income taxes/benefits are allocated among the entities based upon separate tax liabilities. Deferred income taxes are provided for temporary differences between the tax basis of assets and liabilities and the reported amounts of those assets and liabilities for financial reporting purposes. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Income tax expense provisions increase or decrease in the same period in which a change in tax rates is enacted. A valuation allowance is established to reduce deferred tax assets to their net realizable value if it is “more likely than not” that a tax benefit will not be realized. In February 2018, the Financial Accounting Standards Board (FASB) issued updated guidance in Income Statement-Comprehensive Income Topic 220 of the Accounting Standards Codification TM (Codification or ASC). The objective of this update is to allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (TCJA), and requires certain disclosures about the stranded tax effects. The Company adopted this guidance in 2017, and elected to transfer the stranded tax effects in accumulated other comprehensive income to retained earnings as reflected in the consolidated statements of stockholders' equity. The Company releases the tax effects in accumulated other comprehensive income on an individual unit of account basis. An assessment of the Company’s current tax positions indicated no uncertainties that would warrant different recognition and valuation from that applied in the Company’s tax returns.
Stock-Based Compensation	Stock-Based Compensation The Company has a stock-based compensation plan for non-employee directors. Compensation expense under this plan is based upon grant date fair value, which is recognized as the requisite service period is rendered. The Company has no other stock-based compensation plans of its own; however, Employers Mutual has several stock plans that utilize the common stock of the Company. The Company receives the current fair value for all shares issued under Employers Mutual's plans, and a portion of the compensation expense recognized by Employers Mutual is allocated to the Company’s property and casualty insurance subsidiaries though their participation in the pooling agreement (see note 2). For granted options and restricted stock awards, the expense is based upon the grant date fair value, which is recognized as the requisite service periods are rendered. For granted restricted stock units, the expense is determined in accordance with the liability-based model, whereby Employers Mutual records a liability representing the current value of the Company's stock granted for the portion of the service period that has been rendered (both the liability and the resulting expense are allocated to the Company's property and casualty insurance subsidiaries through the pooling agreement). Excess tax benefits (deficiencies) related to non-qualified stock option activities allocated to the Company's property and casualty insurance subsidiaries through the pooling agreement are recognized through the consolidated statements of income as components of current and deferred income taxes, with the associated cash flows reflected as cash flows from operating activities. Because a portion of Employers Mutual’s stock compensation expense is reflected in the Company’s financial statements and issuances of the Company’s stock under Employers Mutual’s stock plans have an impact on the Company’s capital accounts, the disclosures required by the Compensation – Stock Compensation Topic 718 of the FASB ASC are included in the Company’s consolidated financial statements (see note 13).
Employee Retirement Plans	Employee Retirement Plans Employers Mutual has various employee benefit plans, including two defined benefit pension plans, and two postretirement benefit plans that provide retiree healthcare and life insurance benefits. Although the Company has no employees of its own, it is responsible for its share of the plans' expenses and related prepaid assets and liabilities (the "funded status") as determined under the terms of the pooling agreement. Accordingly, the Company recognizes its share of the funded status of Employers Mutual’s pension and postretirement benefit plans on its balance sheet, with changes in the funded status of the plans recognized through “other comprehensive income.” In addition, the Company is responsible for its share of costs of these plans allocated by Employers Mutual to subsidiaries that do not participate in the pooling agreement (see note 2). During 2016, Employers Mutual's management determined that an allocation of the plans' funded status to the Company's reinsurance subsidiary would no longer be made because the amounts were immaterial and significant time and cost was needed to determine the allocation. As a result, the assets and liabilities allocated to the reinsurance subsidiary as of December 31, 2015 were settled with Employers Mutual during 2016.
Accounts Receivable	Accounts Receivable The accounts receivable balance consists of assumed reinsurance premiums receivable (net of any commissions) on business written directly by the reinsurance subsidiary, and commission income receivable on excess and surplus lines business marketed by EMC Underwriters, LLC. These receivables are carried at their initial recognition amounts. It is the Company’s policy to reflect the impairment of receivables through a valuation allowance until ultimately collected or charged-off. No valuation allowance is currently carried, as no amounts are deemed impaired. No interest income, other fees, or deferred costs related to these receivables are assessed or recognized.
Off-Balance-Sheet Credit Exposure	Off-Balance-Sheet Credit Exposure Employers Mutual collects from agents, policyholders and ceding companies all written premiums associated with the insurance business produced by the pool participants and the assumed reinsurance business ceded to the reinsurance subsidiary. Employers Mutual also collects from its reinsurers all losses and settlement expenses recoverable under the reinsurance contracts protecting the pool participants and, starting in 2016, the reinsurance subsidiary (see note 2), as well as the fronting business ceded to the reinsurance subsidiary. Employers Mutual settles with the pool participants (monthly) and the reinsurance subsidiary (quarterly) the premiums written from these insurance policies and the paid losses and settlement expenses recoverable under the external reinsurance contracts, providing full credit for the premiums written and the paid losses and settlement expenses recoverable under the external reinsurance contracts generated during the period (not just the collected portion). Due to this arrangement, and since a significant portion of the premium balances are collected over the course of the underlying coverage periods, Employers Mutual carries a substantial receivable balance for insurance and reinsurance premiums in process of collection and, to a lesser extent, paid losses and settlement expenses recoverable from the external reinsurance companies. Any of these receivable amounts that are ultimately deemed to be uncollectible are charged-off by Employers Mutual and the expense is charged to the reinsurance subsidiary or allocated to the pool members on the basis of pool participation. As a result, the Company has off-balance sheet arrangements with an unconsolidated entity that results in credit-risk exposures (Employers Mutual’s insurance and reinsurance premium receivable balances, and paid loss and settlement expense recoverable amounts) that are not reflected in the Company’s financial statements. The average annual expense for such charge-offs allocated to the Company over the past ten years is $380,000 . Based on this historical data, this credit-risk exposure is not considered to be material to the Company’s results of operations or financial position and, accordingly, no loss contingency liability has been recorded.
Foreign Currency Transactions	Foreign Currency Transactions Included in the underlying reinsurance business assumed by the reinsurance subsidiary are reinsurance transactions conducted with foreign cedants denominated in their local functional currencies. In accordance with the terms of the quota share agreement (see note 2), the reinsurance subsidiary assumes all foreign currency exchange gains/losses associated with contracts that are subject to the quota share agreement. The reinsurance subsidiary also has foreign currency exchange gains/losses associated with the business assumed outside the quota share agreement. The assets and liabilities resulting from these foreign reinsurance transactions are reported in U.S. dollars based on the foreign currency exchange rates that existed at the balance sheet dates. The foreign currency exchange rate gains/losses reported in the consolidated statements of income that resulted from these foreign reinsurance transactions are reported in U.S. dollars re-measured from the foreign currency exchange rates that existed at the inception of each reinsurance contract. The foreign currency exchange rate gains/losses resulting from these re-measurements to U.S. dollars are reported as a component of other income in the consolidated statements of income.
Net Income (Loss) Per Share - Basic and Diluted	Net Income Per Share - Basic and Diluted The Company’s basic and diluted net income per share is computed by dividing net income by the weighted average number of common shares outstanding during each period. As previously noted, the Company receives the current fair value for all shares issued under Employers Mutual’s stock plans. As a result, with the exception of the immaterial number of shares of outstanding non-vested restricted stock issued to the Company's non-employee directors, the Company had no potential common shares outstanding during 2017 , 2016 or 2015 that would have been dilutive to the calculation of net income per share. The outstanding non-vested restricted stock issued to the Company's non-employee directors is not material enough to produce a diluted net income per share different from the basic net income per share; therefore, the Company does not disclose an amount for the diluted weighted average number of common shares outstanding.
Goodwill	Goodwill Goodwill represents the excess of cost over the fair value of net assets of acquired subsidiaries. Goodwill is not amortized, but is instead subject to impairment if the carrying value of the goodwill exceeds the estimated fair value of net assets. If the carrying amount of the reporting unit (including goodwill) exceeds the computed fair value, an impairment loss is recognized through the income statement equal to the excess amount, but not greater than the balance of the goodwill. Goodwill was not deemed to be impaired in 2017 , 2016 or 2015 .
New Accounting Pronouncements Not Yet Adopted	New Accounting Pronouncements Not Yet Adopted In May 2014, the FASB updated its guidance related to the Revenue from Contracts with Customers Topic 606 of the ASC. The objective of this update (and other related following updates) is to improve the reporting of revenue by providing a more robust framework for addressing revenue issues, and improved disclosure requirements. Current revenue recognition guidance in U.S. GAAP is comprised of broad revenue recognition concepts together with numerous revenue requirements for particular industries or transactions, which sometimes result in different accounting for economically similar transactions. This guidance is to be applied retrospectively to annual and interim reporting periods beginning after December 15, 2017, with early adoption permitted as of the original effective date (annual and interim reporting periods beginning after December 15, 2016). The Company has adopted this guidance as of January 1, 2018. Since premium revenue from insurance contracts is excluded, the Company has only minimal revenue items that are covered by this guidance. The largest revenue item, outside of premium income, is commission income on excess and surplus lines business marketed by EMC Underwriters, LLC, which is included in "Other income" in the consolidated statements of income. Applying this new revenue recognition guidance to commission income produces no material difference compared to that recognized under current practices, as the commission income is typically recognized in full at the time the policy is issued, which is when substantially all of the performance obligation is performed. Adoption of this guidance will have no impact on the consolidated financial condition or operating results of the Company. In January 2016, the FASB updated its guidance related to the Financial Instruments-Overall Subtopic 825-10 of the ASC. The objective of this update is to enhance the reporting model for financial instruments to provide financial statement users with more decision-useful information. The major change in reporting from this update that will impact the Company is a requirement that equity investments (excluding those accounted for under the equity method of accounting or those that are consolidated) be measured at fair value, with changes in fair value recognized in net income. While all of the Company's equity investments are already measured at fair value (with the exception of those that are consolidated and those that are accounted for under the equity method of accounting), the Company currently classifies all of its investments in equity securities as available-for-sale, and as such, the changes in fair value are currently recognized in other comprehensive income rather than net income. This guidance is to be applied to annual and interim reporting periods beginning after December 15, 2017, with recognition of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. Early adoption is not permitted. The Company adopted this guidance on January 1, 2018, and reclassified $66.2 million from accumulated other comprehensive income to retained earnings which is equal to the amount of net unrealized gains on available-for-sale equity securities as of December 31, 2017, net of deferred income tax. Adoption of this guidance is expected to introduce volatility to the Company's consolidated net income. In February 2016, the FASB issued updated guidance in Leases Topic 842 of the ASC, which supersedes the guidance in Leases Topic 840 of the ASC. The objective of this update is to increase transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet, and disclosure of key information about leasing arrangements. This guidance is effective for interim and annual periods beginning after December 15, 2018, and is to be applied using a modified retrospective approach. Early adoption is permitted. The Company will adopt this guidance during the first quarter of 2019. Management continues to research this guidance, which thus far has led management to a preliminary determination that lease costs allocated to the Company through the pooling and quota share agreements can not be attributed to a specified asset, and therefore do not meet the definition of a leased asset contained in the guidance. As a result, adoption of this guidance is not expected to have a material impact on the Company's consolidated financial condition or net income. In June 2016, the FASB issued updated guidance in Financial Instruments-Credit Losses Topic 326 of the ASC. The objective of this update is to provide information about expected credit losses on financial instruments and other commitments to extend credit. Specifically, this updated guidance replaces the current incurred loss impairment methodology, which delays recognition of a loss until it is probable a loss has been incurred, with a methodology that reflects expected credit losses considering a broader range of reasonable and supportable information. This guidance covers financial assets that are not accounted for at fair value through net income, thus will not be applicable to the Company's equity investments upon implementation of the updated guidance described above for the Financial Instruments-Overall Subtopic 825-10. This guidance is effective for interim and annual periods beginning after December 15, 2019, and is to be applied with a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective (modified-retrospective approach). Early adoption is permitted, but only to fiscal years beginning after December 15, 2018. The Company will adopt this guidance during the first quarter of 2020. The Company is currently evaluating the impact this guidance will have on the Company's consolidated financial condition and net income. In March 2017, the FASB issued updated guidance in Compensation-Retirement Benefits Topic 715 of the ASC. The objective of this update is to improve the presentation of net periodic pension and postretirement benefit costs by disaggregating the components of these expenses (disclosing the service cost component separately from the other components) for income statement reporting. Also included in this update is a prohibition against including components of the net periodic pension and postretirement benefit costs, other than the service cost component, in any capitalized assets. This guidance is effective for interim and annual periods beginning after December 15, 2017. The portion of the guidance related to the income statement display of net periodic pension and postretirement benefit costs is to be applied retrospectively, while the prohibition against including these costs, other than the service cost component, in capitalized assets is to be applied prospectively. Early adoption is permitted. The Company has adopted this guidance as of January 1, 2018. Adoption will not impact consolidated stockholders' equity initially; however, the prohibition against including components of the net periodic pension and postretirement benefit costs, other than the service cost component, in capitalized assets is expected to result in a relatively small change in the deferred policy acquisition cost asset starting March 31, 2018, which is expected to have an immaterial impact, net of tax, on consolidated stockholders' equity and net income from that which would otherwise have been reported.

REINSURANCE (Tables)

REINSURANCE (Tables)	12 Months Ended
	Dec. 31, 2017
Reinsurance Disclosures [Abstract]
Schedule of reinsurance transactions for insurance companies	The effect of reinsurance on premiums written and earned, and losses and settlement expenses incurred, for the three years ended December 31, 2017 is presented below. The classification of the assumed and ceded reinsurance amounts between affiliates and nonaffiliates is based on the participants in the underlying reinsurance agreements, and is intended to provide an understanding of the actual source of the reinsurance activities. This presentation differs from the classifications used in the consolidated financial statements, where all amounts flowing through the pooling and quota share agreements and inter-company reinsurance programs with Employers Mutual are reported as “affiliated” balances. Year ended December 31, 2017 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 391,029 $ — $ 391,029 Assumed from nonaffiliates 4,454 147,284 151,738 Assumed from affiliates 520,932 — 520,932 Ceded to nonaffiliates (34,019 ) (10,160 ) (44,179 ) Ceded to affiliates (398,369 ) (4,850 ) (403,219 ) Net premiums written $ 484,027 $ 132,274 $ 616,301 Premiums earned Direct $ 384,993 $ — $ 384,993 Assumed from nonaffiliates 4,299 149,952 154,251 Assumed from affiliates 505,795 — 505,795 Ceded to nonaffiliates (30,385 ) (10,313 ) (40,698 ) Ceded to affiliates (392,333 ) (4,850 ) (397,183 ) Net premiums earned $ 472,369 $ 134,789 $ 607,158 Losses and settlement expenses incurred Direct $ 252,007 $ — $ 252,007 Assumed from nonaffiliates 2,879 142,687 145,566 Assumed from affiliates 334,240 1,330 335,570 Ceded to nonaffiliates (14,968 ) (8,183 ) (23,151 ) Ceded to affiliates (271,185 ) (16,838 ) (288,023 ) Net losses and settlement expenses incurred $ 302,973 $ 118,996 $ 421,969 Year ended December 31, 2016 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 383,811 $ — $ 383,811 Assumed from nonaffiliates 4,544 146,236 150,780 Assumed from affiliates 491,315 — 491,315 Ceded to nonaffiliates (24,346 ) (10,126 ) (34,472 ) Ceded to affiliates (391,651 ) (5,080 ) (396,731 ) Net premiums written $ 463,673 $ 131,030 $ 594,703 Premiums earned Direct $ 382,300 $ — $ 382,300 Assumed from nonaffiliates 4,444 148,851 153,295 Assumed from affiliates 483,759 — 483,759 Ceded to nonaffiliates (23,896 ) (7,830 ) (31,726 ) Ceded to affiliates (390,140 ) (5,080 ) (395,220 ) Net premiums earned $ 456,467 $ 135,941 $ 592,408 Losses and settlement expenses incurred Direct $ 229,859 $ — $ 229,859 Assumed from nonaffiliates 2,712 93,306 96,018 Assumed from affiliates 304,007 1,811 305,818 Ceded to nonaffiliates (4,891 ) (3,056 ) (7,947 ) Ceded to affiliates (237,318 ) 467 (236,851 ) Net losses and settlement expenses incurred $ 294,369 $ 92,528 $ 386,897 Year ended December 31, 2015 ($ in thousands) Property and Reinsurance Total Premiums written Direct $ 370,955 $ — $ 370,955 Assumed from nonaffiliates 4,392 138,700 143,092 Assumed from affiliates 474,323 — 474,323 Ceded to nonaffiliates (24,281 ) (3,369 ) (27,650 ) Ceded to affiliates (370,955 ) (10,827 ) (381,782 ) Net premiums written $ 454,434 $ 124,504 $ 578,938 Premiums earned Direct $ 366,752 $ — $ 366,752 Assumed from nonaffiliates 4,240 139,839 144,079 Assumed from affiliates 466,966 — 466,966 Ceded to nonaffiliates (24,009 ) (5,943 ) (29,952 ) Ceded to affiliates (366,752 ) (10,827 ) (377,579 ) Net premiums earned $ 447,197 $ 123,069 $ 570,266 Losses and settlement expenses incurred Direct $ 198,504 $ — $ 198,504 Assumed from nonaffiliates 2,407 83,515 85,922 Assumed from affiliates 294,324 857 295,181 Ceded to nonaffiliates (4,848 ) (4,897 ) (9,745 ) Ceded to affiliates (198,504 ) (622 ) (199,126 ) Net losses and settlement expenses incurred $ 291,883 $ 78,853 $ 370,736

LIABILITY FOR LOSSES AND SETT36

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES (Tables)	12 Months Ended
	Dec. 31, 2017
Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract]
Schedule of reconciliation of beginning and ending reserves for losses and settlement expenses	The following table sets forth a reconciliation of beginning and ending reserves for losses and settlement expenses of the Company. Amounts presented are on a net basis, with a reconciliation of beginning and ending reserves to the gross amounts presented in the consolidated financial statements. Year ended December 31, ($ in thousands) 2017 2016 2015 Gross reserves at beginning of year $ 690,532 $ 678,774 $ 661,309 Re-valuation due to foreign currency exchange rates (1,913 ) (2,475 ) (2,061 ) Less ceded reserves at beginning of year 20,664 23,477 28,253 Net reserves at beginning of year 671,781 657,772 635,117 Incurred losses and settlement expenses related to: Current year 441,588 427,838 405,850 Prior years (19,619 ) (40,941 ) (35,114 ) Total incurred losses and settlement expenses 421,969 386,897 370,736 Paid losses and settlement expenses related to: Current year 179,354 172,652 154,958 Prior years 213,232 200,236 193,123 Total paid losses and settlement expenses 392,586 372,888 348,081 Net reserves at end of year 701,164 671,781 657,772 Plus ceded reserves at end of year 30,923 20,664 23,477 Re-valuation due to foreign currency exchange rates 525 (1,913 ) (2,475 ) Gross reserves at end of year $ 732,612 $ 690,532 $ 678,774
Short-duration insurance contracts, claims development	($ in thousands) Commercial auto liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 29,898 $ 30,082 $ 29,433 $ 27,968 $ 26,886 $ 26,923 $ 26,878 $ 26,741 $ 26,768 $ 26,764 $ (1 ) 11,511 2009 28,973 27,923 26,667 25,370 24,986 24,874 24,730 24,655 24,697 15 10,482 2010 30,377 27,480 26,478 26,401 26,252 26,479 26,166 26,166 — 11,393 2011 32,775 29,790 31,098 31,961 31,914 31,635 31,638 275 11,767 2012 32,768 34,235 37,098 37,681 37,693 37,753 (203 ) 11,941 2013 37,265 40,382 42,086 42,336 43,159 (52 ) 13,640 2014 50,342 49,998 51,455 51,933 1,225 15,059 2015 53,883 57,824 58,627 1,664 16,494 2016 59,468 61,188 6,307 16,829 2017 63,909 16,652 15,220 Total $ 425,834 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 6,551 $ 13,437 $ 19,204 $ 23,144 $ 25,215 $ 26,306 $ 26,527 $ 26,648 $ 26,750 $ 26,756 2009 6,952 12,957 17,359 21,532 24,001 24,495 24,593 24,608 24,628 2010 7,025 13,278 19,274 23,547 24,674 25,558 26,039 26,088 2011 6,801 14,875 22,206 26,598 29,121 30,293 30,878 2012 8,830 19,398 26,023 32,636 35,406 36,541 2013 8,729 19,975 29,997 36,232 40,807 2014 12,069 25,746 37,433 44,783 2015 13,336 27,424 39,478 2016 13,583 30,233 2017 14,474 Total $ 314,666 All outstanding liabilities before 2008, net of reinsurance (34 ) Liability for losses and settlement expenses, net of reinsurance $ 111,134 ($ in thousands) Commercial property insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 48,559 $ 42,870 $ 42,645 $ 42,422 $ 42,562 $ 42,649 $ 42,784 $ 42,765 $ 42,707 $ 42,786 $ 23 15,799 2009 39,511 36,003 35,985 35,881 35,622 35,926 36,056 36,020 36,292 (71 ) 14,654 2010 40,422 38,650 38,770 39,071 39,154 39,379 39,428 39,347 (75 ) 16,276 2011 58,930 57,614 57,271 57,629 57,703 58,375 58,148 22 19,509 2012 41,535 44,157 45,313 46,273 46,566 46,750 22 16,054 2013 50,266 50,976 52,511 53,070 52,966 268 16,005 2014 60,018 60,990 60,662 60,867 456 16,735 2015 55,508 56,798 55,659 99 14,366 2016 59,708 58,343 (176 ) 14,866 2017 55,459 65 13,818 Total $ 506,617 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 31,514 $ 40,603 $ 41,868 $ 41,991 $ 42,071 $ 42,607 $ 42,691 $ 42,755 $ 42,755 $ 42,761 2009 25,321 32,602 34,624 35,422 35,803 35,803 35,849 35,893 36,224 2010 28,032 35,730 36,931 37,926 38,901 39,314 39,318 39,323 2011 41,524 53,226 54,803 56,249 57,065 57,607 58,106 2012 32,879 41,862 43,628 44,543 46,270 46,562 2013 36,555 47,683 50,460 51,457 52,182 2014 43,022 55,679 58,045 59,255 2015 37,208 50,068 52,444 2016 41,652 51,103 2017 38,114 Total $ 476,074 All outstanding liabilities before 2008, net of reinsurance (1 ) Liability for losses and settlement expenses, net of reinsurance $ 30,542 ($ in thousands) Workers' compensation insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 49,577 $ 46,240 $ 44,113 $ 43,156 $ 43,766 $ 43,338 $ 43,301 $ 43,737 $ 42,943 $ 43,272 $ 1,540 21,622 2009 46,130 43,335 44,098 44,041 44,093 43,590 43,724 42,774 43,417 1,642 19,236 2010 46,328 49,336 50,057 49,906 49,851 50,069 49,145 49,435 2,032 19,624 2011 47,836 46,724 44,709 44,506 44,427 43,695 44,056 1,831 19,569 2012 51,099 50,094 47,756 46,928 45,088 45,276 2,335 19,380 2013 52,141 51,637 48,946 46,102 45,949 2,509 19,843 2014 51,515 50,973 47,472 47,836 2,902 19,457 2015 54,960 48,919 47,227 1,777 19,177 2016 57,832 48,276 3,084 20,147 2017 52,409 6,721 19,181 Total $ 467,153 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 12,432 $ 25,214 $ 31,110 $ 34,302 $ 36,024 $ 37,270 $ 37,938 $ 38,654 $ 39,099 $ 39,496 2009 11,879 25,157 31,802 35,363 37,409 38,329 39,167 39,583 39,908 2010 14,237 28,074 35,029 39,001 41,437 42,651 43,614 44,175 2011 13,291 26,291 32,237 35,295 37,027 38,437 39,167 2012 14,015 28,109 33,943 37,307 39,456 40,292 2013 14,917 29,219 35,061 37,907 39,254 2014 14,692 28,894 35,883 39,046 2015 14,956 29,023 35,458 2016 15,473 29,592 2017 16,863 Total $ 363,251 All outstanding liabilities before 2008, net of reinsurance 34,420 Liability for losses and settlement expenses, net of reinsurance $ 138,322 ($ in thousands) Other liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 46,327 $ 40,005 $ 38,877 $ 34,689 $ 38,755 $ 37,005 $ 36,305 $ 35,528 $ 35,491 $ 34,941 $ 538 10,957 2009 44,497 39,908 37,650 34,263 35,614 32,827 32,384 32,521 32,063 647 9,844 2010 41,624 36,213 34,655 38,829 36,137 34,655 34,556 33,736 639 10,144 2011 44,490 42,982 35,125 35,177 33,649 32,452 31,711 992 9,994 2012 42,661 42,081 41,139 40,275 37,093 37,180 38 10,043 2013 47,974 43,837 42,544 42,187 39,175 3,666 10,580 2014 61,382 54,403 52,601 51,047 1,662 10,878 2015 54,221 47,553 43,379 9,566 10,496 2016 59,052 56,384 12,913 10,262 2017 59,420 25,293 8,407 Total $ 419,036 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 4,299 $ 10,443 $ 16,525 $ 24,139 $ 28,476 $ 31,270 $ 32,514 $ 32,863 $ 33,162 $ 33,451 2009 3,294 10,707 16,718 22,276 26,255 28,172 29,722 30,176 30,488 2010 3,403 8,315 15,041 21,732 27,612 29,688 30,711 31,776 2011 4,730 10,572 17,308 22,154 25,647 28,228 29,060 2012 4,720 12,851 19,661 25,095 29,651 32,753 2013 4,414 11,894 21,122 27,642 31,752 2014 5,630 17,267 27,506 35,318 2015 4,331 11,588 19,022 2016 6,403 18,784 2017 6,322 Total $ 268,726 All outstanding liabilities before 2008, net of reinsurance 13,369 Liability for losses and settlement expenses, net of reinsurance $ 163,679 ($ in thousands) Personal auto liability insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 9,024 $ 8,221 $ 8,121 $ 8,098 $ 8,094 $ 7,909 $ 7,876 $ 7,833 $ 7,862 $ 7,804 $ — 6,783 2009 10,168 9,653 9,452 9,386 9,353 9,382 9,339 9,325 9,312 (2 ) 7,523 2010 9,815 9,851 9,736 9,698 9,700 9,656 9,676 9,649 2 7,431 2011 9,741 9,388 9,331 9,432 9,460 9,311 9,413 10 8,051 2012 10,917 10,756 11,023 10,731 10,537 10,626 7 7,872 2013 10,492 10,384 10,376 10,085 10,085 22 7,235 2014 10,573 9,631 9,331 9,204 27 6,312 2015 9,119 8,638 8,378 181 5,666 2016 7,404 6,584 108 4,693 2017 7,043 553 4,427 Total $ 88,098 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 3,096 $ 5,798 $ 6,743 $ 7,291 $ 7,558 $ 7,794 $ 7,810 $ 7,809 $ 7,805 $ 7,804 2009 3,564 6,393 7,966 8,905 9,049 9,194 9,204 9,278 9,314 2010 3,988 6,666 8,250 9,108 9,401 9,562 9,632 9,631 2011 3,950 6,842 8,129 8,883 9,038 9,153 9,335 2012 4,779 7,439 9,091 9,871 10,244 10,415 2013 4,377 7,521 8,985 9,648 9,932 2014 3,970 6,392 7,755 8,598 2015 3,800 6,229 7,535 2016 3,505 5,427 2017 3,467 Total $ 81,458 All outstanding liabilities before 2008, net of reinsurance 71 Liability for losses and settlement expenses, net of reinsurance $ 6,711 ($ in thousands) Homeowners insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 22,736 $ 20,222 $ 19,894 $ 19,924 $ 19,905 $ 19,886 $ 19,886 $ 19,901 $ 19,908 $ 19,911 $ — 12,999 2009 18,109 16,606 16,467 16,379 16,352 16,394 16,465 16,464 16,467 — 11,486 2010 17,875 17,523 17,074 17,053 17,093 17,129 17,146 17,139 7 12,146 2011 24,530 23,389 22,975 23,309 23,448 23,415 23,350 (19 ) 14,287 2012 16,057 16,496 16,836 16,929 16,892 16,879 (24 ) 10,113 2013 14,844 14,833 14,685 14,784 14,737 (14 ) 8,688 2014 13,228 13,328 13,447 13,427 18 7,423 2015 11,233 11,153 11,041 (25 ) 5,940 2016 11,801 11,377 87 7,281 2017 9,926 (221 ) 7,359 Total $ 154,254 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 15,642 $ 19,385 $ 19,550 $ 19,787 $ 19,891 $ 19,902 $ 19,903 $ 19,902 $ 19,908 $ 19,911 2009 12,645 15,885 16,135 16,246 16,288 16,315 16,421 16,464 16,467 2010 13,457 16,633 16,909 17,011 17,128 17,128 17,130 17,132 2011 19,828 22,421 22,737 23,136 23,403 23,370 23,368 2012 13,759 16,283 16,582 16,793 16,859 16,905 2013 11,735 14,285 14,621 14,681 14,703 2014 11,065 13,025 13,215 13,269 2015 8,650 10,456 10,730 2016 10,573 10,869 2017 8,760 Total $ 152,114 All outstanding liabilities before 2008, net of reinsurance 91 Liability for losses and settlement expenses, net of reinsurance $ 2,231 ($ in thousands) Auto physical damage insurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 19,589 $ 17,743 $ 17,598 $ 17,584 $ 17,578 $ 17,567 $ 17,562 $ 17,558 $ 17,540 $ 17,541 $ (9 ) 28,635 2009 18,077 16,744 16,720 16,639 16,593 16,605 16,602 16,587 16,590 (11 ) 29,424 2010 19,249 18,657 18,538 18,549 18,527 18,532 18,488 18,494 (28 ) 31,518 2011 21,965 21,003 20,919 20,917 20,915 20,877 20,867 (27 ) 34,394 2012 21,389 21,342 21,263 21,233 21,161 21,184 (30 ) 31,099 2013 22,847 22,553 22,486 22,371 22,408 (4 ) 31,041 2014 24,897 24,115 23,904 23,946 (51 ) 31,580 2015 27,950 26,612 26,331 (10 ) 30,665 2016 28,070 27,629 (310 ) 30,715 2017 28,523 (1,868 ) 29,755 Total $ 223,513 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 16,491 $ 17,662 $ 17,577 $ 17,570 $ 17,577 $ 17,564 $ 17,560 $ 17,557 $ 17,555 $ 17,550 2009 15,566 16,661 16,687 16,636 16,592 16,603 16,602 16,601 16,599 2010 17,113 18,557 18,529 18,540 18,523 18,528 18,521 18,521 2011 19,849 20,984 20,912 20,904 20,912 20,900 20,892 2012 19,719 21,328 21,256 21,227 21,216 21,216 2013 20,774 22,512 22,463 22,417 22,408 2014 22,743 24,110 23,987 23,978 2015 24,483 26,538 26,327 2016 26,871 27,883 2017 27,452 Total $ 222,826 All outstanding liabilities before 2008, net of reinsurance (33 ) Liability for losses and settlement expenses, net of reinsurance $ 654 ($ in thousands) Assumed pro rata reinsurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 29,931 $ 25,463 $ 24,129 $ 24,473 $ 23,972 $ 24,103 $ 23,914 $ 24,068 $ 24,126 $ 24,084 $ 261 Unavailable 2009 23,812 19,364 18,442 17,626 17,447 17,274 17,212 17,204 17,183 225 2010 19,629 17,279 16,658 15,993 15,807 15,589 15,539 15,533 135 2011 30,231 30,316 29,848 29,075 28,459 28,440 28,339 182 2012 22,113 21,580 21,110 18,429 17,855 17,644 349 2013 23,306 30,174 27,545 26,936 25,442 1,883 2014 31,516 27,776 28,007 26,419 753 2015 38,442 35,356 35,148 1,704 2016 35,830 39,412 7,664 2017 29,989 14,704 Total $ 259,193 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 9,263 $ 18,268 $ 20,525 $ 21,744 $ 22,284 $ 22,700 $ 22,950 $ 23,253 $ 23,395 $ 23,476 2009 6,105 13,004 14,644 15,481 16,024 16,283 16,463 16,651 16,748 2010 5,059 12,057 14,081 14,499 15,172 15,212 15,254 15,299 2011 10,220 23,008 26,733 27,477 27,901 27,973 28,037 2012 4,478 12,826 15,159 16,403 16,772 16,852 2013 3,886 12,639 17,963 21,123 21,864 2014 6,052 16,185 20,745 23,567 2015 9,569 22,042 30,356 2016 9,673 22,280 2017 7,674 Total $ 206,153 All outstanding liabilities before 2008, net of reinsurance 2,599 Liability for losses and settlement expenses, net of reinsurance $ 55,639 ($ in thousands) Assumed excess of loss reinsurance Incurred losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, As of December 31, 2017 Supplementary unaudited information Audited Audited Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 IBNR Cumulative 2008 $ 43,963 $ 39,939 $ 41,427 $ 40,162 $ 39,019 $ 39,606 $ 37,519 $ 37,063 $ 36,928 $ 37,786 $ 1,384 Unavailable 2009 38,903 30,552 29,987 30,518 30,167 28,233 27,913 27,142 26,922 1,496 2010 47,426 41,011 40,820 40,307 39,675 40,432 39,628 39,166 1,857 2011 72,124 61,787 60,948 59,345 59,090 58,700 58,279 1,977 2012 58,852 56,119 54,494 53,247 52,896 52,003 2,898 2013 52,699 47,705 45,103 44,947 44,829 3,188 2014 65,573 59,108 60,454 62,009 5,061 2015 60,183 55,190 51,924 6,372 2016 66,995 67,206 9,099 2017 91,994 29,426 Total $ 532,118 Cumulative paid losses and allocated settlement expenses, net of reinsurance, for the years ended December 31, Supplementary unaudited information Audited Accident 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2008 $ 14,314 $ 25,556 $ 28,756 $ 30,690 $ 31,320 $ 32,634 $ 32,784 $ 33,216 $ 33,660 $ 33,837 2009 8,554 15,896 18,803 21,011 21,882 22,231 22,854 23,032 23,264 2010 9,282 24,759 28,037 30,858 32,700 33,709 35,387 35,646 2011 25,309 42,214 47,965 50,613 52,611 53,906 54,628 2012 21,320 36,266 40,641 43,637 45,174 46,735 2013 11,732 27,635 33,422 37,717 39,520 2014 22,172 39,361 46,163 50,242 2015 13,434 30,495 36,918 2016 18,408 38,913 2017 27,881 Total $ 387,584 All outstanding liabilities before 2008, net of reinsurance 18,772 Liability for losses and settlement expenses, net of reinsurance $ 163,306
Short-duration insurance contracts, reconciliation of claims development to liability	The following table sets forth a reconciliation of the incurred and paid claims development tables to the liability for losses and settlement expenses: ($ in thousands) December 31, 2017 Net outstanding liabilities for losses and allocated settlement expenses: Commercial auto liability insurance $ 111,134 Commercial property insurance 30,542 Workers' compensation insurance 138,322 Other liability insurance 163,679 Personal auto liability insurance 6,711 Homeowners insurance 2,231 Auto physical damage insurance 654 Assumed pro rata reinsurance 55,639 Assumed excess of loss reinsurance 163,306 Other lines of insurance 2,283 Liability for losses and allocated settlement expenses, net of reinsurance 674,501 Ceded reserves for losses and allocated settlement expenses: Commercial auto liability insurance 768 Commercial property insurance 4,624 Workers' compensation insurance 10,005 Other liability insurance 3,938 Personal auto liability insurance 1,337 Homeowners insurance 573 Auto physical damage insurance 228 Assumed pro rata reinsurance 7,167 Assumed excess of loss reinsurance 1,444 Other lines of insurance 839 Total ceded reserves for losses and allocated settlement expenses 30,923 Unallocated settlement expenses 27,188 Gross reserve for losses and settlement expenses $ 732,612
Short-duration insurance contracts, schedule of historical claims duration	Average annual percentage payout of incurred claims by age, net of reinsurance Supplementary unaudited information Years 1 2 3 4 5 6 7 8 9 10 Commercial auto liability insurance 23.5 % 25.7 % 21.2 % 15.4 % 8.0 % 3.2 % 1.2 % 0.3 % 0.3 % 0.0 % Commercial property insurance 70.3 % 20.1 % 4.0 % 1.9 % 1.7 % 0.8 % 0.3 % 0.1 % 0.5 % 0.0 % Workers' compensation insurance 30.5 % 29.8 % 13.8 % 7.2 % 4.2 % 2.5 % 1.8 % 1.3 % 0.9 % 0.9 % Other liability insurance 11.5 % 19.6 % 19.5 % 17.2 % 12.7 % 7.3 % 3.5 % 1.9 % 1.0 % 0.8 % Personal auto liability insurance 44.1 % 29.4 % 14.9 % 8.2 % 2.6 % 1.8 % 0.7 % 0.3 % 0.2 % 0.0 % Homeowners insurance 82.2 % 14.9 % 1.7 % 0.9 % 0.5 % 0.1 % 0.2 % 0.1 % 0.0 % 0.0 % Auto physical damage insurance 94.3 % 6.6 % (0.3 )% (0.1 )% (0.1 )% 0.0 % 0.0 % 0.0 % 0.0 % 0.0 % Assumed pro rata reinsurance 28.4 % 39.5 % 15.0 % 6.5 % 2.7 % 0.9 % 0.6 % 0.9 % 0.6 % 0.3 % Assumed excess of loss reinsurance 32.3 % 31.2 % 10.3 % 6.7 % 3.3 % 2.5 % 2.1 % 0.8 % 1.1 % 0.5 %

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summarized financial information for segments	Summarized financial information for the Company’s segments is as follows: Year ended December 31, 2017 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 472,369 $ 134,789 $ — $ 607,158 Underwriting profit (loss): SAP underwriting profit (loss) 2,702 (15,386 ) — (12,684 ) GAAP adjustments 5,217 (670 ) — 4,547 GAAP underwriting profit (loss) 7,919 (16,056 ) — (8,137 ) Net investment income (loss) 32,670 12,771 38 45,479 Net realized investment gains (losses) 4,896 1,660 — 6,556 Other income (loss) 1,171 (1,519 ) — (348 ) Interest expense 337 — — 337 Other expenses 1,128 — 2,269 3,397 Income (loss) before income tax expense (benefit) $ 45,191 $ (3,144 ) $ (2,231 ) $ 39,816 Assets $ 1,200,636 $ 484,678 $ 604,105 $ 2,289,419 Eliminations — — (599,036 ) (599,036 ) Reclassifications (1,393 ) (6,273 ) (777 ) (8,443 ) Total assets $ 1,199,243 $ 478,405 $ 4,292 $ 1,681,940 Year ended December 31, 2016 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 456,467 $ 135,941 $ — $ 592,408 Underwriting profit (loss): SAP underwriting profit (loss) 4,276 11,377 — 15,653 GAAP adjustments (934 ) (1,023 ) — (1,957 ) GAAP underwriting profit (loss) 3,342 10,354 — 13,696 Net investment income (loss) 33,886 13,591 13 47,490 Net realized investment gains (losses) 4,082 (8 ) — 4,074 Other income (loss) 594 417 — 1,011 Interest expense 337 — — 337 Other expenses 721 — 2,006 2,727 Income (loss) before income tax expense (benefit) $ 40,846 $ 24,354 $ (1,993 ) $ 63,207 Assets $ 1,122,037 $ 455,493 $ 554,164 $ 2,131,694 Eliminations — — (540,249 ) (540,249 ) Reclassifications — (1,932 ) (700 ) (2,632 ) Total assets $ 1,122,037 $ 453,561 $ 13,215 $ 1,588,813 Year ended December 31, 2015 Property and Reinsurance Parent Consolidated ($ in thousands) Premiums earned $ 447,197 $ 123,069 $ — $ 570,266 Underwriting profit (loss): SAP underwriting profit (loss) 2,494 13,228 — 15,722 GAAP adjustments 5,460 41 — 5,501 GAAP underwriting profit (loss) 7,954 13,269 — 21,223 Net investment income (loss) 32,668 12,923 (9 ) 45,582 Net realized investment gains (losses) 4,163 1,990 — 6,153 Other income (loss) 771 954 — 1,725 Interest expense 337 — — 337 Other expenses 748 — 1,942 2,690 Income (loss) before income tax expense (benefit) $ 44,471 $ 29,136 $ (1,951 ) $ 71,656
Summary of net premiums earned by line of insurance	The following table displays the premiums earned for the property and casualty insurance segment and the reinsurance segment for the three years ended December 31, 2017 , by line of insurance. Year ended December 31, ($ in thousands) 2017 2016 2015 Property and casualty insurance segment Commercial lines: Automobile $ 118,224 $ 110,941 $ 105,904 Property 108,162 105,012 104,303 Workers' compensation 100,552 96,517 92,828 Other liability 98,674 96,630 92,665 Other 8,719 8,374 8,079 Total commercial lines 434,331 417,474 403,779 Personal lines 38,038 38,993 43,418 Total property and casualty insurance $ 472,369 $ 456,467 $ 447,197 Reinsurance segment Pro rata reinsurance $ 44,636 $ 56,317 $ 47,421 Excess of loss reinsurance 90,153 79,624 75,648 Total reinsurance $ 134,789 $ 135,941 $ 123,069 Consolidated $ 607,158 $ 592,408 $ 570,266

DISCLOSURES ABOUT THE FAIR VA38

DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Summary of carrying amount and estimated fair value of financial instruments	The carrying amounts and the estimated fair values of the Company’s financial instruments as of December 31, 2017 and 2016 are summarized in the tables below. December 31, 2017 Carrying Estimated ($ in thousands) Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 8,078 $ 8,078 U.S. government-sponsored agencies 297,949 297,949 Obligations of states and political subdivisions 307,536 307,536 Commercial mortgage-backed 83,980 83,980 Residential mortgage-backed 119,799 119,799 Other asset-backed 24,114 24,114 Corporate 433,560 433,560 Total fixed maturity securities available-for-sale 1,275,016 1,275,016 Equity securities available-for-sale: Common stocks: Financial services 43,522 43,522 Information technology 35,810 35,810 Healthcare 30,595 30,595 Consumer staples 14,127 14,127 Consumer discretionary 20,538 20,538 Energy 16,905 16,905 Industrials 28,489 28,489 Other 16,421 16,421 Non-redeemable preferred stocks 21,708 21,708 Total equity securities available-for-sale 228,115 228,115 Short-term investments 23,613 23,613 Liabilities: Surplus notes 25,000 16,689 December 31, 2016 Carrying Estimated ($ in thousands) Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 7,830 $ 7,830 U.S. government-sponsored agencies 239,197 239,197 Obligations of states and political subdivisions 335,757 335,757 Commercial mortgage-backed 37,572 37,572 Residential mortgage-backed 96,434 96,434 Other asset-backed 26,393 26,393 Corporate 456,516 456,516 Total fixed maturity securities available-for-sale 1,199,699 1,199,699 Equity securities available-for-sale: Common stocks: Financial services 35,122 35,122 Information technology 30,542 30,542 Healthcare 24,707 24,707 Consumer staples 19,100 19,100 Consumer discretionary 22,321 22,321 Energy 19,071 19,071 Industrials 24,245 24,245 Other 18,384 18,384 Non-redeemable preferred stocks 20,347 20,347 Total equity securities available-for-sale 213,839 213,839 Short-term investments 39,670 39,670 Liabilities: Surplus notes 25,000 11,228
Summary of assets and liabilities measured on recurring and non-recurring basis	Presented in the tables below are the estimated fair values of the Company’s financial instruments as of December 31, 2017 and 2016 . December 31, 2017 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Financial instruments reported at fair value on recurring basis: Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 8,078 $ — $ 8,078 $ — U.S. government-sponsored agencies 297,949 — 297,949 — Obligations of states and political subdivisions 307,536 — 307,536 — Commercial mortgage-backed 83,980 — 83,980 — Residential mortgage-backed 119,799 — 119,799 — Other asset-backed 24,114 — 24,114 — Corporate 433,560 — 432,940 620 Total fixed maturity securities available-for-sale 1,275,016 — 1,274,396 620 Equity securities available-for-sale: Common stocks: Financial services 43,522 43,519 — 3 Information technology 35,810 35,810 — — Healthcare 30,595 30,595 — — Consumer staples 14,127 14,127 — — Consumer discretionary 20,538 20,538 — — Energy 16,905 16,905 — — Industrials 28,489 28,489 — — Other 16,421 16,421 — — Non-redeemable preferred stocks 21,708 9,512 10,196 2,000 Total equity securities available-for-sale 228,115 215,916 10,196 2,003 Short-term investments 23,613 23,613 — — Financial instruments not reported at fair value: Liabilities: Surplus notes 16,689 — — 16,689 December 31, 2016 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Financial instruments reported at fair value on recurring basis: Assets: Fixed maturity securities available-for-sale: U.S. treasury $ 7,830 $ — $ 7,830 $ — U.S. government-sponsored agencies 239,197 — 239,197 — Obligations of states and political subdivisions 335,757 — 335,757 — Commercial mortgage-backed 37,572 — 37,572 — Residential mortgage-backed 96,434 — 96,434 — Other asset-backed 26,393 — 26,393 — Corporate 456,516 — 455,534 982 Total fixed maturity securities available-for-sale 1,199,699 — 1,198,717 982 Equity securities available-for-sale: Common stocks: Financial services 35,122 35,119 — 3 Information technology 30,542 30,542 — — Healthcare 24,707 24,707 — — Consumer staples 19,100 19,100 — — Consumer discretionary 22,321 22,321 — — Energy 19,071 19,071 — — Industrials 24,245 24,245 — — Other 18,384 18,384 — — Non-redeemable preferred stocks 20,347 11,074 7,273 2,000 Total equity securities available-for-sale 213,839 204,563 7,273 2,003 Short-term investments 39,670 39,670 — — Financial instruments not reported at fair value: Liabilities: Surplus notes 11,228 — — 11,228
Reconciliation of assets measured at fair value on recurring basis using significant unobservable inputs	Presented in the table below is a reconciliation of the assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2017 and 2016 . Any unrealized gains or losses on these securities are recognized in other comprehensive income (loss). Any gains or losses from settlements, disposals or impairments of these securities are reported as realized investment gains or losses in net income. Fair value measurements using significant unobservable (Level 3) inputs ($ in thousands) Fixed maturity securities available-for-sale, corporate Equity securities Equity securities available-for-sale, non-redeemable preferred stocks Total Balance at December 31, 2015 $ 1,329 $ 3 $ — $ 1,332 Purchases — — 2,000 2,000 Settlements (345 ) — — (345 ) Unrealized losses included in other comprehensive income (loss) (2 ) — — (2 ) Balance at December 31, 2016 982 3 2,000 2,985 Settlements (356 ) — — (356 ) Unrealized losses included in other comprehensive income (loss) (6 ) — — (6 ) Balance at December 31, 2017 $ 620 $ 3 $ 2,000 $ 2,623

INVESTMENTS (Tables)

INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Reconciliation of available-for-sale securities from cost basis to fair value	The amortized cost and estimated fair value of securities available-for-sale as of December 31, 2017 and 2016 are as follows. All securities are classified as available-for-sale and are carried at fair value. December 31, 2017 Amortized Gross Gross Estimated ($ in thousands) Securities available-for-sale: Fixed maturity securities: U.S. treasury $ 8,115 $ — $ 37 $ 8,078 U.S. government-sponsored agencies 303,932 122 6,105 297,949 Obligations of states and political subdivisions 290,038 17,729 231 307,536 Commercial mortgage-backed 84,058 591 669 83,980 Residential mortgage-backed 120,554 2,479 3,234 119,799 Other asset-backed 23,934 625 445 24,114 Corporate 422,535 11,490 465 433,560 Total fixed maturity securities 1,253,166 33,036 11,186 1,275,016 Equity securities: Common stocks: Financial services 30,103 13,594 175 43,522 Information technology 18,308 17,504 2 35,810 Healthcare 18,877 11,876 158 30,595 Consumer staples 9,275 4,917 65 14,127 Consumer discretionary 10,935 9,640 37 20,538 Energy 12,441 5,381 917 16,905 Industrials 12,746 15,757 14 28,489 Other 11,058 5,363 — 16,421 Non-redeemable preferred stocks 20,531 1,216 39 21,708 Total equity securities 144,274 85,248 1,407 228,115 Total securities available-for-sale $ 1,397,440 $ 118,284 $ 12,593 $ 1,503,131 December 31, 2016 Amortized Gross Gross Estimated ($ in thousands) Securities available-for-sale: Fixed maturity securities: U.S. treasury $ 7,841 $ — $ 11 $ 7,830 U.S. government-sponsored agencies 249,495 311 10,609 239,197 Obligations of states and political subdivisions 319,663 17,034 940 335,757 Commercial mortgage-backed 37,964 741 1,133 37,572 Residential mortgage-backed 102,307 1,435 7,308 96,434 Other asset-backed 26,592 732 931 26,393 Corporate 445,663 12,232 1,379 456,516 Total fixed maturity securities 1,189,525 32,485 22,311 1,199,699 Equity securities: Common stocks: Financial services 22,922 12,410 210 35,122 Information technology 19,832 10,739 29 30,542 Healthcare 16,092 8,700 85 24,707 Consumer staples 13,438 5,787 125 19,100 Consumer discretionary 14,812 7,672 163 22,321 Energy 14,276 4,873 78 19,071 Industrials 13,005 11,258 18 24,245 Other 13,071 5,345 32 18,384 Non-redeemable preferred stocks 20,031 483 167 20,347 Total equity securities 147,479 67,267 907 213,839 Total securities available-for-sale $ 1,337,004 $ 99,752 $ 23,218 $ 1,413,538
Estimated fair value and gross unrealized losses associated with investment securities	The following tables set forth the estimated fair values and gross unrealized losses associated with investment securities that were in an unrealized loss position as of December 31, 2017 and 2016 , listed by length of time the securities were consistently in an unrealized loss position. December 31, 2017 Less than twelve months Twelve months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. treasury $ 8,078 $ 37 $ — $ — $ 8,078 $ 37 U.S. government-sponsored agencies 134,284 1,491 127,604 4,614 261,888 6,105 Obligations of states and political subdivisions — — 14,416 231 14,416 231 Commercial mortgage-backed 32,155 221 8,530 448 40,685 669 Residential mortgage-backed 30,003 394 22,948 2,840 52,951 3,234 Other asset-backed — — 13,440 445 13,440 445 Corporate 28,314 329 4,047 136 32,361 465 Total fixed maturity securities 232,834 2,472 190,985 8,714 423,819 11,186 Equity securities: Common stocks: Financial services 4,391 175 — — 4,391 175 Information technology 344 2 — — 344 2 Healthcare 2,532 158 — — 2,532 158 Consumer staples 575 65 — — 575 65 Consumer discretionary 992 37 — — 992 37 Energy 3,181 917 — — 3,181 917 Industrials 3,016 14 — — 3,016 14 Non-redeemable preferred stocks — — 1,961 39 1,961 39 Total equity securities 15,031 1,368 1,961 39 16,992 1,407 Total temporarily impaired securities $ 247,865 $ 3,840 $ 192,946 $ 8,753 $ 440,811 $ 12,593 December 31, 2016 Less than twelve months Twelve months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized Fixed maturity securities: U.S. treasury $ 7,830 $ 11 $ — $ — $ 7,830 $ 11 U.S. government-sponsored agencies 202,900 10,609 — — 202,900 10,609 Obligations of states and political subdivisions 43,777 940 — — 43,777 940 Commercial mortgage-backed 21,695 1,133 — — 21,695 1,133 Residential mortgage-backed 26,217 1,232 23,625 6,076 49,842 7,308 Other asset-backed 19,091 931 — — 19,091 931 Corporate 82,657 1,273 8,625 106 91,282 1,379 Total fixed maturity securities 404,167 16,129 32,250 6,182 436,417 22,311 Equity securities: Common stocks: Financial services 1,462 12 908 198 2,370 210 Information technology 1,947 29 — — 1,947 29 Healthcare 3,585 85 — — 3,585 85 Consumer staples 2,427 125 — — 2,427 125 Consumer discretionary 1,637 163 — — 1,637 163 Energy 1,621 33 1,188 45 2,809 78 Industrials 779 18 — — 779 18 Other 1,472 32 — — 1,472 32 Non-redeemable preferred stocks 3,356 44 1,877 123 5,233 167 Total equity securities 18,286 541 3,973 366 22,259 907 Total temporarily impaired securities $ 422,453 $ 16,670 $ 36,223 $ 6,548 $ 458,676 $ 23,218
Amortized cost and estimated fair value of fixed maturity securities	The amortized cost and estimated fair values of fixed maturity securities at December 31, 2017 , by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations, with or without call or prepayment penalties. ($ in thousands) Amortized Estimated Securities available-for-sale: Due in one year or less $ 40,543 $ 41,094 Due after one year through five years 173,741 177,883 Due after five years through ten years 368,782 376,119 Due after ten years 463,572 474,251 Securities not due at a single maturity date 206,528 205,669 Totals $ 1,253,166 $ 1,275,016
Summary of realized investment gains and (losses)	A summary of realized investment gains and (losses) is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Fixed maturity securities available-for-sale: Gross realized investment gains $ 545 $ 2,054 $ 725 Gross realized investment losses (4,849 ) (2,829 ) (251 ) Equity securities available-for-sale: Gross realized investment gains 19,792 15,078 12,741 Gross realized investment losses (1,592 ) (2,675 ) (4,110 ) "Other-than-temporary" impairments (1,088 ) (1,055 ) (1,481 ) Other long-term investments, net (6,252 ) (6,499 ) (1,471 ) Totals $ 6,556 $ 4,074 $ 6,153
Summary of net investment income	A summary of net investment income is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Interest on fixed maturity securities $ 39,992 $ 41,499 $ 42,261 Dividends on equity securities 6,032 6,922 5,617 Income on reverse repurchase agreements 306 236 117 Interest on short-term investments 273 121 2 Return on long-term investments 1,126 514 (461 ) Total investment income 47,729 49,292 47,536 Securities litigation income 12 111 32 Investment expenses (2,262 ) (1,913 ) (1,986 ) Net investment income $ 45,479 $ 47,490 $ 45,582
Summary of net changes in unrealized holding gains (losses) on securities available-for-sale	A summary of net changes in unrealized holding gains (losses) on securities available-for-sale is included in the table below. Year ended December 31, ($ in thousands) 2017 2016 2015 Fixed maturity securities $ 11,676 $ (20,634 ) $ (16,685 ) Deferred income tax expense (benefit) 4,086 (7,222 ) (5,840 ) Total fixed maturity securities 7,590 (13,412 ) (10,845 ) Equity securities 17,481 4,293 (10,997 ) Deferred income tax expense (benefit) 6,119 1,502 (3,849 ) Total equity securities 11,362 2,791 (7,148 ) Total available-for-sale securities $ 18,952 $ (10,621 ) $ (17,993 )

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	Temporary differences between the consolidated financial statement carrying amount and tax basis of assets and liabilities that give rise to significant portions of the deferred income tax asset (liability) at December 31, 2017 and 2016 are as follows: December 31, ($ in thousands) 2017 2016 Loss reserve discounting $ 7,507 $ 13,442 Unearned premium reserve limitation 10,284 16,497 Other policyholders' funds payable 2,103 4,574 Other, net 2,202 2,561 Total deferred income tax asset 22,096 37,074 Net unrealized holding gains on investment securities (22,195 ) (26,786 ) Deferred policy acquisition costs (8,634 ) (14,328 ) Retirement benefits (3,714 ) (3,510 ) Other, net (2,573 ) (3,771 ) Total deferred income tax liability (37,116 ) (48,395 ) Net deferred income tax liability $ (15,020 ) $ (11,321 )
Reconciliation of income tax expense (benefit)	The actual income tax expense for the years ended December 31, 2017 , 2016 and 2015 differed from the “expected” income tax expense for those years (computed by applying the United States federal corporate tax rate of 35 percent to income before income tax expense) as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Computed "expected" income tax expense $ 13,936 $ 22,123 $ 25,079 Increases (decreases) in tax resulting from: Deferred income tax benefit from enactment of the TCJA (9,056 ) — — Tax-exempt interest income (2,715 ) (2,803 ) (2,805 ) Dividends received deduction (1,291 ) (1,429 ) (1,136 ) Proration of tax-exempt interest and dividends received deduction 601 635 591 Investment tax credits (672 ) (1,392 ) — Other, net (225 ) (130 ) (235 ) Total income tax expense $ 578 $ 17,004 $ 21,494
Schedule Of Components Of Comprehensive Income Tax Expense Benefit [Table Text Block]	Comprehensive income tax expense included in the consolidated financial statements for the years ended December 31, 2017 , 2016 and 2015 is as follows. The deferred income tax benefit that resulted from the enactment of the TCJA in 2017 is included in the "operations" line. Year ended December 31, ($ in thousands) 2017 2016 2015 Income tax expense (benefit) on: Operations $ 578 $ 17,004 $ 21,494 Change in unrealized holding gains on investment securities 10,205 (5,720 ) (9,689 ) Change in funded status of retirement benefit plans: Pension plans 1,694 414 (1,748 ) Postretirement benefit plans (774 ) (1,345 ) (1,071 ) Comprehensive income tax expense $ 11,703 $ 10,353 $ 8,986

EMPLOYEE RETIREMENT PLANS (Tabl

EMPLOYEE RETIREMENT PLANS (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of funded status of Employers Mutual's pension and postretirement benefit plans	The following table sets forth the funded status of Employers Mutual’s pension and postretirement benefit plans as of December 31, 2017 and 2016 , based upon measurement dates of December 31, 2017 and 2016 , respectively. Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Change in projected benefit obligation: Benefit obligation at beginning of year $ 284,194 $ 269,904 $ 55,651 $ 51,449 Service cost 15,135 14,432 1,362 1,273 Interest cost 11,190 10,161 2,281 2,215 Actuarial loss 12,577 5,361 3,278 357 Benefits paid (14,852 ) (15,664 ) (2,455 ) (2,377 ) Medicare subsidy reimbursements — — — 553 Plan amendments — — (1,113 ) 2,181 Projected benefit obligation at end of year 308,244 284,194 59,004 55,651 Change in plan assets: Fair value of plan assets at beginning of year 300,915 283,231 67,809 66,320 Actual return on plan assets 54,255 23,081 10,304 3,866 Employer contributions 8,686 10,267 — — Benefits paid (14,852 ) (15,664 ) (2,455 ) (2,377 ) Fair value of plan assets at end of year 349,004 300,915 75,658 67,809 Funded status $ 40,760 $ 16,721 $ 16,654 $ 12,158
Schedule of amounts recognized in consolidated balance sheet	Amounts recognized in the Company’s consolidated balance sheets: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Assets: Prepaid pension and postretirement benefits $ 16,327 $ 9,065 $ 4,356 $ 3,249 Liability: Pension and postretirement benefits (4,185 ) (4,097 ) — — Net amount recognized $ 12,142 $ 4,968 $ 4,356 $ 3,249
Schedule of amounts recognized in consolidated balance sheets under the caption accumulated other comprehensive income	Amounts recognized in the Company’s consolidated balance sheets under the caption “accumulated other comprehensive income”, before deferred income taxes: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Net actuarial loss $ (11,598 ) $ (18,927 ) $ (4,950 ) $ (6,147 ) Prior service (cost) credit — (6 ) 16,407 19,441 Net amount recognized $ (11,598 ) $ (18,933 ) $ 11,457 $ 13,294
Schedule of amounts recognized in consolidated statements of comprehensive income	Amounts recognized in the Company’s consolidated statements of comprehensive income, before deferred income taxes: Pension plans Postretirement benefit plans ($ in thousands) 2017 2016 2017 2016 Net actuarial gain (loss) $ 7,329 $ 1,174 $ 1,197 $ 376 Prior service (cost) credit 6 9 (3,034 ) (4,221 ) Net amount recognized $ 7,335 $ 1,183 $ (1,837 ) $ (3,845 )
Schedule of projected benefit obligation, accumulated benefit obligation and fair value of plan assets	The following table sets forth the projected benefit obligation, accumulated benefit obligation and fair value of plan assets of Employers Mutual’s non-qualified pension plan. The amounts related to the qualified pension plan are not included since the plan assets exceeded the accumulated benefit obligation. Year ended December 31, ($ in thousands) 2017 2016 Projected benefit obligation $ 13,950 $ 13,656 Accumulated benefit obligation 12,272 12,182 Fair value of plan assets — —
Components of net periodic benefit cost	The components of net periodic benefit cost (income) for Employers Mutual’s pension and postretirement benefit plans is as follows: Year ended December 31, ($ in thousands) 2017 2016 2015 Pension plans: Service cost $ 15,135 $ 14,432 $ 13,962 Interest cost 11,190 10,161 9,311 Expected return on plan assets (20,765 ) (19,361 ) (20,298 ) Amortization of net actuarial loss 3,643 4,311 2,710 Amortization of prior service cost 20 31 31 Net periodic pension benefit cost $ 9,223 $ 9,574 $ 5,716 Postretirement benefit plans: Service cost $ 1,362 $ 1,273 $ 1,411 Interest cost 2,281 2,215 2,148 Expected return on plan assets (4,311 ) (4,224 ) (4,416 ) Amortization of net actuarial loss 1,371 1,494 1,745 Amortization of prior service credit (11,154 ) (11,338 ) (11,466 ) Net periodic postretirement benefit income $ (10,451 ) $ (10,580 ) $ (10,578 )
Schedule of weighted-average assumptions used	The weighted-average assumptions used to measure the benefit obligations are as follows: Year ended December 31, 2017 2016 Pension plans: Discount rate 3.60 % 4.07 % Rate of compensation increase: Qualified pension plan 5.09 % 5.07 % Non-qualified pension plan 4.45 % 4.53 % Postretirement benefit plans: Discount rate 3.63 % 4.21 % The weighted-average assumptions used to measure the net periodic benefit costs are as follows: Year ended December 31, 2017 2016 2015 Pension plans: Discount rate 4.07 % 3.90 % 3.57 % Expected long-term rate of return on plan assets 7.00 % 7.00 % 7.00 % Rate of compensation increase: Qualified pension plan 5.08 % 5.07 % 4.73 % Non-qualified pension plan 4.47 % 4.56 % 4.68 % Postretirement benefit plans: Discount rate 4.21 % 4.42 % 4.04 % Expected long-term rate of return on plan assets 6.50 % 6.50 % 6.50 %
Schedule of expected future benefit payments	The following benefit payments, which reflect expected future service, are expected to be paid from the plans over the next ten years: ($ in thousands) Pension benefits Postretirement benefits 2018 $ 20,276 $ 3,175 2019 22,628 3,383 2020 23,050 3,560 2021 19,841 3,636 2022 22,655 3,690 2023 - 2027 119,538 18,679
Employers Mutual VEBA Trust
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of fair value of plan assets	The fair values of the assets held in Employers Mutual’s VEBA trust are as follows: December 31, 2017 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Money market fund $ 1,254 $ 1,254 $ — $ — Emerging markets ETF 4,803 4,803 — — Mutual funds 54,180 54,180 — — Life insurance contracts 14,524 — — 14,524 Cash 897 897 — — Total benefit plan assets $ 75,658 $ 61,134 $ — $ 14,524 December 31, 2016 Fair value measurements using ($ in thousands) Total Quoted Significant Significant Money market fund $ 1,485 $ 1,485 $ — $ — Emerging markets ETF 3,743 3,743 — — Mutual funds 47,916 47,916 — — Life insurance contracts 14,159 — — 14,159 Cash 506 506 — — Total benefit plan assets $ 67,809 $ 53,650 $ — $ 14,159
Reconciliation of assets measured at fair value using significant unobservable inputs	Presented below is a reconciliation of the assets measured at fair value using significant unobservable inputs (Level 3) for the years ended December 31, 2017 and 2016 . Fair value measurements Life insurance contracts ($ in thousands) 2017 2016 Balance at beginning of year $ 14,159 $ 13,792 Actual return on plan assets: Increase in cash surrender value of life insurance contracts 365 367 Balance at end of year $ 14,524 $ 14,159
Employers Mutual Defined Benefit Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Schedule of fair value of plan assets	In accordance with ASU 2015-07, a fair value hierarchy table is not included here since all of the Plan's investments are measured at fair value using the net asset value per share (or its equivalent) practical expedient, which are not classified in the fair value hierarchy. Presented below are the fair values of assets held in Employers Mutual's defined benefit retirement plan: December 31, ($ in thousands) 2017 2016 Pooled separate accounts $ 349,004 $ 300,915 Total benefit plan assets $ 349,004 $ 300,915

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of the activity under Employers Mutual's stock option plans	A summary of the stock option activity under Employers Mutual’s stock plans for 2017 , 2016 and 2015 is as follows: Year ended December 31, 2017 2016 2015 Number Weighted- Number Weighted- Number Weighted- Outstanding, beginning of year 649,012 $ 14.65 1,006,171 $ 14.92 1,351,802 $ 14.89 Exercised (222,921 ) 14.88 (321,312 ) 15.31 (323,486 ) 14.86 Expired (18,805 ) 15.16 (34,947 ) 16.32 (20,850 ) 14.11 Forfeited (975 ) 13.99 (900 ) 13.99 (1,295 ) 14.68 Outstanding, end of year 406,311 $ 14.51 649,012 $ 14.65 1,006,171 $ 14.92 Exercisable, end of year 406,311 $ 14.51 593,224 $ 14.72 824,365 $ 14.95
Summary of non-vested share activity	As discussed above, during 2017 Employers Mutual began issuing restricted stock unit awards to eligible employees. These awards are accounted for as liability-based awards, whereby the liability is remeasured at each reporting date as the average of the high and low trading prices of the Company's common stock on that date. Upon settlement, the Company will receive the full fair value for all shares issued. The Company's share of this liability at December 31, 2017 was $543,000 . A summary of restricted stock unit awards activity for 2017 is as follows: Year ended December 31, 2017 Number of awards Non-vested, beginning of year — Granted 116,288 Vested — Forfeited 2,233 Non-vested, end of year 114,055 For restricted stock awards, the average of the high and low trading prices of the Company's common stock on the dates of grant were used to determine their fair values. The Company received in 2016 and 2015 the full fair value, as of the grant date, for all shares issued in connection with Employers Mutual's grant of restricted stock awards. At December 31, 2017 , the Company’s portion of the unrecognized compensation cost associated with restricted stock awards that are not currently vested was $640,000 with a 1.56 year weighted-average period over which the compensation expense is expected to be recognized. The Company's portion of the total fair value of restricted stock awards that vested was $545,000 , $414,000 and $233,000 in 2017 , 2016 and 2015 , respectively. A summary of restricted stock awards activity for 2017 , 2016 and 2015 is as follows: Year ended December 31, 2017 2016 2015 Number Weighted- Number Weighted- Number Weighted- Non-vested, beginning of year 234,281 $ 22.31 216,944 $ 20.40 155,864 $ 19.21 Granted 2,000 26.95 118,588 24.56 117,146 21.36 Vested (85,192 ) 21.31 (69,057 ) 19.98 (40,941 ) 18.99 Forfeited (7,039 ) 22.57 (32,194 ) 22.73 (15,125 ) 19.35 Non-vested, end of year 144,050 $ 22.96 234,281 $ 22.31 216,944 $ 20.40
Summary of additional information relating to options outstanding and options vested (exercisable)	Additional information relating to options outstanding and options vested (exercisable) at December 31, 2017 is as follows: December 31, 2017 ($ in thousands, except share and per share amounts) Number of options Weighted-average exercise price Aggregate intrinsic value Weighted-average remaining term Options outstanding 406,311 $ 14.51 $ 5,910 2.81 Options exercisable 406,311 $ 14.51 $ 5,910 2.81
Summary of employee stock purchase plan activity	During 2017 , shares were purchased under the plan at prices ranging from $23.64 to $25.15 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 349,404 414,883 471,459 Shares purchased under the plan (77,819 ) (65,479 ) (56,576 ) Shares available for purchase, end of year 271,585 349,404 414,883
Summary of non-employee director stock option plan activity	During 2017 , shares were purchased under the plan at prices ranging from $20.15 to $23.15 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 249,843 264,446 279,809 Shares purchased under the plan (14,470 ) (14,603 ) (15,363 ) Shares available for purchase, end of year 235,373 249,843 264,446
Summary of dividend reinvestment plan activity	Employers Mutual did not participate in this plan in 2017 , 2016 or 2015 . Activity under the plan was as follows: Year ended December 31, 2017 2016 2015 Shares available for purchase, beginning of year 971,222 976,697 982,227 Shares purchased under the plan (5,421 ) (5,475 ) (5,530 ) Shares available for purchase, end of year 965,801 971,222 976,697 Lowest purchase price $ 26.94 $ 22.09 $ 21.02 Highest purchase price $ 31.09 $ 30.50 $ 26.43

ACCUMULATED OTHER COMPREHENSI43

ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	12 Months Ended
	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of beginning and ending balances of accumulated other comprehensive income	The following table reconciles, by component, the beginning and ending balances of accumulated other comprehensive income, net of tax. Accumulated other comprehensive income by component Unrealized Unrecognized pension and postretirement benefit obligations ($ in thousands) Net actuarial loss Prior service credit Total Total Balance at December 31, 2015 $ 60,369 $ (17,306 ) $ 15,370 $ (1,936 ) $ 58,433 Other comprehensive income (loss) before reclassifications (3,885 ) (542 ) (339 ) (881 ) (4,766 ) Amounts reclassified from accumulated other comprehensive income (6,736 ) 1,549 (2,399 ) (850 ) (7,586 ) Other comprehensive income (loss) (10,621 ) 1,007 (2,738 ) (1,731 ) (12,352 ) Balance at December 31, 2016 49,748 (16,299 ) 12,632 (3,667 ) 46,081 Other comprehensive income (loss) before reclassifications 27,278 5,571 96 5,667 32,945 Amounts reclassified from accumulated other comprehensive income (8,326 ) 958 (2,047 ) (1,089 ) (9,415 ) Other comprehensive income (loss) 18,952 6,529 (1,951 ) 4,578 23,530 Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA 14,797 (3,304 ) 2,280 (1,024 ) 13,773 Balance at December 31, 2017 $ 83,497 $ (13,074 ) $ 12,961 $ (113 ) $ 83,384
Amounts reclassified out of accumulated other comprehensive income (loss)	The following tables display amounts reclassified out of accumulated other comprehensive income and into net income during the three years ended December 31, 2017 . ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2017 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 12,809 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (4,483 ) Total income tax expense Net reclassification adjustment 8,326 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (1,474 ) (1) Prior service credit 3,150 (1) Total before tax 1,676 Deferred income tax expense (587 ) Net reclassification adjustment 1,089 Total reclassification adjustment $ 9,415 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details). ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2016 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 10,364 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (3,628 ) Total income tax expense Net reclassification adjustment 6,736 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (2,383 ) (1) Prior service credit 3,690 (1) Total before tax 1,307 Deferred income tax expense (457 ) Net reclassification adjustment 850 Total reclassification adjustment $ 7,586 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details). ($ in thousands) Amounts reclassified from accumulated other comprehensive income Accumulated other comprehensive income components Year ended December 31, 2015 Affected line item in the consolidated statements of income Unrealized gains on investments: Reclassification adjustment for net realized investment gains included in net income $ 7,624 Net realized investment gains, excluding impairment losses on securities available-for-sale Deferred income tax expense (2,668 ) Total income tax expense Net reclassification adjustment 4,956 Net income Unrecognized pension and postretirement benefit obligations: Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income: Net actuarial loss (1,327 ) (1) Prior service credit 3,307 (1) Total before tax 1,980 Deferred income tax expense (693 ) Net reclassification adjustment 1,287 Total reclassification adjustment $ 6,243 (1) These reclassified components of accumulated other comprehensive income are included in the computation of net periodic pension and postretirement benefit income (see note 12, Employee Retirement Plans, for additional details).

LEASES, COMMITMENTS AND CONTI44

LEASES, COMMITMENTS AND CONTINGENT LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of lease commitments	The following table reflects the Company's share of lease commitments as of December 31, 2017 . Payments due by period ($ in thousands) Total Less than 1 - 3 4 - 5 More than Lease commitments Real estate operating leases $ 2,207 $ 423 $ 820 $ 530 $ 434

UNAUDITED INTERIM FINANCIAL I45

UNAUDITED INTERIM FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of unaudited interim financial information	Three months ended, ($ in thousands, except per share amounts) March 31 June 30 September 30 December 31 2017 Total revenues $ 154,457 $ 164,150 $ 165,918 $ 174,320 Income (loss) before income tax expense (benefit) $ 8,440 $ 7,229 $ (440 ) $ 24,587 Income tax expense (benefit) 1,636 1,725 (1,186 ) (1,597 ) Net income $ 6,804 $ 5,504 $ 746 $ 26,184 Net income per common share - basic and diluted 1 $ 0.32 $ 0.26 $ 0.03 $ 1.23 Three months ended, ($ in thousands, except per share amounts) March 31 June 30 September 30 December 31 2016 Total revenues $ 153,871 $ 160,336 $ 162,378 $ 168,398 Income (loss) before income tax expense (benefit) $ 20,877 $ 8,087 $ 5,047 $ 29,196 Income tax expense (benefit) 6,223 1,959 918 7,904 Net income $ 14,654 $ 6,128 $ 4,129 $ 21,292 Net income per common share - basic and diluted 1 $ 0.70 $ 0.29 $ 0.20 $ 1.01 1 Since the weighted-average number of shares outstanding for the quarters are calculated independently of the weighted-average number of shares outstanding for the year, quarterly net income per share may not total to annual net income per share.

SUMMARY OF SIGNIFICANT ACCOUN46

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Percentage of premium written in Iowa and contiguous states (in hundredths)		37.00%
Percentage of net premiums written subject to policyholder dividends (in hundredths)		26.00%	22.00%
Investment securities on deposit		$ 11,300	$ 11,000
Average annual expense for accounts receivable charge-offs over past ten years		380
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment for adoption of new accounting principle		0
Accumulated Other Comprehensive Income (Loss) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment for adoption of new accounting principle		$ (13,773)
Scenario, Forecast [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment for adoption of new accounting principle	$ (66,234)

AFFILIATION AND TRANSACTIONS 47

AFFILIATION AND TRANSACTIONS WITH AFFILIATES (Details) $ in Thousands	6 Months Ended				12 Months Ended
	Dec. 31, 2017USD ($)Plan	Jun. 30, 2017USD ($)Plan	Dec. 31, 2016USD ($)Plan	Jun. 30, 2016USD ($)Plan	Dec. 31, 2017USD ($)Plan	Dec. 31, 2016USD ($)Plan	Dec. 31, 2015USD ($)Plan
Related Party Transaction [Line Items]
Percentage of pool participation (in hundredths)					30.00%	30.00%	30.00%
Ceded premiums earned					$ 437,881	$ 426,946	$ 407,531
Property and casualty insurance [Member]
Related Party Transaction [Line Items]
Percentage of pool participation (in hundredths)					30.00%	30.00%	30.00%
Reinsurance [Member]
Related Party Transaction [Line Items]
Foreign currency transaction gain (loss)					$ (1,600)	$ 356	$ 898
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Ceded premiums earned					397,183	395,220	377,579
Ceded losses and settlement expenses incurred					288,023	236,851	199,126
Cost allocation to the Company not from pooling agreement					4,400	4,700	3,400
Investment expenses allocated to Company					$ 1,600	$ 1,400	$ 1,400
Affiliated Entity [Member] | Property and casualty insurance [Member]
Related Party Transaction [Line Items]
Percentage of pool participation (in hundredths)					30.00%	30.00%	30.00%
Ceded premiums earned					$ 392,333	$ 390,140	$ 366,752
Ceded losses and settlement expenses incurred					271,185	237,318	198,504
Cost allocation to the Company from pooling agreement					$ 97,700	$ 92,300	$ 87,400
Number of reinsurance program treaties | Plan	1	1	1	1	2	2
Affiliated Entity [Member] | Property and casualty insurance [Member] | Annual Aggregate Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount	$ 15,000	$ 20,000	$ 15,000	$ 20,000
Affiliated reinsurance contract first layer limit	12,000	24,000	12,000	24,000
Ceded premiums earned	$ 1,400	$ 6,000	$ 1,500	$ 6,300
Ceded losses and settlement expenses incurred					$ 19,200	$ 7,500
Commutation settlement amount					$ 2,800
Affiliated Entity [Member] | Reinsurance [Member]
Related Party Transaction [Line Items]
Quota share agreement portion assumed (in hundredths)					100.00%	100.00%	100.00%
Assumed quota share earned premium					$ 135,700	$ 135,200	$ 129,600
Ceded premiums earned					4,850	5,080	10,827
Ceded losses and settlement expenses incurred					16,838	(467)	622
Losses and settlement expenses assumed by the reinsurance subsidiary through the quota share agreement					131,100	90,900	77,500
Commutation settlement amount					0
Commissions paid by the reinsurance subsidiary to Employers Mutual					27,500	27,400	27,300
Foreign currency transaction gain (loss)					$ (978)	$ 367	$ 386
Number of reinsurance program treaties | Plan					2	2	1
Affiliated Entity [Member] | Reinsurance [Member] | Per Occurrence Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount					$ 10,000	$ 10,000	$ 4,000
First layer excess of loss coinsurance percentage (in hundredths)					20.00%	20.00%	20.00%
Affiliated reinsurance contract first layer limit					$ 10,000	$ 10,000	$ 10,000
Second layer excess of loss coinsurance percentage (in hundredths)							10.00%
Second layer excess of loss limit							$ 50,000
Percentage cost of protection to assumed reinsurance premiums written (in hundredths)							8.00%
Ceded premiums earned					1,700	2,000	$ 10,800
Affiliated Entity [Member] | Reinsurance [Member] | Annual Aggregate Catastrophe Excess of Loss [Member]
Related Party Transaction [Line Items]
Catastrophe claims, retention amount					$ 20,000	$ 20,000
First layer excess of loss coinsurance percentage (in hundredths)					20.00%	20.00%
Affiliated reinsurance contract first layer limit					$ 100,000	$ 100,000
Ceded premiums earned					3,200	3,200
Catastrophe event minimum amount					$ 500	$ 500

REINSURANCE (Details)

REINSURANCE (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)reinsurer	Dec. 31, 2016USD ($)reinsurer	Dec. 31, 2015USD ($)
Reinsurance Transactions For Insurance Companies, by Product Segment [Line Items]
Number of significant nonaffiliated reinsurers | reinsurer	3	2
Total receivable amount from significant nonaffiliated reinsurers	$ 22,700	$ 10,400
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Premiums written
Net premiums written	$ 616,301	$ 594,703	$ 578,938
Premiums earned
Direct	384,993	382,300	366,752
Assumed	660,046	637,054	611,045
Ceded	(437,881)	(426,946)	(407,531)
Net premiums earned	607,158	592,408	570,266
Losses and settlement expenses incurred
Net losses and settlement expenses incurred	421,969	386,897	370,736
Affiliated Entity [Member]
Premiums written
Assumed	520,932	491,315	474,323
Ceded	(403,219)	(396,731)	(381,782)
Premiums earned
Assumed	505,795	483,759	466,966
Ceded	(397,183)	(395,220)	(377,579)
Losses and settlement expenses incurred
Assumed	335,570	305,818	295,181
Ceded	(288,023)	(236,851)	(199,126)
Non Affiliated Entity [Member]
Premiums written
Direct	391,029	383,811	370,955
Assumed	151,738	150,780	143,092
Ceded	(44,179)	(34,472)	(27,650)
Premiums earned
Direct	384,993	382,300	366,752
Assumed	154,251	153,295	144,079
Ceded	(40,698)	(31,726)	(29,952)
Losses and settlement expenses incurred
Direct	252,007	229,859	198,504
Assumed	145,566	96,018	85,922
Ceded	$ (23,151)	$ (7,947)	$ (9,745)
Property and casualty insurance [Member]
Reinsurance Transactions For Insurance Companies, by Product Segment [Line Items]
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Premiums written
Net premiums written	$ 484,027	$ 463,673	$ 454,434
Premiums earned
Net premiums earned	472,369	456,467	447,197
Losses and settlement expenses incurred
Net losses and settlement expenses incurred	$ 302,973	$ 294,369	$ 291,883
Property and casualty insurance [Member] | Affiliated Entity [Member]
Reinsurance Transactions For Insurance Companies, by Product Segment [Line Items]
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Premiums written
Assumed	$ 520,932	$ 491,315	$ 474,323
Ceded	(398,369)	(391,651)	(370,955)
Premiums earned
Assumed	505,795	483,759	466,966
Ceded	(392,333)	(390,140)	(366,752)
Losses and settlement expenses incurred
Assumed	334,240	304,007	294,324
Ceded	(271,185)	(237,318)	(198,504)
Property and casualty insurance [Member] | Non Affiliated Entity [Member]
Premiums written
Direct	391,029	383,811	370,955
Assumed	4,454	4,544	4,392
Ceded	(34,019)	(24,346)	(24,281)
Premiums earned
Direct	384,993	382,300	366,752
Assumed	4,299	4,444	4,240
Ceded	(30,385)	(23,896)	(24,009)
Losses and settlement expenses incurred
Direct	252,007	229,859	198,504
Assumed	2,879	2,712	2,407
Ceded	(14,968)	(4,891)	(4,848)
Reinsurance [Member]
Premiums written
Net premiums written	132,274	131,030	124,504
Premiums earned
Net premiums earned	134,789	135,941	123,069
Losses and settlement expenses incurred
Net losses and settlement expenses incurred	118,996	92,528	78,853
Reinsurance [Member] | Affiliated Entity [Member]
Premiums written
Assumed	0	0	0
Ceded	(4,850)	(5,080)	(10,827)
Premiums earned
Assumed	0	0	0
Ceded	(4,850)	(5,080)	(10,827)
Losses and settlement expenses incurred
Assumed	1,330	1,811	857
Ceded	(16,838)	467	(622)
Reinsurance [Member] | Non Affiliated Entity [Member]
Premiums written
Direct	0	0	0
Assumed	147,284	146,236	138,700
Ceded	(10,160)	(10,126)	(3,369)
Premiums earned
Direct	0	0	0
Assumed	149,952	148,851	139,839
Ceded	(10,313)	(7,830)	(5,943)
Losses and settlement expenses incurred
Direct	0	0	0
Assumed	142,687	93,306	83,515
Ceded	$ (8,183)	$ (3,056)	$ (4,897)

LIABILITY FOR LOSSES AND SETT49

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of beginning and ending reserves for losses and settlement expenses [Roll Forward]
Gross reserves at beginning of year	$ 690,532	$ 678,774	$ 661,309
Re-valuation due to foreign currency exchange rates	(1,913)	(2,475)	(2,061)
Less ceded reserves at beginning of year	20,664	23,477	28,253
Net reserves at beginning of year	671,781	657,772	635,117
Incurred losses and settlement expenses related to:
Current year	441,588	427,838	405,850
Prior years	(19,619)	(40,941)	(35,114)
Total incurred losses and settlement expenses	421,969	386,897	370,736
Paid losses and settlement expenses related to:
Current year	179,354	172,652	154,958
Prior years	213,232	200,236	193,123
Total paid losses and settlement expenses	392,586	372,888	348,081
Net reserves at end of year	701,164	671,781	657,772
Plus ceded reserves at end of year	30,923	20,664	23,477
Re-valuation due to foreign currency exchange rates	525	(1,913)	(2,475)
Gross reserves at end of year	$ 732,612	$ 690,532	$ 678,774
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Property and casualty insurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (15,700)	$ (30,000)	$ (13,800)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(3.20%)	(5.10%)	(2.90%)
Paid losses and settlement expenses related to:
Adjustment for favorable (adverse) development included in the reported development amount that had no impact on earnings		$ 5,600	$ 400
Approximation of the implied amount of favorable development that had an impact on earnings		$ 24,400	$ 13,400
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Reinsurance [Member]
Incurred losses and settlement expenses related to:
Prior years	$ (3,900)	$ (10,900)	$ (21,300)
Percentage change in loss and settlement expense reserves for prior accident years (in hundredths)	(1.90%)	(5.50%)	(11.30%)
Paid losses and settlement expenses related to:
Adjustment for favorable (adverse) development included in the reported development amount that had no impact on earnings			$ (1,000)
Approximation of the implied amount of favorable development that had an impact on earnings			$ 22,300
Affiliated Entity [Member] | Property and casualty insurance [Member]
Paid losses and settlement expenses related to:
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%

LIABILITY FOR LOSSES AND SETT50

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES SHORT-DURATION INSURANCE CONTRACTS DEVELOPMENT TABLES (Details) $ in Thousands	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)
Claims development [Line Items]
Liability for losses and settlement expenses, net of reinsurance	$ 674,501
Commercial Auto Liability [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	425,834
Cumulative paid losses and allocated settlement expenses, net of reinsurance	314,666
All outstanding liabilities before 2008, net of reinsurance	(34)
Liability for losses and settlement expenses, net of reinsurance	111,134
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	26,764	$ 26,768	$ 26,741	$ 26,878	$ 26,923	$ 26,886	$ 27,968	$ 29,433	$ 30,082	$ 29,898
IBNR reserves carried	$ (1)
Cumulative number of reported claims	11,511
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 26,756	26,750	26,648	26,527	26,306	25,215	23,144	19,204	13,437	6,551
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	24,697	24,655	24,730	24,874	24,986	25,370	26,667	27,923	28,973
IBNR reserves carried	$ 15
Cumulative number of reported claims	10,482
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 24,628	24,608	24,593	24,495	24,001	21,532	17,359	12,957	6,952
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	26,166	26,166	26,479	26,252	26,401	26,478	27,480	30,377
IBNR reserves carried	$ 0
Cumulative number of reported claims	11,393
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 26,088	26,039	25,558	24,674	23,547	19,274	13,278	7,025
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	31,638	31,635	31,914	31,961	31,098	29,790	32,775
IBNR reserves carried	$ 275
Cumulative number of reported claims	11,767
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 30,878	30,293	29,121	26,598	22,206	14,875	6,801
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	37,753	37,693	37,681	37,098	34,235	32,768
IBNR reserves carried	$ (203)
Cumulative number of reported claims	11,941
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 36,541	35,406	32,636	26,023	19,398	8,830
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	43,159	42,336	42,086	40,382	37,265
IBNR reserves carried	$ (52)
Cumulative number of reported claims	13,640
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 40,807	36,232	29,997	19,975	8,729
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	51,933	51,455	49,998	50,342
IBNR reserves carried	$ 1,225
Cumulative number of reported claims	15,059
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 44,783	37,433	25,746	12,069
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	58,627	57,824	53,883
IBNR reserves carried	$ 1,664
Cumulative number of reported claims	16,494
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,478	27,424	13,336
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	61,188	59,468
IBNR reserves carried	$ 6,307
Cumulative number of reported claims	16,829
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 30,233	13,583
Commercial Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	63,909
IBNR reserves carried	$ 16,652
Cumulative number of reported claims	15,220
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 14,474
Commercial Property [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	506,617
Cumulative paid losses and allocated settlement expenses, net of reinsurance	476,074
All outstanding liabilities before 2008, net of reinsurance	(1)
Liability for losses and settlement expenses, net of reinsurance	30,542
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	42,786	42,707	42,765	42,784	42,649	42,562	42,422	42,645	42,870	48,559
IBNR reserves carried	$ 23
Cumulative number of reported claims	15,799
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 42,761	42,755	42,755	42,691	42,607	42,071	41,991	41,868	40,603	31,514
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	36,292	36,020	36,056	35,926	35,622	35,881	35,985	36,003	39,511
IBNR reserves carried	$ (71)
Cumulative number of reported claims	14,654
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 36,224	35,893	35,849	35,803	35,803	35,422	34,624	32,602	25,321
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	39,347	39,428	39,379	39,154	39,071	38,770	38,650	40,422
IBNR reserves carried	$ (75)
Cumulative number of reported claims	16,276
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,323	39,318	39,314	38,901	37,926	36,931	35,730	28,032
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	58,148	58,375	57,703	57,629	57,271	57,614	58,930
IBNR reserves carried	$ 22
Cumulative number of reported claims	19,509
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 58,106	57,607	57,065	56,249	54,803	53,226	41,524
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	46,750	46,566	46,273	45,313	44,157	41,535
IBNR reserves carried	$ 22
Cumulative number of reported claims	16,054
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 46,562	46,270	44,543	43,628	41,862	32,879
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	52,966	53,070	52,511	50,976	50,266
IBNR reserves carried	$ 268
Cumulative number of reported claims	16,005
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 52,182	51,457	50,460	47,683	36,555
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	60,867	60,662	60,990	60,018
IBNR reserves carried	$ 456
Cumulative number of reported claims	16,735
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 59,255	58,045	55,679	43,022
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	55,659	56,798	55,508
IBNR reserves carried	$ 99
Cumulative number of reported claims	14,366
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 52,444	50,068	37,208
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	58,343	59,708
IBNR reserves carried	$ (176)
Cumulative number of reported claims	14,866
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 51,103	41,652
Commercial Property [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	55,459
IBNR reserves carried	$ 65
Cumulative number of reported claims	13,818
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 38,114
Workers' Compensation [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	467,153
Cumulative paid losses and allocated settlement expenses, net of reinsurance	363,251
All outstanding liabilities before 2008, net of reinsurance	34,420
Liability for losses and settlement expenses, net of reinsurance	138,322
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	43,272	42,943	43,737	43,301	43,338	43,766	43,156	44,113	46,240	49,577
IBNR reserves carried	$ 1,540
Cumulative number of reported claims	21,622
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,496	39,099	38,654	37,938	37,270	36,024	34,302	31,110	25,214	12,432
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	43,417	42,774	43,724	43,590	44,093	44,041	44,098	43,335	46,130
IBNR reserves carried	$ 1,642
Cumulative number of reported claims	19,236
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,908	39,583	39,167	38,329	37,409	35,363	31,802	25,157	11,879
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	49,435	49,145	50,069	49,851	49,906	50,057	49,336	46,328
IBNR reserves carried	$ 2,032
Cumulative number of reported claims	19,624
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 44,175	43,614	42,651	41,437	39,001	35,029	28,074	14,237
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	44,056	43,695	44,427	44,506	44,709	46,724	47,836
IBNR reserves carried	$ 1,831
Cumulative number of reported claims	19,569
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,167	38,437	37,027	35,295	32,237	26,291	13,291
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	45,276	45,088	46,928	47,756	50,094	51,099
IBNR reserves carried	$ 2,335
Cumulative number of reported claims	19,380
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 40,292	39,456	37,307	33,943	28,109	14,015
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	45,949	46,102	48,946	51,637	52,141
IBNR reserves carried	$ 2,509
Cumulative number of reported claims	19,843
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,254	37,907	35,061	29,219	14,917
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	47,836	47,472	50,973	51,515
IBNR reserves carried	$ 2,902
Cumulative number of reported claims	19,457
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 39,046	35,883	28,894	14,692
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	47,227	48,919	54,960
IBNR reserves carried	$ 1,777
Cumulative number of reported claims	19,177
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 35,458	29,023	14,956
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	48,276	57,832
IBNR reserves carried	$ 3,084
Cumulative number of reported claims	20,147
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 29,592	15,473
Workers' Compensation [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	52,409
IBNR reserves carried	$ 6,721
Cumulative number of reported claims	19,181
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 16,863
Other Liability [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	419,036
Cumulative paid losses and allocated settlement expenses, net of reinsurance	268,726
All outstanding liabilities before 2008, net of reinsurance	13,369
Liability for losses and settlement expenses, net of reinsurance	163,679
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	34,941	35,491	35,528	36,305	37,005	38,755	34,689	38,877	40,005	46,327
IBNR reserves carried	$ 538
Cumulative number of reported claims	10,957
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 33,451	33,162	32,863	32,514	31,270	28,476	24,139	16,525	10,443	4,299
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	32,063	32,521	32,384	32,827	35,614	34,263	37,650	39,908	44,497
IBNR reserves carried	$ 647
Cumulative number of reported claims	9,844
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 30,488	30,176	29,722	28,172	26,255	22,276	16,718	10,707	3,294
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	33,736	34,556	34,655	36,137	38,829	34,655	36,213	41,624
IBNR reserves carried	$ 639
Cumulative number of reported claims	10,144
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 31,776	30,711	29,688	27,612	21,732	15,041	8,315	3,403
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	31,711	32,452	33,649	35,177	35,125	42,982	44,490
IBNR reserves carried	$ 992
Cumulative number of reported claims	9,994
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 29,060	28,228	25,647	22,154	17,308	10,572	4,730
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	37,180	37,093	40,275	41,139	42,081	42,661
IBNR reserves carried	$ 38
Cumulative number of reported claims	10,043
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 32,753	29,651	25,095	19,661	12,851	4,720
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	39,175	42,187	42,544	43,837	47,974
IBNR reserves carried	$ 3,666
Cumulative number of reported claims	10,580
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 31,752	27,642	21,122	11,894	4,414
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	51,047	52,601	54,403	61,382
IBNR reserves carried	$ 1,662
Cumulative number of reported claims	10,878
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 35,318	27,506	17,267	5,630
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	43,379	47,553	54,221
IBNR reserves carried	$ 9,566
Cumulative number of reported claims	10,496
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 19,022	11,588	4,331
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	56,384	59,052
IBNR reserves carried	$ 12,913
Cumulative number of reported claims	10,262
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 18,784	6,403
Other Liability [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	59,420
IBNR reserves carried	$ 25,293
Cumulative number of reported claims	8,407
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 6,322
Personal Auto Liability [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	88,098
Cumulative paid losses and allocated settlement expenses, net of reinsurance	81,458
All outstanding liabilities before 2008, net of reinsurance	71
Liability for losses and settlement expenses, net of reinsurance	6,711
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	7,804	7,862	7,833	7,876	7,909	8,094	8,098	8,121	8,221	9,024
IBNR reserves carried	$ 0
Cumulative number of reported claims	6,783
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 7,804	7,805	7,809	7,810	7,794	7,558	7,291	6,743	5,798	3,096
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	9,312	9,325	9,339	9,382	9,353	9,386	9,452	9,653	10,168
IBNR reserves carried	$ (2)
Cumulative number of reported claims	7,523
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 9,314	9,278	9,204	9,194	9,049	8,905	7,966	6,393	3,564
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	9,649	9,676	9,656	9,700	9,698	9,736	9,851	9,815
IBNR reserves carried	$ 2
Cumulative number of reported claims	7,431
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 9,631	9,632	9,562	9,401	9,108	8,250	6,666	3,988
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	9,413	9,311	9,460	9,432	9,331	9,388	9,741
IBNR reserves carried	$ 10
Cumulative number of reported claims	8,051
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 9,335	9,153	9,038	8,883	8,129	6,842	3,950
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	10,626	10,537	10,731	11,023	10,756	10,917
IBNR reserves carried	$ 7
Cumulative number of reported claims	7,872
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 10,415	10,244	9,871	9,091	7,439	4,779
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	10,085	10,085	10,376	10,384	10,492
IBNR reserves carried	$ 22
Cumulative number of reported claims	7,235
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 9,932	9,648	8,985	7,521	4,377
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	9,204	9,331	9,631	10,573
IBNR reserves carried	$ 27
Cumulative number of reported claims	6,312
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 8,598	7,755	6,392	3,970
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	8,378	8,638	9,119
IBNR reserves carried	$ 181
Cumulative number of reported claims	5,666
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 7,535	6,229	3,800
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	6,584	7,404
IBNR reserves carried	$ 108
Cumulative number of reported claims	4,693
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 5,427	3,505
Personal Auto Liability [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	7,043
IBNR reserves carried	$ 553
Cumulative number of reported claims	4,427
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 3,467
Homeowners Insurance [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	154,254
Cumulative paid losses and allocated settlement expenses, net of reinsurance	152,114
All outstanding liabilities before 2008, net of reinsurance	91
Liability for losses and settlement expenses, net of reinsurance	2,231
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	19,911	19,908	19,901	19,886	19,886	19,905	19,924	19,894	20,222	22,736
IBNR reserves carried	$ 0
Cumulative number of reported claims	12,999
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 19,911	19,908	19,902	19,903	19,902	19,891	19,787	19,550	19,385	15,642
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	16,467	16,464	16,465	16,394	16,352	16,379	16,467	16,606	18,109
IBNR reserves carried	$ 0
Cumulative number of reported claims	11,486
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 16,467	16,464	16,421	16,315	16,288	16,246	16,135	15,885	12,645
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	17,139	17,146	17,129	17,093	17,053	17,074	17,523	17,875
IBNR reserves carried	$ 7
Cumulative number of reported claims	12,146
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 17,132	17,130	17,128	17,128	17,011	16,909	16,633	13,457
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	23,350	23,415	23,448	23,309	22,975	23,389	24,530
IBNR reserves carried	$ (19)
Cumulative number of reported claims	14,287
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 23,368	23,370	23,403	23,136	22,737	22,421	19,828
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	16,879	16,892	16,929	16,836	16,496	16,057
IBNR reserves carried	$ (24)
Cumulative number of reported claims	10,113
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 16,905	16,859	16,793	16,582	16,283	13,759
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	14,737	14,784	14,685	14,833	14,844
IBNR reserves carried	$ (14)
Cumulative number of reported claims	8,688
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 14,703	14,681	14,621	14,285	11,735
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	13,427	13,447	13,328	13,228
IBNR reserves carried	$ 18
Cumulative number of reported claims	7,423
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 13,269	13,215	13,025	11,065
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	11,041	11,153	11,233
IBNR reserves carried	$ (25)
Cumulative number of reported claims	5,940
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 10,730	10,456	8,650
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	11,377	11,801
IBNR reserves carried	$ 87
Cumulative number of reported claims	7,281
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 10,869	10,573
Homeowners Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	9,926
IBNR reserves carried	$ (221)
Cumulative number of reported claims	7,359
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 8,760
Auto Physical Damage [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	223,513
Cumulative paid losses and allocated settlement expenses, net of reinsurance	222,826
All outstanding liabilities before 2008, net of reinsurance	(33)
Liability for losses and settlement expenses, net of reinsurance	654
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	17,541	17,540	17,558	17,562	17,567	17,578	17,584	17,598	17,743	19,589
IBNR reserves carried	$ (9)
Cumulative number of reported claims	28,635
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 17,550	17,555	17,557	17,560	17,564	17,577	17,570	17,577	17,662	16,491
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	16,590	16,587	16,602	16,605	16,593	16,639	16,720	16,744	18,077
IBNR reserves carried	$ (11)
Cumulative number of reported claims	29,424
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 16,599	16,601	16,602	16,603	16,592	16,636	16,687	16,661	15,566
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	18,494	18,488	18,532	18,527	18,549	18,538	18,657	19,249
IBNR reserves carried	$ (28)
Cumulative number of reported claims	31,518
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 18,521	18,521	18,528	18,523	18,540	18,529	18,557	17,113
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	20,867	20,877	20,915	20,917	20,919	21,003	21,965
IBNR reserves carried	$ (27)
Cumulative number of reported claims	34,394
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 20,892	20,900	20,912	20,904	20,912	20,984	19,849
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	21,184	21,161	21,233	21,263	21,342	21,389
IBNR reserves carried	$ (30)
Cumulative number of reported claims	31,099
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 21,216	21,216	21,227	21,256	21,328	19,719
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	22,408	22,371	22,486	22,553	22,847
IBNR reserves carried	$ (4)
Cumulative number of reported claims	31,041
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 22,408	22,417	22,463	22,512	20,774
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	23,946	23,904	24,115	24,897
IBNR reserves carried	$ (51)
Cumulative number of reported claims	31,580
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 23,978	23,987	24,110	22,743
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	26,331	26,612	27,950
IBNR reserves carried	$ (10)
Cumulative number of reported claims	30,665
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 26,327	26,538	24,483
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	27,629	28,070
IBNR reserves carried	$ (310)
Cumulative number of reported claims	30,715
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 27,883	26,871
Auto Physical Damage [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	28,523
IBNR reserves carried	$ (1,868)
Cumulative number of reported claims	29,755
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 27,452
Assumed Pro Rata [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	259,193
Cumulative paid losses and allocated settlement expenses, net of reinsurance	206,153
All outstanding liabilities before 2008, net of reinsurance	2,599
Liability for losses and settlement expenses, net of reinsurance	55,639
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	24,084	24,126	24,068	23,914	24,103	23,972	24,473	24,129	25,463	29,931
IBNR reserves carried	261
Cumulative paid losses and allocated settlement expenses, net of reinsurance	23,476	23,395	23,253	22,950	22,700	22,284	21,744	20,525	18,268	9,263
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	17,183	17,204	17,212	17,274	17,447	17,626	18,442	19,364	23,812
IBNR reserves carried	225
Cumulative paid losses and allocated settlement expenses, net of reinsurance	16,748	16,651	16,463	16,283	16,024	15,481	14,644	13,004	6,105
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	15,533	15,539	15,589	15,807	15,993	16,658	17,279	19,629
IBNR reserves carried	135
Cumulative paid losses and allocated settlement expenses, net of reinsurance	15,299	15,254	15,212	15,172	14,499	14,081	12,057	5,059
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	28,339	28,440	28,459	29,075	29,848	30,316	30,231
IBNR reserves carried	182
Cumulative paid losses and allocated settlement expenses, net of reinsurance	28,037	27,973	27,901	27,477	26,733	23,008	10,220
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	17,644	17,855	18,429	21,110	21,580	22,113
IBNR reserves carried	349
Cumulative paid losses and allocated settlement expenses, net of reinsurance	16,852	16,772	16,403	15,159	12,826	4,478
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	25,442	26,936	27,545	30,174	23,306
IBNR reserves carried	1,883
Cumulative paid losses and allocated settlement expenses, net of reinsurance	21,864	21,123	17,963	12,639	3,886
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	26,419	28,007	27,776	31,516
IBNR reserves carried	753
Cumulative paid losses and allocated settlement expenses, net of reinsurance	23,567	20,745	16,185	6,052
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	35,148	35,356	38,442
IBNR reserves carried	1,704
Cumulative paid losses and allocated settlement expenses, net of reinsurance	30,356	22,042	9,569
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	39,412	35,830
IBNR reserves carried	7,664
Cumulative paid losses and allocated settlement expenses, net of reinsurance	22,280	9,673
Assumed Pro Rata [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	29,989
IBNR reserves carried	14,704
Cumulative paid losses and allocated settlement expenses, net of reinsurance	7,674
Assumed Excess of Loss [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	532,118
Cumulative paid losses and allocated settlement expenses, net of reinsurance	387,584
All outstanding liabilities before 2008, net of reinsurance	18,772
Liability for losses and settlement expenses, net of reinsurance	163,306
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2008 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	37,786	36,928	37,063	37,519	39,606	39,019	40,162	41,427	39,939	43,963
IBNR reserves carried	1,384
Cumulative paid losses and allocated settlement expenses, net of reinsurance	33,837	33,660	33,216	32,784	32,634	31,320	30,690	28,756	25,556	$ 14,314
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2009 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	26,922	27,142	27,913	28,233	30,167	30,518	29,987	30,552	38,903
IBNR reserves carried	1,496
Cumulative paid losses and allocated settlement expenses, net of reinsurance	23,264	23,032	22,854	22,231	21,882	21,011	18,803	15,896	$ 8,554
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2010 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	39,166	39,628	40,432	39,675	40,307	40,820	41,011	47,426
IBNR reserves carried	1,857
Cumulative paid losses and allocated settlement expenses, net of reinsurance	35,646	35,387	33,709	32,700	30,858	28,037	24,759	$ 9,282
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	58,279	58,700	59,090	59,345	60,948	61,787	72,124
IBNR reserves carried	1,977
Cumulative paid losses and allocated settlement expenses, net of reinsurance	54,628	53,906	52,611	50,613	47,965	42,214	$ 25,309
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	52,003	52,896	53,247	54,494	56,119	58,852
IBNR reserves carried	2,898
Cumulative paid losses and allocated settlement expenses, net of reinsurance	46,735	45,174	43,637	40,641	36,266	$ 21,320
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	44,829	44,947	45,103	47,705	52,699
IBNR reserves carried	3,188
Cumulative paid losses and allocated settlement expenses, net of reinsurance	39,520	37,717	33,422	27,635	$ 11,732
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	62,009	60,454	59,108	65,573
IBNR reserves carried	5,061
Cumulative paid losses and allocated settlement expenses, net of reinsurance	50,242	46,163	39,361	$ 22,172
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	51,924	55,190	60,183
IBNR reserves carried	6,372
Cumulative paid losses and allocated settlement expenses, net of reinsurance	36,918	30,495	$ 13,434
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	67,206	66,995
IBNR reserves carried	9,099
Cumulative paid losses and allocated settlement expenses, net of reinsurance	38,913	$ 18,408
Assumed Excess of Loss [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims development [Line Items]
Incurred losses and allocated settlement expenses, net of reinsurance	91,994
IBNR reserves carried	29,426
Cumulative paid losses and allocated settlement expenses, net of reinsurance	$ 27,881

LIABILITY FOR LOSSES AND SETT51

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES RECONCILIATION TO LIABILITY (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	$ 674,501
Ceded reserves	30,923	$ 20,664	$ 23,477	$ 28,253
Unallocated settlement expenses	27,188
Gross reserve for losses and settlement expenses	732,612	$ 690,532	$ 678,774	$ 661,309
Commercial Auto Liability [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	111,134
Ceded reserves	768
Commercial Property [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	30,542
Ceded reserves	4,624
Workers' Compensation [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	138,322
Ceded reserves	10,005
Other Liability [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	163,679
Ceded reserves	3,938
Personal Auto Liability [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	6,711
Ceded reserves	1,337
Homeowners Insurance [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	2,231
Ceded reserves	573
Auto Physical Damage [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	654
Ceded reserves	228
Assumed Pro Rata [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	55,639
Ceded reserves	7,167
Assumed Excess of Loss [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	163,306
Ceded reserves	1,444
Other Short-duration Insurance Product Line [Member]
Short-duration insurance contracts, reconciliation of claims development to liability [Line Items]
Net outstanding liability	2,283
Ceded reserves	$ 839

LIABILITY FOR LOSSES AND SETT52

LIABILITY FOR LOSSES AND SETTLEMENT EXPENSES HISTORICAL CLAIMS DURATION (Details)	Dec. 31, 2017
Commercial Auto Liability [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	23.50%
Short-duration insurance contracts, historical claims duration, year two	25.70%
Short-duration insurance contracts, historical claims duration, year three	21.20%
Short-duration insurance contracts, historical claims duration, year four	15.40%
Short-duration insurance contracts, historical claims duration, year five	8.00%
Short-duration insurance contracts, historical claims duration, year six	3.20%
Short-duration insurance contracts, historical claims duration, year seven	1.20%
Short-duration insurance contracts, historical claims duration, year eight	0.30%
Short-duration insurance contracts, historical claims duration, year nine	0.30%
Short-duration insurance contracts, historical claims duration, year ten	0.00%
Commercial Property [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	70.30%
Short-duration insurance contracts, historical claims duration, year two	20.10%
Short-duration insurance contracts, historical claims duration, year three	4.00%
Short-duration insurance contracts, historical claims duration, year four	1.90%
Short-duration insurance contracts, historical claims duration, year five	1.70%
Short-duration insurance contracts, historical claims duration, year six	0.80%
Short-duration insurance contracts, historical claims duration, year seven	0.30%
Short-duration insurance contracts, historical claims duration, year eight	0.10%
Short-duration insurance contracts, historical claims duration, year nine	0.50%
Short-duration insurance contracts, historical claims duration, year ten	0.00%
Workers' Compensation [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	30.50%
Short-duration insurance contracts, historical claims duration, year two	29.80%
Short-duration insurance contracts, historical claims duration, year three	13.80%
Short-duration insurance contracts, historical claims duration, year four	7.20%
Short-duration insurance contracts, historical claims duration, year five	4.20%
Short-duration insurance contracts, historical claims duration, year six	2.50%
Short-duration insurance contracts, historical claims duration, year seven	1.80%
Short-duration insurance contracts, historical claims duration, year eight	1.30%
Short-duration insurance contracts, historical claims duration, year nine	0.90%
Short-duration insurance contracts, historical claims duration, year ten	0.90%
Other Liability [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	11.50%
Short-duration insurance contracts, historical claims duration, year two	19.60%
Short-duration insurance contracts, historical claims duration, year three	19.50%
Short-duration insurance contracts, historical claims duration, year four	17.20%
Short-duration insurance contracts, historical claims duration, year five	12.70%
Short-duration insurance contracts, historical claims duration, year six	7.30%
Short-duration insurance contracts, historical claims duration, year seven	3.50%
Short-duration insurance contracts, historical claims duration, year eight	1.90%
Short-duration insurance contracts, historical claims duration, year nine	1.00%
Short-duration insurance contracts, historical claims duration, year ten	0.80%
Personal Auto Liability [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	44.10%
Short-duration insurance contracts, historical claims duration, year two	29.40%
Short-duration insurance contracts, historical claims duration, year three	14.90%
Short-duration insurance contracts, historical claims duration, year four	8.20%
Short-duration insurance contracts, historical claims duration, year five	2.60%
Short-duration insurance contracts, historical claims duration, year six	1.80%
Short-duration insurance contracts, historical claims duration, year seven	0.70%
Short-duration insurance contracts, historical claims duration, year eight	0.30%
Short-duration insurance contracts, historical claims duration, year nine	0.20%
Short-duration insurance contracts, historical claims duration, year ten	0.00%
Homeowners Insurance [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	82.20%
Short-duration insurance contracts, historical claims duration, year two	14.90%
Short-duration insurance contracts, historical claims duration, year three	1.70%
Short-duration insurance contracts, historical claims duration, year four	0.90%
Short-duration insurance contracts, historical claims duration, year five	0.50%
Short-duration insurance contracts, historical claims duration, year six	0.10%
Short-duration insurance contracts, historical claims duration, year seven	0.20%
Short-duration insurance contracts, historical claims duration, year eight	0.10%
Short-duration insurance contracts, historical claims duration, year nine	0.00%
Short-duration insurance contracts, historical claims duration, year ten	0.00%
Auto Physical Damage [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	94.30%
Short-duration insurance contracts, historical claims duration, year two	6.60%
Short-duration insurance contracts, historical claims duration, year three	(0.30%)
Short-duration insurance contracts, historical claims duration, year four	(0.10%)
Short-duration insurance contracts, historical claims duration, year five	(0.10%)
Short-duration insurance contracts, historical claims duration, year six	0.00%
Short-duration insurance contracts, historical claims duration, year seven	0.00%
Short-duration insurance contracts, historical claims duration, year eight	0.00%
Short-duration insurance contracts, historical claims duration, year nine	0.00%
Short-duration insurance contracts, historical claims duration, year ten	0.00%
Assumed Pro Rata [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	28.40%
Short-duration insurance contracts, historical claims duration, year two	39.50%
Short-duration insurance contracts, historical claims duration, year three	15.00%
Short-duration insurance contracts, historical claims duration, year four	6.50%
Short-duration insurance contracts, historical claims duration, year five	2.70%
Short-duration insurance contracts, historical claims duration, year six	0.90%
Short-duration insurance contracts, historical claims duration, year seven	0.60%
Short-duration insurance contracts, historical claims duration, year eight	0.90%
Short-duration insurance contracts, historical claims duration, year nine	0.60%
Short-duration insurance contracts, historical claims duration, year ten	0.30%
Assumed Excess of Loss [Member]
Short-duration insurance contracts, historical claims duration [Line Items]
Short-duration insurance contracts, historical claims duration, year one	32.30%
Short-duration insurance contracts, historical claims duration, year two	31.20%
Short-duration insurance contracts, historical claims duration, year three	10.30%
Short-duration insurance contracts, historical claims duration, year four	6.70%
Short-duration insurance contracts, historical claims duration, year five	3.30%
Short-duration insurance contracts, historical claims duration, year six	2.50%
Short-duration insurance contracts, historical claims duration, year seven	2.10%
Short-duration insurance contracts, historical claims duration, year eight	0.80%
Short-duration insurance contracts, historical claims duration, year nine	1.10%
Short-duration insurance contracts, historical claims duration, year ten	0.50%

ASBESTOS AND ENVIRONMENTAL CL53

ASBESTOS AND ENVIRONMENTAL CLAIMS (Details) $ in Thousands	12 Months Ended	108 Months Ended
	Dec. 31, 2017USD ($)policyholderclaimlawsuit	Dec. 31, 2017USD ($)claimlawsuit	Dec. 31, 2016USD ($)
Liability for Asbestos and Environmental Claims [Abstract]
Average asbestos and environmental losses paid by company per year over past five years	$ 2,900
Reserves for asbestos and environmental related claims, before reinsurance	11,700	$ 11,700	$ 13,300
Reserves for asbestos and environmental related claims, net of reinsurance	$ 11,400	$ 11,400	$ 13,000
Number of asbestos bodily injury lawsuits | lawsuit	1,872	1,872
Number of policyholders producing recent higher paid asbestos amounts | policyholder	1
Company's share of asbestos related claims settled		$ 12,500
Number of asbestos exposure claims associated with furnace manufacturer, a former policyholder, remain open | claim	692	692
Payments for legal settlements	$ 4,500
Asbestos reserve strengthening	$ 900

STATUTORY INFORMATION AND DIV54

STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
STATUTORY INFORMATION AND DIVIDEND RESTRICTIONS [Abstract]
Statutory surplus of the Company's insurance subsidiaries	$ 560.1	$ 526.8
Statutory net income (loss)	$ 30.1	$ 48.3	$ 48.8
Risk-based capital model assessment for Company	At December 31, 2017, the Company’s insurance subsidiaries had total adjusted statutory capital well in excess of the minimum risk-based capital requirement.
Statutory accounting practices, statutory capital and surplus required	$ 94.4
Percentage of statutory surplus as maximum dividend allowable without prior approval of insurance regulatory authorities (in hundredths)	10.00%	10.00%	10.00%
Amount available for distribution to the Company without prior approval	$ 54.2

SEGMENT INFORMATION - Summarize

SEGMENT INFORMATION - Summarized financial information by segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of operating profit loss from segment to consolidated
Premiums earned									$ 607,158	$ 592,408	$ 570,266
SAP underwriting profit (loss)									(12,684)	15,653	15,722
GAAP adjustments									4,547	(1,957)	5,501
GAAP underwriting profit (loss)									(8,137)	13,696	21,223
Net investment income (loss)									45,479	47,490	45,582
Net realized investment gains (losses)									6,556	4,074	6,153
Other income (loss)									(348)	1,011	1,725
Interest expense									337	337	337
Other expenses									3,397	2,727	2,690
Income before income tax expense	$ 24,587	$ (440)	$ 7,229	$ 8,440	$ 29,196	$ 5,047	$ 8,087	$ 20,877	39,816	63,207	71,656
Reconciliation of assets from segment to consolidated
Assets	2,289,419				2,131,694				2,289,419	2,131,694
Eliminations	(599,036)				(540,249)				(599,036)	(540,249)
Reclassifications	(8,443)				(2,632)				(8,443)	(2,632)
Total assets	1,681,940				1,588,813				1,681,940	1,588,813
Property and casualty insurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned									472,369	456,467	447,197
SAP underwriting profit (loss)									2,702	4,276	2,494
GAAP adjustments									5,217	(934)	5,460
GAAP underwriting profit (loss)									7,919	3,342	7,954
Net investment income (loss)									32,670	33,886	32,668
Net realized investment gains (losses)									4,896	4,082	4,163
Other income (loss)									1,171	594	771
Interest expense									337	337	337
Other expenses									1,128	721	748
Income before income tax expense									45,191	40,846	44,471
Reconciliation of assets from segment to consolidated
Assets	1,200,636				1,122,037				1,200,636	1,122,037
Eliminations	0				0				0	0
Reclassifications	(1,393)				0				(1,393)	0
Total assets	1,199,243				1,122,037				1,199,243	1,122,037
Reinsurance [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned									134,789	135,941	123,069
SAP underwriting profit (loss)									(15,386)	11,377	13,228
GAAP adjustments									(670)	(1,023)	41
GAAP underwriting profit (loss)									(16,056)	10,354	13,269
Net investment income (loss)									12,771	13,591	12,923
Net realized investment gains (losses)									1,660	(8)	1,990
Other income (loss)									(1,519)	417	954
Interest expense									0	0	0
Other expenses									0	0	0
Income before income tax expense									(3,144)	24,354	29,136
Reconciliation of assets from segment to consolidated
Assets	484,678				455,493				484,678	455,493
Eliminations	0				0				0	0
Reclassifications	(6,273)				(1,932)				(6,273)	(1,932)
Total assets	478,405				453,561				478,405	453,561
Parent company [Member]
Reconciliation of operating profit loss from segment to consolidated
Premiums earned									0	0	0
SAP underwriting profit (loss)									0	0	0
GAAP adjustments									0	0	0
GAAP underwriting profit (loss)									0	0	0
Net investment income (loss)									38	13	(9)
Net realized investment gains (losses)									0	0	0
Other income (loss)									0	0	0
Interest expense									0	0	0
Other expenses									2,269	2,006	1,942
Income before income tax expense									(2,231)	(1,993)	$ (1,951)
Reconciliation of assets from segment to consolidated
Assets	604,105				554,164				604,105	554,164
Eliminations	(599,036)				(540,249)				(599,036)	(540,249)
Reclassifications	(777)				(700)				(777)	(700)
Total assets	$ 4,292				$ 13,215				$ 4,292	$ 13,215

SEGMENT INFORMATION - Net premi

SEGMENT INFORMATION - Net premiums earned by segment and lines of insurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Premiums earned	$ 607,158	$ 592,408	$ 570,266
Property and casualty insurance [Member]
Revenue from External Customer [Line Items]
Premiums earned	472,369	456,467	447,197
Property and casualty insurance [Member] | Commercial Lines [Member]
Revenue from External Customer [Line Items]
Premiums earned	434,331	417,474	403,779
Property and casualty insurance [Member] | Commercial Lines [Member] | Automobile Insurance L O B [Member]
Revenue from External Customer [Line Items]
Premiums earned	118,224	110,941	105,904
Property and casualty insurance [Member] | Commercial Lines [Member] | Property Insurance L O B [Member]
Revenue from External Customer [Line Items]
Premiums earned	108,162	105,012	104,303
Property and casualty insurance [Member] | Commercial Lines [Member] | Workers' Compensation [Member]
Revenue from External Customer [Line Items]
Premiums earned	100,552	96,517	92,828
Property and casualty insurance [Member] | Commercial Lines [Member] | Other Liability [Member]
Revenue from External Customer [Line Items]
Premiums earned	98,674	96,630	92,665
Property and casualty insurance [Member] | Commercial Lines [Member] | Other Insurance L O B [Member]
Revenue from External Customer [Line Items]
Premiums earned	8,719	8,374	8,079
Property and casualty insurance [Member] | Personal Lines [Member]
Revenue from External Customer [Line Items]
Premiums earned	38,038	38,993	43,418
Reinsurance [Member]
Revenue from External Customer [Line Items]
Premiums earned	134,789	135,941	123,069
Reinsurance [Member] | Assumed Pro Rata [Member]
Revenue from External Customer [Line Items]
Premiums earned	44,636	56,317	47,421
Reinsurance [Member] | Assumed Excess of Loss [Member]
Revenue from External Customer [Line Items]
Premiums earned	$ 90,153	$ 79,624	$ 75,648

DISCLOSURES ABOUT THE FAIR VA57

DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Security	Dec. 31, 2016USD ($)Security
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 1,503,131	$ 1,413,538
Short-term investments	23,613	39,670
Liabilities [Abstract]
Surplus notes	$ 25,000	$ 25,000
Period for surplus notes included in assumptions	25 years	25 years
Current interest rate on surplus notes	1.35%	1.35%
Upward adjustment to fair value input discount rate (percent)	0.50%	0.50%
Period after which rate is adjusted	5 years	5 years
Debt Securities [Member]
Assets [Abstract]
Number Of Broker Quoted Securities | Security	0	0
Number of securities not priced by independent pricing service | Security	8	9
Available-for-sale Securities, Fair Value Disclosure	$ 1,275,016	$ 1,199,699
US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	433,560	456,516
Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	228,115	213,839
Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,522	35,122
Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	21,708	20,347
Carrying amount [Member]
Assets [Abstract]
Short-term investments	23,613	39,670
Liabilities [Abstract]
Surplus notes	25,000	25,000
Carrying amount [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1,275,016	1,199,699
Carrying amount [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
Carrying amount [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
Carrying amount [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Carrying amount [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Carrying amount [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Carrying amount [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Carrying amount [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	433,560	456,516
Carrying amount [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	228,115	213,839
Carrying amount [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,522	35,122
Carrying amount [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Carrying amount [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Carrying amount [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Carrying amount [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Carrying amount [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Carrying amount [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Carrying amount [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Carrying amount [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	21,708	20,347
Estimated fair value [Member]
Assets [Abstract]
Short-term investments	23,613	39,670
Liabilities [Abstract]
Surplus notes	16,689	11,228
Estimated fair value [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1,275,016	1,199,699
Estimated fair value [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
Estimated fair value [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
Estimated fair value [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Estimated fair value [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Estimated fair value [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Estimated fair value [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Estimated fair value [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	433,560	456,516
Estimated fair value [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	228,115	213,839
Estimated fair value [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,522	35,122
Estimated fair value [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Estimated fair value [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Estimated fair value [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Estimated fair value [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Estimated fair value [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Estimated fair value [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Estimated fair value [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Estimated fair value [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 21,708	$ 20,347

DISCLOSURES ABOUT THE FAIR VA58

DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS, Recurring Measurement Inputs (Details) $ in Thousands	Dec. 31, 2017USD ($)Security	Dec. 31, 2016USD ($)Security
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 1,503,131	$ 1,413,538
Short-term investments	23,613	39,670
Liabilities [Abstract]
Surplus notes	25,000	25,000
Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1,275,016	1,199,699
US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	433,560	456,516
Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	228,115	213,839
Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,522	35,122
Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	21,708	20,347
Recurring [Member]
Assets [Abstract]
Short-term investments	23,613	39,670
Recurring [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1,275,016	1,199,699
Recurring [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
Recurring [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Recurring [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Recurring [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Recurring [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Recurring [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	433,560	456,516
Recurring [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	228,115	213,839
Recurring [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,522	35,122
Recurring [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Recurring [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Recurring [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Recurring [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Recurring [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Recurring [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Recurring [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Recurring [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	21,708	20,347
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Assets [Abstract]
Short-term investments	23,613	39,670
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	215,916	204,563
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	43,519	35,119
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	35,810	30,542
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	30,595	24,707
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	14,127	19,100
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	20,538	22,321
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,905	19,071
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	28,489	24,245
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	16,421	18,384
Recurring [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	9,512	11,074
Recurring [Member] | Significant other observable inputs (Level 2) [Member]
Assets [Abstract]
Short-term investments	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	1,274,396	1,198,717
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	8,078	7,830
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	297,949	239,197
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	307,536	335,757
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	83,980	37,572
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	119,799	96,434
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	24,114	26,393
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	432,940	455,534
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	10,196	7,273
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant other observable inputs (Level 2) [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	10,196	7,273
Recurring [Member] | Significant unobservable inputs (Level 3) [Member]
Assets [Abstract]
Short-term investments	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 620	$ 982
Number of securities categorized as Level 3 fair value measurements | Security	2	2
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | US Treasury Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 0	$ 0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Commercial Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Residential Mortgage Backed Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Collateralized Debt Obligations [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Corporate Debt Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	620	982
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Equity Securities [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 2,003	$ 2,003
Number of securities categorized as Level 3 fair value measurements | Security	2	2
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Financial services [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$ 3	$ 3
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Information technology [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Healthcare [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Consumer staples [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Consumer discretionary [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Energy [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Industrials [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Common stocks Other [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	0	0
Recurring [Member] | Significant unobservable inputs (Level 3) [Member] | Nonredeemable Preferred Stock [Member]
Assets [Abstract]
Available-for-sale Securities, Fair Value Disclosure	2,000	2,000
Not Reported At Fair Value [Member]
Liabilities [Abstract]
Surplus notes	16,689	11,228
Not Reported At Fair Value [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Liabilities [Abstract]
Surplus notes	0	0
Not Reported At Fair Value [Member] | Significant other observable inputs (Level 2) [Member]
Liabilities [Abstract]
Surplus notes	0	0
Not Reported At Fair Value [Member] | Significant unobservable inputs (Level 3) [Member]
Liabilities [Abstract]
Surplus notes	$ 16,689	$ 11,228

DISCLOSURES ABOUT THE FAIR VA59

DISCLOSURES ABOUT THE FAIR VALUE OF FINANCIAL INSTRUMENTS, Unobservable Input Reconciliation (Details) - Recurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of assets measured at fair value on recurring basis using significant unobservable inputs [Roll Forward]
Beginning balance	$ 2,985	$ 1,332
Purchases		2,000
Settlements	(356)	(345)
Unrealized losses included in other comprehensive income (loss)	(6)	(2)
Balance at end of period	2,623	2,985
Corporate Debt Securities [Member]
Reconciliation of assets measured at fair value on recurring basis using significant unobservable inputs [Roll Forward]
Beginning balance	982	1,329
Purchases		0
Settlements	(356)	(345)
Unrealized losses included in other comprehensive income (loss)	(6)	(2)
Balance at end of period	620	982
Common stocks Financial services [Member]
Reconciliation of assets measured at fair value on recurring basis using significant unobservable inputs [Roll Forward]
Beginning balance	3	3
Purchases		0
Settlements	0	0
Unrealized losses included in other comprehensive income (loss)	0	0
Balance at end of period	3	3
Nonredeemable Preferred Stock [Member]
Reconciliation of assets measured at fair value on recurring basis using significant unobservable inputs [Roll Forward]
Beginning balance	2,000	0
Purchases		2,000
Settlements	0	0
Unrealized losses included in other comprehensive income (loss)	0	0
Balance at end of period	$ 2,000	$ 2,000

INVESTMENTS (Details)

INVESTMENTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	$ 1,397,440	$ 1,337,004
Gross unrealized gains	118,284	99,752
Gross unrealized losses	12,593	23,218
Estimated fair values	1,503,131	1,413,538
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	247,865	422,453
Less than twelve months, Unrealized losses	3,840	16,670
Twelve months or longer, Fair value	192,946	36,223
Twelve months or longer, Unrealized losses	8,753	6,548
Total, Fair value	440,811	458,676
Total, Unrealized losses	12,593	23,218
Amortized cost
Due in one year or less	40,543
Due after one year through five years	173,741
Due after five years through ten years	368,782
Due after ten years	463,572
Securities not due at a single maturity date	206,528
Totals	1,253,166	1,189,525
Estimated fair value
Due in one year or less	41,094
Due after one year through five years	177,883
Due after five years through ten years	376,119
Due after ten years	474,251
Securities not due at a single maturity date	205,669
Totals	1,275,016	1,199,699
Realized Investment Gains (Losses) [Abstract]
'Other-than-temporary' impairments	(1,088)	(1,264)	$ (1,481)
Net realized investment gains (losses)	6,556	4,074	6,153
Investment Income, Net [Abstract]
Interest on fixed maturity securities	39,992	41,499	42,261
Dividends on equity securities	6,032	6,922	5,617
Income on reverse repurchase agreements	306	236	117
Interest on short-term investments	273	121	2
Return on long-term investments	1,126	514	(461)
Total investment income	47,729	49,292	47,536
Securities litigation income	12	111	32
Investment expenses	(2,262)	(1,913)	(1,986)
Net investment income (loss)	45,479	47,490	45,582
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax [Abstract]
Deferred income tax expense (benefit)	10,205	(5,720)	(9,689)
Net changes in unrealized holding gains (losses) net of tax	18,952	(10,621)	(17,993)
Debt Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	1,253,166	1,189,525
Gross unrealized gains	33,036	32,485
Gross unrealized losses	11,186	22,311
Estimated fair values	1,275,016	1,199,699
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	232,834	404,167
Less than twelve months, Unrealized losses	2,472	16,129
Twelve months or longer, Fair value	190,985	32,250
Twelve months or longer, Unrealized losses	8,714	6,182
Total, Fair value	423,819	436,417
Total, Unrealized losses	11,186	22,311
Realized Investment Gains (Losses) [Abstract]
Available-for-sale, Gross realized investment gains	545	2,054	725
Available-for-sale, Gross realized investment losses	(4,849)	(2,829)	(251)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax [Abstract]
Net changes in unrealized holding gains (losses) before tax	11,676	(20,634)	(16,685)
Deferred income tax expense (benefit)	4,086	(7,222)	(5,840)
Net changes in unrealized holding gains (losses) net of tax	7,590	(13,412)	(10,845)
US Treasury Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	8,115	7,841
Gross unrealized gains	0	0
Gross unrealized losses	37	11
Estimated fair values	8,078	7,830
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	8,078	7,830
Less than twelve months, Unrealized losses	37	11
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	8,078	7,830
Total, Unrealized losses	37	11
US Government-sponsored Enterprises Debt Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	303,932	249,495
Gross unrealized gains	122	311
Gross unrealized losses	6,105	10,609
Estimated fair values	297,949	239,197
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	134,284	202,900
Less than twelve months, Unrealized losses	1,491	10,609
Twelve months or longer, Fair value	127,604	0
Twelve months or longer, Unrealized losses	4,614	0
Total, Fair value	261,888	202,900
Total, Unrealized losses	6,105	10,609
US States and Political Subdivisions Debt Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	290,038	319,663
Gross unrealized gains	17,729	17,034
Gross unrealized losses	231	940
Estimated fair values	307,536	335,757
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	0	43,777
Less than twelve months, Unrealized losses	0	940
Twelve months or longer, Fair value	14,416	0
Twelve months or longer, Unrealized losses	231	0
Total, Fair value	14,416	43,777
Total, Unrealized losses	231	940
Commercial Mortgage Backed Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	84,058	37,964
Gross unrealized gains	591	741
Gross unrealized losses	669	1,133
Estimated fair values	83,980	37,572
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	32,155	21,695
Less than twelve months, Unrealized losses	221	1,133
Twelve months or longer, Fair value	8,530	0
Twelve months or longer, Unrealized losses	448	0
Total, Fair value	40,685	21,695
Total, Unrealized losses	669	1,133
Residential Mortgage Backed Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	120,554	102,307
Gross unrealized gains	2,479	1,435
Gross unrealized losses	3,234	7,308
Estimated fair values	119,799	96,434
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	30,003	26,217
Less than twelve months, Unrealized losses	394	1,232
Twelve months or longer, Fair value	22,948	23,625
Twelve months or longer, Unrealized losses	2,840	6,076
Total, Fair value	52,951	49,842
Total, Unrealized losses	3,234	7,308
Collateralized Debt Obligations [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	23,934	26,592
Gross unrealized gains	625	732
Gross unrealized losses	445	931
Estimated fair values	24,114	26,393
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	0	19,091
Less than twelve months, Unrealized losses	0	931
Twelve months or longer, Fair value	13,440	0
Twelve months or longer, Unrealized losses	445	0
Total, Fair value	13,440	19,091
Total, Unrealized losses	445	931
Corporate Debt Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	422,535	445,663
Gross unrealized gains	11,490	12,232
Gross unrealized losses	465	1,379
Estimated fair values	433,560	456,516
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	28,314	82,657
Less than twelve months, Unrealized losses	329	1,273
Twelve months or longer, Fair value	4,047	8,625
Twelve months or longer, Unrealized losses	136	106
Total, Fair value	32,361	91,282
Total, Unrealized losses	465	1,379
Equity Securities [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	144,274	147,479
Gross unrealized gains	85,248	67,267
Gross unrealized losses	1,407	907
Estimated fair values	228,115	213,839
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	15,031	18,286
Less than twelve months, Unrealized losses	1,368	541
Twelve months or longer, Fair value	1,961	3,973
Twelve months or longer, Unrealized losses	39	366
Total, Fair value	16,992	22,259
Total, Unrealized losses	1,407	907
Realized Investment Gains (Losses) [Abstract]
Available-for-sale, Gross realized investment gains	19,792	15,078	12,741
Available-for-sale, Gross realized investment losses	(1,592)	(2,675)	(4,110)
'Other-than-temporary' impairments	(1,088)	(1,055)	(1,481)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax [Abstract]
Net changes in unrealized holding gains (losses) before tax	17,481	4,293	(10,997)
Deferred income tax expense (benefit)	6,119	1,502	(3,849)
Net changes in unrealized holding gains (losses) net of tax	11,362	2,791	(7,148)
Common stocks Financial services [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	30,103	22,922
Gross unrealized gains	13,594	12,410
Gross unrealized losses	175	210
Estimated fair values	43,522	35,122
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	4,391	1,462
Less than twelve months, Unrealized losses	175	12
Twelve months or longer, Fair value	0	908
Twelve months or longer, Unrealized losses	0	198
Total, Fair value	4,391	2,370
Total, Unrealized losses	175	210
Common stocks Information technology [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	18,308	19,832
Gross unrealized gains	17,504	10,739
Gross unrealized losses	2	29
Estimated fair values	35,810	30,542
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	344	1,947
Less than twelve months, Unrealized losses	2	29
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	344	1,947
Total, Unrealized losses	2	29
Common stocks Healthcare [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	18,877	16,092
Gross unrealized gains	11,876	8,700
Gross unrealized losses	158	85
Estimated fair values	30,595	24,707
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	2,532	3,585
Less than twelve months, Unrealized losses	158	85
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	2,532	3,585
Total, Unrealized losses	158	85
Common stocks Consumer staples [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	9,275	13,438
Gross unrealized gains	4,917	5,787
Gross unrealized losses	65	125
Estimated fair values	14,127	19,100
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	575	2,427
Less than twelve months, Unrealized losses	65	125
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	575	2,427
Total, Unrealized losses	65	125
Common stocks Consumer discretionary [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	10,935	14,812
Gross unrealized gains	9,640	7,672
Gross unrealized losses	37	163
Estimated fair values	20,538	22,321
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	992	1,637
Less than twelve months, Unrealized losses	37	163
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	992	1,637
Total, Unrealized losses	37	163
Common stocks Energy [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	12,441	14,276
Gross unrealized gains	5,381	4,873
Gross unrealized losses	917	78
Estimated fair values	16,905	19,071
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	3,181	1,621
Less than twelve months, Unrealized losses	917	33
Twelve months or longer, Fair value	0	1,188
Twelve months or longer, Unrealized losses	0	45
Total, Fair value	3,181	2,809
Total, Unrealized losses	917	78
Common stocks Industrials [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	12,746	13,005
Gross unrealized gains	15,757	11,258
Gross unrealized losses	14	18
Estimated fair values	28,489	24,245
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	3,016	779
Less than twelve months, Unrealized losses	14	18
Twelve months or longer, Fair value	0	0
Twelve months or longer, Unrealized losses	0	0
Total, Fair value	3,016	779
Total, Unrealized losses	14	18
Common stocks Other [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	11,058	13,071
Gross unrealized gains	5,363	5,345
Gross unrealized losses	0	32
Estimated fair values	16,421	18,384
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value		1,472
Less than twelve months, Unrealized losses		32
Twelve months or longer, Fair value		0
Twelve months or longer, Unrealized losses		0
Total, Fair value		1,472
Total, Unrealized losses		32
Nonredeemable Preferred Stock [Member]
Amortized cost and estimated fair value of available-for-sale securities [Abstract]
Amortized cost	20,531	20,031
Gross unrealized gains	1,216	483
Gross unrealized losses	39	167
Estimated fair values	21,708	20,347
Available for sale securities continuous unrealized loss position [Abstract]
Less than twelve months, Fair value	0	3,356
Less than twelve months, Unrealized losses	0	44
Twelve months or longer, Fair value	1,961	1,877
Twelve months or longer, Unrealized losses	39	123
Total, Fair value	1,961	5,233
Total, Unrealized losses	39	167
Other Long-term Investments [Member]
Realized Investment Gains (Losses) [Abstract]
'Other-than-temporary' impairments		(209)
Net realized investment gains (losses)	$ (6,252)	$ (6,499)	$ (1,471)

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of Deferred Tax Assets [Abstract]
Loss reserve discounting	$ 7,507				$ 13,442				$ 7,507	$ 13,442
Unearned premium reserve limitation	10,284				16,497				10,284	16,497
Other policyholders' funds payable	2,103				4,574				2,103	4,574
Other, net	2,202				2,561				2,202	2,561
Total deferred income tax asset	22,096				37,074				22,096	37,074
Net unrealized holding gains on investment securities	(22,195)				(26,786)				(22,195)	(26,786)
Deferred policy acquisition costs	(8,634)				(14,328)				(8,634)	(14,328)
Retirement benefits	(3,714)				(3,510)				(3,714)	(3,510)
Other, net	(2,573)				(3,771)				(2,573)	(3,771)
Total deferred income tax liability	(37,116)				(48,395)				(37,116)	(48,395)
Net deferred income tax liability	(15,020)				(11,321)				$ (15,020)	$ (11,321)
Income tax expense (benefit) reconciliation [Abstract]
United States federal corporate tax rate (in hundredths)									35.00%	35.00%	35.00%
United States federal corporate tax rate enacted for future periods									21.00%
Computed expected income tax expense									$ 13,936	$ 22,123	$ 25,079
Increases (decreases) in tax resulting from:
Deferred income tax benefit from enactment of the TCJA									(9,056)	0	0
Tax-exempt interest income									(2,715)	(2,803)	(2,805)
Dividends received deduction									(1,291)	(1,429)	(1,136)
Proration of tax-exempt interest and dividends received deduction									601	635	591
Investment tax credits									(672)	(1,392)	0
Other, net									(225)	(130)	(235)
Operations	(1,597)	$ (1,186)	$ 1,725	$ 1,636	7,904	$ 918	$ 1,959	$ 6,223	578	17,004	21,494
Comprehensive Income Loss Tax [Abstract]
Operations	(1,597)	$ (1,186)	$ 1,725	$ 1,636	7,904	$ 918	$ 1,959	$ 6,223	578	17,004	21,494
Change in unrealized holding gains on investment securities									10,205	(5,720)	(9,689)
Change in funded status of retirement benefit plans:
Pension plans									1,694	414	(1,748)
Postretirement benefit plans									(774)	(1,345)	(1,071)
Comprehensive income tax expense									11,703	10,353	8,986
Provision for uncertain tax positions	$ 0				$ 0				0	0
Income tax examination, penalties and interest expense									$ 0	$ 0	$ 0

SURPLUS NOTES (Details)

SURPLUS NOTES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SURPLUS NOTES [Abstract]
Surplus notes payable to affiliate	$ 25,000	$ 25,000
Interest rate on surplus notes (in hundredths)	1.35%	1.35%	1.35%
Approved interest rate not yet effective on surplus notes (in hundredths)	2.73%
Period for review of interest rate	5 years	5 years	5 years
Interest expense (all affiliated)	$ 337	$ 337	$ 337

EMPLOYEE RETIREMENT PLANS (Deta

EMPLOYEE RETIREMENT PLANS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Percentage of pool participation (in hundredths)	30.00%	30.00%	30.00%
Other benefit plans expenses (including 401(k)) allocated to the Company	$ 2,900	$ 2,700	$ 2,500
Pension Plans [Member] | EMC Insurance Group, Inc. [Member]
ASSETS
Prepaid pension and postretirement benefits				$ 16,327	$ 9,065
Liability [Abstract]
Pension and postretirement benefits				(4,185)	(4,097)
Net amount recognized				12,142	4,968
Amounts recognized in the Company's consolidated balance sheets under the caption "accumulated other comprehensive income", before deferred income taxes [Abstract]
Net actuarial loss				(11,598)	(18,927)
Prior service (cost) credit				0	(6)
Net amount recognized				(11,598)	(18,933)
Amounts that will be amortized from accumulated other comprehensive income (loss) in next fiscal year [Abstract]
Amortization of net actuarial loss				150
Amortization of prior service cost (credit)				0
Amounts recognized in the Company's consolidated statements of comprehensive income [Abstract]
Net actuarial gain (loss)	7,329	1,174
Prior service (cost) credit	6	9
Net amount recognized	7,335	1,183
Components of net periodic benefit cost [Abstract]
Net periodic benefit cost (income)	2,800	2,900	1,800
Pension Plans [Member] | EMC Insurance Companies [Member]
Change in projected benefit obligation [Abstract]
Benefit obligation at beginning of year	284,194	269,904
Service cost	15,135	14,432	13,962
Interest cost	11,190	10,161	9,311
Actuarial loss	12,577	5,361
Benefits paid	(14,852)	(15,664)
Medicare subsidy reimbursements	0	0
Plan amendments	0	0
Projected benefit obligation at end of year	308,244	284,194	269,904
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	300,915	283,231
Actual return on plan assets	54,255	23,081
Employer contributions	8,686	10,267
Benefits paid	(14,852)	(15,664)
Fair value of plan assets at end of year	349,004	300,915	283,231
Funded status				$ 40,760	$ 16,721
Components of net periodic benefit cost [Abstract]
Service cost	15,135	14,432	13,962
Interest cost	11,190	10,161	9,311
Expected return on plan assets	(20,765)	(19,361)	(20,298)
Amortization of net actuarial loss	3,643	4,311	2,710
Amortization of prior service cost (credit)	20	31	31
Net periodic benefit cost (income)	$ 9,223	$ 9,574	$ 5,716
Weighted-average assumptions used to measure the benefit obligations [Abstract]
Discount rate (in hundredths)				3.60%	4.07%
Weighted-average assumptions used to measure the net periodic benefit costs [Abstract]
Discount rate (in hundredths)	4.07%	3.90%	3.57%
Expected long-term rate of return on plan assets (in hundredths)	7.00%	7.00%	7.00%
Expected future benefit payments to be paid from the plans over the next ten years [Abstract]
2,018				$ 20,276
2,019				22,628
2,020				23,050
2,021				19,841
2,022				22,655
2023 - 2027				119,538
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	$ 300,915	$ 283,231	$ 283,231	$ 349,004	$ 300,915
Qualified Pension Plan [Member] | EMC Insurance Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, vest years of service	3 years
Defined benefit plan, age of attainment years	55 years
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	$ 300,915
Fair value of plan assets at end of year	$ 349,004	$ 300,915
Weighted-average assumptions used to measure the benefit obligations [Abstract]
Rate of compensation increase (in hundredths)				5.09%	5.07%
Weighted-average assumptions used to measure the net periodic benefit costs [Abstract]
Rate of compensation increase (in hundredths)	5.08%	5.07%	4.73%
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	$ 300,915	$ 300,915		$ 349,004	$ 300,915
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Defined benefit plan estimated future parent total contributions next fiscal year				8,000
Qualified Pension Plan [Member] | EMC Insurance Companies [Member] | Pooled Separate Accounts [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	300,915
Fair value of plan assets at end of year	349,004	300,915
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	$ 300,915	$ 300,915		349,004	300,915
Non-Qualified Pension Plan [Member] | EMC Insurance Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, vest years of service	3 years
Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract]
Projected benefit obligation				13,950	13,656
Accumulated benefit obligation				12,272	12,182
Fair value of plan assets				$ 0	$ 0
Weighted-average assumptions used to measure the benefit obligations [Abstract]
Rate of compensation increase (in hundredths)				4.45%	4.53%
Weighted-average assumptions used to measure the net periodic benefit costs [Abstract]
Rate of compensation increase (in hundredths)	4.47%	4.56%	4.68%
Postretirement Benefit Plans [Member] | EMC Insurance Group, Inc. [Member]
ASSETS
Prepaid pension and postretirement benefits				$ 4,356	$ 3,249
Liability [Abstract]
Pension and postretirement benefits				0	0
Net amount recognized				4,356	3,249
Amounts recognized in the Company's consolidated balance sheets under the caption "accumulated other comprehensive income", before deferred income taxes [Abstract]
Net actuarial loss				(4,950)	(6,147)
Prior service (cost) credit				16,407	19,441
Net amount recognized				11,457	13,294
Amounts that will be amortized from accumulated other comprehensive income (loss) in next fiscal year [Abstract]
Amortization of net actuarial loss				260
Amortization of prior service cost (credit)				(3,200)
Amounts recognized in the Company's consolidated statements of comprehensive income [Abstract]
Net actuarial gain (loss)	$ 1,197	$ 376
Prior service (cost) credit	(3,034)	(4,221)
Net amount recognized	(1,837)	(3,845)
Components of net periodic benefit cost [Abstract]
Net periodic benefit cost (income)	$ (2,900)	(3,000)	$ (3,000)
Postretirement Benefit Plans [Member] | EMC Insurance Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, age of attainment years	55 years
Change in projected benefit obligation [Abstract]
Benefit obligation at beginning of year	$ 55,651	51,449
Service cost	1,362	1,273	1,411
Interest cost	2,281	2,215	2,148
Actuarial loss	3,278	357
Benefits paid	(2,455)	(2,377)
Medicare subsidy reimbursements	0	553
Plan amendments	$ (1,113)	2,181
Amortization period for prior service credit from plan amendment	10 years
Projected benefit obligation at end of year	$ 59,004	55,651	51,449
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	67,809	66,320
Actual return on plan assets	10,304	3,866
Employer contributions	0	0
Benefits paid	(2,455)	(2,377)
Fair value of plan assets at end of year	75,658	67,809	66,320
Funded status				$ 16,654	$ 12,158
Components of net periodic benefit cost [Abstract]
Service cost	1,362	1,273	1,411
Interest cost	2,281	2,215	2,148
Expected return on plan assets	(4,311)	(4,224)	(4,416)
Amortization of net actuarial loss	1,371	1,494	1,745
Amortization of prior service cost (credit)	(11,154)	(11,338)	(11,466)
Net periodic benefit cost (income)	$ (10,451)	$ (10,580)	$ (10,578)
Weighted-average assumptions used to measure the benefit obligations [Abstract]
Discount rate (in hundredths)				3.63%	4.21%
Weighted-average assumptions used to measure the net periodic benefit costs [Abstract]
Discount rate (in hundredths)	4.21%	4.42%	4.04%
Expected long-term rate of return on plan assets (in hundredths)	6.50%	6.50%	6.50%
Expected future benefit payments to be paid from the plans over the next ten years [Abstract]
2,018				$ 3,175
2,019				3,383
2,020				3,560
2,021				3,636
2,022				3,690
2023 - 2027				18,679
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	$ 67,809	$ 66,320	$ 66,320	75,658	$ 67,809
Postretirement Benefit Plans [Member] | EMC Insurance Companies [Member] | HRA Maximum Adjustment [Member]
Change in projected benefit obligation [Abstract]
Plan amendments	2,700
Postretirement Benefit Plans [Member] | EMC Insurance Companies [Member] | Life Insuance Amount Adjustment [Member]
Change in projected benefit obligation [Abstract]
Plan amendments	(3,800)
VEBA Trust [Member] | EMC Insurance Companies [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	67,809
Fair value of plan assets at end of year	75,658	67,809
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	67,809	67,809		75,658	67,809
Defined Benefit Plan, Expected Future Employer Contributions [Abstract]
Defined benefit plan estimated future parent total contributions next fiscal year				$ 0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Money Market Funds [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	1,485
Fair value of plan assets at end of year	1,254	1,485
Fair values of the plan assets held [Abstract]
Net asset value per share (in dollars per share)				$ 1
Assets, Fair Value Disclosure	1,485	1,485		$ 1,254	1,485
VEBA Trust [Member] | EMC Insurance Companies [Member] | Emerging Markets ETF [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	3,743
Fair value of plan assets at end of year	4,803	3,743
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	3,743	3,743		4,803	3,743
VEBA Trust [Member] | EMC Insurance Companies [Member] | Mutual Fund [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	47,916
Fair value of plan assets at end of year	54,180	47,916
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	47,916	47,916		$ 54,180	47,916
VEBA Trust [Member] | EMC Insurance Companies [Member] | Life Insurance Contracts [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	14,159
Fair value of plan assets at end of year	14,524	14,159
Fair values of the plan assets held [Abstract]
Guaranteed interest rate life insurance policy				4.50%
Assets, Fair Value Disclosure	14,159	14,159		$ 14,524	14,159
Reconciliation of the plan assets measured at fair value using significant unobservable inputs (Level 3) [Roll Forward]
Beginning balance	14,159	13,792
Actual return on plan assets [Abstract]
Increase in cash surrender value of life insurance contracts	365	367
Balance at end of period	14,524	14,159	$ 13,792
VEBA Trust [Member] | EMC Insurance Companies [Member] | Cash [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	506
Fair value of plan assets at end of year	897	506
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	506	506		897	506
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	53,650
Fair value of plan assets at end of year	61,134	53,650
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	53,650	53,650		61,134	53,650
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Money Market Funds [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	1,485
Fair value of plan assets at end of year	1,254	1,485
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	1,485	1,485		1,254	1,485
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Emerging Markets ETF [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	3,743
Fair value of plan assets at end of year	4,803	3,743
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	3,743	3,743		4,803	3,743
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Mutual Fund [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	47,916
Fair value of plan assets at end of year	54,180	47,916
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	47,916	47,916		54,180	47,916
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Life Insurance Contracts [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Quoted prices in active markets for identical assets (Level 1) [Member] | Cash [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	506
Fair value of plan assets at end of year	897	506
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	506	506		897	506
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member] | Money Market Funds [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member] | Emerging Markets ETF [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member] | Mutual Fund [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member] | Life Insurance Contracts [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant other observable inputs (Level 2) [Member] | Cash [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	14,159
Fair value of plan assets at end of year	14,524	14,159
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	14,159	14,159		14,524	14,159
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member] | Money Market Funds [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member] | Emerging Markets ETF [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member] | Mutual Fund [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	0	0		0	0
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member] | Life Insurance Contracts [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	14,159
Fair value of plan assets at end of year	14,524	14,159
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	14,159	14,159		14,524	14,159
VEBA Trust [Member] | EMC Insurance Companies [Member] | Significant unobservable inputs (Level 3) [Member] | Cash [Member]
Change in plan assets [Abstract]
Fair value of plan assets at beginning of year	0
Fair value of plan assets at end of year	0	0
Fair values of the plan assets held [Abstract]
Assets, Fair Value Disclosure	$ 0	$ 0		$ 0	$ 0

STOCK-BASED COMPENSATION (Detai

STOCK-BASED COMPENSATION (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Plan$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock option plans | Plan	2
Stock repurchased and retired during period, shares	67,974	17,300
Average cost per share of stock repurchased | $ / shares	$ 27.34	$ 22.14
Recognized compensation expense | $	$ 801	$ 788	$ 500
Recognized compensation expense, net of tax | $	521	512	325
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost associated with restricted stock awards, not currently vested | $	$ 640
Weighted-average period over which the compensation expense is expected to be recognized	1 year 6 months 21 days
Total fair value of restricted stock awards that vested | $	$ 545	$ 414	$ 233
Non-vested restricted stock awards activity in shares
Non-vested, beginning of year (in shares)	234,281	216,944	155,864
Granted (in shares)	2,000	118,588	117,146
Vested (in shares)	(85,192)	(69,057)	(40,941)
Forfeited (in shares)	(7,039)	(32,194)	(15,125)
Non-vested, end of year (in shares)	144,050	234,281	216,944
Non-vested restricted stock awards activity in dollars per share weighted-average grant-date fair value
Non-vested, beginning of year (in dollars per share) | $ / shares	$ 22.31	$ 20.40	$ 19.21
Granted (in dollars per share) | $ / shares	26.95	24.56	21.36
Vested (in dollars per share) | $ / shares	21.31	19.98	18.99
Forfeited (in dollars per share) | $ / shares	22.57	22.73	19.35
Non-vested, end of year (in dollars per share) | $ / shares	$ 22.96	$ 22.31	$ 20.40
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based arrangements, liability, current and noncurrent | $	$ 543
Non-vested restricted stock awards activity in shares
Non-vested, beginning of year (in shares)	0
Granted (in shares)	116,288
Vested (in shares)	0
Forfeited (in shares)	2,233
Non-vested, end of year (in shares)	114,055	0
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years	5 years	5 years
Total intrinsic value of options exercised under Employers Mutual's stock option plans | $	$ 901	$ 1,100	$ 770
Portion of the current tax deduction realized from exercises of stock options | $	$ 239	$ 284	$ 121
Number of options [Roll Forward]
Outstanding, beginning of year (in shares)	649,012	1,006,171	1,351,802
Exercised (in shares)	(222,921)	(321,312)	(323,486)
Expired (in shares)	(18,805)	(34,947)	(20,850)
Forfeited (in shares)	(975)	(900)	(1,295)
Outstanding, end of year (in shares)	406,311	649,012	1,006,171
Options Exercisable, end of year (in shares)	406,311	593,224	824,365
Weighted-average exercise price [Roll Forward]
Outstanding, beginning of year (in dollars per share) | $ / shares	$ 14.65	$ 14.92	$ 14.89
Exercised (in dollars per share) | $ / shares	14.88	15.31	14.86
Expired (in dollars per share) | $ / shares	15.16	16.32	14.11
Forfeited (in dollars per share) | $ / shares	13.99	13.99	14.68
Outstanding, end of year (in dollars per share) | $ / shares	14.51	14.65	14.92
Exercisable, end of year (in dollars per share) | $ / shares	$ 14.51	$ 14.72	$ 14.95
Additional information relating to options outstanding and options vested (exercisable) [Abstract]
Options outstanding, Number of options (in shares)	406,311
Options outstanding, Weighted-average exercise price (in dollars per share) | $ / shares	$ 14.51
Options outstanding, Aggregate intrinsic value | $	$ 5,910
Options outstanding, Weighted-average remaining term	2 years 9 months 21 days
Options exercisable, Number of options (in shares)	406,311
Options exercisable, Weighted-average exercise price (in dollars per share) | $ / shares	$ 14.51
Options exercisable, Aggregate intrinsic value | $	$ 5,910
Options exercisable, Weighted-average remaining term	2 years 9 months 21 days
EMC Insurance Group Inc. 2017 Non-Employee Director Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	150,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	750,000	750,000	750,000
Fair market value of the stock on the date of purchase (in hundredths)	85.00%	85.00%	85.00%
Employee stock purchase plan administrative expense | $	$ 100	$ 78	$ 59
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	349,404	414,883	471,459
Shares purchased under the plan (in shares)	(77,819)	(65,479)	(56,576)
Shares available for purchase, end of year (in shares)	271,585	349,404	414,883
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share) | $ / shares	$ 23.64
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share) | $ / shares	$ 25.15
Non-Employee Director Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	300,000	300,000	300,000
Fair market value to purchase stock under Non-employee director stock option plan (in hundredths)	75.00%	75.00%	75.00%
Minimum cash retainer used to purchase common stock (in hundredths)	25.00%	25.00%	25.00%
Maximum cash retainer used to purchase common stock (in hundredths)	100.00%	100.00%	100.00%
Non employee director stock option plan administrative expense | $	$ 65	$ 84	$ 62
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	249,843	264,446	279,809
Shares purchased under the plan (in shares)	(14,470)	(14,603)	(15,363)
Shares available for purchase, end of year (in shares)	235,373	249,843	264,446
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share) | $ / shares	$ 20.15
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share) | $ / shares	$ 23.15
Dividend Reinvestment Plan [Member]
Other Stock Purchase Plan Shares Activity [Roll Forward]
Shares available for purchase, beginning of year (in shares)	971,222	976,697	982,227
Shares purchased under the plan (in shares)	(5,421)	(5,475)	(5,530)
Shares available for purchase, end of year (in shares)	965,801	971,222	976,697
Other stock purchase plan stock option exercise price range lower range limit (in dollars per share) | $ / shares	$ 26.94	$ 22.09	$ 21.02
Other stock purchase plan stock option exercise price range upper range limit (in dollars per share) | $ / shares	$ 31.09	$ 30.50	$ 26.43
Employers Mutual Casualty Company Stock Incentive 2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	3,000,000	3,000,000	3,000,000
Time limit for granting awards	10 years	10 years	10 years
Employers Mutual Casualty Company 2017 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Registered shares (in shares)	1,000,000
Time limit for granting awards	10 years
Employee [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years	4 years	4 years
Employee [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Approved retirement threshold	70
Approved retirement minimum age	55 years
Automatic age for approved retirement	65 years
Accelerated period non-forfeiture upon approved retirement eligibility	12 months
Non-Employee Director [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year	3 years
Age to attain automatic vesting		75 years
Non-vested restricted stock awards activity in shares
Granted (in shares)	2,000	2,000

ACCUMULATED OTHER COMPREHENSI65

ACCUMULATED OTHER COMPREHENSIVE INCOME - Components of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss) before reclassifications	$ 32,945	$ (4,766)
Amounts reclassified from accumulated other comprehensive income	(9,415)	(7,586)	$ (6,243)
Other comprehensive income (loss)	23,530	(12,352)	(23,229)
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	0
Unrealized gains (losses) on available-for- sale securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	49,748	60,369
Other comprehensive income (loss) before reclassifications	27,278	(3,885)
Amounts reclassified from accumulated other comprehensive income	(8,326)	(6,736)
Other comprehensive income (loss)	18,952	(10,621)
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	14,797
Balance	83,497	49,748	60,369
Unrecognized pension and postretirement benefit obligations, net actuarial loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(16,299)	(17,306)
Other comprehensive income (loss) before reclassifications	5,571	(542)
Amounts reclassified from accumulated other comprehensive income	958	1,549
Other comprehensive income (loss)	6,529	1,007
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	(3,304)
Balance	(13,074)	(16,299)	(17,306)
Unrecognized pension and postretirement benefit obligations, prior service credit
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	12,632	15,370
Other comprehensive income (loss) before reclassifications	96	(339)
Amounts reclassified from accumulated other comprehensive income	(2,047)	(2,399)
Other comprehensive income (loss)	(1,951)	(2,738)
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	2,280
Balance	12,961	12,632	15,370
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(3,667)	(1,936)
Other comprehensive income (loss) before reclassifications	5,667	(881)
Amounts reclassified from accumulated other comprehensive income	(1,089)	(850)	(1,287)
Other comprehensive income (loss)	4,578	(1,731)
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	(1,024)
Balance	(113)	(3,667)	(1,936)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	46,081	58,433
Reclassification of tax effects from accumulated other comprehensive income resulting from TCJA	13,773
Balance	$ 83,384	$ 46,081	$ 58,433

ACCUMULATED OTHER COMPREHENSI66

ACCUMULATED OTHER COMPREHENSIVE INCOME - Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized investment gains, excluding impairment losses on securities available-for-sale									$ 7,644	$ 5,338	$ 7,634
Total income tax expense	$ 1,597	$ 1,186	$ (1,725)	$ (1,636)	$ (7,904)	$ (918)	$ (1,959)	$ (6,223)	(578)	(17,004)	(21,494)
Net income	$ 26,184	$ 746	$ 5,504	$ 6,804	$ 21,292	$ 4,129	$ 6,128	$ 14,654	39,238	46,203	50,162
Net reclassification adjustment									9,415	7,586	6,243
Unrealized gains on investments: | Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized investment gains, excluding impairment losses on securities available-for-sale									12,809	10,364	7,624
Total income tax expense									(4,483)	(3,628)	(2,668)
Net income									8,326	6,736	4,956
Unrecognized pension and postretirement benefit obligations, net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income:									(1,474)	(2,383)	(1,327)
Net reclassification adjustment									(958)	(1,549)
Unrecognized pension and postretirement benefit obligations, prior service credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income:									3,150	3,690	3,307
Net reclassification adjustment									2,047	2,399
Total
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income:									1,676	1,307	1,980
Deferred income tax expense									(587)	(457)	(693)
Net reclassification adjustment									$ 1,089	$ 850	$ 1,287

STOCK REPURCHASE PROGRAMS (Deta

STOCK REPURCHASE PROGRAMS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2005	Dec. 31, 2017	Dec. 31, 2016	Nov. 03, 2011
Equity [Abstract]
Authorized amount of stock repurchase program				$ 15,000
Stock repurchased and retired during period, shares		67,974	17,300
Average cost per share of stock repurchased		$ 27.34	$ 22.14
Parent entity stock purchase program authorized amount	$ 15,000
Parent entity stock purchase program remaining authorized purchase amount		$ 4,500

LEASES, COMMITMENTS AND CONTI68

LEASES, COMMITMENTS AND CONTINGENT LIABILITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Lease commitments, Payments due by period [Abstract]
Real estate operating leases, Total	$ 2,207
Real estate operating leases, Less than 1 year	423
Real estate operating leases, 1 - 3 years	820
Real estate operating leases, 4 - 5 years	530
Real estate operating leases, More than 5 years	434
Loss Contingencies [Line Items]
Premium tax offsets	$ 897	$ 1,000
Period for guaranty fund assessments expected to be paid	2 years
Period for premium tax offsets are expected to be realized	10 years
Entity's share of case loss reserves, eliminated by the purchase of annuities	$ 110
Contingent liability for aggregate guaranteed amount of annuities	183
Guaranty Fund [Member]
Loss Contingencies [Line Items]
Accrued estimated fund assessments	706	851
Second-Injury Fund [Member]
Loss Contingencies [Line Items]
Accrued estimated fund assessments	$ 2,000	$ 1,900

UNAUDITED INTERIM FINANCIAL I69

UNAUDITED INTERIM FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 174,320		$ 165,918		$ 164,150		$ 154,457		$ 168,398		$ 162,378		$ 160,336		$ 153,871		$ 658,845	$ 644,983	$ 623,726
Income (loss) before income tax expense (benefit)	24,587		(440)		7,229		8,440		29,196		5,047		8,087		20,877		39,816	63,207	71,656
Income tax expense (benefit)	(1,597)		(1,186)		1,725		1,636		7,904		918		1,959		6,223		578	17,004	21,494
Net income	$ 26,184		$ 746		$ 5,504		$ 6,804		$ 21,292		$ 4,129		$ 6,128		$ 14,654		$ 39,238	$ 46,203	$ 50,162
Net income per common share - basic and diluted1	$ 1.23	[1]	$ 0.03	[1]	$ 0.26	[1]	$ 0.32	[1]	$ 1.01	[1]	$ 0.20	[1]	$ 0.29	[1]	$ 0.70	[1]	$ 1.84	$ 2.20	$ 2.43
[1]	Since the weighted-average number of shares outstanding for the quarters are calculated independently of the weighted-average number of shares outstanding for the year, quarterly net income per share may not total to annual net income per share.

Schedule I - Summary of Inves70

Schedule I - Summary of Investments-Other than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2017USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	$ 1,434,701
Amount at which shown in the balance sheet	1,540,392
Debt Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,253,166
Fair value	1,275,016
Amount at which shown in the balance sheet	1,275,016
US Treasury Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	8,115
Fair value	8,078
Amount at which shown in the balance sheet	8,078
US Government-sponsored Enterprises Debt Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	303,932
Fair value	297,949
Amount at which shown in the balance sheet	297,949
Obligations of States and Political Subdivisions [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	290,038
Fair value	307,536
Amount at which shown in the balance sheet	307,536
Commercial Mortgage Backed Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	84,058
Fair value	83,980
Amount at which shown in the balance sheet	83,980
Residential Mortgage Backed Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	120,554
Fair value	119,799
Amount at which shown in the balance sheet	119,799
Other Asset Backed [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	23,934
Fair value	24,114
Amount at which shown in the balance sheet	24,114
Corporate Debt Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	422,535
Fair value	433,560
Amount at which shown in the balance sheet	433,560
Equity Securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	144,274
Fair value	228,115
Amount at which shown in the balance sheet	228,115
Common stocks Financial services [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	30,103
Fair value	43,522
Amount at which shown in the balance sheet	43,522
Common stocks Information technology [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	18,308
Fair value	35,810
Amount at which shown in the balance sheet	35,810
Common stocks Healthcare [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	18,877
Fair value	30,595
Amount at which shown in the balance sheet	30,595
Common stocks Consumer staples [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	9,275
Fair value	14,127
Amount at which shown in the balance sheet	14,127
Common stocks Consumer discretionary [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	10,935
Fair value	20,538
Amount at which shown in the balance sheet	20,538
Common stocks Energy [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	12,441
Fair value	16,905
Amount at which shown in the balance sheet	16,905
Common stocks Industrials [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	12,746
Fair value	28,489
Amount at which shown in the balance sheet	28,489
Common stocks Other [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	11,058
Fair value	16,421
Amount at which shown in the balance sheet	16,421
Nonredeemable Preferred Stock [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	20,531
Fair value	21,708
Amount at which shown in the balance sheet	21,708
Other Long-term Investments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	13,648
Amount at which shown in the balance sheet	13,648
Short-term Investments [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	23,613
Fair value	23,613
Amount at which shown in the balance sheet	$ 23,613

Schedule II - Condensed Finan71

Schedule II - Condensed Financial Information of Registrant (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Equity securities available-for-sale, at fair value (cost $2,000 and $2,000)												$ 228,115	$ 213,839
Short-term investments												23,613	39,670
Total investments												1,540,392	1,465,714
Cash	$ 347			$ 307	$ 307			$ 224	$ 307	$ 224	$ 383	347	307	$ 224	$ 383
Accrued investment income												11,286	11,050
Accounts receivable												1,604	2,076
Total assets												2,289,419	2,131,694
LIABILITIES
Amounts due affiliate to settle inter-company transaction balances												367	11,222
Deferred income taxes												15,020	11,321
Total liabilities												1,078,094	1,035,471
STOCKHOLDERS' EQUITY
Common stock, $1 par value, authorized 30,000,000 shares; issued and outstanding, 21,455,545 shares in 2017 and 21,222,535 shares in 2016												21,455	21,223
Additional paid-in capital												124,556	119,054
Accumulated other comprehensive income												83,384	46,081
Retained earnings												374,451	366,984
Total stockholders' equity												603,846	553,342	524,938	502,886
Total liabilities and stockholders' equity												1,681,940	1,588,813
REVENUES
Investment income (loss)									45,479	47,490	45,582
Total revenues	174,320	$ 165,918	$ 164,150	154,457	168,398	$ 162,378	$ 160,336	153,871	658,845	644,983	623,726
Other expenses									3,397	2,727	2,690
Income Tax Expense (Benefit)	(1,597)	(1,186)	1,725	1,636	7,904	918	1,959	6,223	578	17,004	21,494
Net income	26,184	746	5,504	6,804	21,292	4,129	6,128	14,654	39,238	46,203	50,162
Condensed Statements of Comprehensive Income [Abstract]
Net income	26,184	$ 746	$ 5,504	6,804	21,292	$ 4,129	$ 6,128	14,654	39,238	46,203	50,162
OTHER COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) on investment securities, net of deferred income taxes									27,278	(3,885)	(13,037)
Reclassification adjustment for realized investment gains included in net income, net of income taxes									(8,326)	(6,736)	(4,956)
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income, net of deferred income taxes:
Net actuarial loss									958	1,549	863
Prior service credit									(2,047)	(2,399)	(2,150)
Total reclassification adjustment associated with affiliate's pension and postretirement benefit plans									(1,089)	(850)	(1,287)
Change in funded status of affiliate's pension and postretirement benefit plans, net of deferred income taxes:
Net actuarial gain (loss)									5,571	(542)	(3,637)
Prior service credit (cost)									96	(339)	(312)
Total change in funded status of affiliate's pension and postretirement benefit plans									5,667	(881)	(3,949)
Other comprehensive income (loss)									23,530	(12,352)	(23,229)
Total comprehensive income									62,768	33,851	26,933
Condensed Statements of Cash Flows [Abstract]
Net cash provided by operating activities									58,902	83,434	85,612
Cash flows from investing activities
Purchases of equity securities available-for-sale									(62,939)	(63,683)	(83,098)
Net (purchases) disposals of short-term investments									16,057	(1,071)	14,663
Net cash used in investing activities									(46,533)	(77,842)	(80,770)
Cash flows from financing activities
Issuance of common stock through affiliate’s stock plans									7,527	11,070	9,078
Excess tax benefit associated with affiliate’s stock plans									0	0	95
Repurchase of common stock									(1,858)	(383)	0
Dividends paid to stockholders (affiliated $(10,006), $(9,182) and $(8,162))									(17,998)	(16,196)	(14,174)
Net cash used in financing activities									(12,329)	(5,509)	(5,001)
Net increase (decrease) in cash									40	83	(159)
Cash at the beginning of the year				307				224	307	224	383
Cash at the end of the year	347				307				347	307	224
Income taxes recovered									(9,820)	(13,967)	(20,254)
Interest paid									337	337	337
Parent company [Member]
ASSETS
Common stock of subsidiaries (equity method)												599,036	540,249
Equity securities available-for-sale, at fair value (cost $2,000 and $2,000)												2,000	2,000
Short-term investments												1,900	10,874
Total investments												602,936	553,123
Cash	255			184	184			136	184	136	274	255	184	$ 136	$ 274
Accrued investment income												1	3
Prepaid assets												136	154
Income taxes recoverable												777	700
Total assets												604,105	554,164
LIABILITIES
Accounts payable												80	46
Amounts due affiliate to settle inter-company transaction balances												160	740
Deferred income taxes												19	36
Total liabilities												259	822
STOCKHOLDERS' EQUITY
Common stock, $1 par value, authorized 30,000,000 shares; issued and outstanding, 21,455,545 shares in 2017 and 21,222,535 shares in 2016												21,455	21,223
Additional paid-in capital												124,556	119,054
Accumulated other comprehensive income												83,384	46,081
Retained earnings												374,451	366,984
Total stockholders' equity												603,846	553,342
Total liabilities and stockholders' equity												$ 604,105	$ 554,164
REVENUES
Dividends received from subsidiaries									5,719	9,707	9,180
Investment income (loss)									38	13	(9)
Total revenues									5,757	9,720	9,171
Other expenses									2,269	2,006	1,942
Income before income tax benefit and equity in undistributed net income of subsidiaries									3,488	7,714	7,229
Income Tax Expense (Benefit)									(794)	(698)	(682)
Income before equity in undistributed net income of subsidiaries									4,282	8,412	7,911
Equity in undistributed net income of subsidiaries									34,956	37,791	42,251
Net income									39,238	46,203	50,162
Condensed Statements of Comprehensive Income [Abstract]
Net income									39,238	46,203	50,162
OTHER COMPREHENSIVE INCOME (LOSS)
Unrealized holding gains (losses) on investment securities, net of deferred income taxes									27,278	(3,885)	(13,037)
Reclassification adjustment for realized investment gains included in net income, net of income taxes									(8,326)	(6,736)	(4,956)
Reclassification adjustment for amounts amortized into net periodic pension and postretirement benefit income, net of deferred income taxes:
Net actuarial loss									958	1,549	863
Prior service credit									(2,047)	(2,399)	(2,150)
Total reclassification adjustment associated with affiliate's pension and postretirement benefit plans									(1,089)	(850)	(1,287)
Change in funded status of affiliate's pension and postretirement benefit plans, net of deferred income taxes:
Net actuarial gain (loss)									5,571	(542)	(3,637)
Prior service credit (cost)									96	(339)	(312)
Total change in funded status of affiliate's pension and postretirement benefit plans									5,667	(881)	(3,949)
Other comprehensive income (loss)									23,530	(12,352)	(23,229)
Total comprehensive income									62,768	33,851	26,933
Condensed Statements of Cash Flows [Abstract]
Net cash provided by operating activities									3,726	9,170	7,893
Cash flows from investing activities
Capital contributions to subsidiaries									(300)	(500)	0
Purchases of equity securities available-for-sale									0	(2,000)	0
Net (purchases) disposals of short-term investments									8,974	(1,113)	(3,030)
Net cash used in investing activities									8,674	(3,613)	(3,030)
Cash flows from financing activities
Issuance of common stock through affiliate’s stock plans									7,527	11,070	9,078
Excess tax benefit associated with affiliate’s stock plans									0	0	95
Repurchase of common stock									(1,858)	(383)	0
Dividends paid to stockholders (affiliated $(10,006), $(9,182) and $(8,162))									(17,998)	(16,196)	(14,174)
Net cash used in financing activities									(12,329)	(5,509)	(5,001)
Net increase (decrease) in cash									71	48	(138)
Cash at the beginning of the year				$ 184				$ 136	184	136	274
Cash at the end of the year	$ 255				$ 184				255	184	136
Income taxes recovered									700	716	559
Interest paid									$ 0	$ 0	$ 0

Schedule II - Condensed Finan72

Schedule II - Condensed Financial Information of Registrant, Parenthetical (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Balance Sheets [Abstract]
Equity securities available-for-sale, cost	$ 144,274	$ 147,479
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	21,455,545	21,222,535
Common stock, shares outstanding (in shares)	21,455,545	21,222,535
Condensed Statements of Income [Abstract]
Operating expense, affiliated	$ 1,825	$ 1,860	$ 1,822
Condensed Statements of Cash Flows [Abstract]
Dividends paid to stockholders, affiliated	(10,006)	(9,182)	(8,162)
Parent company [Member]
Condensed Balance Sheets [Abstract]
Equity securities available-for-sale, cost	$ 2,000	$ 2,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	21,455,545	21,222,535
Common stock, shares outstanding (in shares)	21,455,545	21,222,535
Condensed Statements of Income [Abstract]
Operating expense, affiliated	$ 1,124	$ 1,139	1,074
Condensed Statements of Cash Flows [Abstract]
Dividends paid to stockholders, affiliated	$ (10,006)	$ (9,182)	$ (8,162)

Schedule III - Supplementary 73

Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	$ 41,114	$ 40,939	$ 40,720
Loss and settlement expense reserves	732,612	690,532	678,774
Unearned premiums	257,797	244,885	239,435
Premium revenue	607,158	592,408	570,266
Net investment income	45,479	47,490	45,582
Losses and settlement expenses incurred	421,969	386,897	370,736
Amortization of deferred policy acquisition costs	108,910	108,403	102,184
Other underwriting expenses	76,806	69,612	68,418
Premiums written	616,301	594,703	578,938
Property and casualty insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	37,140	36,295	35,219
Loss and settlement expense reserves	502,864	486,387	480,413
Unearned premiums	236,030	220,697	212,652
Premium revenue	472,369	456,467	447,197
Net investment income	32,670	33,886	32,668
Losses and settlement expenses incurred	302,973	294,369	291,883
Amortization of deferred policy acquisition costs	79,734	78,493	75,701
Other underwriting expenses	74,133	66,463	63,954
Premiums written	484,027	463,673	454,434
Reinsurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	3,974	4,644	5,501
Loss and settlement expense reserves	229,748	204,145	198,361
Unearned premiums	21,767	24,188	26,783
Premium revenue	134,789	135,941	123,069
Net investment income	12,771	13,591	12,923
Losses and settlement expenses incurred	118,996	92,528	78,853
Amortization of deferred policy acquisition costs	29,176	29,910	26,483
Other underwriting expenses	2,673	3,149	4,464
Premiums written	132,274	131,030	124,504
Parent company [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	0	0	0
Loss and settlement expense reserves	0	0	0
Unearned premiums	0	0	0
Premium revenue	0	0	0
Net investment income	38	13	(9)
Losses and settlement expenses incurred	0	0	0
Amortization of deferred policy acquisition costs	0	0	0
Other underwriting expenses	0	0	0
Premiums written	$ 0	$ 0	$ 0

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated earned premiums [Abstract]
Gross amount	$ 384,993	$ 382,300	$ 366,752
Ceded to other companies	437,881	426,946	407,531
Assumed from other companies	660,046	637,054	611,045
Net amount	$ 607,158	$ 592,408	$ 570,266
Percentage of amount assumed to net	108.70%	107.50%	107.20%

Schedule VI - Supplemental In75

Schedule VI - Supplemental Information Concerning Property-Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Deferred policy acquisition costs	$ 41,114	$ 40,939	$ 40,720
Reserves for losses and settlement expenses	732,612	690,532	678,774
Discount, if any, deducted from reserves	0	0	0
Unearned premiums	257,797	244,885	239,435
Earned premiums	607,158	592,408	570,266
Net investment income	45,441	47,477	45,591
Losses and settlement expenses incurred related to current year	441,588	427,838	405,850
Losses and settlement expenses incurred related to prior years	(19,619)	(40,941)	(35,114)
Amortization of deferred policy acquisition costs	108,910	108,403	102,184
Paid losses and settlement expenses	392,586	372,888	348,081
Premiums written	$ 616,301	$ 594,703	$ 578,938