Donegal (DGICA) 10-K 9 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 01, 2018	Jun. 30, 2017
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	DGICA
Entity Registrant Name	DONEGAL GROUP INC
Entity Central Index Key	800,457
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 187,725,762
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		22,623,231
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,576,775

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Fixed maturities
Held to maturity, at amortized cost (fair value $380,450,428 and $344,647,138 )	$ 366,655,077	$ 336,100,948
Available for sale, at fair value (amortized cost $538,414,337 and $511,629,644)	538,946,050	515,074,940
Equity securities, available for sale, at fair value (cost $44,219,097 and $42,431,695)	50,445,243	47,087,842
Investment in Donegal Financial Services Corporation	38,773,420	37,884,918
Short-term investments, at cost, which approximates fair value	11,049,915	9,371,007
Total investments	1,005,869,705	945,519,655
Cash	37,833,435	24,587,214
Accrued investment income	6,553,121	6,295,513
Premiums receivable	160,406,432	159,389,667
Reinsurance receivable	298,342,563	263,028,008
Deferred policy acquisition costs	60,289,860	56,309,196
Deferred tax asset, net	7,128,843	19,043,413
Prepaid reinsurance premiums	135,032,641	124,255,495
Property and equipment, net	7,280,415	6,668,489
Accounts receivable - securities	180,525
Federal income taxes recoverable	10,935,105	1,108,250
Due from affiliate		9,204,910
Goodwill	5,625,354	5,625,354
Other intangible assets	958,010	958,010
Other	1,483,769	1,137,863
Total assets	1,737,919,778	1,623,131,037
Liabilities
Losses and loss expenses	676,671,727	606,664,590
Unearned premiums	503,456,541	466,055,228
Accrued expenses	28,033,776	28,246,691
Reinsurance balances payable	4,116,159	4,369,528
Borrowings under lines of credit	59,000,000	69,000,000
Cash dividends declared to stockholders	3,841,820	3,622,821
Subordinated debentures	5,000,000	5,000,000
Due to affiliate	7,314,368
Other	1,789,283	1,556,859
Total liabilities	1,289,223,674	1,184,515,717
Stockholders' Equity
Preferred stock, $.01 par value, authorized 2,000,000 shares; none issued
Additional paid-in capital	255,401,558	236,851,709
Accumulated other comprehensive loss	(2,684,275)	(2,254,271)
Retained earnings	236,893,041	244,942,913
Treasury stock, at cost	(41,226,357)	(41,226,357)
Total stockholders' equity	448,696,104	438,615,320
Total liabilities and stockholders' equity	1,737,919,778	1,623,131,037
Class A Common Stock [Member]
Stockholders' Equity
Common stock value	255,645	244,834
Total stockholders' equity	255,645	244,834
Class B Common Stock [Member]
Stockholders' Equity
Common stock value	56,492	56,492
Total stockholders' equity	$ 56,492	$ 56,492

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Held to maturity, fair value	$ 380,450,428	$ 344,647,138
Available for sale, amortized cost	538,414,337	511,629,644
Equity securities, available for sale, at cost	$ 44,219,097	$ 42,431,695
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Class A Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	25,564,481	24,483,377
Common stock, shares outstanding	22,561,893	21,480,789
Class B Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	5,649,240	5,649,240
Common stock, shares outstanding	5,576,775	5,576,775

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Net premiums earned (includes affiliated reinsurance of $190,924,704, $184,656,732 and $175,024,905 - see note 3)	$ 702,514,755	$ 656,204,797	$ 605,640,728
Investment income, net of investment expenses	23,527,304	22,632,730	20,949,698
Installment payment fees	5,157,163	5,302,896	5,834,897
Lease income	500,455	670,865	750,287
Net realized investment gains	5,705,255	2,525,575	1,934,424
Equity in earnings of Donegal Financial Services Corporation	1,621,605	1,086,157	1,277,229
Total revenues	739,026,537	688,423,020	636,387,263
Expenses
Net losses and loss expenses (includes affiliated reinsurance of $114,865,113, $102,124,332 and $100,110,773 - see note 3)	487,268,054	423,315,903	398,366,874
Amortization of deferred policy acquisition costs	115,065,000	107,876,000	99,513,000
Other underwriting expenses	116,538,431	108,458,742	97,709,656
Policyholder dividends	5,014,624	4,373,377	3,862,606
Interest	1,593,437	1,657,647	1,111,441
Premium paid on purchase of treasury stock			5,780,000
Other	1,432,529	1,412,944	2,451,418
Total expenses	726,912,075	647,094,613	608,794,995
Income before income tax expense	12,114,462	41,328,407	27,592,268
Income tax expense (benefit)	4,998,362	10,527,270	6,602,235
Net income	7,116,100	30,801,137	20,990,033
Statements of Comprehensive Income
Net income	7,116,100	30,801,137	20,990,033
Unrealized gain (loss) on securities:
Unrealized holding gain (loss) arising during the period, net of income tax expense (benefit) of $1,964,385, ($746,518) and ($1,788,852)	3,811,151	(1,386,391)	(3,322,149)
Reclassification adjustment for gains included in net income, net of income tax of $1,939,787, $883,951 and $677,048	(3,765,468)	(1,641,624)	(1,257,376)
Other comprehensive income (loss)	45,683	(3,028,015)	(4,579,525)
Comprehensive income	$ 7,161,783	$ 27,773,122	$ 16,410,508
Class A Common Stock [Member]
Basic earnings per common share:
Common stock - Basic	$ 0.27	$ 1.19	$ 0.78
Diluted earnings per common share:
Common stock - Diluted	0.26	1.16	0.77
Class B Common Stock [Member]
Basic earnings per common share:
Common stock - Basic	0.22	1.06	0.69
Diluted earnings per common share:
Common stock - Diluted	$ 0.22	$ 1.06	$ 0.69

Consolidated Statements of Inc5

Consolidated Statements of Income and Comprehensive Income (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net premiums earned - affiliated reinsurance	$ 190,924,704	$ 184,656,732	$ 175,024,905
Net realized investment gains	5,705,255	2,525,575	1,934,424
Net losses and loss expenses - affiliated reinsurance	114,865,113	102,124,332	100,110,773
Income tax expense (benefit)	4,998,362	10,527,270	6,602,235
Income tax expense (benefit) on unrealized holding gain (loss) arising during the period	1,964,385	(746,518)	(1,788,852)
Income tax on reclassification adjustment for gains	1,939,787	883,951	677,048
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net realized investment gains	5,705,255	2,525,575	1,934,424
Income tax expense (benefit)	$ 1,939,787	$ 883,951	$ 677,048

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member]
Beginning balance at Dec. 31, 2014	$ 416,134,643	$ 200,348,783	$ 5,353,269	$ 223,253,887	$ (13,101,682)	$ 223,894	$ 56,492
Beginning balance, shares at Dec. 31, 2014						22,389,369	5,649,240
Issuance of common stock (stock compensation plans)	1,837,357	1,836,067				$ 1,290
Issuance of common stock (stock compensation plans), shares						129,066
Stock-based compensation	16,630,510	16,620,676				$ 9,834
Stock-based compensation, Shares						983,370
Net income	20,990,033			20,990,033
Cash dividends	(14,499,775)			(14,499,775)
Grant of stock options		719,775		(719,775)
Purchase of treasury stock	(28,124,675)				(28,124,675)
Other comprehensive income (loss)	(4,579,525)		(4,579,525)
Ending balance at Dec. 31, 2015	408,388,568	219,525,301	773,744	229,024,370	(41,226,357)	$ 235,018	$ 56,492
Ending balance, shares at Dec. 31, 2015						23,501,805	5,649,240
Issuance of common stock (stock compensation plans)	2,119,962	2,118,471				$ 1,491
Issuance of common stock (stock compensation plans), shares						149,105
Stock-based compensation	14,530,542	14,522,217				$ 8,325
Stock-based compensation, Shares						832,467
Net income	30,801,137			30,801,137
Cash dividends	(14,196,874)			(14,196,874)
Grant of stock options		685,720		(685,720)
Other comprehensive income (loss)	(3,028,015)		(3,028,015)
Ending balance at Dec. 31, 2016	438,615,320	236,851,709	(2,254,271)	244,942,913	(41,226,357)	$ 244,834	$ 56,492
Ending balance, shares at Dec. 31, 2016						24,483,377	5,649,240
Issuance of common stock (stock compensation plans)	2,488,333	2,486,762				$ 1,571
Issuance of common stock (stock compensation plans), shares						157,085
Stock-based compensation	15,471,719	15,462,479				$ 9,240
Stock-based compensation, Shares						924,019
Net income	7,116,100			7,116,100
Cash dividends	(15,041,051)			(15,041,051)
Grant of stock options		600,608		(600,608)
Reclassification of tax effects			(475,687)	475,687
Other comprehensive income (loss)	45,683		45,683
Ending balance at Dec. 31, 2017	$ 448,696,104	$ 255,401,558	$ (2,684,275)	$ 236,893,041	$ (41,226,357)	$ 255,645	$ 56,492
Ending balance, shares at Dec. 31, 2017						25,564,481	5,649,240

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income	$ 7,116,100	$ 30,801,137	$ 20,990,033
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other non-cash items	6,109,869	6,587,282	6,740,346
Net realized investment gains	(5,705,255)	(2,525,575)	(1,934,424)
Equity in earnings of Donegal Financial Services Corporation	(1,621,605)	(1,086,157)	(1,277,229)
Changes in Assets and Liabilities:
Losses and loss expenses	70,007,137	28,459,481	39,946,703
Unearned premiums	37,401,313	36,562,025	20,846,840
Accrued expenses	(212,915)	5,786,216	3,030,848
Premiums receivable	(1,016,765)	(18,122,256)	(7,960,450)
Deferred policy acquisition costs	(3,980,664)	(4,200,808)	(3,809,780)
Deferred income taxes	11,889,970	2,030,865	168,395
Reinsurance receivable	(35,314,555)	(3,299,895)	(6,092,223)
Accrued investment income	(257,608)	(304,316)	(239,821)
Amounts due from affiliate	16,519,278	(12,762,087)	1,147,830
Reinsurance balances payable	(253,369)	889,122	(4,360,766)
Prepaid reinsurance premiums	(10,777,146)	(10,732,990)	2,349,278
Current income taxes	(9,826,855)	379,406	(906,179)
Other, net	(113,482)	(22,628)	(2,235,228)
Dividends received from Donegal Financial Services Corporation	1,036,750	1,591,300	1,783,700
Net adjustments	73,884,098	29,228,985	47,197,840
Net cash provided by operating activities	81,000,198	60,030,122	68,187,873
Purchases of fixed maturities:
Held to maturity	(51,049,152)	(44,907,210)	(31,310,026)
Available for sale	(138,675,907)	(161,873,868)	(181,106,519)
Purchases of equity securities	(17,033,093)	(15,222,724)	(14,759,861)
Sales of fixed maturities:
Available for sale	10,081,785	55,731,299	40,321,838
Maturity of fixed maturities:
Held to maturity	20,577,326	19,488,644	28,575,153
Available for sale	99,544,479	82,586,588	66,744,045
Sales of equity securities	20,880,814	9,201,657	8,761,474
Net purchases of property and equipment	(1,090,726)	(384,207)	(151,536)
Net (purchases) sales of short-term investments	(1,678,908)	4,061,475	6,861,166
Net cash used in investing activities	(58,443,382)	(51,318,346)	(76,064,266)
Cash Flows from Financing Activities:
Issuance of common stock	15,511,457	13,822,228	15,516,870
Cash dividends paid	(14,822,052)	(14,085,934)	(14,455,167)
Purchases of treasury stock			(28,124,675)
Payments on lines of credit	(10,000,000)	(12,000,000)	(9,500,000)
Borrowings under lines of credit			37,000,000
Net cash (used in) provided by financing activities	(9,310,595)	(12,263,706)	437,028
Net increase (decrease) in cash	13,246,221	(3,551,930)	(7,439,365)
Cash at beginning of year	24,587,214	28,139,144	35,578,509
Cash at end of year	$ 37,833,435	$ 24,587,214	$ 28,139,144

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1 - Summary of Significant Accounting Policies Organization and Business Donegal Mutual Insurance Company (“Donegal Mutual”) organized us as an insurance holding company on August 26, 1986. Our insurance subsidiaries, Atlantic States Insurance Company (“Atlantic States”), Southern Insurance Company of Virginia (“Southern”), Le Mars Insurance Company (“Le Mars”), the Peninsula Insurance Group (“Peninsula”), which consists of Peninsula Indemnity Company and The Peninsula Insurance Company, Sheboygan Falls Insurance Company (“Sheboygan”) and Michigan Insurance Company (“MICO”), write personal and commercial lines of property and casualty coverages exclusively through a network of independent insurance agents in certain Mid-Atlantic, We have four segments: our investment function, our personal lines of insurance, our commercial lines of insurance and our investment in DFSC. The personal lines products of our insurance subsidiaries consist primarily of homeowners and private passenger automobile policies. The commercial lines products of our insurance subsidiaries consist primarily of commercial automobile, commercial multi-peril and workers’ compensation policies. At December 31, 2017, Donegal Mutual held approximately 44% of our outstanding Class A common stock and approximately 83% of our outstanding Class B common stock. This ownership provides Donegal Mutual with approximately 72% of the total voting power of our common stock. Our insurance subsidiaries and Donegal Mutual have interrelated operations due to a pooling agreement and other intercompany agreements and transactions. While each company maintains its separate corporate existence, our insurance subsidiaries and Donegal Mutual conduct business together as the Donegal Insurance Group. As such, Donegal Mutual and our insurance subsidiaries share the same business philosophy, the same management, the same employees and the same facilities and offer the same types of insurance products. Atlantic States, our largest subsidiary, participates in a pooling agreement with Donegal Mutual. Under the pooling agreement, the two companies pool their insurance business and each company receives an allocated percentage of the pooled business. Atlantic States has an 80% share of the results of the pooled business, and Donegal Mutual has a 20% share of the results of the pooled business. The same executive management and underwriting personnel administer products, classes of business underwritten, pricing practices and underwriting standards of Donegal Mutual and our insurance subsidiaries. In addition, as the Donegal Insurance Group, Donegal Mutual and our insurance subsidiaries share a combined business plan to achieve market penetration and underwriting profitability objectives. The products our insurance subsidiaries and Donegal Mutual market are generally complementary, thereby allowing the Donegal Insurance Group to offer a broader range of products to a given market and to expand the Donegal Insurance Group’s ability to service an entire personal lines or commercial lines account. Distinctions within the products of Donegal Mutual and our insurance subsidiaries generally relate to specific risk profiles targeted within similar classes of business, such as preferred tier versus standard tier products, but we do not allocate all of the standard risk gradients to one company. Therefore, the underwriting profitability of the business the individual companies write directly will vary. However, as the risk characteristics of all business Donegal Mutual and Atlantic States write directly are homogenized within the underwriting pool, Donegal Mutual and Atlantic States share the underwriting results in proportion to their respective participation in the pool. Pooled business represents the predominant percentage of the net underwriting activity of both Donegal Mutual and Atlantic States. We refer to Note 3 - Transactions with Affiliates for more information regarding the pooling agreement. Basis of Consolidation Our consolidated financial statements, which we have prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), include our accounts and those of our wholly owned subsidiaries. We have eliminated all significant inter-company accounts and transactions in consolidation. The terms “we,” “us,” “our” or the “Company” as we use them in the notes to our consolidated financial statements refer to the consolidated entity. Use of Estimates In preparing our consolidated financial statements, our management makes estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the balance sheet and revenues and expenses for the period then ended. Actual results could differ significantly from those estimates. We make estimates and assumptions that could have a significant effect on amounts and disclosures we report in our consolidated financial statements. The most significant estimates relate to our insurance subsidiaries’ reserves for property and casualty insurance unpaid losses and loss expenses, valuation of investments and determination of other-than-temporary impairment of investment securities and our insurance subsidiaries’ policy acquisition costs. While we believe our estimates and the estimates of our insurance subsidiaries are appropriate, the ultimate amounts may differ from the estimates provided. We regularly review our methods for making these estimates as well as the continuing appropriateness of the estimated amounts, and we reflect any adjustment we consider necessary in our current results of operations. Reclassification We have made certain reclassifications in our prior period financial statements to conform to the current year presentation. Investments We classify our debt and equity securities into the following categories: Held to Maturity - Debt securities that we have the positive intent and ability to hold to maturity; reported at amortized cost. Available for Sale - Debt and equity securities not classified as held to maturity; reported at fair value, with unrealized gains and losses excluded from income and reported as a separate component of stockholders’ equity (net of tax effects). Short-term investments carried at amortized cost, which approximates fair value. We make estimates concerning the valuation of our investments and the recognition of other-than-temporary declines in the value of our investments. For equity securities, we write down the investment to its fair value and we reflect the amount of the write-down as a realized loss in our results of operations when we consider the decline in value of an individual investment to be other than temporary. We individually monitor all of our investments for other-than-temporary declines in value. Generally, we assume there has been an other-than-temporary decline in value if an individual equity security has depreciated in value by more than 20% of original cost and has been in such an unrealized loss position for more than six months. With respect to a debt security that is in an unrealized loss position, we first assess if we intend to sell the debt security. If we determine we intend to sell the debt security, we recognize the impairment loss in our results of operations. If we do not intend to sell the debt security, we determine whether it is more likely than not that we will be required to sell the debt security prior to recovery. If we determine it is more likely than not that we will be required to sell the debt security prior to recovery, we recognize an impairment loss in our results of operations. If we determine it is more likely than not that we will not be required to sell the debt security prior to recovery, we then evaluate whether a credit loss has occurred. We determine whether a credit loss has occurred by comparing the amortized cost of the debt security to the present value of the cash flows we expect to collect. If we expect a cash flow shortfall, we consider that a credit loss has occurred. If we determine that a credit loss has occurred, we consider the impairment to be other than temporary. We then recognize the amount of the impairment loss related to the credit loss in our results of operations, and we recognize the remaining portion of the impairment loss in our other comprehensive income, net of applicable taxes. In addition, we may write down securities in an unrealized loss position based on a number of other factors, including when the fair value of an investment is significantly below its cost, when the financial condition of the issuer of a security has deteriorated, the occurrence of industry, company or geographic events that have negatively impacted the value of a security and rating agency downgrades. We amortize premiums and discounts on debt securities over the life of the security as an adjustment to yield using the effective interest method. We compute realized investment gains and losses using the specific identification method. We amortize premiums and discounts for mortgage-backed debt securities using anticipated prepayments. We account for our investment in affiliate using the equity method of accounting. Under the equity method, we record our investment at cost, with adjustments for our share of the affiliate’s earnings and losses as well as changes in the affiliate’s equity due to unrealized gains and losses. Fair Values of Financial Instruments We use the following methods and assumptions in estimating our fair value disclosures: Investments - We present our investments in available-for-sale Cash and Short-Term Investments - The carrying amounts we report in the balance sheet for these instruments approximate their fair values. Premiums and Reinsurance Receivables and Payables - The carrying amounts we report in the balance sheet for these instruments related to premiums and paid losses and loss expenses approximate their fair values. Subordinated Debentures - The carrying amounts we report in the balance sheet for these instruments approximate their fair values. Revenue Recognition Our insurance subsidiaries recognize insurance premiums as income over the terms of the policies they issue. Our insurance subsidiaries calculate unearned premiums on a daily pro-rata Policy Acquisition Costs We defer our insurance subsidiaries’ policy acquisition costs, consisting primarily of commissions, premium taxes and certain other underwriting costs, reduced by ceding commissions, that vary with and relate directly to the production of business. We amortize these deferred policy acquisition costs over the period in which our insurance subsidiaries earn the premiums. The method we follow in computing deferred policy acquisition costs limits the amount of such deferred costs to their estimated realizable value, which gives effect to the premium to be earned, related investment income, losses and loss expenses and certain other costs we expect to incur as our insurance subsidiaries earn the premium. Estimates in the calculation of policy acquisition costs have not shown material variability because of uncertainties in applying accounting principles or as a result of sensitivities to changes in key assumptions. Property and Equipment We report property and equipment at depreciated cost that we compute using the straight-line method based upon estimated useful lives of the assets. Losses and Loss Expenses Liabilities for losses and loss expenses are estimates at a given point in time of the amounts an insurer expects to pay with respect to incurred policyholder claims based on facts and circumstances the insurer knows at that point in time. At the time of establishing its estimates, an insurer recognizes that its ultimate liability for losses and loss expenses will exceed or be less than such estimates. Our insurance subsidiaries base their estimates of liabilities for losses and loss expenses on assumptions as to future loss trends, expected claims severity, judicial theories of liability and other factors. However, during the loss adjustment period, our insurance subsidiaries may learn additional facts regarding individual claims, and, consequently, it often becomes necessary for our insurance subsidiaries to refine and adjust their estimates for these liabilities. We reflect any adjustments to the liabilities for losses and loss expenses of our insurance subsidiaries in our consolidated results of operations in the period in which our insurance subsidiaries make adjustments to their estimates. Our insurance subsidiaries maintain liabilities for the payment of losses and loss expenses with respect to both reported and unreported claims. Our insurance subsidiaries establish these liabilities for the purpose of covering the ultimate costs of settling all losses, including investigation and litigation costs. Our insurance subsidiaries base the amount of their liability for reported losses primarily upon a case-by-case Reserve estimates can change over time because of unexpected changes in assumptions related to our insurance subsidiaries’ external environment and, to a lesser extent, assumptions related to our insurance subsidiaries’ internal operations. For example, our insurance subsidiaries have experienced a decrease in claims frequency on workers’ compensation claims during the past several years while the severity of these claims has gradually increased. These trend changes give rise to greater uncertainty as to the pattern of future loss settlements on workers’ compensation claims. Related uncertainties regarding future trends include the cost of medical technologies and procedures and changes in the utilization of medical procedures. Assumptions related to our insurance subsidiaries’ external environment include the absence of significant changes in tort law and the legal environment that increase liability exposure, consistency in judicial interpretations of insurance coverage and policy provisions and the rate of loss cost inflation. Internal assumptions include consistency in the recording of premium and loss statistics, consistency in the recording of claims, payment and case reserving methodology, accurate measurement of the impact of rate changes and changes in policy provisions, consistency in the quality and characteristics of business written within a given line of business and consistency in reinsurance coverage and collectability of reinsured losses, among other items. To the extent our insurance subsidiaries determine that underlying factors impacting their assumptions have changed, our insurance subsidiaries make adjustments in their reserves that they consider appropriate for such changes. Accordingly, our insurance subsidiaries’ ultimate liability for unpaid losses and loss expenses will likely differ from the amount recorded. Our insurance subsidiaries seek to enhance their underwriting results by carefully selecting the product lines they underwrite. Our insurance subsidiaries’ personal lines products primarily include standard and preferred risks in private passenger automobile and homeowners lines. Our insurance subsidiaries’ commercial lines products primarily include business offices, wholesalers, service providers, contractors, artisans and light manufacturing operations. Our insurance subsidiaries have limited exposure to asbestos and other environmental liabilities. Our insurance subsidiaries write no medical malpractice liability risks. Income Taxes We currently file a consolidated federal income tax return. We account for income taxes using the asset and liability method. The objective of the asset and liability method is to establish deferred tax assets and liabilities for the temporary differences between the financial reporting basis and the tax basis of our assets and liabilities at enacted tax rates we expect to be in effect when we realize or settle such amounts. Credit Risk Our objective is to earn competitive returns by investing in a diversified portfolio of securities. Our portfolio of fixed maturity securities and, to a lesser extent, short-term investments is subject to credit risk. We define this risk as the potential loss in fair value resulting from adverse changes in the borrower’s ability to repay its debt to us. We manage this risk by performing an analysis of prospective investments and through regular reviews of our portfolio by our investment personnel. We also limit the amount of our total investment portfolio that we invest in any one security. Our insurance subsidiaries provide property and liability insurance coverages through independent insurance agencies located throughout their operating areas. Our insurance subsidiaries bill the majority of this business directly to their policyholders, although our insurance subsidiaries bill a portion of their commercial business through their agents, to whom they extend credit in the normal course of business. Our insurance subsidiaries have reinsurance agreements with Donegal Mutual and with a number of major unaffiliated reinsurers. Reinsurance Accounting and Reporting Our insurance subsidiaries rely upon reinsurance agreements to limit their maximum net loss from large single risks or risks in concentrated areas and to increase their capacity to write insurance. Reinsurance does not relieve our insurance subsidiaries from liability to their respective policyholders. To the extent that a reinsurer cannot pay losses for which it is liable under the terms of a reinsurance agreement with one or more of our insurance subsidiaries, our insurance subsidiaries retain continued liability for such losses. However, in an effort to reduce the risk of non-payment, A- A- Stock-Based Compensation We measure all share-based payments to our directors and the directors and employees of our subsidiaries and affiliates, including grants of stock options, using a fair-value-based method and record such expense in our results of operations. In determining the expense we record for stock options we grant to our directors and the directors and employees of our subsidiaries and affiliates, we estimate the fair value of each option award on the date of grant using the Black-Scholes option pricing model. The significant assumptions we utilize in applying the Black-Scholes option pricing model are the risk-free interest rate, expected term, dividend yield and expected volatility. In 2017, 2016 and 2015, we realized $873,515, $788,700 and $437,474, respectively, in tax benefits upon the exercise of stock options. Earnings Per Share We calculate basic earnings per share by dividing net income by the weighted-average number of common shares outstanding for the period. Diluted earnings per share reflects the dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock. We have two classes of common stock, which we refer to as Class A common stock and Class B common stock. Our Class A common stock is entitled to the declaration and payment of cash dividends that are at least 10% higher than those we declare and pay on our Class B common stock. Accordingly, we use the two-class two-class Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price over the underlying fair value of acquired entities. When completing acquisitions, we seek also to identify separately identifiable intangible assets that we have acquired. We assess goodwill and intangible assets with an indefinite useful life for impairment annually. We also assess goodwill and other intangible assets for impairment upon the occurrence of certain events. In making our assessment, we consider a number of factors including operating results, business plans, economic projections, anticipated future cash flows and current market data. Inherent uncertainties exist with respect to these factors and to our judgment in applying them when we make our assessment. Impairment of goodwill and other intangible assets could result from changes in economic and operating conditions in future periods.

Impact of New Accounting Standa

Impact of New Accounting Standards	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Standards	2 - Impact of New Accounting Standards In May 2014, the Financial Accounting Standards Board (the “FASB”) issued guidance that requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. While this guidance will replace most existing GAAP revenue recognition guidance, the scope of the guidance excludes insurance contracts. The new standard is effective on January 1, 2018. The standard permits the use of either the retrospective or the cumulative effect transition method. Because the accounting for insurance contracts is outside of the scope of the standard, the adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In January 2016, the FASB issued guidance that generally requires entities to measure equity investments at fair value and recognize changes in fair value in their results of operations. This guidance also simplifies the impairment assessment of equity investments without readily determinable fair values by requiring entities to perform a qualitative assessment to identify impairment. The FASB issued other disclosure and presentation improvements related to financial instruments within the guidance. The guidance is effective for annual and interim reporting periods beginning after December 15, 2017. As a result of this guidance, we will reflect changes in the fair value of our equity investments in our results of operations beginning January 1, 2018. In February 2016, the FASB issued guidance that requires lessees to recognize leases, including operating leases, on the lessee’s balance sheet, unless a lease is considered a short-term lease. This guidance also requires entities to make new judgments to identify leases. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018 and permits early adoption. We do not expect the adoption of this guidance to have a significant impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance that simplifies and improves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The guidance was effective for annual and interim reporting periods beginning after December 15, 2016. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In June 2016, the FASB issued guidance that amends previous guidance on the impairment of financial instruments by adding an impairment model that requires an entity to recognize expected credit losses as an allowance rather than impairments as credit losses are incurred. The intent of this guidance is to reduce complexity and result in a more timely recognition of expected credit losses. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. We do not expect the adoption of this guidance to have a significant impact on our financial position, results of operations or cash flows. In March 2017, the FASB issued guidance that amends previous guidance on the amortization period for certain purchased callable debt securities held at a premium. This new guidance shortens the amortization period to the earliest call date. The intent of the new guidance is to align interest income recognition with the expectations incorporated in the market pricing on the underlying securities. The new standard is effective for annual and interim reporting periods beginning after December 15, 2018, with early adoption permitted. We adopted this guidance effective January 1, 2017. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In February 2018, the FASB issued updated guidance that allows entities to reclassify the stranded tax effects in accumulated other comprehensive income (“AOCI”) resulting from the Tax Cuts and Jobs Act of 2017 (the “TCJA”) from AOCI to retained earnings. Current guidance requires entities to report the effect of a change in tax laws or tax rates on deferred tax balances in income from continuing operations in the accounting period that includes the period of enactment, even if the entities originally charged or credited related income tax effects directly to AOCI. If an entity elects to reclassify the stranded tax effects, the guidance requires the reclassification to include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, related to items in AOCI at the date of the enactment of TCJA. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018 and permits early adoption. We adopted this guidance effective on the December 22, 2017 date of the enactment of the TCJA. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows.

Transactions with Affiliates

Transactions with Affiliates	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Transactions with Affiliates	3 - Transactions with Affiliates Our insurance subsidiaries conduct business and have various agreements with Donegal Mutual that we describe in the following subparagraphs: a. Reinsurance Pooling and Other Reinsurance Arrangements Atlantic States, our largest insurance subsidiary, and Donegal Mutual have a pooling agreement under which both companies contribute substantially all of their direct written business to the pool and receive an allocated percentage of the pooled underwriting results, excluding certain reinsurance Donegal Mutual assumes from our insurance subsidiaries. Atlantic States has an 80% share of the results of the pool, and Donegal Mutual has a 20% share of the results of the pool. The intent of the pooling agreement is to produce more uniform and stable underwriting results from year to year for each pool participant than they would experience individually and to spread the risk of loss between the participants based on each participant’s relative amount of surplus and relative access to capital. Each participant in the pool has at its disposal the capacity of the entire pool, rather than being limited to policy exposures of a size commensurate with its own capital and surplus. The following amounts represent reinsurance Atlantic States ceded to the pool during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 200,752,599 $ 185,444,009 $ 170,418,931 Losses and loss expenses 140,015,950 115,371,839 115,029,244 Prepaid reinsurance premiums 103,991,861 95,469,329 87,780,338 Liability for losses and loss expenses 136,786,070 120,434,535 108,672,769 The following amounts represent reinsurance Atlantic States assumed from the pool during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 451,470,894 $ 422,985,921 $ 396,098,036 Losses and loss expenses 289,503,373 240,394,302 240,197,659 Unearned premiums 228,988,598 214,372,048 199,966,888 Liability for losses and loss expenses 252,263,547 230,543,393 216,194,945 Until February 1, 2016, Donegal Mutual and Le Mars had a quota-share reinsurance agreement under which Le Mars assumed 100% of the premiums and losses related to certain products Donegal Mutual offered in certain Midwestern states, which provided the availability of complementary products to Le Mars’ commercial accounts. Until October 31, 2012, Donegal Mutual and Southern had a quota-share reinsurance agreement whereby Southern assumed 100% of the premiums and losses related to personal lines products Donegal Mutual offered in Virginia through the use of its automated policy quoting and issuance system. The following amounts represent reinsurance Southern and Le Mars assumed from Donegal Mutual pursuant to the quota-share reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ (271 ) $ (1,512 ) $ 880,787 Losses and loss expenses (690,268 ) (378,199 ) 1,492,673 Unearned premiums — — — Liability for losses and loss expenses 827,193 3,222,100 5,722,000 Donegal Mutual and MICO have a quota-share reinsurance agreement under which Donegal Mutual assumes 25% of the premiums and losses related to the business of MICO. Donegal Mutual and Peninsula have a quota-share reinsurance agreement under which Donegal Mutual assumes 100% of the premiums and losses related to the workers’ compensation product line of Peninsula in certain states. The business Donegal Mutual assumes under the reinsurance agreements is subject to the pooling agreement between Donegal Mutual and Atlantic States. The following amounts represent reinsurance ceded to Donegal Mutual pursuant to these quota-share reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 42,578,047 $ 39,917,800 $ 37,299,760 Losses and loss expenses 24,978,631 21,524,856 19,735,479 Prepaid reinsurance premiums 19,827,115 19,180,421 17,172,112 Liability for losses and loss expenses 36,396,109 31,881,756 29,968,948 Atlantic States, Southern and Le Mars each have a catastrophe reinsurance agreement with Donegal Mutual that provides coverage under any one catastrophic occurrence above a set retention ($2,000,000, $1,500,000 and $750,000 for Atlantic States, Southern and Le Mars, respectively, for 2017, 2016 and 2015), with a combined retention of $4,000,000 for a catastrophe involving a combination of these subsidiaries, up to the amount Donegal Mutual and our insurance subsidiaries retain under catastrophe reinsurance agreements with unaffiliated reinsurers. Donegal Mutual and Southern have an excess of loss reinsurance agreement in which Donegal Mutual assumes up to $500,000 of Southern’s losses in excess of $500,000. The following amounts represent reinsurance that our insurance subsidiaries ceded to Donegal Mutual pursuant to these reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 17,215,273 $ 12,965,868 $ 14,235,227 Losses and loss expenses 8,953,411 995,076 6,814,836 Liability for losses and loss expenses 3,399,207 3,136,438 4,485,201 The following amounts represent the effect of affiliated reinsurance transactions on net premiums our insurance subsidiaries earned during 2017, 2016 and 2015: 2017 2016 2015 Assumed $ 451,470,623 $ 422,984,409 $ 396,978,823 Ceded (260,545,919 ) (238,327,677 ) (221,953,918 ) Net $ 190,924,704 $ 184,656,732 $ 175,024,905 The following amounts represent the effect of affiliated reinsurance transactions on net losses and loss expenses our insurance subsidiaries incurred during 2017, 2016 and 2015: 2017 2016 2015 Assumed $ 288,813,105 $ 240,016,103 $ 241,690,332 Ceded (173,947,992 ) (137,891,771 ) (141,579,559 ) Net $ 114,865,113 $ 102,124,332 $ 100,110,773 b. Expense Sharing Donegal Mutual provides facilities, management and other services to us and our insurance subsidiaries. Donegal Mutual allocates certain related expenses to Atlantic States in relation to the relative participation of Atlantic States and Donegal Mutual in the pooling agreement. Our insurance subsidiaries other than Atlantic States reimburse Donegal Mutual for their personnel costs and bear their proportionate share of information services costs based on their percentage of the total written premiums of the Donegal Insurance Group. Charges for these services totalled $124,999,770, $122,428,117 and $108,473,146 for 2017, 2016 and 2015, respectively. c. Lease Agreement We lease office equipment and automobiles with terms ranging from 3 to 10 years to Donegal Mutual under a 10-year d. Legal Services Donald H. Nikolaus, our Chairman of the Board and one of our directors, is a partner in the law firm of Nikolaus & Hohenadel. Such firm has served as our general counsel since 1986, principally in connection with the defense of claims litigation arising in Lancaster, Dauphin and York counties of Pennsylvania. We pay such firm its customary fees for such services. e. Union Community Bank At December 31, 2017 and 2016, we had $32,373,544 and $16,981,744, respectively, in checking accounts with UCB, a wholly owned subsidiary of DFSC. We earned $286,410, $87,941 and $3,317 in interest on these accounts during 2017, 2016 and 2015, respectively.

Investments

Investments	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Investments	4 - Investments The amortized cost and estimated fair values of our fixed maturities and equity securities at December 31, 2017 and 2016 are as follows: 2017 Amortized Cost Gross Gross Estimated Fair Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 71,736,445 $ 804,012 $ 546,868 $ 71,993,589 Obligations of states and political subdivisions 137,581,155 11,161,650 112,193 148,630,612 Corporate securities 108,024,776 2,860,255 730,843 110,154,188 Mortgage-backed securities 49,312,701 515,976 156,638 49,672,039 Totals $ 366,655,077 $ 15,341,893 $ 1,546,542 $ 380,450,428 2017 Amortized Cost Gross Gross Estimated Fair Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,759,456 $ 20,377 $ 730,409 $ 44,049,424 Obligations of states and political subdivisions 128,478,000 3,941,610 302,440 132,117,170 Corporate securities 105,254,120 1,010,744 525,445 105,739,419 Mortgage-backed securities 259,922,761 444,603 3,327,327 257,040,037 Fixed maturities 538,414,337 5,417,334 4,885,621 538,946,050 Equity securities 44,219,097 6,505,287 279,141 50,445,243 Totals $ 582,633,434 $ 11,922,621 $ 5,164,762 $ 589,391,293 2016 Amortized Cost Gross Gross Estimated Fair Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 61,381,605 $ 1,255,480 $ 674,371 $ 61,962,714 Obligations of states and political subdivisions 122,793,411 8,403,996 368,530 130,828,877 Corporate securities 91,555,136 1,172,002 1,678,133 91,049,005 Mortgage-backed securities 60,370,796 545,812 110,066 60,806,542 Totals $ 336,100,948 $ 11,377,290 $ 2,831,100 $ 344,647,138 2016 Amortized Cost Gross Gross Estimated Fair Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 39,093,734 $ 99,429 $ 605,139 $ 38,588,024 Obligations of states and political subdivisions 179,889,661 6,635,941 442,717 186,082,885 Corporate securities 87,715,049 662,132 921,362 87,455,819 Mortgage-backed securities 204,931,200 637,268 2,620,256 202,948,212 Fixed maturities 511,629,644 8,034,770 4,589,474 515,074,940 Equity securities 42,431,695 4,788,218 132,071 47,087,842 Totals $ 554,061,339 $ 12,822,988 $ 4,721,545 $ 562,162,782 At December 31, 2017, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $190.7 million and an amortized cost of $181.4 million. Our holdings also included special revenue bonds with an aggregate fair value of $90.0 million and an amortized cost of $84.7 million. With respect to both categories of bonds, we held no securities of any issuer that comprised more than 10% of that category at December 31, 2017. Education bonds and water and sewer utility bonds represented 53% and 26%, respectively, of our total investments in special revenue bonds based on their carrying values at December 31, 2017. Many of the issuers of the special revenue bonds we held at December 31, 2017 have the authority to impose ad valorem taxes. In that respect, many of the special revenue bonds we held are similar to general obligation bonds. At December 31, 2016, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $220.1 million and an amortized cost of $211.0 million. Our holdings also included special revenue bonds with an aggregate fair value of $96.8 million and an amortized cost of $91.7 million. With respect to both categories of bonds, we held no securities of any issuer that comprised more than 10% of that category at December 31, 2016. Education bonds and water and sewer utility bonds represented 62% and 23%, respectively, of our total investments in special revenue bonds based on their carrying values at December 31, 2016. Many of the issuers of the special revenue bonds we held at December 31, 2016 have the authority to impose ad valorem taxes. In that respect, many of the special revenue bonds we held are similar to general obligation bonds. We have segregated within accumulated other comprehensive loss the net unrealized losses of $15.1 million arising prior to the November 30, 2013 reclassification date for fixed maturities reclassified from available for sale to held to maturity. We will amortize this balance over the remaining life of the related securities as an adjustment of yield in a manner consistent with the accretion of discount on the same fixed maturities. During 2017, we recorded amortization of $1.2 million in accumulated other comprehensive income. At December 31, 2017 and 2016, net unrealized losses of $9.8 million and $11.0 million, respectively, remained within accumulated other comprehensive loss. We set forth below the amortized cost and estimated fair value of fixed maturities at December 31, 2017 by contractual maturity. 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. Amortized Cost Estimated Fair Value Held to maturity Due in one year or less $ 4,096,270 $ 4,090,120 Due after one year through five years 57,702,099 58,997,125 Due after five years through ten years 118,294,836 121,747,801 Due after ten years 137,249,171 145,943,343 Mortgage-backed securities 49,312,701 49,672,039 Total held to maturity $ 366,655,077 $ 380,450,428 Available for sale Due in one year or less $ 49,257,873 $ 49,729,548 Due after one year through five years 97,814,378 98,914,332 Due after five years through ten years 103,015,782 103,609,213 Due after ten years 28,403,543 29,652,920 Mortgage-backed securities 259,922,761 257,040,037 Total available for sale $ 538,414,337 $ 538,946,050 The amortized cost of fixed maturities on deposit with various regulatory authorities at December 31, 2017 and 2016 amounted to $9,646,390 and $9,632,126, respectively. Our investment in DFSC represented our 48.2% investment in the amount of $38,773,420 and $37,884,918 at December 31, 2017 and 2016, respectively. We account for our investment in DFSC using the equity method of accounting. Under this method, we record our investment at cost, with adjustments for our share of DFSC’s earnings and losses as well as changes in DFSC’s equity due to its unrealized gains and losses. We include our share of DFSC’s net income in our results of operations. We have compiled the following summary financial information for DFSC at December 31, 2017 and 2016 from the financial statements of DFSC. December 31, 2017 2016 Balance sheets: Total assets $ 567,935,408 $ 535,590,133 Total liabilities $ 487,603,999 $ 457,101,287 Stockholders’ equity 80,331,409 78,488,846 Total liabilities and stockholders’ equity $ 567,935,408 $ 535,590,133 Year Ended December 31, 2017 2016 2015 Income statements: Net income $ 3,362,861 $ 2,252,456 $ 2,372,650 Other comprehensive income (loss) in our statements of comprehensive income includes net unrealized gains (losses) of $112,053, ($103,331) and ($263,991) for 2017, 2016 and 2015, respectively, representing our share of DFSC’s unrealized investment gains or losses. We received distributions from DFSC of $1.0 million and $1.6 million during 2017 and 2016, respectively. Based on the nature of the activities that generated these distributions, we made an accounting policy election to classify these distributions as a return on our investment in DFSC. We derive net investment income, consisting primarily of interest and dividends, from the following sources: 2017 2016 2015 Fixed maturities $ 26,143,924 $ 25,066,582 $ 23,636,468 Equity securities 999,335 1,187,814 707,703 Short-term investments 407,580 115,763 181,154 Other 33,316 108,003 33,450 Investment income 27,584,155 26,478,162 24,558,775 Investment expenses (4,056,851 ) (3,845,432 ) (3,609,077 ) Net investment income $ 23,527,304 $ 22,632,730 $ 20,949,698 We present below gross realized gains and losses from investments, including those we classified as held to maturity, and the change in the difference between fair value and cost of investments: 2017 2016 2015 Gross realized gains: Fixed maturities $ 168,855 $ 2,161,108 $ 2,259,045 Equity securities 6,197,253 1,378,548 1,088,467 6,366,108 3,539,656 3,347,512 Gross realized losses: Fixed maturities 98,723 281,131 105,432 Equity securities 562,130 732,950 1,307,656 660,853 1,014,081 1,413,088 Net realized gains $ 5,705,255 $ 2,525,575 $ 1,934,424 Change in difference between fair value and cost of investments: Fixed maturities $ 2,335,578 $ (12,932,470 ) $ (10,787,772 ) Equity securities 1,569,999 3,160,356 659,597 Totals $ 3,905,577 $ (9,772,114 ) $ (10,128,175 ) We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2017 as follows: Less than 12 months 12 months or longer Fair Value Unrealized Losses Fair Value Unrealized U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 24,024,445 $ 286,518 $ 33,987,229 $ 990,759 Obligations of states and political subdivisions 10,223,383 120,076 14,127,415 294,557 Corporate securities 35,203,959 253,241 31,560,591 1,003,047 Mortgage-backed securities 100,533,516 817,315 124,061,502 2,666,650 Equity securities 4,291,875 279,141 — — Totals $ 174,277,178 $ 1,756,291 $ 203,736,737 $ 4,955,013 We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2016 as follows: Less than 12 months 12 months or longer Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 37,729,947 $ 1,279,510 $ — $ — Obligations of states and political subdivisions 40,739,099 802,311 710,280 8,936 Corporate securities 80,181,238 2,127,451 4,706,945 472,044 Mortgage-backed securities 168,771,543 2,727,720 416,828 2,602 Equity securities 5,420,875 132,071 — — Totals $ 332,842,702 $ 7,069,063 $ 5,834,053 $ 483,582 We make estimates concerning the valuation of our investments and the recognition of other-than-temporary declines in the value of our investments. For equity securities, we write down the investment to its fair value, and we reflect the amount of the write-down as a realized loss in our results of operations when we consider the decline in value of an individual investment to be other than temporary. We individually monitor all investments for other-than-temporary declines in value. Generally, we assume there has been an other-than-temporary decline in value if an individual equity security has depreciated in value by more than 20% of original cost and has been in such an unrealized loss position for more than six months. We held five equity securities that were in an unrealized loss position at December 31, 2017. Based upon our analysis of general market conditions and underlying factors impacting these equity securities, we considered these declines in value to be temporary. With respect to a debt security that is in an unrealized loss position, we first assess if we intend to sell the debt security. If we determine we intend to sell the debt security, we recognize the impairment loss in our results of operations. If we do not intend to sell the debt security, we determine whether it is more likely than not that we will be required to sell the debt security prior to recovery. If we determine it is more likely than not that we will be required to sell the debt security prior to recovery, we recognize an impairment loss in our results of operations. If we determine it is more likely than not that we will not be required to sell the debt security prior to recovery, we then evaluate whether a credit loss has occurred. We determine whether a credit loss has occurred by comparing the amortized cost of the debt security to the present value of the cash flows we expect to collect. If we expect a cash flow shortfall, we consider that a credit loss has occurred. If we determine that a credit loss has occurred, we consider the impairment to be other than temporary. We then recognize the amount of the impairment loss related to the credit loss in our results of operations, and we recognize the remaining portion of the impairment loss in our other comprehensive income, net of applicable taxes. In addition, we may write down securities in an unrealized loss position based on a number of other factors, including when the fair value of an investment is significantly below its cost, when the financial condition of the issuer of a security has deteriorated, the occurrence of industry, company or geographic events that have negatively impacted the value of a security and rating agency downgrades. We held 280 debt securities that were in an unrealized loss position at December 31, 2017. Based upon our analysis of general market conditions and underlying factors impacting these debt securities, we considered these declines in value to be temporary. We did not recognize any impairment losses in 2017, 2016 or 2015. We had no sales or transfers from our held to maturity portfolio in 2017, 2016 or 2015. We had no derivative instruments or hedging activities during 2017, 2016 or 2015.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	5 - Fair Value Measurements We account for financial assets using a framework that establishes a hierarchy that ranks the quality and reliability of inputs, or assumptions, used in the determination of fair value, and we classify financial assets and liabilities carried at fair value in one of the following three categories: Level 1 - quoted prices in active markets for identical assets and liabilities; Level 2 - directly or indirectly observable inputs other than Level 1 quoted prices; and Level 3 - unobservable inputs not corroborated by market data. For investments that have quoted market prices in active markets, we use the quoted market price as fair value and include these investments in Level 1 of the fair value hierarchy. We classify publicly traded equity securities as Level 1. When quoted market prices in active markets are not available, we base fair values on quoted market prices of comparable instruments or price estimates we obtain from independent pricing services. We classify our fixed maturity investments as Level 2. Our fixed maturity investments consist of U.S. Treasury securities and obligations of U.S. government corporations and agencies, obligations of states and political subdivisions, corporate securities and mortgage-backed securities. We present our investments in available-for-sale We present our cash and short-term investments at estimated fair value. The carrying values in our balance sheet for premium receivables and reinsurance receivables and payables for premiums and paid losses and loss expenses approximate their fair values. The carrying amounts reported in the balance sheet for our subordinated debentures and borrowings under lines of credit approximate their fair values. We classify these items as Level 3. We evaluate our assets and liabilities on a regular basis to determine the appropriate level at which to classify them for each reporting period. Based on our review of the methodology and summary of inputs the pricing services use, we have concluded that our Level 1 and Level 2 investments were classified properly at December 31, 2017 and 2016. The following table presents our fair value measurements for our investments in available-for-sale Fair Value Measurements Using Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,049,424 $ — $ 44,049,424 $ — Obligations of states and political subdivisions 132,117,170 — 132,117,170 — Corporate securities 105,739,419 — 105,739,419 — Mortgage-backed securities 257,040,037 — 257,040,037 — Equity securities 36,736,121 36,736,121 — — Total investments in the fair value hierarchy 575,682,171 36,736,121 538,946,050 — Investment measured at net asset value 13,709,122 — — — Totals $ 589,391,293 $ 36,736,121 $ 538,946,050 $ — The following table presents our fair value measurements for our investments in available-for-sale Fair Value Measurements Using Fair Value Quoted Prices in Significant Significant U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 38,588,024 $ — $ 38,588,024 $ — Obligations of states and political subdivisions 186,082,885 — 186,082,885 — Corporate securities 87,455,819 — 87,455,819 — Mortgage-backed securities 202,948,212 — 202,948,212 — Equity securities 35,922,337 35,922,337 — — Total investments in the fair value hierarchy 550,997,277 35,922,337 515,074,940 — Investment measured at net asset value 11,165,505 — — — Totals $ 562,162,782 $ 35,922,337 $ 515,074,940 $ —

Deferred Policy Acquisition Cos

Deferred Policy Acquisition Costs	12 Months Ended
	Dec. 31, 2017
Insurance [Abstract]
Deferred Policy Acquisition Costs	6 - Deferred Policy Acquisition Costs Changes in our insurance subsidiaries’ deferred policy acquisition costs are as follows: 2017 2016 2015 Balance, January 1 $ 56,309,196 $ 52,108,388 $ 48,298,608 Acquisition costs deferred 119,045,664 112,076,808 103,322,780 Amortization charged to earnings (115,065,000 ) (107,876,000 ) (99,513,000 ) Balance, December 31 $ 60,289,860 $ 56,309,196 $ 52,108,388

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	7 - Property and Equipment Property and equipment at December 31, 2017 and 2016 consisted of the following: 2017 2016 Estimated Useful Life Office equipment $ 9,918,045 $ 9,129,318 3-15 years Automobiles 779,357 1,334,385 5 years Real estate 7,971,590 7,685,228 5-50 Software 2,794,864 2,794,864 5 years 21,463,856 20,943,795 Accumulated depreciation (14,183,441 ) (14,275,306 ) $ 7,280,415 $ 6,668,489 Depreciation expense for 2017, 2016 and 2015 amounted to $478,800, $742,861 and $792,733, respectively.

Liability for Losses and Loss E

Liability for Losses and Loss Expenses	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Liability for Losses and Loss Expenses	8 - Liability for Losses and Loss Expenses The establishment of an appropriate liability for losses and loss expenses is an inherently uncertain process, and we can provide no assurance that our insurance subsidiaries’ ultimate liability will not exceed their loss and loss expense reserves and have an adverse effect on our results of operations and financial condition. Furthermore, we cannot predict the timing, frequency and extent of adjustments to our insurance subsidiaries’ estimated future liabilities, because the historical conditions and events that serve as a basis for our insurance subsidiaries’ estimates of ultimate claim costs may change. As is the case for substantially all property and casualty insurance companies, our insurance subsidiaries have found it necessary in the past to increase their estimated future liabilities for losses and loss expenses in certain periods, and, in other periods, their estimates have exceeded their actual liabilities. Changes in our insurance subsidiaries’ estimate of their liability for losses and loss expenses generally reflect actual payments and their evaluation of information received since the prior reporting date. We summarize activity in our insurance subsidiaries’ liability for losses and loss expenses as follows: 2017 2016 2015 Balance at January 1 $ 606,664,590 $ 578,205,109 $ 538,258,406 Less reinsurance recoverable (259,147,147 ) (256,150,860 ) (245,957,364 ) Net balance at January 1 347,517,443 322,054,249 292,301,042 Incurred related to: Current year 480,646,641 420,327,164 391,166,740 Prior years 6,621,413 2,988,739 7,200,134 Total incurred 487,268,054 423,315,903 398,366,874 Paid related to: Current year 288,379,600 248,106,788 236,834,666 Prior years 163,005,427 149,745,921 131,779,001 Total paid 451,385,027 397,852,709 368,613,667 Net balance at December 31 383,400,470 347,517,443 322,054,249 Plus reinsurance recoverable 293,271,257 259,147,147 256,150,860 Balance at December 31 $ 676,671,727 $ 606,664,590 $ 578,205,109 Our insurance subsidiaries recognized an increase in their liability for losses and loss expenses of prior years of $6.6 million, $3.0 million and $7.2 million in 2017, 2016 and 2015, respectively. Our insurance subsidiaries made no significant changes in their reserving philosophy, key reserving assumptions or claims management personnel, and they have made no significant offsetting changes in estimates that increased or decreased their loss and loss expense reserves in those years. The 2017 development represented 1.9% of the December 31, 2016 net carried reserves and resulted primarily from higher-than-expected severity in the commercial multiple peril, personal automobile and commercial automobile lines of business, offset by lower-than-expected severity in the workers’ compensation line of business, in accident years prior to 2017. The majority of the 2017 development related to increases in the liability for losses and loss expenses of prior years for Atlantic States and Peninsula. The 2016 development represented 0.9% of the December 31, 2015 net carried reserves and resulted primarily from higher-than-expected severity in the commercial multiple peril and commercial automobile liability lines of business, offset by lower-than-expected severity in the workers’ compensation line of business, in accident years prior to 2016. The majority of the 2016 development related to increases in the liability for losses and loss expenses of prior years for Atlantic States and Southern. The 2015 development represented 2.5% of the December 31, 2014 net carried reserves and resulted primarily from higher-than-expected severity in the private passenger automobile liability, commercial multiple peril and commercial automobile lines of business in accident years prior to 2015. The majority of the 2015 development related to increases in the liability for losses and loss expenses of prior years for Atlantic States and Southern. Short-duration contracts are contracts for which our insurance subsidiaries receive premiums that they recognize as revenue over the period of the contract in proportion to the amount of insurance protection our insurance subsidiaries provide. Our insurance subsidiaries consider the policies they issue to be short-duration contracts. We consider our insurance subsidiaries’ material lines of business to be personal automobile, homeowners, commercial automobile, commercial multi-peril and workers’ compensation. Our insurance subsidiaries determine incurred but not reported (“IBNR”) reserves by subtracting the cumulative loss and loss expense amounts our insurance subsidiaries have paid and the case reserves our insurance subsidiaries have established at the balance sheet date from their actuaries’ estimate of the ultimate cost of losses and loss expenses. Accordingly, our insurance subsidiaries’ IBNR reserves include their actuaries’ projections of the cost of unreported claims as well as their actuaries’ projected development of case reserves on known claims and reopened claims. Our insurance subsidiaries’ methodology for estimating IBNR reserves has been in place for many years, and their actuaries made no significant changes to that methodology during 2017. The actuaries for our insurance subsidiaries generally prepare an initial estimate for ultimate losses and loss expenses for the current accident year by multiplying earned premium by an expected loss ratio for each line of business our insurance subsidiaries write. Expected loss ratios represent the actuaries’ expectation of losses at the time our insurance subsidiaries price and write their policies, before the emergence of any actual claims experience. The actuaries determine an expected loss ratio by analyzing historical experience and adjusting for loss cost trends, loss frequency and severity trends, premium rate level changes, reported and paid loss emergence patterns and other known or observed factors. The actuaries use a variety of actuarial methods to estimate the ultimate cost of losses and loss expenses. These methods include paid loss development, incurred loss development and the Bornhuetter-Ferguson method. The actuaries base their selection of a point estimate on a judgmental weighting of estimates each of these methods produce. The actuaries consider loss frequency and severity trends when they develop expected loss ratios and point estimates. Loss frequency is a measure of the number of claims per unit of insured exposure, and loss severity is a measure of the average size of claims. Factors that affect loss frequency include changes in weather patterns or economic activity. Factors that affect loss severity include changes in policy limits, reinsurance retentions, inflation rates and judicial interpretations. Our insurance subsidiaries create a claim file when they receive notice of an actual demand for payment, an event that may lead to a demand for payment or when they otherwise determine that a demand for payment could potentially lead to a future demand for payment on another coverage under the same policy or another policy they have issued. In recent years, our insurance subsidiaries have noted an increase in the period of time between the occurrence of a casualty loss event and the date on which they receive notice of a liability claim. Changes in the length of time between the loss occurrence date and the claim reporting date affect the actuaries’ ability to accurately predict loss frequency and the amount of IBNR reserves our insurance subsidiaries require. Our insurance subsidiaries generally create a claim file for a policy at the claimant level by type of coverage and generally recognize one count for each claim event. In certain lines of business where it is common for multiple parties to claim damages arising from a single claim event, our insurance subsidiaries recognize one count for each claimant involved in the event. Atlantic States recognizes one count for each claim event, or claimant involved in a multiple-party claim event, related to losses Atlantic States assumes through its participation in its pooling agreement with Donegal Mutual. Our insurance subsidiaries accumulate the claim counts and report them by line of business. For purposes of the claim development tables we present below, our insurance subsidiaries count claims on policies they issue even if they eventually close such claims without making a loss payment. Claims our insurance subsidiaries close without making a loss payment typically generate loss expenses. The methods our insurance subsidiaries have used to summarize claim counts have not changed significantly over the time periods we report in the tables below. The following tables present information about incurred and paid claims development as of December 31, 2017, net of reinsurance, as well as cumulative claim frequency and the total of IBNR reserves plus expected development on reported claims that our insurance subsidiaries included within their net incurred claims amounts. The tables include unaudited information about incurred and paid claims development for the years ended December 31, 2008 through 2016, which we present as supplementary information. We present amounts retrospectively for MICO, which we acquired in December 2010, for all accident years prior to 2010. Personal Automobile At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 98,139 $ 101,937 $ 100,782 $ 101,388 $ 101,119 $ 100,819 $ 100,984 $ 100,923 $ 100,918 $ 100,915 $ 9 61 2009 105,707 106,313 106,841 107,589 107,190 106,705 106,549 106,499 106,713 15 65 2010 117,967 117,552 118,562 118,876 118,916 118,587 118,385 118,289 45 70 2011 127,929 131,678 132,987 133,229 133,617 133,218 133,145 97 74 2012 130,415 133,201 135,592 136,493 136,552 136,463 249 69 2013 124,965 130,737 131,594 132,643 132,604 438 66 2014 124,426 124,806 124,210 126,200 905 71 2015 137,569 139,334 139,181 2,713 70 2016 150,215 153,937 7,327 73 2017 166,690 26,640 77 Total $ 1,314,137 Personal Automobile Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 66,648 $ 85,262 $ 93,325 $ 97,134 $ 99,110 $ 100,153 $ 100,642 $ 100,712 $ 100,778 $ 100,790 2009 69,585 89,089 97,349 102,332 104,779 105,577 105,922 106,017 106,477 2010 75,889 96,749 107,662 113,243 116,748 117,812 117,978 118,054 2011 87,191 110,249 121,621 127,545 131,319 132,479 132,714 2012 87,517 111,941 124,652 130,862 133,428 134,581 2013 84,241 109,051 120,118 125,946 130,026 2014 85,377 104,736 114,893 120,491 2015 93,611 116,303 128,395 2016 102,433 129,507 2017 111,964 Total 1,212,999 All outstanding liabilities before 2008, net of reinsurance 540 Liabilities for claims and claims adjustment expenses, net of $ 101,678 Homeowners At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 40,989 $ 42,790 $ 42,944 $ 42,700 $ 42,839 $ 42,897 $ 42,862 $ 42,852 $ 42,844 $ 42,833 $ — 18 2009 51,054 50,621 50,333 49,998 50,137 50,405 50,419 50,433 50,435 — 18 2010 60,315 60,729 60,248 59,972 60,355 60,440 60,443 60,542 — 25 2011 71,256 70,461 70,436 70,381 70,297 70,351 70,479 (3 ) 27 2012 53,962 54,794 54,468 54,351 54,281 54,381 44 19 2013 50,887 51,121 51,122 50,874 50,988 47 13 2014 56,916 58,378 57,680 57,332 6 18 2015 63,359 63,925 63,053 157 14 2016 62,443 64,064 833 13 2017 79,283 4,166 17 Total $ 593,390 Homeowners Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 32,548 $ 40,037 $ 41,582 $ 42,095 $ 42,511 $ 42,699 $ 42,797 $ 42,817 $ 42,812 $ 42,833 2009 39,961 49,180 49,827 50,021 50,301 50,430 50,429 50,433 50,435 2010 47,419 57,334 59,283 59,875 60,239 60,486 60,501 60,525 2011 57,588 69,345 70,125 70,351 70,541 70,626 70,648 2012 46,566 53,619 54,028 54,298 54,317 54,356 2013 40,949 49,410 50,210 50,478 51,043 2014 45,823 56,255 56,990 57,195 2015 51,885 61,542 62,204 2016 50,125 61,145 2017 67,077 Total 577,461 All outstanding liabilities before 2008, net of 15 Liabilities for claims and claims adjustment expenses, $ 15,944 Commercial Automobile At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 18,164 $ 17,889 $ 17,719 $ 17,941 $ 17,960 $ 18,158 $ 18,063 $ 18,054 $ 18,051 $ 18,049 $ — 6 2009 18,735 18,549 18,998 19,015 19,346 19,569 19,430 19,461 19,449 3 6 2010 19,315 19,913 20,695 21,477 21,490 21,756 21,746 21,713 5 7 2011 26,642 27,157 28,570 28,893 29,112 29,107 29,487 1 9 2012 26,557 27,720 30,606 31,435 31,278 31,648 12 8 2013 32,902 33,749 34,751 35,240 36,404 196 9 2014 42,760 44,544 47,326 48,213 747 11 2015 46,526 48,323 51,412 2,639 12 2016 54,302 57,353 4,793 13 2017 61,484 17,554 13 Total $ 375,212 Commercial Automobile Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 9,204 $ 12,330 $ 14,115 $ 16,077 $ 17,110 $ 17,548 $ 18,052 $ 18,051 $ 18,051 $ 18,049 2009 9,309 12,872 15,479 17,160 18,696 19,389 19,386 19,408 19,413 2010 10,778 14,180 16,426 19,030 20,804 21,014 21,482 21,549 2011 13,876 19,106 24,267 26,973 28,014 28,758 28,836 2012 13,642 20,240 23,718 27,417 29,873 30,402 2013 16,306 23,557 26,879 31,053 34,083 2014 22,707 31,089 39,436 44,374 2015 23,875 35,342 41,678 2016 27,033 38,237 2017 28,707 Total 305,328 All outstanding liabilities before 2008, net of 10 Liabilities for claims and claims adjustment expenses, $ 69,894 Commercial Multi-Peril At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 26,868 $ 27,693 $ 26,796 $ 26,906 $ 27,286 $ 27,023 $ 27,182 $ 27,258 $ 27,184 $ 26,998 $ — 5 2009 26,712 26,454 27,357 27,357 27,739 27,959 27,625 27,484 27,508 — 6 2010 28,745 29,656 29,390 29,169 29,373 29,453 29,463 29,779 — 6 2011 33,054 35,411 35,942 37,576 37,385 38,270 38,105 13 7 2012 29,789 30,716 32,449 34,117 35,755 36,214 33 6 2013 35,683 35,679 37,292 37,205 37,981 155 6 2014 48,204 50,135 51,843 52,336 608 7 2015 42,070 43,874 44,728 3,028 6 2016 43,005 46,988 4,991 6 2017 56,185 13,847 6 Total $ 396,822 Commercial Multi-Peril Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 16,128 $ 21,645 $ 22,991 $ 24,161 $ 25,154 $ 25,983 $ 26,760 $ 26,956 $ 27,017 $ 26,996 2009 13,675 19,356 21,560 24,977 26,212 26,780 27,287 27,357 27,409 2010 17,007 22,017 24,749 26,832 27,768 28,681 28,906 29,632 2011 18,773 24,767 30,286 33,526 36,722 37,759 38,240 2012 16,666 23,384 26,634 29,370 33,327 35,331 2013 19,875 26,216 29,159 33,614 35,104 2014 27,920 35,520 40,936 47,021 2015 21,837 29,419 34,323 2016 19,660 29,402 2017 27,399 Total 330,857 All outstanding liabilities before 2008, net of reinsurance 266 Liabilities for claims and claims adjustment expenses, net of reinsurance $ 66,231 Workers’ Compensation At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 24,034 $ 26,361 $ 27,037 $ 26,791 $ 26,471 $ 26,226 $ 25,941 $ 25,963 $ 25,713 $ 25,797 $ 61 5 2009 21,571 22,497 21,894 21,826 22,848 22,278 22,172 22,114 22,079 65 4 2010 27,304 27,859 27,010 26,637 26,944 27,121 27,037 26,984 98 5 2011 32,490 35,757 36,614 36,369 35,670 35,039 35,194 138 6 2012 39,142 39,516 38,827 37,926 37,163 36,468 211 6 2013 46,325 47,027 44,289 42,828 42,327 447 6 2014 51,508 51,553 49,288 48,537 996 6 2015 53,332 49,615 45,991 2,470 6 2016 58,814 49,802 6,741 6 2017 60,450 21,116 6 Total $ 393,629 Workers’ Compensation Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 6,562 $ 14,776 $ 19,199 $ 21,933 $ 23,782 $ 24,551 $ 24,880 $ 25,017 $ 25,112 $ 25,250 2009 6,490 12,627 16,516 18,329 19,665 20,476 20,939 21,117 21,400 2010 8,066 15,937 21,176 23,137 24,539 25,337 25,804 26,050 2011 9,157 21,450 27,517 31,905 32,394 33,067 33,577 2012 11,097 22,963 28,812 31,244 33,196 34,177 2013 13,052 26,043 32,783 36,351 38,877 2014 13,932 28,513 36,284 40,393 2015 13,071 27,531 34,192 2016 14,709 30,344 2017 15,581 Total 299,841 All outstanding liabilities before 2008, net of 3,445 Liabilities for claims and claims adjustment expenses, $ 97,233 The following table presents a reconciliation of the net incurred and paid claims development tables to the liability for claims and claims adjustment expenses in our consolidated balance sheet: (in thousands) At December 31, Net outstanding liabilities: Personal automobile $ 101,678 Homeowners 15,944 Commercial automobile 69,894 Commercial multi-peril 66,231 Workers ’ 97,233 Other 5,404 356,384 Reinsurance recoverable: Personal automobile $ 94,091 Homeowners 11,465 Commercial automobile 45,201 Commercial multi-peril 40,685 Workers ’ 85,528 Other 3,831 280,801 Unallocated loss adjustment expenses $ 39,487 Gross liability for unpaid losses and loss expenses $ 676,672 The following table presents supplementary information about average historical claims duration as of December 31, 2017: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 8 9 10 Personal automobile 65.7 % 17.5 % 8.5 % 4.4 % 2.5 % 0.9 % 0.3 % 0.1 % 0.2 % — % Homeowners 80.6 16.6 1.7 0.6 0.6 0.3 0.1 — — — Commercial automobile 47.1 18.8 12.6 10.6 6.9 2.2 1.3 0.1 — — Commercial multi-peril 50.7 17.9 9.3 9.0 5.8 3.3 1.7 1.1 0.2 — Workers’ compensation 28.4 31.1 16.7 8.9 5.2 2.8 1.6 0.7 0.8 0.5

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Borrowings	9 - Borrowings Lines of Credit In July 2017, we renewed our existing credit agreement with Manufacturers and Traders Trust Company (“M&T”) relating to a $60.0 million unsecured, revolving line of credit. The line of credit now expires in July 2020. We have the right to extend the term of the credit agreement for one year as of each anniversary date of the agreement. At December 31, 2017, we had $24.0 million in outstanding borrowings and had the ability to borrow an additional $36.0 million at interest rates equal to M&T’s current prime rate or the then-current LIBOR rate plus 2.25%. The interest rate on our outstanding borrowings is adjustable quarterly. At December 31, 2017, the interest rate on our outstanding borrowings was 3.82%. We pay a fee of 0.25% per annum on the loan commitment amount regardless of usage. The credit agreement requires our compliance with certain covenants. These covenants include minimum levels of our net worth, leverage ratio, statutory surplus and the A.M. Best ratings of our insurance subsidiaries. We complied with all requirements of the credit agreement during 2017. MICO has an agreement with the Federal Home Loan Bank (“FHLB”) of Indianapolis. Through its membership, MICO has the ability to issue debt to the FHLB of Indianapolis in exchange for cash advances. There were no outstanding borrowings at December 31, 2017 or 2016. The table below presents the amount of FHLB of Indianapolis stock MICO purchased, collateral pledged and assets related to MICO’s agreement at December 31, 2017. FHLB stock purchased and owned as part of the agreement $ 267,700 Collateral pledged, at par (carrying value $2,751,398) 2,850,000 Borrowing capacity currently available 2,592,075 Atlantic States is a member of the FHLB of Pittsburgh. Through its membership, Atlantic States has the ability to issue debt to the FHLB of Pittsburgh in exchange for cash advances. Atlantic States had $35.0 million in outstanding advances at December 31, 2017. The interest rate on the advances was 1.25% at December 31, 2017. The table below presents the amount of FHLB of Pittsburgh stock Atlantic States purchased, collateral pledged and assets related to Atlantic States’ membership in the FHLB of Pittsburgh at December 31, 2017. FHLB stock purchased and owned as part of the agreement $ 1,599,700 Collateral pledged, at par (carrying value $36,850,815) 37,322,954 Borrowing capacity currently available 576,324 Subordinated Debentures In January 2002, West Bend purchased a surplus note from MICO for $5.0 million to increase MICO’s statutory surplus. On December 1, 2010, Donegal Mutual purchased the surplus note from West Bend at face value. The surplus note carries an interest rate of 5.00%, and any repayment of principal or interest requires prior insurance regulatory approval. Upon receipt of regulatory approval, MICO paid $250,000 in interest to Donegal Mutual during each of 2017, 2016 and 2015.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2017
Insurance [Abstract]
Reinsurance	10 - Reinsurance Unaffiliated Reinsurers Our insurance subsidiaries and Donegal Mutual purchase certain third-party reinsurance on a combined basis. Le Mars, MICO, Peninsula and Sheboygan also have separate third-party reinsurance programs that provide certain coverage that is commensurate with their relative size and exposures. Our insurance subsidiaries use several different reinsurers, all of which, consistent with the requirements of our insurance subsidiaries and Donegal Mutual, have an A.M. Best rating of A- A- rating Through December 1, 2010, MICO and West Bend Mutual Insurance Company (“West Bend”) were parties to quota-share reinsurance agreements whereby MICO ceded 75% of its business to West Bend. MICO and West Bend agreed to terminate the reinsurance agreement in effect at November 30, 2010 on a run-off For policies effective through December 31, 2014, MICO maintained a quota-share reinsurance agreement with third-party reinsurers to reduce its net exposures. Effective January 1, 2015, MICO no longer maintains a quota-share reinsurance agreement with third-party reinsurers. The following amounts represent ceded reinsurance transactions with unaffiliated reinsurers during 2017, 2016 and 2015: 2017 2016 2015 Premiums written $ 51,241,267 $ 45,354,233 $ 40,997,351 Premiums earned 49,633,348 44,318,542 49,758,371 Losses and loss expenses 44,575,268 18,588,114 30,722,807 Prepaid reinsurance premiums 11,213,665 9,605,746 8,570,055 Liability for losses and loss expenses 116,689,871 103,694,418 113,023,942 Total Reinsurance The following amounts represent total ceded reinsurance transactions with both affiliated and unaffiliated reinsurers during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 310,179,267 $ 282,646,219 $ 271,712,289 Losses and loss expenses 218,523,260 156,479,885 172,302,366 Prepaid reinsurance premiums 135,032,641 124,255,495 113,522,505 Liability for losses and loss expenses 293,271,257 259,147,147 256,150,860 The following amounts represent the effect of reinsurance on premiums written for 2017, 2016 and 2015: 2017 2016 2015 Direct $ 584,007,351 $ 537,880,237 $ 492,073,587 Assumed 466,087,983 437,532,812 406,126,275 Ceded (320,956,412 ) (293,379,217 ) (269,363,012 ) Net premiums written $ 729,138,922 $ 682,033,832 $ 628,836,850 The following amounts represent the effect of reinsurance on premiums earned for 2017, 2016 and 2015: 2017 2016 2015 Direct $ 561,178,447 $ 515,721,745 $ 480,210,534 Assumed 451,515,575 423,129,271 397,142,483 Ceded (310,179,267 ) (282,646,219 ) (271,712,289 ) Net premiums earned $ 702,514,755 $ 656,204,797 $ 605,640,728 Percentage of assumed premiums earned to net premiums earned 64.3 % 64.5 % 65.6 %

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	11 - Income Taxes On December 22, 2017, TCJA was signed into law. The TCJA contains significant changes to corporate taxation, including the reduction of the corporate income tax rate to 21%, the acceleration of expensing for certain business assets, the one-time The key impacts of the TCJA on our financial statements for 2017 were the revaluation of our deferred tax balances to the new corporate tax rate that resulted in additional tax expense of $4.8 million and the reclassification of an alternative minimum tax credit carryforward of $8.5 million from net deferred tax assets to federal income taxes recoverable. We will recover the alternative minimum tax credit carryforward over the next three years. While we cannot reasonably estimate the impact of the TCJA on our consolidated financial results for 2018 and subsequent years, we generally expect the reduction of the corporate income tax rate to reduce our effective tax rate and income tax expense beginning in 2018. Our provision for income tax for 2017, 2016 and 2015 consisted of the following: 2017 2016 2015 Current $ (2,139,061 ) $ 8,496,405 $ 5,621,367 Deferred 7,137,423 2,030,865 980,868 Federal income tax provision $ 4,998,362 $ 10,527,270 $ 6,602,235 Our effective tax rate is different from the amount computed at the statutory federal rate of 35% for 2017, 2016 and 2015. The reasons for such difference and the related tax effects are as follows: 2017 2016 2015 Income before income taxes $ 12,114,462 $ 41,328,407 $ 27,592,268 Computed “expected” taxes 4,240,062 14,464,942 9,657,294 Tax-exempt (3,241,530 ) (3,951,926 ) (4,806,855 ) Proration 518,948 629,697 737,644 Effect of tax reform 4,752,547 — — Dividends received deduction (508,409 ) (691,616 ) (701,658 ) Tax benefit on exercise of options (873,515 ) — — Other, net 110,259 76,173 1,715,810 Federal income tax provision $ 4,998,362 $ 10,527,270 $ 6,602,235 The tax effects of temporary differences that give rise to significant portions of our deferred tax assets and deferred tax liabilities at December 31, 2017 and 2016 are as follows: 2017 2016 Deferred tax assets: Unearned premium $ 15,511,854 $ 23,964,558 Loss reserves 4,164,246 6,460,683 Net operating loss carryforward - Le Mars 683,979 1,271,411 Alternative minimum tax credit carryforward — 7,357,733 Net state operating loss carryforward - DGI Parent 77,132,006 72,049,234 Net unrealized losses 713,549 1,213,836 Other 2,300,595 3,307,286 Total gross deferred tax assets 100,506,229 115,624,741 Less valuation allowance (77,396,473 ) (72,490,012 ) Net deferred tax assets 23,109,756 43,134,729 Deferred tax liabilities: Deferred policy acquisition costs 12,660,871 19,708,220 Other 3,320,042 4,383,096 Total gross deferred tax liabilities 15,980,913 24,091,316 Net deferred tax asset $ 7,128,843 $ 19,043,413 We provide a valuation allowance when we believe it is more likely than not that we will not realize some portion of a deferred tax asset. At December 31, 2017 and 2016, we established a valuation allowance of $264,467 and $440,778, respectively, related to a portion of the net operating loss carryforward of Le Mars that we acquired on January 1, 2004 and a valuation allowance of $77.1 million and $72.0 million, respectively, for the net state operating loss carryforward of DGI. We determined that we were not required to establish a valuation allowance for the other net deferred tax assets of $23.1 million and $43.1 million at December 31, 2017 and 2016, respectively, since it is more likely than not that we will realize these deferred tax assets through reversals of existing temporary differences, future taxable income and our implementation of tax-planning Tax years 2014 through 2017 remained open for examination by tax authorities at December 31, 2017. The net operating loss carryforward of $3.3 million of Le Mars will begin to expire in 2020 if not utilized and is subject to an annual limitation of approximately $376,000.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	12 - Stockholders’ Equity Each share of our Class A common stock outstanding at the time of the declaration of any dividend or other distribution payable in cash upon the shares of our Class B common stock is entitled to a dividend or distribution payable at the same time and to stockholders of record on the same date in an amount at least 10% greater than any dividend declared upon each share of our Class B common stock. In the event of our merger or consolidation with or into another entity, the holders of our Class A common stock and the holders of our Class B common stock are entitled to receive the same per share consideration in such merger or consolidation. In the event of our liquidation, dissolution or winding-up, pro-rata On July 18, 2013, our board of directors authorized a share repurchase program pursuant to which we have the authority to purchase up to 500,000 additional shares of our Class A common stock at prices prevailing from time to time in the open market subject to the provisions of the SEC Rule 10b-18 On December 18, 2015, we and Donegal Mutual entered into a Stock Purchase and Standstill Agreement (the “Purchase Agreement”) with Gregory M. Shepard (“Mr. Shepard”). Under the terms of the Purchase Agreement, we purchased 2,000,000 shares of our Class A common stock from Mr. Shepard on December 22, 2015 for a price of $33.0 million, or $16.50 per share, representing a premium of approximately $5.8 million from the market price of our Class A common stock on the date of the Purchase Agreement. We reported this premium in excess of the market price as an expense in our consolidated statements of income and comprehensive income for 2015 that we include in this Form 10-K At December 31, 2017 and 2016, our treasury stock consisted of 3,002,588 and 72,465 shares of Class A common stock and Class B common stock, respectively.

Stock Compensation Plans

Stock Compensation Plans	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Stock Compensation Plans	13 - Stock Compensation Plans Equity Incentive Plans Since 1996, we have maintained an Equity Incentive Plan for Employees. During 2015, we adopted a plan that made a total of 4,500,000 shares of Class A common stock available for issuance to employees of our subsidiaries and affiliates. The plan provides for the granting of awards by our board of directors in the form of stock options, stock appreciation rights, restricted stock or any combination of the above. The plan provides that stock options may become exercisable up to five years from their date of grant, with an option price not less than fair market value on the date preceding the date of grant. We have not granted any stock appreciation rights. Since 1996, we have maintained an Equity Incentive Plan for Directors. During 2015, we adopted a plan that made 500,000 shares of Class A common stock available for issuance to our directors and the directors of our subsidiaries and affiliates.We may make awards in the form of stock options. The plan also provides for the issuance of 500 shares of restricted stock on the first business day of January in each year to each of our directors and each director of Donegal Mutual who does not serve as one of our directors. We issued 9,000 shares of restricted stock on January 3, 2017 under our director plan. We issued 8,500 shares of restricted stock on January 4, 2016 under our director plan. We issued 7,200 shares of restricted stock on January 2, 2015 under our director plan. We measure all share-based payments to employees, including grants of employee stock options, using a fair-value-based method and record such expense in our results of operations. In determining the expense we record for stock options granted to directors and employees of our subsidiaries and affiliates, we estimate the fair value of each option award on the date of grant using the Black-Scholes option pricing model. The significant assumptions we utilize in applying the Black-Scholes option pricing model are the risk-free interest rate, expected term, dividend yield and expected volatility. The risk-free interest rate is the implied yield currently available on U.S. Treasury zero coupon issues with a remaining term equal to the expected term used as the assumption in the model. We base the expected term of an option award on our historical experience for similar awards. We determine the dividend yield by dividing the per share dividend by the grant date stock price. We base the expected volatility on the volatility of our stock price over a historical period comparable to the expected term. The weighted-average grant date fair value of options we granted during 2017 was $1.81. We calculated this fair value based upon a risk-free interest rate of 2.01%, an expected life of three years, an expected volatility of 19% and an expected dividend yield of 3%. The weighted-average grant date fair value of options we granted during 2016 was $1.94. We calculated this fair value based upon a risk-free interest rate of 2.23%, an expected life of three years, an expected volatility of 20% and an expected dividend yield of 3%. The weighted-average grant date fair value of options we granted during 2015 was $1.55. We calculated this fair value based upon a risk-free interest rate of 1.86%, an expected life of three years, an expected volatility of 23% and an expected dividend yield of 4%. We charged compensation expense for our stock compensation plans against income before income taxes of $2.0 million, $2.5 million and $2.6 million for the years ended December 31, 2017, 2016 and 2015, respectively, with a corresponding income tax benefit of $692,164, $864,210 and $896,753. At December 31, 2017 and 2016, our total unrecognized compensation cost related to non-vested During 2017, we received cash from option exercises under all stock compensation plans of $13.4 million. We realized actual tax benefits for the tax deductions from option exercises of share-based compensation of $873,515 for 2017. During 2016, we received cash from option exercises under all stock compensation plans of $11.2 million. We realized actual tax benefits for the tax deductions from option exercises of share-based compensation of $788,700 for 2016. During 2015, we received cash from option exercises under all stock compensation plans of $13.7 million. We realized actual tax benefits for the tax deductions from option exercises of share-based compensation of $437,474 for 2015. No further shares are available for future option grants for plans in effect prior to 2015. Information regarding activity in our stock option plans follows: Number of Weighted- Outstanding at December 31, 2014 8,183,430 $ 14.69 Granted - 2015 1,710,500 13.64 Exercised - 2015 (983,370 ) 13.91 Forfeited - 2015 (114,967 ) 15.30 Expired - 2015 (641 ) 14.00 Outstanding at December 31, 2015 8,794,952 14.57 Granted - 2016 1,417,500 16.44 Exercised - 2016 (832,467 ) 13.44 Forfeited - 2016 (41,337 ) 14.97 Outstanding at December 31, 2016 9,338,648 14.95 Granted - 2017 943,000 17.58 Exercised - 2017 (924,019 ) 14.45 Forfeited - 2017 (93,167 ) 15.43 Outstanding at December 31, 2017 9,264,462 $ 15.26 Exercisable at: December 31, 2015 5,250,338 $ 14.42 December 31, 2016 6,347,470 $ 14.77 December 31, 2017 6,946,677 $ 14.90 Shares available for future option grants at December 31, 2017 totaled 974,001 shares under all plans. The following table summarizes information about stock options outstanding at December 31, 2017: Grant Date Exercise Price Number of Weighted-Average Number of July 27, 2011 $ 12.50 1,027,606 4.0 years 1,027,606 December 20, 2012 14.50 1,062,319 5.0 years 1,062,319 December 19, 2013 15.90 2,102,006 6.0 years 2,102,006 December 18, 2014 15.80 1,362,415 7.0 years 1,362,415 December 17, 2015 13.64 1,404,174 3.0 years 936,022 December 15, 2016 16.48 1,368,942 4.0 years 456,309 December 21, 2017 17.60 937,000 5.0 years — Total 9,264,462 6,946,677 Employee Stock Purchase Plan Since 1996, we have maintained an Employee Stock Purchase Plan. During 2011, we adopted a plan that made 300,000 shares of our Class A common stock available for issuance. The plan extends over a 10-year A summary of plan activity follows: Shares Issued Price Shares January 1, 2015 $ 12.40 17,662 July 1, 2015 12.95 20,006 January 1, 2016 11.97 18,387 July 1, 2016 11.83 22,418 January 1, 2017 13.76 18,512 July 1, 2017 13.52 25,155 On January 1, 2018, we issued 20,662 shares at a price of $13.34 per share under this plan. Agency Stock Purchase Plan Since 1996, we have maintained an Agency Stock Purchase Plan. During 2015, we adopted a plan that made 350,000 shares of our Class A common stock available for issuance to agents of our insurance subsidiaries and Donegal Mutual. The plan permits an agent to invest up to $12,000 per subscription period (April 1 to September 30 and October 1 to March 31 of each year) under various methods. We issue stock at the end of each subscription period at a price equal to 90% of the average market price during the last ten trading days of each subscription period. During 2017, 2016 and 2015, we issued 104,418, 99,800 and 84,198 shares, respectively, under this plan. The expense we recognized under the plan was not material.

Statutory Net Income, Capital a

Statutory Net Income, Capital and Surplus and Dividend Restrictions	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Statutory Net Income, Capital and Surplus and Dividend Restrictions	14 - Statutory Net Income, Capital and Surplus and Dividend Restrictions The following table presents selected information, as filed with state insurance regulatory authorities, for our insurance subsidiaries as determined in accordance with accounting practices prescribed or permitted by such insurance regulatory authorities: 2017 2016 2015 Atlantic States: Statutory capital and surplus $ 223,170,835 $ 227,907,377 $ 207,636,824 Statutory unassigned surplus 161,760,924 167,872,138 149,257,062 Statutory net (loss) income (312,221 ) 15,750,876 13,352,784 Southern: Statutory capital and surplus 54,503,581 63,331,001 61,742,861 Statutory unassigned surplus 2,914,532 11,881,309 10,459,840 Statutory net (loss) income (3,375,434 ) 1,774,299 2,301,009 Le Mars: Statutory capital and surplus 23,434,801 25,543,803 26,168,865 Statutory unassigned surplus 10,394,533 12,614,756 13,367,321 Statutory net (loss) income (1,679,335 ) 603,226 (600,608 ) Peninsula: Statutory capital and surplus 39,396,818 41,977,034 41,838,137 Statutory unassigned surplus 21,148,253 23,826,681 23,813,003 Statutory net (loss) income (841,119 ) 966,391 1,976,093 Sheboygan: Statutory capital and surplus 13,823,118 13,129,143 13,254,117 Statutory unassigned surplus 554,498 914,773 1,107,421 Statutory net (loss) income (46,116 ) 644,344 1,719,703 MICO: Statutory capital and surplus 52,796,379 49,863,705 46,199,534 Statutory unassigned surplus 26,162,540 23,380,942 19,894,850 Statutory net income 7,931,774 7,187,213 3,562,536 Our principal source of cash for payment of dividends is dividends from our insurance subsidiaries. State insurance laws require our insurance subsidiaries to maintain certain minimum capital and surplus amounts on a statutory basis. Our insurance subsidiaries are subject to regulations that restrict the payment of dividends from statutory surplus and may require prior approval of their domiciliary insurance regulatory authorities. Our insurance subsidiaries are also subject to risk-based capital (“RBC”) requirements that may further impact their ability to pay dividends. Our insurance subsidiaries’ statutory capital and surplus at December 31, 2017 exceeded the amount of statutory capital and surplus necessary to satisfy regulatory requirements, including the RBC requirements, by a significant margin. Amounts available for distribution to us as dividends from our insurance subsidiaries without prior approval of insurance regulatory authorities in 2018 are $22.3 million from Atlantic States, $5.5 million from Southern, $2.3 million from Le Mars, $1.6 million from Peninsula, $0 from Sheboygan and $5.3 million from MICO, or a total of approximately $37.0 million.

Reconciliation of Statutory Fil

Reconciliation of Statutory Filings to Amounts Reported Herein	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Reconciliation of Statutory Filings to Amounts Reported Herein	15 - Reconciliation of Statutory Filings to Amounts Reported Herein Our insurance subsidiaries must file financial statements with state insurance regulatory authorities using accounting principles and practices prescribed or permitted by those authorities. We refer to these accounting principles and practices as statutory accounting principles (“SAP”). Accounting principles used to prepare these SAP financial statements differ from those used to prepare financial statements on the basis of GAAP. Reconciliations of statutory net income and capital and surplus, as determined using SAP, to the amounts included in the accompanying GAAP financial statements are as follows: Year Ended December 31, 2017 2016 2015 Statutory net income of insurance subsidiaries $ 1,677,549 $ 26,926,349 $ 22,311,517 Increases (decreases): Deferred policy acquisition costs 3,980,664 4,200,808 3,809,780 Deferred federal income taxes 1,334,410 (2,030,865 ) (168,395 ) Salvage and subrogation recoverable 1,199,200 1,502,600 1,082,800 Consolidating eliminations and adjustments (13,534,428 ) (12,327,517 ) (3,679,277 ) Parent-only net income (loss) 12,458,705 12,529,762 (2,366,392 ) Net income as reported herein $ 7,116,100 $ 30,801,137 $ 20,990,033 December 31, 2017 2016 2015 Statutory capital and surplus of insurance subsidiaries $ 407,125,532 $ 421,752,063 $ 396,840,338 Increases (decreases): Deferred policy acquisition costs 60,289,860 56,309,196 52,108,388 Deferred federal income taxes (14,422,511 ) (20,843,506 ) (16,930,202 ) Salvage and subrogation recoverable 17,976,600 16,777,400 15,274,800 Non-admitted 1,960,089 1,689,814 2,441,591 Fixed maturities (8,748,140 ) (7,271,932 ) 957,401 Parent-only equity and other adjustments (15,485,326 ) (29,797,715 ) (42,303,748 ) Stockholders’ equity as reported herein $ 448,696,104 $ 438,615,320 $ 408,388,568

Supplementary Cash Flow Informa

Supplementary Cash Flow Information	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Supplementary Cash Flow Information	16 - Supplementary Cash Flow Information The following table reflects net income taxes and interest we paid during 2017, 2016 and 2015: 2017 2016 2015 Income taxes $ 3,050,000 $ 7,305,000 $ 7,100,000 Interest 1,341,706 1,377,247 870,675

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	17 - Earnings Per Share We have two classes of common stock, which we refer to as Class A common stock and Class B common stock. Our Class A common stock is entitled to be paid cash dividends that are at least 10% higher than the cash dividends we pay on our Class B common stock. Accordingly, we use the two-class We present below a reconciliation of the numerators and denominators we used in the basic and diluted per share computations for our Class A common stock: Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic earnings per share: Numerator: Allocation of net income $ 5,879 $ 24,885 $ 17,155 Denominator: Weighted-average shares outstanding 21,799 20,917 22,046 Basic earnings per share $ 0.27 $ 1.19 $ 0.78 Diluted earnings per share: Numerator: Allocation of net income $ 5,879 $ 24,885 $ 17,155 Denominator: Number of shares used in basic computation 21,799 20,917 22,046 Weighted-average effect of dilutive securities Add: Director and employee stock options 843 613 348 Number of shares used in per share computations 22,642 21,530 22,394 Diluted earnings per share $ 0.26 $ 1.16 $ 0.77 We used the following information in the basic and diluted per share computations for our Class B common stock: Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic and diluted earnings per share: Numerator: Allocation of net income $ 1,237 $ 5,916 $ 3,835 Denominator: Weighted-average shares outstanding 5,577 5,577 5,577 Basic and diluted earnings per share $ 0.22 $ 1.06 $ 0.69 During 2017, we did not include options to purchase 937,000 shares of our Class A common stock in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of our Class A common stock.

Condensed Financial Information

Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company	18 - Condensed Financial Information of Parent Company Condensed Balance Sheets (in thousands) December 31, 2017 2016 Assets Investment in subsidiaries/affiliates (equity method) $ 509,011 $ 510,731 Short-term investments 29 30 Cash 3,237 1,820 Property and equipment 994 342 Other 1,479 1,010 Total assets $ 514,750 $ 513,933 Liabilities and Stockholders’ Equity Liabilities Cash dividends declared to stockholders $ 3,842 $ 3,623 Borrowings under lines of credit 59,000 69,000 Other 3,212 2,695 Total liabilities 66,054 75,318 Stockholders’ equity 448,696 438,615 Total liabilities and stockholders’ equity $ 514,750 $ 513,933 Condensed Statements of Income and Comprehensive Income (in thousands) Year Ended December 31, 2017 2016 2015 Statements of Income Revenues Dividends from subsidiaries $ 13,000 $ 13,000 $ 3,875 Other 2,131 1,759 2,028 Total revenues 15,131 14,759 5,903 Expenses Operating expenses 1,433 1,413 2,451 Premium paid on purchase of treasury stock — — 5,780 Interest 1,929 1,747 1,066 Total expenses 3,362 3,160 9,297 Income (loss) before income tax benefit and equity in undistributed net (loss) income of subsidiaries 11,769 11,599 (3,394 ) Income tax benefit 690 931 1,028 Income (loss) before equity in undistributed net (loss) income of subsidiaries 12,459 12,530 (2,366 ) Equity in undistributed net (loss) income of subsidiaries (5,343 ) 18,271 23,356 Net income $ 7,116 $ 30,801 $ 20,990 Statements of Comprehensive Income Net income $ 7,116 $ 30,801 $ 20,990 Other comprehensive income (loss), net of tax Unrealized gain (loss) - subsidiaries 46 (3,028 ) (4,579 ) Other comprehensive income (loss), net of tax 46 (3,028 ) (4,579 ) Comprehensive income $ 7,162 $ 27,773 $ 16,411 Condensed Statements of Cash Flows (in thousands) Year Ended December 31, 2017 2016 2015 Cash flows from operating activities: Net income $ 7,116 $ 30,801 $ 20,990 Adjustments: Equity in undistributed net (loss) income of subsidiaries 5,343 (18,271 ) (23,356 ) Other (401 ) (27 ) 539 Net adjustments 4,942 (18,298 ) (22,817 ) Net cash provided (used) 12,058 12,503 (1,827 ) Cash flows from investing activities: Net sale of short-term investments 1 2 498 Net purchase of property and equipment (788 ) (11 ) (23 ) Investment in subsidiaries (2,992 ) (2,393 ) (2,427 ) Other (1 ) — — Net cash used (3,780 ) (2,402 ) (1,952 ) Cash flows from financing activities: Cash dividends paid (14,821 ) (14,085 ) (14,454 ) Issuance of common stock 17,960 16,651 18,468 Payments on line of credit (10,000 ) (12,000 ) (9,500 ) Borrowings under lines of credit — — 37,000 Purchase of treasury stock — — (28,125 ) Net cash (used) provided (6,861 ) (9,434 ) 3,389 Net change in cash 1,417 667 (390 ) Cash at beginning of year 1,820 1,153 1,543 Cash at end of year $ 3,237 $ 1,820 $ 1,153

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information	19 - Segment Information We have four reportable segments, which consist of our investment function, our personal lines of insurance, our commercial lines of insurance and our investment in DFSC. Using independent agents, our insurance subsidiaries market personal lines of insurance to individuals and commercial lines of insurance to small and medium-sized We evaluate the performance of the personal lines and commercial lines primarily based upon our insurance subsidiaries’ underwriting results as determined under SAP for our total business. We do not allocate assets to the personal and commercial lines and review the two segments in total for purposes of decision-making. We operate only in the United States, and no single customer or agent provides 10 percent or more of our revenues. Financial data by segment is as follows: 2017 2016 2015 (in thousands) Revenues: Premiums earned: Commercial lines $ 318,391 $ 295,077 $ 261,286 Personal lines 384,124 361,128 344,355 GAAP premiums earned 702,515 656,205 605,641 Net investment income 23,527 22,633 20,950 Realized investment gains 5,705 2,526 1,934 Equity in earnings of DFSC 1,622 1,086 1,277 Other 5,658 5,973 6,585 Total revenues $ 739,027 $ 688,423 $ 636,387 2017 2016 2015 (in thousands) Income before income taxes: Underwriting (loss) income: Commercial lines $ 13,263 $ 18,284 $ 9,259 Personal lines (39,042 ) (10,745 ) (6,414 ) SAP underwriting (loss) income (25,779 ) 7,539 2,845 GAAP adjustments 4,408 4,642 3,344 GAAP underwriting (loss) income (21,371 ) 12,181 6,189 Net investment income 23,527 22,633 20,950 Realized investment gains 5,705 2,526 1,934 Equity in earnings of DFSC 1,622 1,086 1,277 Premium paid on purchase of treasury stock — — (5,780 ) Other 2,631 2,902 3,022 Income before income taxes $ 12,114 $ 41,328 $ 27,592

Guaranty Fund and Other Insuran

Guaranty Fund and Other Insurance-Related Assessments	12 Months Ended
	Dec. 31, 2017
Insurance [Abstract]
Guaranty Fund and Other Insurance-Related Assessments	20 - Guaranty Fund and Other Insurance-Related Assessments Our insurance subsidiaries’ liabilities for guaranty fund and other insurance-related assessments were $1.6 million and $1.5 million at December 31, 2017 and 2016, respectively. These liabilities included $562,799 and $447,620 related to surcharges collected by our insurance subsidiaries on behalf of regulatory authorities for 2017 and 2016, respectively.

Interim Financial Data

Interim Financial Data	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Interim Financial Data	21 - Interim Financial Data (unaudited) 2017 First Quarter Second Quarter Third Quarter Fourth Quarter Net premiums earned $ 169,156,147 $ 175,014,872 $ 177,283,816 $ 181,059,920 Total revenues 178,970,963 183,580,716 185,716,027 190,758,831 Net losses and loss expenses 114,433,458 128,005,914 114,386,379 130,442,303 Net income (loss) 5,104,818 (2,318,648 ) 7,108,574 (2,778,644 ) Net earnings (loss) per common share: Class A common stock - basic 0.19 (0.09 ) 0.27 (0.10 ) Class A common stock - diluted 0.18 (0.08 ) 0.26 (0.10 ) Class B common stock - basic and diluted 0.17 (0.08 ) 0.24 (0.11 ) 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Net premiums earned $ 158,475,279 $ 161,942,637 $ 166,809,851 $ 168,977,030 Total revenues 166,068,776 169,846,867 175,311,263 177,196,114 Net losses and loss expenses 95,578,065 103,193,915 111,174,963 113,368,960 Net income 11,848,913 8,584,654 4,813,404 5,554,166 Net earnings per common share: Class A common stock - basic 0.46 0.33 0.19 0.21 Class A common stock - diluted 0.46 0.32 0.18 0.20 Class B common stock - basic and diluted 0.42 0.30 0.16 0.18

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2017
Supplementary Insurance Information [Abstract]
Schedule III - Supplementary Insurance Information	DONEGAL GROUP INC. AND SUBSIDIARIES SCHEDULE III — SUPPLEMENTARY INSURANCE INFORMATION Years Ended December 31, 2017, 2016 and 2015 ($ in thousands) Segment Net Net Net Losses Amortization Other Net Year Ended December 31, 2017 Personal lines $ 384,124 $ — $ 289,924 $ 62,916 $ 63,721 $ 400,023 Commercial lines 318,391 — 197,344 52,149 52,817 329,116 Investments — 23,527 — — — — $ 702,515 $ 23,527 $ 487,268 $ 115,065 $ 116,538 $ 729,139 Year Ended December 31, 2016 Personal lines $ 361,128 $ — $ 247,323 $ 59,367 $ 59,688 $ 371,657 Commercial lines 295,077 — 175,993 48,509 48,771 310,377 Investments — 22,633 — — — — $ 656,205 $ 22,633 $ 423,316 $ 107,876 $ 108,459 $ 682,034 Year Ended December 31, 2015 Personal lines $ 344,355 $ — $ 235,717 $ 56,581 $ 55,556 $ 352,327 Commercial lines 261,286 — 162,650 42,932 42,154 276,510 Investments — 20,950 — — — — $ 605,641 $ 20,950 $ 398,367 $ 99,513 $ 97,710 $ 628,837 At December 31, Segment Deferred Liability Unearned Other Policy 2017 Personal lines $ 33,823 $ 239,542 $ 282,439 $ — Commercial lines 26,467 437,130 221,018 — Investments — — — — $ 60,290 $ 676,672 $ 503,457 $ — 2016 Personal lines $ 31,477 $ 217,793 $ 260,525 $ — Commercial lines 24,832 388,872 205,530 — Investments — — — — $ 56,309 $ 606,665 $ 466,055 $ —

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Organization and Business	Organization and Business Donegal Mutual Insurance Company (“Donegal Mutual”) organized us as an insurance holding company on August 26, 1986. Our insurance subsidiaries, Atlantic States Insurance Company (“Atlantic States”), Southern Insurance Company of Virginia (“Southern”), Le Mars Insurance Company (“Le Mars”), the Peninsula Insurance Group (“Peninsula”), which consists of Peninsula Indemnity Company and The Peninsula Insurance Company, Sheboygan Falls Insurance Company (“Sheboygan”) and Michigan Insurance Company (“MICO”), write personal and commercial lines of property and casualty coverages exclusively through a network of independent insurance agents in certain Mid-Atlantic, We have four segments: our investment function, our personal lines of insurance, our commercial lines of insurance and our investment in DFSC. The personal lines products of our insurance subsidiaries consist primarily of homeowners and private passenger automobile policies. The commercial lines products of our insurance subsidiaries consist primarily of commercial automobile, commercial multi-peril and workers’ compensation policies. At December 31, 2017, Donegal Mutual held approximately 44% of our outstanding Class A common stock and approximately 83% of our outstanding Class B common stock. This ownership provides Donegal Mutual with approximately 72% of the total voting power of our common stock. Our insurance subsidiaries and Donegal Mutual have interrelated operations due to a pooling agreement and other intercompany agreements and transactions. While each company maintains its separate corporate existence, our insurance subsidiaries and Donegal Mutual conduct business together as the Donegal Insurance Group. As such, Donegal Mutual and our insurance subsidiaries share the same business philosophy, the same management, the same employees and the same facilities and offer the same types of insurance products. Atlantic States, our largest subsidiary, participates in a pooling agreement with Donegal Mutual. Under the pooling agreement, the two companies pool their insurance business and each company receives an allocated percentage of the pooled business. Atlantic States has an 80% share of the results of the pooled business, and Donegal Mutual has a 20% share of the results of the pooled business. The same executive management and underwriting personnel administer products, classes of business underwritten, pricing practices and underwriting standards of Donegal Mutual and our insurance subsidiaries. In addition, as the Donegal Insurance Group, Donegal Mutual and our insurance subsidiaries share a combined business plan to achieve market penetration and underwriting profitability objectives. The products our insurance subsidiaries and Donegal Mutual market are generally complementary, thereby allowing the Donegal Insurance Group to offer a broader range of products to a given market and to expand the Donegal Insurance Group’s ability to service an entire personal lines or commercial lines account. Distinctions within the products of Donegal Mutual and our insurance subsidiaries generally relate to specific risk profiles targeted within similar classes of business, such as preferred tier versus standard tier products, but we do not allocate all of the standard risk gradients to one company. Therefore, the underwriting profitability of the business the individual companies write directly will vary. However, as the risk characteristics of all business Donegal Mutual and Atlantic States write directly are homogenized within the underwriting pool, Donegal Mutual and Atlantic States share the underwriting results in proportion to their respective participation in the pool. Pooled business represents the predominant percentage of the net underwriting activity of both Donegal Mutual and Atlantic States. We refer to Note 3 - Transactions with Affiliates for more information regarding the pooling agreement.
Basis of Consolidation	Basis of Consolidation Our consolidated financial statements, which we have prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), include our accounts and those of our wholly owned subsidiaries. We have eliminated all significant inter-company accounts and transactions in consolidation. The terms “we,” “us,” “our” or the “Company” as we use them in the notes to our consolidated financial statements refer to the consolidated entity.
Use of Estimates	Use of Estimates In preparing our consolidated financial statements, our management makes estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the balance sheet and revenues and expenses for the period then ended. Actual results could differ significantly from those estimates. We make estimates and assumptions that could have a significant effect on amounts and disclosures we report in our consolidated financial statements. The most significant estimates relate to our insurance subsidiaries’ reserves for property and casualty insurance unpaid losses and loss expenses, valuation of investments and determination of other-than-temporary impairment of investment securities and our insurance subsidiaries’ policy acquisition costs. While we believe our estimates and the estimates of our insurance subsidiaries are appropriate, the ultimate amounts may differ from the estimates provided. We regularly review our methods for making these estimates as well as the continuing appropriateness of the estimated amounts, and we reflect any adjustment we consider necessary in our current results of operations.
Reclassification	Reclassification We have made certain reclassifications in our prior period financial statements to conform to the current year presentation.
Investments	Investments We classify our debt and equity securities into the following categories: Held to Maturity - Debt securities that we have the positive intent and ability to hold to maturity; reported at amortized cost. Available for Sale - Debt and equity securities not classified as held to maturity; reported at fair value, with unrealized gains and losses excluded from income and reported as a separate component of stockholders’ equity (net of tax effects). Short-term investments carried at amortized cost, which approximates fair value. We make estimates concerning the valuation of our investments and the recognition of other-than-temporary declines in the value of our investments. For equity securities, we write down the investment to its fair value and we reflect the amount of the write-down as a realized loss in our results of operations when we consider the decline in value of an individual investment to be other than temporary. We individually monitor all of our investments for other-than-temporary declines in value. Generally, we assume there has been an other-than-temporary decline in value if an individual equity security has depreciated in value by more than 20% of original cost and has been in such an unrealized loss position for more than six months. With respect to a debt security that is in an unrealized loss position, we first assess if we intend to sell the debt security. If we determine we intend to sell the debt security, we recognize the impairment loss in our results of operations. If we do not intend to sell the debt security, we determine whether it is more likely than not that we will be required to sell the debt security prior to recovery. If we determine it is more likely than not that we will be required to sell the debt security prior to recovery, we recognize an impairment loss in our results of operations. If we determine it is more likely than not that we will not be required to sell the debt security prior to recovery, we then evaluate whether a credit loss has occurred. We determine whether a credit loss has occurred by comparing the amortized cost of the debt security to the present value of the cash flows we expect to collect. If we expect a cash flow shortfall, we consider that a credit loss has occurred. If we determine that a credit loss has occurred, we consider the impairment to be other than temporary. We then recognize the amount of the impairment loss related to the credit loss in our results of operations, and we recognize the remaining portion of the impairment loss in our other comprehensive income, net of applicable taxes. In addition, we may write down securities in an unrealized loss position based on a number of other factors, including when the fair value of an investment is significantly below its cost, when the financial condition of the issuer of a security has deteriorated, the occurrence of industry, company or geographic events that have negatively impacted the value of a security and rating agency downgrades. We amortize premiums and discounts on debt securities over the life of the security as an adjustment to yield using the effective interest method. We compute realized investment gains and losses using the specific identification method. We amortize premiums and discounts for mortgage-backed debt securities using anticipated prepayments. We account for our investment in affiliate using the equity method of accounting. Under the equity method, we record our investment at cost, with adjustments for our share of the affiliate’s earnings and losses as well as changes in the affiliate’s equity due to unrealized gains and losses.
Fair Values of Financial Instruments	Fair Values of Financial Instruments We use the following methods and assumptions in estimating our fair value disclosures: Investments - We present our investments in available-for-sale Cash and Short-Term Investments - The carrying amounts we report in the balance sheet for these instruments approximate their fair values. Premiums and Reinsurance Receivables and Payables - The carrying amounts we report in the balance sheet for these instruments related to premiums and paid losses and loss expenses approximate their fair values. Subordinated Debentures - The carrying amounts we report in the balance sheet for these instruments approximate their fair values.
Revenue Recognition	Revenue Recognition Our insurance subsidiaries recognize insurance premiums as income over the terms of the policies they issue. Our insurance subsidiaries calculate unearned premiums on a daily pro-rata
Policy Acquisition Costs	Policy Acquisition Costs We defer our insurance subsidiaries’ policy acquisition costs, consisting primarily of commissions, premium taxes and certain other underwriting costs, reduced by ceding commissions, that vary with and relate directly to the production of business. We amortize these deferred policy acquisition costs over the period in which our insurance subsidiaries earn the premiums. The method we follow in computing deferred policy acquisition costs limits the amount of such deferred costs to their estimated realizable value, which gives effect to the premium to be earned, related investment income, losses and loss expenses and certain other costs we expect to incur as our insurance subsidiaries earn the premium. Estimates in the calculation of policy acquisition costs have not shown material variability because of uncertainties in applying accounting principles or as a result of sensitivities to changes in key assumptions.
Property and Equipment	Property and Equipment We report property and equipment at depreciated cost that we compute using the straight-line method based upon estimated useful lives of the assets.
Losses and Loss Expenses	Losses and Loss Expenses Liabilities for losses and loss expenses are estimates at a given point in time of the amounts an insurer expects to pay with respect to incurred policyholder claims based on facts and circumstances the insurer knows at that point in time. At the time of establishing its estimates, an insurer recognizes that its ultimate liability for losses and loss expenses will exceed or be less than such estimates. Our insurance subsidiaries base their estimates of liabilities for losses and loss expenses on assumptions as to future loss trends, expected claims severity, judicial theories of liability and other factors. However, during the loss adjustment period, our insurance subsidiaries may learn additional facts regarding individual claims, and, consequently, it often becomes necessary for our insurance subsidiaries to refine and adjust their estimates for these liabilities. We reflect any adjustments to the liabilities for losses and loss expenses of our insurance subsidiaries in our consolidated results of operations in the period in which our insurance subsidiaries make adjustments to their estimates. Our insurance subsidiaries maintain liabilities for the payment of losses and loss expenses with respect to both reported and unreported claims. Our insurance subsidiaries establish these liabilities for the purpose of covering the ultimate costs of settling all losses, including investigation and litigation costs. Our insurance subsidiaries base the amount of their liability for reported losses primarily upon a case-by-case Reserve estimates can change over time because of unexpected changes in assumptions related to our insurance subsidiaries’ external environment and, to a lesser extent, assumptions related to our insurance subsidiaries’ internal operations. For example, our insurance subsidiaries have experienced a decrease in claims frequency on workers’ compensation claims during the past several years while the severity of these claims has gradually increased. These trend changes give rise to greater uncertainty as to the pattern of future loss settlements on workers’ compensation claims. Related uncertainties regarding future trends include the cost of medical technologies and procedures and changes in the utilization of medical procedures. Assumptions related to our insurance subsidiaries’ external environment include the absence of significant changes in tort law and the legal environment that increase liability exposure, consistency in judicial interpretations of insurance coverage and policy provisions and the rate of loss cost inflation. Internal assumptions include consistency in the recording of premium and loss statistics, consistency in the recording of claims, payment and case reserving methodology, accurate measurement of the impact of rate changes and changes in policy provisions, consistency in the quality and characteristics of business written within a given line of business and consistency in reinsurance coverage and collectability of reinsured losses, among other items. To the extent our insurance subsidiaries determine that underlying factors impacting their assumptions have changed, our insurance subsidiaries make adjustments in their reserves that they consider appropriate for such changes. Accordingly, our insurance subsidiaries’ ultimate liability for unpaid losses and loss expenses will likely differ from the amount recorded. Our insurance subsidiaries seek to enhance their underwriting results by carefully selecting the product lines they underwrite. Our insurance subsidiaries’ personal lines products primarily include standard and preferred risks in private passenger automobile and homeowners lines. Our insurance subsidiaries’ commercial lines products primarily include business offices, wholesalers, service providers, contractors, artisans and light manufacturing operations. Our insurance subsidiaries have limited exposure to asbestos and other environmental liabilities. Our insurance subsidiaries write no medical malpractice liability risks.
Income Taxes	Income Taxes We currently file a consolidated federal income tax return. We account for income taxes using the asset and liability method. The objective of the asset and liability method is to establish deferred tax assets and liabilities for the temporary differences between the financial reporting basis and the tax basis of our assets and liabilities at enacted tax rates we expect to be in effect when we realize or settle such amounts.
Credit Risk	Credit Risk Our objective is to earn competitive returns by investing in a diversified portfolio of securities. Our portfolio of fixed maturity securities and, to a lesser extent, short-term investments is subject to credit risk. We define this risk as the potential loss in fair value resulting from adverse changes in the borrower’s ability to repay its debt to us. We manage this risk by performing an analysis of prospective investments and through regular reviews of our portfolio by our investment personnel. We also limit the amount of our total investment portfolio that we invest in any one security. Our insurance subsidiaries provide property and liability insurance coverages through independent insurance agencies located throughout their operating areas. Our insurance subsidiaries bill the majority of this business directly to their policyholders, although our insurance subsidiaries bill a portion of their commercial business through their agents, to whom they extend credit in the normal course of business. Our insurance subsidiaries have reinsurance agreements with Donegal Mutual and with a number of major unaffiliated reinsurers.
Reinsurance Accounting and Reporting	Reinsurance Accounting and Reporting Our insurance subsidiaries rely upon reinsurance agreements to limit their maximum net loss from large single risks or risks in concentrated areas and to increase their capacity to write insurance. Reinsurance does not relieve our insurance subsidiaries from liability to their respective policyholders. To the extent that a reinsurer cannot pay losses for which it is liable under the terms of a reinsurance agreement with one or more of our insurance subsidiaries, our insurance subsidiaries retain continued liability for such losses. However, in an effort to reduce the risk of non-payment, A- A-
Stock-Based Compensation	Stock-Based Compensation We measure all share-based payments to our directors and the directors and employees of our subsidiaries and affiliates, including grants of stock options, using a fair-value-based method and record such expense in our results of operations. In determining the expense we record for stock options we grant to our directors and the directors and employees of our subsidiaries and affiliates, we estimate the fair value of each option award on the date of grant using the Black-Scholes option pricing model. The significant assumptions we utilize in applying the Black-Scholes option pricing model are the risk-free interest rate, expected term, dividend yield and expected volatility. In 2017, 2016 and 2015, we realized $873,515, $788,700 and $437,474, respectively, in tax benefits upon the exercise of stock options.
Earnings per Share	Earnings Per Share We calculate basic earnings per share by dividing net income by the weighted-average number of common shares outstanding for the period. Diluted earnings per share reflects the dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock. We have two classes of common stock, which we refer to as Class A common stock and Class B common stock. Our Class A common stock is entitled to the declaration and payment of cash dividends that are at least 10% higher than those we declare and pay on our Class B common stock. Accordingly, we use the two-class two-class
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price over the underlying fair value of acquired entities. When completing acquisitions, we seek also to identify separately identifiable intangible assets that we have acquired. We assess goodwill and intangible assets with an indefinite useful life for impairment annually. We also assess goodwill and other intangible assets for impairment upon the occurrence of certain events. In making our assessment, we consider a number of factors including operating results, business plans, economic projections, anticipated future cash flows and current market data. Inherent uncertainties exist with respect to these factors and to our judgment in applying them when we make our assessment. Impairment of goodwill and other intangible assets could result from changes in economic and operating conditions in future periods.
Impact of New Accounting Standards	In May 2014, the Financial Accounting Standards Board (the “FASB”) issued guidance that requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. While this guidance will replace most existing GAAP revenue recognition guidance, the scope of the guidance excludes insurance contracts. The new standard is effective on January 1, 2018. The standard permits the use of either the retrospective or the cumulative effect transition method. Because the accounting for insurance contracts is outside of the scope of the standard, the adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In January 2016, the FASB issued guidance that generally requires entities to measure equity investments at fair value and recognize changes in fair value in their results of operations. This guidance also simplifies the impairment assessment of equity investments without readily determinable fair values by requiring entities to perform a qualitative assessment to identify impairment. The FASB issued other disclosure and presentation improvements related to financial instruments within the guidance. The guidance is effective for annual and interim reporting periods beginning after December 15, 2017. As a result of this guidance, we will reflect changes in the fair value of our equity investments in our results of operations beginning January 1, 2018. In February 2016, the FASB issued guidance that requires lessees to recognize leases, including operating leases, on the lessee’s balance sheet, unless a lease is considered a short-term lease. This guidance also requires entities to make new judgments to identify leases. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018 and permits early adoption. We do not expect the adoption of this guidance to have a significant impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance that simplifies and improves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The guidance was effective for annual and interim reporting periods beginning after December 15, 2016. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In June 2016, the FASB issued guidance that amends previous guidance on the impairment of financial instruments by adding an impairment model that requires an entity to recognize expected credit losses as an allowance rather than impairments as credit losses are incurred. The intent of this guidance is to reduce complexity and result in a more timely recognition of expected credit losses. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. We do not expect the adoption of this guidance to have a significant impact on our financial position, results of operations or cash flows. In March 2017, the FASB issued guidance that amends previous guidance on the amortization period for certain purchased callable debt securities held at a premium. This new guidance shortens the amortization period to the earliest call date. The intent of the new guidance is to align interest income recognition with the expectations incorporated in the market pricing on the underlying securities. The new standard is effective for annual and interim reporting periods beginning after December 15, 2018, with early adoption permitted. We adopted this guidance effective January 1, 2017. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows. In February 2018, the FASB issued updated guidance that allows entities to reclassify the stranded tax effects in accumulated other comprehensive income (“AOCI”) resulting from the Tax Cuts and Jobs Act of 2017 (the “TCJA”) from AOCI to retained earnings. Current guidance requires entities to report the effect of a change in tax laws or tax rates on deferred tax balances in income from continuing operations in the accounting period that includes the period of enactment, even if the entities originally charged or credited related income tax effects directly to AOCI. If an entity elects to reclassify the stranded tax effects, the guidance requires the reclassification to include the effect of the change in the U.S. federal corporate income tax rate on the gross deferred tax amounts and related valuation allowances, if any, related to items in AOCI at the date of the enactment of TCJA. The guidance is effective for annual and interim reporting periods beginning after December 15, 2018 and permits early adoption. We adopted this guidance effective on the December 22, 2017 date of the enactment of the TCJA. The adoption of this guidance did not have a significant impact on our financial position, results of operations or cash flows.

Transactions with Affiliates (T

Transactions with Affiliates (Tables)	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Schedule of Reinsurance Atlantic States Ceded to Pool	The following amounts represent reinsurance Atlantic States ceded to the pool during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 200,752,599 $ 185,444,009 $ 170,418,931 Losses and loss expenses 140,015,950 115,371,839 115,029,244 Prepaid reinsurance premiums 103,991,861 95,469,329 87,780,338 Liability for losses and loss expenses 136,786,070 120,434,535 108,672,769
Schedule of Reinsurance Atlantic States Assumed from Pool	The following amounts represent reinsurance Atlantic States assumed from the pool during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 451,470,894 $ 422,985,921 $ 396,098,036 Losses and loss expenses 289,503,373 240,394,302 240,197,659 Unearned premiums 228,988,598 214,372,048 199,966,888 Liability for losses and loss expenses 252,263,547 230,543,393 216,194,945
Schedule of Southern and Le Mars Assumed from Donegal Mutual Pursuant to Quota-Share Reinsurance Agreements	The following amounts represent reinsurance Southern and Le Mars assumed from Donegal Mutual pursuant to the quota-share reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ (271 ) $ (1,512 ) $ 880,787 Losses and loss expenses (690,268 ) (378,199 ) 1,492,673 Unearned premiums — — — Liability for losses and loss expenses 827,193 3,222,100 5,722,000
Schedule of Reinsurance Ceded to Donegal Mutual Pursuant to these Quota-Share Reinsurance Agreements	The following amounts represent reinsurance ceded to Donegal Mutual pursuant to these quota-share reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 42,578,047 $ 39,917,800 $ 37,299,760 Losses and loss expenses 24,978,631 21,524,856 19,735,479 Prepaid reinsurance premiums 19,827,115 19,180,421 17,172,112 Liability for losses and loss expenses 36,396,109 31,881,756 29,968,948
Schedule of Insurance Subsidiaries Ceded to Donegal Mutual Pursuant to these Reinsurance Agreements	The following amounts represent reinsurance that our insurance subsidiaries ceded to Donegal Mutual pursuant to these reinsurance agreements during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 17,215,273 $ 12,965,868 $ 14,235,227 Losses and loss expenses 8,953,411 995,076 6,814,836 Liability for losses and loss expenses 3,399,207 3,136,438 4,485,201
Schedule of Affiliated Reinsurance Transactions on Net Premiums Our Insurance Subsidiaries Earned	The following amounts represent the effect of affiliated reinsurance transactions on net premiums our insurance subsidiaries earned during 2017, 2016 and 2015: 2017 2016 2015 Assumed $ 451,470,623 $ 422,984,409 $ 396,978,823 Ceded (260,545,919 ) (238,327,677 ) (221,953,918 ) Net $ 190,924,704 $ 184,656,732 $ 175,024,905
Schedule of Reinsurance Transactions on Net Losses and Loss Expenses Our Insurance Subsidiaries Incurred	The following amounts represent the effect of affiliated reinsurance transactions on net losses and loss expenses our insurance subsidiaries incurred during 2017, 2016 and 2015: 2017 2016 2015 Assumed $ 288,813,105 $ 240,016,103 $ 241,690,332 Ceded (173,947,992 ) (137,891,771 ) (141,579,559 ) Net $ 114,865,113 $ 102,124,332 $ 100,110,773

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Values of Fixed Maturities and Equity Securities	The amortized cost and estimated fair values of our fixed maturities and equity securities at December 31, 2017 and 2016 are as follows: 2017 Amortized Cost Gross Gross Estimated Fair Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 71,736,445 $ 804,012 $ 546,868 $ 71,993,589 Obligations of states and political subdivisions 137,581,155 11,161,650 112,193 148,630,612 Corporate securities 108,024,776 2,860,255 730,843 110,154,188 Mortgage-backed securities 49,312,701 515,976 156,638 49,672,039 Totals $ 366,655,077 $ 15,341,893 $ 1,546,542 $ 380,450,428 2017 Amortized Cost Gross Gross Estimated Fair Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,759,456 $ 20,377 $ 730,409 $ 44,049,424 Obligations of states and political subdivisions 128,478,000 3,941,610 302,440 132,117,170 Corporate securities 105,254,120 1,010,744 525,445 105,739,419 Mortgage-backed securities 259,922,761 444,603 3,327,327 257,040,037 Fixed maturities 538,414,337 5,417,334 4,885,621 538,946,050 Equity securities 44,219,097 6,505,287 279,141 50,445,243 Totals $ 582,633,434 $ 11,922,621 $ 5,164,762 $ 589,391,293 2016 Amortized Cost Gross Gross Estimated Fair Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 61,381,605 $ 1,255,480 $ 674,371 $ 61,962,714 Obligations of states and political subdivisions 122,793,411 8,403,996 368,530 130,828,877 Corporate securities 91,555,136 1,172,002 1,678,133 91,049,005 Mortgage-backed securities 60,370,796 545,812 110,066 60,806,542 Totals $ 336,100,948 $ 11,377,290 $ 2,831,100 $ 344,647,138 2016 Amortized Cost Gross Gross Estimated Fair Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 39,093,734 $ 99,429 $ 605,139 $ 38,588,024 Obligations of states and political subdivisions 179,889,661 6,635,941 442,717 186,082,885 Corporate securities 87,715,049 662,132 921,362 87,455,819 Mortgage-backed securities 204,931,200 637,268 2,620,256 202,948,212 Fixed maturities 511,629,644 8,034,770 4,589,474 515,074,940 Equity securities 42,431,695 4,788,218 132,071 47,087,842 Totals $ 554,061,339 $ 12,822,988 $ 4,721,545 $ 562,162,782
Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity	We set forth below the amortized cost and estimated fair value of fixed maturities at December 31, 2017 by contractual maturity. 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. Amortized Cost Estimated Fair Value Held to maturity Due in one year or less $ 4,096,270 $ 4,090,120 Due after one year through five years 57,702,099 58,997,125 Due after five years through ten years 118,294,836 121,747,801 Due after ten years 137,249,171 145,943,343 Mortgage-backed securities 49,312,701 49,672,039 Total held to maturity $ 366,655,077 $ 380,450,428 Available for sale Due in one year or less $ 49,257,873 $ 49,729,548 Due after one year through five years 97,814,378 98,914,332 Due after five years through ten years 103,015,782 103,609,213 Due after ten years 28,403,543 29,652,920 Mortgage-backed securities 259,922,761 257,040,037 Total available for sale $ 538,414,337 $ 538,946,050
Summary of Financial Information	We include our share of DFSC’s net income in our results of operations. We have compiled the following summary financial information for DFSC at December 31, 2017 and 2016 from the financial statements of DFSC. December 31, 2017 2016 Balance sheets: Total assets $ 567,935,408 $ 535,590,133 Total liabilities $ 487,603,999 $ 457,101,287 Stockholders’ equity 80,331,409 78,488,846 Total liabilities and stockholders’ equity $ 567,935,408 $ 535,590,133 Year Ended December 31, 2017 2016 2015 Income statements: Net income $ 3,362,861 $ 2,252,456 $ 2,372,650
Summary of Net Investment Income, consisting Primarily of Interest and Dividends	We derive net investment income, consisting primarily of interest and dividends, from the following sources: 2017 2016 2015 Fixed maturities $ 26,143,924 $ 25,066,582 $ 23,636,468 Equity securities 999,335 1,187,814 707,703 Short-term investments 407,580 115,763 181,154 Other 33,316 108,003 33,450 Investment income 27,584,155 26,478,162 24,558,775 Investment expenses (4,056,851 ) (3,845,432 ) (3,609,077 ) Net investment income $ 23,527,304 $ 22,632,730 $ 20,949,698
Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes	We present below gross realized gains and losses from investments, including those we classified as held to maturity, and the change in the difference between fair value and cost of investments: 2017 2016 2015 Gross realized gains: Fixed maturities $ 168,855 $ 2,161,108 $ 2,259,045 Equity securities 6,197,253 1,378,548 1,088,467 6,366,108 3,539,656 3,347,512 Gross realized losses: Fixed maturities 98,723 281,131 105,432 Equity securities 562,130 732,950 1,307,656 660,853 1,014,081 1,413,088 Net realized gains $ 5,705,255 $ 2,525,575 $ 1,934,424 Change in difference between fair value and cost of investments: Fixed maturities $ 2,335,578 $ (12,932,470 ) $ (10,787,772 ) Equity securities 1,569,999 3,160,356 659,597 Totals $ 3,905,577 $ (9,772,114 ) $ (10,128,175 )
Summary of Fixed Maturities and Equity Securities with Unrealized Losses	We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2017 as follows: Less than 12 months 12 months or longer Fair Value Unrealized Losses Fair Value Unrealized U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 24,024,445 $ 286,518 $ 33,987,229 $ 990,759 Obligations of states and political subdivisions 10,223,383 120,076 14,127,415 294,557 Corporate securities 35,203,959 253,241 31,560,591 1,003,047 Mortgage-backed securities 100,533,516 817,315 124,061,502 2,666,650 Equity securities 4,291,875 279,141 — — Totals $ 174,277,178 $ 1,756,291 $ 203,736,737 $ 4,955,013 We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2016 as follows: Less than 12 months 12 months or longer Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 37,729,947 $ 1,279,510 $ — $ — Obligations of states and political subdivisions 40,739,099 802,311 710,280 8,936 Corporate securities 80,181,238 2,127,451 4,706,945 472,044 Mortgage-backed securities 168,771,543 2,727,720 416,828 2,602 Equity securities 5,420,875 132,071 — — Totals $ 332,842,702 $ 7,069,063 $ 5,834,053 $ 483,582

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements for Investments in Available-for-Sale Fixed Maturity and Equity Securities	The following table presents our fair value measurements for our investments in available-for-sale Fair Value Measurements Using Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,049,424 $ — $ 44,049,424 $ — Obligations of states and political subdivisions 132,117,170 — 132,117,170 — Corporate securities 105,739,419 — 105,739,419 — Mortgage-backed securities 257,040,037 — 257,040,037 — Equity securities 36,736,121 36,736,121 — — Total investments in the fair value hierarchy 575,682,171 36,736,121 538,946,050 — Investment measured at net asset value 13,709,122 — — — Totals $ 589,391,293 $ 36,736,121 $ 538,946,050 $ — The following table presents our fair value measurements for our investments in available-for-sale Fair Value Measurements Using Fair Value Quoted Prices in Significant Significant U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 38,588,024 $ — $ 38,588,024 $ — Obligations of states and political subdivisions 186,082,885 — 186,082,885 — Corporate securities 87,455,819 — 87,455,819 — Mortgage-backed securities 202,948,212 — 202,948,212 — Equity securities 35,922,337 35,922,337 — — Total investments in the fair value hierarchy 550,997,277 35,922,337 515,074,940 — Investment measured at net asset value 11,165,505 — — — Totals $ 562,162,782 $ 35,922,337 $ 515,074,940 $ —

Deferred Policy Acquisition C34

Deferred Policy Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2017
Insurance [Abstract]
Changes in Insurance Subsidiaries' Deferred Policy Acquisition Costs	Changes in our insurance subsidiaries’ deferred policy acquisition costs are as follows: 2017 2016 2015 Balance, January 1 $ 56,309,196 $ 52,108,388 $ 48,298,608 Acquisition costs deferred 119,045,664 112,076,808 103,322,780 Amortization charged to earnings (115,065,000 ) (107,876,000 ) (99,513,000 ) Balance, December 31 $ 60,289,860 $ 56,309,196 $ 52,108,388

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and equipment at December 31, 2017 and 2016 consisted of the following: 2017 2016 Estimated Useful Life Office equipment $ 9,918,045 $ 9,129,318 3-15 years Automobiles 779,357 1,334,385 5 years Real estate 7,971,590 7,685,228 5-50 Software 2,794,864 2,794,864 5 years 21,463,856 20,943,795 Accumulated depreciation (14,183,441 ) (14,275,306 ) $ 7,280,415 $ 6,668,489

Liability for Losses and Loss36

Liability for Losses and Loss Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Summary of Insurance Subsidiaries' Liability for Losses and Loss Expenses	We summarize activity in our insurance subsidiaries’ liability for losses and loss expenses as follows: 2017 2016 2015 Balance at January 1 $ 606,664,590 $ 578,205,109 $ 538,258,406 Less reinsurance recoverable (259,147,147 ) (256,150,860 ) (245,957,364 ) Net balance at January 1 347,517,443 322,054,249 292,301,042 Incurred related to: Current year 480,646,641 420,327,164 391,166,740 Prior years 6,621,413 2,988,739 7,200,134 Total incurred 487,268,054 423,315,903 398,366,874 Paid related to: Current year 288,379,600 248,106,788 236,834,666 Prior years 163,005,427 149,745,921 131,779,001 Total paid 451,385,027 397,852,709 368,613,667 Net balance at December 31 383,400,470 347,517,443 322,054,249 Plus reinsurance recoverable 293,271,257 259,147,147 256,150,860 Balance at December 31 $ 676,671,727 $ 606,664,590 $ 578,205,109
Summary of Incurred and Paid Claims Development, Net of Reinsurance and Cumulative Claim Frequency and Total of IBNR Reserves Plus Expected Development on Reported Claims	The following tables present information about incurred and paid claims development as of December 31, 2017, net of reinsurance, as well as cumulative claim frequency and the total of IBNR reserves plus expected development on reported claims that our insurance subsidiaries included within their net incurred claims amounts. The tables include unaudited information about incurred and paid claims development for the years ended December 31, 2008 through 2016, which we present as supplementary information. We present amounts retrospectively for MICO, which we acquired in December 2010, for all accident years prior to 2010. Personal Automobile At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 98,139 $ 101,937 $ 100,782 $ 101,388 $ 101,119 $ 100,819 $ 100,984 $ 100,923 $ 100,918 $ 100,915 $ 9 61 2009 105,707 106,313 106,841 107,589 107,190 106,705 106,549 106,499 106,713 15 65 2010 117,967 117,552 118,562 118,876 118,916 118,587 118,385 118,289 45 70 2011 127,929 131,678 132,987 133,229 133,617 133,218 133,145 97 74 2012 130,415 133,201 135,592 136,493 136,552 136,463 249 69 2013 124,965 130,737 131,594 132,643 132,604 438 66 2014 124,426 124,806 124,210 126,200 905 71 2015 137,569 139,334 139,181 2,713 70 2016 150,215 153,937 7,327 73 2017 166,690 26,640 77 Total $ 1,314,137 Personal Automobile Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 66,648 $ 85,262 $ 93,325 $ 97,134 $ 99,110 $ 100,153 $ 100,642 $ 100,712 $ 100,778 $ 100,790 2009 69,585 89,089 97,349 102,332 104,779 105,577 105,922 106,017 106,477 2010 75,889 96,749 107,662 113,243 116,748 117,812 117,978 118,054 2011 87,191 110,249 121,621 127,545 131,319 132,479 132,714 2012 87,517 111,941 124,652 130,862 133,428 134,581 2013 84,241 109,051 120,118 125,946 130,026 2014 85,377 104,736 114,893 120,491 2015 93,611 116,303 128,395 2016 102,433 129,507 2017 111,964 Total 1,212,999 All outstanding liabilities before 2008, net of reinsurance 540 Liabilities for claims and claims adjustment expenses, net of $ 101,678 Homeowners At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 40,989 $ 42,790 $ 42,944 $ 42,700 $ 42,839 $ 42,897 $ 42,862 $ 42,852 $ 42,844 $ 42,833 $ — 18 2009 51,054 50,621 50,333 49,998 50,137 50,405 50,419 50,433 50,435 — 18 2010 60,315 60,729 60,248 59,972 60,355 60,440 60,443 60,542 — 25 2011 71,256 70,461 70,436 70,381 70,297 70,351 70,479 (3 ) 27 2012 53,962 54,794 54,468 54,351 54,281 54,381 44 19 2013 50,887 51,121 51,122 50,874 50,988 47 13 2014 56,916 58,378 57,680 57,332 6 18 2015 63,359 63,925 63,053 157 14 2016 62,443 64,064 833 13 2017 79,283 4,166 17 Total $ 593,390 Homeowners Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 32,548 $ 40,037 $ 41,582 $ 42,095 $ 42,511 $ 42,699 $ 42,797 $ 42,817 $ 42,812 $ 42,833 2009 39,961 49,180 49,827 50,021 50,301 50,430 50,429 50,433 50,435 2010 47,419 57,334 59,283 59,875 60,239 60,486 60,501 60,525 2011 57,588 69,345 70,125 70,351 70,541 70,626 70,648 2012 46,566 53,619 54,028 54,298 54,317 54,356 2013 40,949 49,410 50,210 50,478 51,043 2014 45,823 56,255 56,990 57,195 2015 51,885 61,542 62,204 2016 50,125 61,145 2017 67,077 Total 577,461 All outstanding liabilities before 2008, net of 15 Liabilities for claims and claims adjustment expenses, $ 15,944 Commercial Automobile At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 18,164 $ 17,889 $ 17,719 $ 17,941 $ 17,960 $ 18,158 $ 18,063 $ 18,054 $ 18,051 $ 18,049 $ — 6 2009 18,735 18,549 18,998 19,015 19,346 19,569 19,430 19,461 19,449 3 6 2010 19,315 19,913 20,695 21,477 21,490 21,756 21,746 21,713 5 7 2011 26,642 27,157 28,570 28,893 29,112 29,107 29,487 1 9 2012 26,557 27,720 30,606 31,435 31,278 31,648 12 8 2013 32,902 33,749 34,751 35,240 36,404 196 9 2014 42,760 44,544 47,326 48,213 747 11 2015 46,526 48,323 51,412 2,639 12 2016 54,302 57,353 4,793 13 2017 61,484 17,554 13 Total $ 375,212 Commercial Automobile Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 9,204 $ 12,330 $ 14,115 $ 16,077 $ 17,110 $ 17,548 $ 18,052 $ 18,051 $ 18,051 $ 18,049 2009 9,309 12,872 15,479 17,160 18,696 19,389 19,386 19,408 19,413 2010 10,778 14,180 16,426 19,030 20,804 21,014 21,482 21,549 2011 13,876 19,106 24,267 26,973 28,014 28,758 28,836 2012 13,642 20,240 23,718 27,417 29,873 30,402 2013 16,306 23,557 26,879 31,053 34,083 2014 22,707 31,089 39,436 44,374 2015 23,875 35,342 41,678 2016 27,033 38,237 2017 28,707 Total 305,328 All outstanding liabilities before 2008, net of 10 Liabilities for claims and claims adjustment expenses, $ 69,894 Commercial Multi-Peril At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Expected Development on Reported Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 26,868 $ 27,693 $ 26,796 $ 26,906 $ 27,286 $ 27,023 $ 27,182 $ 27,258 $ 27,184 $ 26,998 $ — 5 2009 26,712 26,454 27,357 27,357 27,739 27,959 27,625 27,484 27,508 — 6 2010 28,745 29,656 29,390 29,169 29,373 29,453 29,463 29,779 — 6 2011 33,054 35,411 35,942 37,576 37,385 38,270 38,105 13 7 2012 29,789 30,716 32,449 34,117 35,755 36,214 33 6 2013 35,683 35,679 37,292 37,205 37,981 155 6 2014 48,204 50,135 51,843 52,336 608 7 2015 42,070 43,874 44,728 3,028 6 2016 43,005 46,988 4,991 6 2017 56,185 13,847 6 Total $ 396,822 Commercial Multi-Peril Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 16,128 $ 21,645 $ 22,991 $ 24,161 $ 25,154 $ 25,983 $ 26,760 $ 26,956 $ 27,017 $ 26,996 2009 13,675 19,356 21,560 24,977 26,212 26,780 27,287 27,357 27,409 2010 17,007 22,017 24,749 26,832 27,768 28,681 28,906 29,632 2011 18,773 24,767 30,286 33,526 36,722 37,759 38,240 2012 16,666 23,384 26,634 29,370 33,327 35,331 2013 19,875 26,216 29,159 33,614 35,104 2014 27,920 35,520 40,936 47,021 2015 21,837 29,419 34,323 2016 19,660 29,402 2017 27,399 Total 330,857 All outstanding liabilities before 2008, net of reinsurance 266 Liabilities for claims and claims adjustment expenses, net of reinsurance $ 66,231 Workers’ Compensation At December 31, 2017 Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Total IBNR Plus Development on Reported Claims Cumulative Number of Reported Claims Unaudited (in thousands) 2008 $ 24,034 $ 26,361 $ 27,037 $ 26,791 $ 26,471 $ 26,226 $ 25,941 $ 25,963 $ 25,713 $ 25,797 $ 61 5 2009 21,571 22,497 21,894 21,826 22,848 22,278 22,172 22,114 22,079 65 4 2010 27,304 27,859 27,010 26,637 26,944 27,121 27,037 26,984 98 5 2011 32,490 35,757 36,614 36,369 35,670 35,039 35,194 138 6 2012 39,142 39,516 38,827 37,926 37,163 36,468 211 6 2013 46,325 47,027 44,289 42,828 42,327 447 6 2014 51,508 51,553 49,288 48,537 996 6 2015 53,332 49,615 45,991 2,470 6 2016 58,814 49,802 6,741 6 2017 60,450 21,116 6 Total $ 393,629 Workers’ Compensation Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Year Ended December 31, Accident Year 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Unaudited (in thousands) 2008 $ 6,562 $ 14,776 $ 19,199 $ 21,933 $ 23,782 $ 24,551 $ 24,880 $ 25,017 $ 25,112 $ 25,250 2009 6,490 12,627 16,516 18,329 19,665 20,476 20,939 21,117 21,400 2010 8,066 15,937 21,176 23,137 24,539 25,337 25,804 26,050 2011 9,157 21,450 27,517 31,905 32,394 33,067 33,577 2012 11,097 22,963 28,812 31,244 33,196 34,177 2013 13,052 26,043 32,783 36,351 38,877 2014 13,932 28,513 36,284 40,393 2015 13,071 27,531 34,192 2016 14,709 30,344 2017 15,581 Total 299,841 All outstanding liabilities before 2008, net of 3,445 Liabilities for claims and claims adjustment expenses, $ 97,233
Reconciliation of Net Incurred and Paid Claims Development Tables to Liability for Claims and Claim Adjustment Expenses	The following table presents a reconciliation of the net incurred and paid claims development tables to the liability for claims and claims adjustment expenses in our consolidated balance sheet: (in thousands) At December 31, Net outstanding liabilities: Personal automobile $ 101,678 Homeowners 15,944 Commercial automobile 69,894 Commercial multi-peril 66,231 Workers ’ 97,233 Other 5,404 356,384 Reinsurance recoverable: Personal automobile $ 94,091 Homeowners 11,465 Commercial automobile 45,201 Commercial multi-peril 40,685 Workers ’ 85,528 Other 3,831 280,801 Unallocated loss adjustment expenses $ 39,487 Gross liability for unpaid losses and loss expenses $ 676,672
Supplementary Information about Average Historical Claims Duration	The following table presents supplementary information about average historical claims duration as of December 31, 2017: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 8 9 10 Personal automobile 65.7 % 17.5 % 8.5 % 4.4 % 2.5 % 0.9 % 0.3 % 0.1 % 0.2 % — % Homeowners 80.6 16.6 1.7 0.6 0.6 0.3 0.1 — — — Commercial automobile 47.1 18.8 12.6 10.6 6.9 2.2 1.3 0.1 — — Commercial multi-peril 50.7 17.9 9.3 9.0 5.8 3.3 1.7 1.1 0.2 — Workers’ compensation 28.4 31.1 16.7 8.9 5.2 2.8 1.6 0.7 0.8 0.5

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
FHLB of Indianapolis [Member]
Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement	The table below presents the amount of FHLB of Indianapolis stock MICO purchased, collateral pledged and assets related to MICO’s agreement at December 31, 2017. FHLB stock purchased and owned as part of the agreement $ 267,700 Collateral pledged, at par (carrying value $2,751,398) 2,850,000 Borrowing capacity currently available 2,592,075
FHLB of Pittsburgh [Member]
Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement	The table below presents the amount of FHLB of Pittsburgh stock Atlantic States purchased, collateral pledged and assets related to Atlantic States’ membership in the FHLB of Pittsburgh at December 31, 2017. FHLB stock purchased and owned as part of the agreement $ 1,599,700 Collateral pledged, at par (carrying value $36,850,815) 37,322,954 Borrowing capacity currently available 576,324

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2017
Insurance [Abstract]
Ceded Reinsurance Transactions with Unaffiliated Reinsurers	The following amounts represent ceded reinsurance transactions with unaffiliated reinsurers during 2017, 2016 and 2015: 2017 2016 2015 Premiums written $ 51,241,267 $ 45,354,233 $ 40,997,351 Premiums earned 49,633,348 44,318,542 49,758,371 Losses and loss expenses 44,575,268 18,588,114 30,722,807 Prepaid reinsurance premiums 11,213,665 9,605,746 8,570,055 Liability for losses and loss expenses 116,689,871 103,694,418 113,023,942
Total Ceded Reinsurance Transactions with both Affiliated and Unaffiliated Reinsurers	The following amounts represent total ceded reinsurance transactions with both affiliated and unaffiliated reinsurers during 2017, 2016 and 2015: 2017 2016 2015 Premiums earned $ 310,179,267 $ 282,646,219 $ 271,712,289 Losses and loss expenses 218,523,260 156,479,885 172,302,366 Prepaid reinsurance premiums 135,032,641 124,255,495 113,522,505 Liability for losses and loss expenses 293,271,257 259,147,147 256,150,860
Amounts Represent Effect of Reinsurance on Premiums Written	The following amounts represent the effect of reinsurance on premiums written for 2017, 2016 and 2015: 2017 2016 2015 Direct $ 584,007,351 $ 537,880,237 $ 492,073,587 Assumed 466,087,983 437,532,812 406,126,275 Ceded (320,956,412 ) (293,379,217 ) (269,363,012 ) Net premiums written $ 729,138,922 $ 682,033,832 $ 628,836,850
Amounts Represent Effect of Reinsurance on Premiums Earned	The following amounts represent the effect of reinsurance on premiums earned for 2017, 2016 and 2015: 2017 2016 2015 Direct $ 561,178,447 $ 515,721,745 $ 480,210,534 Assumed 451,515,575 423,129,271 397,142,483 Ceded (310,179,267 ) (282,646,219 ) (271,712,289 ) Net premiums earned $ 702,514,755 $ 656,204,797 $ 605,640,728 Percentage of assumed premiums earned to net premiums earned 64.3 % 64.5 % 65.6 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for Income Tax	Our provision for income tax for 2017, 2016 and 2015 consisted of the following: 2017 2016 2015 Current $ (2,139,061 ) $ 8,496,405 $ 5,621,367 Deferred 7,137,423 2,030,865 980,868 Federal income tax provision $ 4,998,362 $ 10,527,270 $ 6,602,235
Reconciliation of Federal Income Tax Rate	The reasons for such difference and the related tax effects are as follows: 2017 2016 2015 Income before income taxes $ 12,114,462 $ 41,328,407 $ 27,592,268 Computed “expected” taxes 4,240,062 14,464,942 9,657,294 Tax-exempt (3,241,530 ) (3,951,926 ) (4,806,855 ) Proration 518,948 629,697 737,644 Effect of tax reform 4,752,547 — — Dividends received deduction (508,409 ) (691,616 ) (701,658 ) Tax benefit on exercise of options (873,515 ) — — Other, net 110,259 76,173 1,715,810 Federal income tax provision $ 4,998,362 $ 10,527,270 $ 6,602,235
Schedule of Deferred Tax Assets and Deferred Tax Liabilities	The tax effects of temporary differences that give rise to significant portions of our deferred tax assets and deferred tax liabilities at December 31, 2017 and 2016 are as follows: 2017 2016 Deferred tax assets: Unearned premium $ 15,511,854 $ 23,964,558 Loss reserves 4,164,246 6,460,683 Net operating loss carryforward - Le Mars 683,979 1,271,411 Alternative minimum tax credit carryforward — 7,357,733 Net state operating loss carryforward - DGI Parent 77,132,006 72,049,234 Net unrealized losses 713,549 1,213,836 Other 2,300,595 3,307,286 Total gross deferred tax assets 100,506,229 115,624,741 Less valuation allowance (77,396,473 ) (72,490,012 ) Net deferred tax assets 23,109,756 43,134,729 Deferred tax liabilities: Deferred policy acquisition costs 12,660,871 19,708,220 Other 3,320,042 4,383,096 Total gross deferred tax liabilities 15,980,913 24,091,316 Net deferred tax asset $ 7,128,843 $ 19,043,413

Stock Compensation Plans (Table

Stock Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Postemployment Benefits [Abstract]
Information Regarding Activity in Stock Option Plans	Information regarding activity in our stock option plans follows: Number of Weighted- Outstanding at December 31, 2014 8,183,430 $ 14.69 Granted - 2015 1,710,500 13.64 Exercised - 2015 (983,370 ) 13.91 Forfeited - 2015 (114,967 ) 15.30 Expired - 2015 (641 ) 14.00 Outstanding at December 31, 2015 8,794,952 14.57 Granted - 2016 1,417,500 16.44 Exercised - 2016 (832,467 ) 13.44 Forfeited - 2016 (41,337 ) 14.97 Outstanding at December 31, 2016 9,338,648 14.95 Granted - 2017 943,000 17.58 Exercised - 2017 (924,019 ) 14.45 Forfeited - 2017 (93,167 ) 15.43 Outstanding at December 31, 2017 9,264,462 $ 15.26 Exercisable at: December 31, 2015 5,250,338 $ 14.42 December 31, 2016 6,347,470 $ 14.77 December 31, 2017 6,946,677 $ 14.90
Summary of Information about Stock Options Outstanding	The following table summarizes information about stock options outstanding at December 31, 2017: Grant Date Exercise Price Number of Weighted-Average Number of July 27, 2011 $ 12.50 1,027,606 4.0 years 1,027,606 December 20, 2012 14.50 1,062,319 5.0 years 1,062,319 December 19, 2013 15.90 2,102,006 6.0 years 2,102,006 December 18, 2014 15.80 1,362,415 7.0 years 1,362,415 December 17, 2015 13.64 1,404,174 3.0 years 936,022 December 15, 2016 16.48 1,368,942 4.0 years 456,309 December 21, 2017 17.60 937,000 5.0 years — Total 9,264,462 6,946,677
Summary of Plan Activity	A summary of plan activity follows: Shares Issued Price Shares January 1, 2015 $ 12.40 17,662 July 1, 2015 12.95 20,006 January 1, 2016 11.97 18,387 July 1, 2016 11.83 22,418 January 1, 2017 13.76 18,512 July 1, 2017 13.52 25,155

Statutory Net Income, Capital41

Statutory Net Income, Capital and Surplus and Dividend Restrictions (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Statutory Net Income, Capital and Surplus and Dividend	The following table presents selected information, as filed with state insurance regulatory authorities, for our insurance subsidiaries as determined in accordance with accounting practices prescribed or permitted by such insurance regulatory authorities: 2017 2016 2015 Atlantic States: Statutory capital and surplus $ 223,170,835 $ 227,907,377 $ 207,636,824 Statutory unassigned surplus 161,760,924 167,872,138 149,257,062 Statutory net (loss) income (312,221 ) 15,750,876 13,352,784 Southern: Statutory capital and surplus 54,503,581 63,331,001 61,742,861 Statutory unassigned surplus 2,914,532 11,881,309 10,459,840 Statutory net (loss) income (3,375,434 ) 1,774,299 2,301,009 Le Mars: Statutory capital and surplus 23,434,801 25,543,803 26,168,865 Statutory unassigned surplus 10,394,533 12,614,756 13,367,321 Statutory net (loss) income (1,679,335 ) 603,226 (600,608 ) Peninsula: Statutory capital and surplus 39,396,818 41,977,034 41,838,137 Statutory unassigned surplus 21,148,253 23,826,681 23,813,003 Statutory net (loss) income (841,119 ) 966,391 1,976,093 Sheboygan: Statutory capital and surplus 13,823,118 13,129,143 13,254,117 Statutory unassigned surplus 554,498 914,773 1,107,421 Statutory net (loss) income (46,116 ) 644,344 1,719,703 MICO: Statutory capital and surplus 52,796,379 49,863,705 46,199,534 Statutory unassigned surplus 26,162,540 23,380,942 19,894,850 Statutory net income 7,931,774 7,187,213 3,562,536

Reconciliation of Statutory F42

Reconciliation of Statutory Filings to Amounts Reported Herein (Tables)	12 Months Ended
	Dec. 31, 2017
Text Block [Abstract]
Reconciliations of Statutory Net Income and Capital and Surplus	Reconciliations of statutory net income and capital and surplus, as determined using SAP, to the amounts included in the accompanying GAAP financial statements are as follows: Year Ended December 31, 2017 2016 2015 Statutory net income of insurance subsidiaries $ 1,677,549 $ 26,926,349 $ 22,311,517 Increases (decreases): Deferred policy acquisition costs 3,980,664 4,200,808 3,809,780 Deferred federal income taxes 1,334,410 (2,030,865 ) (168,395 ) Salvage and subrogation recoverable 1,199,200 1,502,600 1,082,800 Consolidating eliminations and adjustments (13,534,428 ) (12,327,517 ) (3,679,277 ) Parent-only net income (loss) 12,458,705 12,529,762 (2,366,392 ) Net income as reported herein $ 7,116,100 $ 30,801,137 $ 20,990,033 December 31, 2017 2016 2015 Statutory capital and surplus of insurance subsidiaries $ 407,125,532 $ 421,752,063 $ 396,840,338 Increases (decreases): Deferred policy acquisition costs 60,289,860 56,309,196 52,108,388 Deferred federal income taxes (14,422,511 ) (20,843,506 ) (16,930,202 ) Salvage and subrogation recoverable 17,976,600 16,777,400 15,274,800 Non-admitted 1,960,089 1,689,814 2,441,591 Fixed maturities (8,748,140 ) (7,271,932 ) 957,401 Parent-only equity and other adjustments (15,485,326 ) (29,797,715 ) (42,303,748 ) Stockholders’ equity as reported herein $ 448,696,104 $ 438,615,320 $ 408,388,568

Supplementary Cash Flow Infor43

Supplementary Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Net Income Taxes and Interest Paid	The following table reflects net income taxes and interest we paid during 2017, 2016 and 2015: 2017 2016 2015 Income taxes $ 3,050,000 $ 7,305,000 $ 7,100,000 Interest 1,341,706 1,377,247 870,675

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Summary of Reconciliation of Numerators and Denominators Used in Basic and Diluted Per Share Computations	We present below a reconciliation of the numerators and denominators we used in the basic and diluted per share computations for our Class A common stock: Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic earnings per share: Numerator: Allocation of net income $ 5,879 $ 24,885 $ 17,155 Denominator: Weighted-average shares outstanding 21,799 20,917 22,046 Basic earnings per share $ 0.27 $ 1.19 $ 0.78 Diluted earnings per share: Numerator: Allocation of net income $ 5,879 $ 24,885 $ 17,155 Denominator: Number of shares used in basic computation 21,799 20,917 22,046 Weighted-average effect of dilutive securities Add: Director and employee stock options 843 613 348 Number of shares used in per share computations 22,642 21,530 22,394 Diluted earnings per share $ 0.26 $ 1.16 $ 0.77 We used the following information in the basic and diluted per share computations for our Class B common stock: Year Ended December 31, (in thousands, except per share amounts) 2017 2016 2015 Basic and diluted earnings per share: Numerator: Allocation of net income $ 1,237 $ 5,916 $ 3,835 Denominator: Weighted-average shares outstanding 5,577 5,577 5,577 Basic and diluted earnings per share $ 0.22 $ 1.06 $ 0.69

Condensed Financial Informati45

Condensed Financial Information of Parent Company (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Summary of Condensed Balance Sheets	Condensed Balance Sheets (in thousands) December 31, 2017 2016 Assets Investment in subsidiaries/affiliates (equity method) $ 509,011 $ 510,731 Short-term investments 29 30 Cash 3,237 1,820 Property and equipment 994 342 Other 1,479 1,010 Total assets $ 514,750 $ 513,933 Liabilities and Stockholders’ Equity Liabilities Cash dividends declared to stockholders $ 3,842 $ 3,623 Borrowings under lines of credit 59,000 69,000 Other 3,212 2,695 Total liabilities 66,054 75,318 Stockholders’ equity 448,696 438,615 Total liabilities and stockholders’ equity $ 514,750 $ 513,933
Summary of Condensed Statements of Income and Comprehensive Income	Condensed Statements of Income and Comprehensive Income (in thousands) Year Ended December 31, 2017 2016 2015 Statements of Income Revenues Dividends from subsidiaries $ 13,000 $ 13,000 $ 3,875 Other 2,131 1,759 2,028 Total revenues 15,131 14,759 5,903 Expenses Operating expenses 1,433 1,413 2,451 Premium paid on purchase of treasury stock — — 5,780 Interest 1,929 1,747 1,066 Total expenses 3,362 3,160 9,297 Income (loss) before income tax benefit and equity in undistributed net (loss) income of subsidiaries 11,769 11,599 (3,394 ) Income tax benefit 690 931 1,028 Income (loss) before equity in undistributed net (loss) income of subsidiaries 12,459 12,530 (2,366 ) Equity in undistributed net (loss) income of subsidiaries (5,343 ) 18,271 23,356 Net income $ 7,116 $ 30,801 $ 20,990 Statements of Comprehensive Income Net income $ 7,116 $ 30,801 $ 20,990 Other comprehensive income (loss), net of tax Unrealized gain (loss) - subsidiaries 46 (3,028 ) (4,579 ) Other comprehensive income (loss), net of tax 46 (3,028 ) (4,579 ) Comprehensive income $ 7,162 $ 27,773 $ 16,411
Summary of Condensed Statements of Cash Flows	Condensed Statements of Cash Flows (in thousands) Year Ended December 31, 2017 2016 2015 Cash flows from operating activities: Net income $ 7,116 $ 30,801 $ 20,990 Adjustments: Equity in undistributed net (loss) income of subsidiaries 5,343 (18,271 ) (23,356 ) Other (401 ) (27 ) 539 Net adjustments 4,942 (18,298 ) (22,817 ) Net cash provided (used) 12,058 12,503 (1,827 ) Cash flows from investing activities: Net sale of short-term investments 1 2 498 Net purchase of property and equipment (788 ) (11 ) (23 ) Investment in subsidiaries (2,992 ) (2,393 ) (2,427 ) Other (1 ) — — Net cash used (3,780 ) (2,402 ) (1,952 ) Cash flows from financing activities: Cash dividends paid (14,821 ) (14,085 ) (14,454 ) Issuance of common stock 17,960 16,651 18,468 Payments on line of credit (10,000 ) (12,000 ) (9,500 ) Borrowings under lines of credit — — 37,000 Purchase of treasury stock — — (28,125 ) Net cash (used) provided (6,861 ) (9,434 ) 3,389 Net change in cash 1,417 667 (390 ) Cash at beginning of year 1,820 1,153 1,543 Cash at end of year $ 3,237 $ 1,820 $ 1,153

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summary of Financial Data by Segment	Financial data by segment is as follows: 2017 2016 2015 (in thousands) Revenues: Premiums earned: Commercial lines $ 318,391 $ 295,077 $ 261,286 Personal lines 384,124 361,128 344,355 GAAP premiums earned 702,515 656,205 605,641 Net investment income 23,527 22,633 20,950 Realized investment gains 5,705 2,526 1,934 Equity in earnings of DFSC 1,622 1,086 1,277 Other 5,658 5,973 6,585 Total revenues $ 739,027 $ 688,423 $ 636,387 2017 2016 2015 (in thousands) Income before income taxes: Underwriting (loss) income: Commercial lines $ 13,263 $ 18,284 $ 9,259 Personal lines (39,042 ) (10,745 ) (6,414 ) SAP underwriting (loss) income (25,779 ) 7,539 2,845 GAAP adjustments 4,408 4,642 3,344 GAAP underwriting (loss) income (21,371 ) 12,181 6,189 Net investment income 23,527 22,633 20,950 Realized investment gains 5,705 2,526 1,934 Equity in earnings of DFSC 1,622 1,086 1,277 Premium paid on purchase of treasury stock — — (5,780 ) Other 2,631 2,902 3,022 Income before income taxes $ 12,114 $ 41,328 $ 27,592

Interim Financial Data (Tables)

Interim Financial Data (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Summary of Interim Financial Data	2017 First Quarter Second Quarter Third Quarter Fourth Quarter Net premiums earned $ 169,156,147 $ 175,014,872 $ 177,283,816 $ 181,059,920 Total revenues 178,970,963 183,580,716 185,716,027 190,758,831 Net losses and loss expenses 114,433,458 128,005,914 114,386,379 130,442,303 Net income (loss) 5,104,818 (2,318,648 ) 7,108,574 (2,778,644 ) Net earnings (loss) per common share: Class A common stock - basic 0.19 (0.09 ) 0.27 (0.10 ) Class A common stock - diluted 0.18 (0.08 ) 0.26 (0.10 ) Class B common stock - basic and diluted 0.17 (0.08 ) 0.24 (0.11 ) 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Net premiums earned $ 158,475,279 $ 161,942,637 $ 166,809,851 $ 168,977,030 Total revenues 166,068,776 169,846,867 175,311,263 177,196,114 Net losses and loss expenses 95,578,065 103,193,915 111,174,963 113,368,960 Net income 11,848,913 8,584,654 4,813,404 5,554,166 Net earnings per common share: Class A common stock - basic 0.46 0.33 0.19 0.21 Class A common stock - diluted 0.46 0.32 0.18 0.20 Class B common stock - basic and diluted 0.42 0.30 0.16 0.18

Summary of Significant Accoun48

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)SegmentOffice	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Operations commenced date	Aug. 26, 1986
Stock ownership percentage owned by third party	51.80%
Number of banking offices | Office	15
Number of operating segments | Segment	4
Voting power percentage of outstanding common stock	72.00%
Depreciation of original cost value	20.00%
Time period for which individual security should be in unrealized position of twenty percentage or more to assume it as other than temporary decline	More than six months
Tax benefits upon the exercise of stock options | $	$ 873,515	$ 788,700	$ 437,474
Minimum percentage of class A common stock declared dividend excess over class B dividend	10.00%
Atlantic States [Member]
Business Acquisition [Line Items]
Percentage of share in results of pooled business subsidiary	80.00%
Donegal Mutual [Member]
Business Acquisition [Line Items]
Percentage of share in results of pooled business owned by third party	20.00%
Donegal Financial Services Corporation [Member]
Business Acquisition [Line Items]
Outstanding stock ownership percentage	48.20%
Class A Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder	44.00%
Class B Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder	83.00%

Transactions with Affiliates -

Transactions with Affiliates - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums and losses related to certain products	64.30%	64.50%	65.60%
Excess of loss reinsured under an agreement	$ 1,000,000
Charges for services	124,999,770	$ 122,428,117	$ 108,473,146
Accounts with UCB	32,373,544	16,981,744
Interest on UCB accounts	$ 286,410	87,941	3,317
Minimum [Member] | Lease Office Equipment And Automobile [Member]
Ceded Credit Risk [Line Items]
Lease office equipment and automobiles range	3 years
Maximum [Member] | Lease Office Equipment And Automobile [Member]
Ceded Credit Risk [Line Items]
Lease office equipment and automobiles range	10 years
Atlantic States [Member]
Ceded Credit Risk [Line Items]
Percentage of share in results of pooled business subsidiary	80.00%
Coverage under catastrophic occurrence	$ 2,000,000	2,000,000	2,000,000
Donegal Mutual [Member]
Ceded Credit Risk [Line Items]
Percentage of share in results of pooled business owned by third party	20.00%
Premiums and losses related to certain products	100.00%
Premiums and losses related to business of MICO	25.00%
Excess of loss reinsured under an agreement	$ 500,000
Period of Donegal Mutual under lease agreement	10 years
Le Mars [Member]
Ceded Credit Risk [Line Items]
Premiums and losses related to certain products	100.00%
Coverage under catastrophic occurrence	$ 750,000	750,000	750,000
Southern [Member]
Ceded Credit Risk [Line Items]
Premiums and losses related to certain products	100.00%
Coverage under catastrophic occurrence	$ 1,500,000	$ 1,500,000	$ 1,500,000
Excess of loss reinsured under an agreement	500,000
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Coverage under catastrophic occurrence	4,000,000
Excess of loss reinsured under an agreement	$ 5,000,000

Transactions with Affiliates 50

Transactions with Affiliates - Schedule of Reinsurance Atlantic States Ceded to Pool (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums earned	$ 310,179,267	$ 282,646,219	$ 271,712,289
Prepaid reinsurance premiums	135,032,641	124,255,495
Affiliated Entity [Member] | Atlantic States Ceded [Member]
Ceded Credit Risk [Line Items]
Premiums earned	200,752,599	185,444,009	170,418,931
Losses and loss expenses	140,015,950	115,371,839	115,029,244
Prepaid reinsurance premiums	103,991,861	95,469,329	87,780,338
Liability for losses and loss expenses	$ 136,786,070	$ 120,434,535	$ 108,672,769

Transactions with Affiliates 51

Transactions with Affiliates - Schedule of Reinsurance Atlantic States Assumed from Pool (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums earned	$ 310,179,267	$ 282,646,219	$ 271,712,289
Liability for losses and loss expenses	356,384,000
Affiliated Entity [Member] | Atlantic States Assumed [Member]
Ceded Credit Risk [Line Items]
Premiums earned	451,470,894	422,985,921	396,098,036
Losses and loss expenses	289,503,373	240,394,302	240,197,659
Unearned premiums	228,988,598	214,372,048	199,966,888
Liability for losses and loss expenses	$ 252,263,547	$ 230,543,393	$ 216,194,945

Transactions with Affiliates 52

Transactions with Affiliates - Schedule of Southern and Le Mars Assumed from Donegal Mutual Pursuant to Quota-Share Reinsurance Agreements (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Losses and loss expenses	$ 114,865,113	$ 102,124,332	$ 100,110,773
Liability for losses and loss expenses	356,384,000
Southern and Le Mars [Member]
Ceded Credit Risk [Line Items]
Premiums earned	(271)	(1,512)	880,787
Losses and loss expenses	(690,268)	(378,199)	1,492,673
Unearned premiums	0	0	0
Liability for losses and loss expenses	$ 827,193	$ 3,222,100	$ 5,722,000

Transactions with Affiliates 53

Transactions with Affiliates - Schedule of Reinsurance Ceded to Donegal Mutual Pursuant to these Quota-Share Reinsurance Agreements (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums earned	$ 310,179,267	$ 282,646,219	$ 271,712,289
Prepaid reinsurance premiums	135,032,641	124,255,495
Donegal Mutual [Member]
Ceded Credit Risk [Line Items]
Premiums earned	42,578,047	39,917,800	37,299,760
Losses and loss expenses	24,978,631	21,524,856	19,735,479
Prepaid reinsurance premiums	19,827,115	19,180,421	17,172,112
Liability for losses and loss expenses	$ 36,396,109	$ 31,881,756	$ 29,968,948

Transactions with Affiliates 54

Transactions with Affiliates - Schedule of Insurance Subsidiaries Ceded to Donegal Mutual Pursuant to these Reinsurance Agreements (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums earned	$ 310,179,267	$ 282,646,219	$ 271,712,289
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Premiums earned	260,545,919	238,327,677	221,953,918
Catastrophe Reinsurance [Member] | Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Premiums earned	17,215,273	12,965,868	14,235,227
Losses and loss expenses	8,953,411	995,076	6,814,836
Liability for losses and loss expenses	$ 3,399,207	$ 3,136,438	$ 4,485,201

Transactions with Affiliates 55

Transactions with Affiliates - Schedule of Affiliated Reinsurance Transactions on Net Premiums Our Insurance Subsidiaries Earned (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Assumed	$ 451,515,575	$ 423,129,271	$ 397,142,483
Ceded	(310,179,267)	(282,646,219)	(271,712,289)
Net	190,924,704	184,656,732	175,024,905
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Assumed	451,470,623	422,984,409	396,978,823
Ceded	(260,545,919)	(238,327,677)	(221,953,918)
Net	$ 190,924,704	$ 184,656,732	$ 175,024,905

Transactions with Affiliates 56

Transactions with Affiliates - Schedule of Reinsurance Transactions on Net Losses and Loss Expenses Our Insurance Subsidiaries Incurred (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Assumed	$ 466,087,983	$ 437,532,812	$ 406,126,275
Ceded	(320,956,412)	(293,379,217)	(269,363,012)
Net premiums written	729,138,922	682,033,832	628,836,850
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Assumed	288,813,105	240,016,103	241,690,332
Ceded	(173,947,992)	(137,891,771)	(141,579,559)
Net premiums written	$ 114,865,113	$ 102,124,332	$ 100,110,773

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Estimated Fair Values of Fixed Maturities and Equity Securities (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	$ 366,655,077	$ 336,100,948
Held to Maturity, Gross Unrealized Gains	15,341,893	11,377,290
Held to Maturity, Gross Unrealized Losses	1,546,542	2,831,100
Total held to maturity, Estimated Fair Value	380,450,428	344,647,138
Available for Sale, Amortized Cost	582,633,434	554,061,339
Available for Sale, Gross Unrealized Gains	11,922,621	12,822,988
Available for Sale, Gross Unrealized Losses	5,164,762	4,721,545
Available for Sale, Estimated Fair Value	589,391,293	562,162,782
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	71,736,445	61,381,605
Held to Maturity, Gross Unrealized Gains	804,012	1,255,480
Held to Maturity, Gross Unrealized Losses	546,868	674,371
Total held to maturity, Estimated Fair Value	71,993,589	61,962,714
Available for Sale, Amortized Cost	44,759,456	39,093,734
Available for Sale, Gross Unrealized Gains	20,377	99,429
Available for Sale, Gross Unrealized Losses	730,409	605,139
Available for Sale, Estimated Fair Value	44,049,424	38,588,024
Obligations of States and Political Subdivisions [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	137,581,155	122,793,411
Held to Maturity, Gross Unrealized Gains	11,161,650	8,403,996
Held to Maturity, Gross Unrealized Losses	112,193	368,530
Total held to maturity, Estimated Fair Value	148,630,612	130,828,877
Available for Sale, Amortized Cost	128,478,000	179,889,661
Available for Sale, Gross Unrealized Gains	3,941,610	6,635,941
Available for Sale, Gross Unrealized Losses	302,440	442,717
Available for Sale, Estimated Fair Value	132,117,170	186,082,885
Corporate Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	108,024,776	91,555,136
Held to Maturity, Gross Unrealized Gains	2,860,255	1,172,002
Held to Maturity, Gross Unrealized Losses	730,843	1,678,133
Total held to maturity, Estimated Fair Value	110,154,188	91,049,005
Available for Sale, Amortized Cost	105,254,120	87,715,049
Available for Sale, Gross Unrealized Gains	1,010,744	662,132
Available for Sale, Gross Unrealized Losses	525,445	921,362
Available for Sale, Estimated Fair Value	105,739,419	87,455,819
Mortgage-Backed Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	49,312,701	60,370,796
Held to Maturity, Gross Unrealized Gains	515,976	545,812
Held to Maturity, Gross Unrealized Losses	156,638	110,066
Total held to maturity, Estimated Fair Value	49,672,039	60,806,542
Available for Sale, Amortized Cost	259,922,761	204,931,200
Available for Sale, Gross Unrealized Gains	444,603	637,268
Available for Sale, Gross Unrealized Losses	3,327,327	2,620,256
Available for Sale, Estimated Fair Value	257,040,037	202,948,212
Equity Securities [Member]
Schedule of Equity Method Investments [Line Items]
Available for Sale, Amortized Cost	44,219,097	42,431,695
Available for Sale, Gross Unrealized Gains	6,505,287	4,788,218
Available for Sale, Gross Unrealized Losses	279,141	132,071
Available for Sale, Estimated Fair Value	50,445,243	47,087,842
Fixed Maturities [Member]
Schedule of Equity Method Investments [Line Items]
Available for Sale, Amortized Cost	538,414,337	511,629,644
Available for Sale, Gross Unrealized Gains	5,417,334	8,034,770
Available for Sale, Gross Unrealized Losses	4,885,621	4,589,474
Available for Sale, Estimated Fair Value	$ 538,946,050	$ 515,074,940

Investments - Additional Inform

Investments - Additional Information (Detail)	Nov. 30, 2013USD ($)	Dec. 31, 2017USD ($)Securities	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Schedule of Investments [Line Items]
Net unrealized losses arising prior to reclassification date	$ 15,100,000
Amortization of unrealized losses recorded in accumulated other comprehensive income		$ 1,200,000
Accumulated other comprehensive loss		(2,684,275)	$ (2,254,271)
Amortized cost of fixed maturities on deposit with various regulatory authorities		9,646,390	9,632,126
Unrealized gains (losses)		$ 112,053	(103,331)	$ (263,991)
Depreciation of original cost value		20.00%
Time period for which individual security should be in unrealized position of twenty percentage or more to assume it as other than temporary decline		More than six months
Impairment losses		$ 0	0	0
Sales or transfers, held to maturity		0	0	0
Derivative instruments or hedging activities		$ 0	0	$ 0
Donegal Financial Services Corporation [Member]
Schedule of Investments [Line Items]
Percentage of ownership interest		48.20%
Investments in affiliates		$ 38,773,420	37,884,918
Distributions received		$ 1,000,000	1,600,000
Equity Securities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale | Securities		5
Obligations of States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		$ 190,700,000	220,100,000
Amortized cost of bond held		181,400,000	211,000,000
Special Revenue Bonds [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		90,000,000	96,800,000
Amortized cost of bond held		$ 84,700,000	$ 91,700,000
Education Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		53.00%	62.00%
Water and Sewer Utility Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		26.00%	23.00%
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale | Securities		280
Accumulated Net Unrealized Investment Losses [Member]
Schedule of Investments [Line Items]
Accumulated other comprehensive loss		$ (9,800,000)	$ (11,000,000)
Minimum [Member]
Schedule of Investments [Line Items]
Percentage of which the company held security of any issuer		10.00%	10.00%
Depreciation of original cost value		20.00%

Investments - Summary of Amor59

Investments - Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Held to maturity
Due in one year or less, Amortized Cost	$ 4,096,270
Due after one year through five years, Amortized Cost	57,702,099
Due after five years through ten years, Amortized Cost	118,294,836
Due after ten years, Amortized Cost	137,249,171
Mortgage-backed securities, Amortized Cost	49,312,701
Total held to maturity, Amortized Cost	366,655,077	$ 336,100,948
Available for sale
Due in one year or less, Amortized Cost	49,257,873
Due after one year through five years, Amortized Cost	97,814,378
Due after five years through ten years, Amortized Cost	103,015,782
Due after ten years, Amortized Cost	28,403,543
Mortgage-backed securities, Amortized Cost	259,922,761
Total available for sale, Amortized Cost	538,414,337	511,629,644
Held to maturity
Due in one year or less, Estimated Fair Value	4,090,120
Due after one year through five years, Estimated Fair Value	58,997,125
Due after five years through ten years, Estimated Fair Value	121,747,801
Due after ten years, Estimated Fair Value	145,943,343
Mortgage-backed securities, Estimated Fair Value	49,672,039
Total held to maturity, Estimated Fair Value	380,450,428	344,647,138
Available for sale
Due in one year or less, Estimated Fair Value	49,729,548
Due after one year through five years, Estimated Fair Value	98,914,332
Due after five years through ten years, Estimated Fair Value	103,609,213
Due after ten years, Estimated Fair Value	29,652,920
Mortgage-backed securities, Estimated Fair Value	257,040,037
Total available for sale, Estimated Fair Value	$ 538,946,050	$ 515,074,940

Investments - Summary of Financ

Investments - Summary of Financial Information (Detail) - Donegal Financial Services Corporation [Member] - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance sheets:
Total assets	$ 567,935,408	$ 535,590,133
Total liabilities	487,603,999	457,101,287
Stockholders' equity	80,331,409	78,488,846
Total liabilities and stockholders' equity	567,935,408	535,590,133
Income statements:
Net income	$ 3,362,861	$ 2,252,456	$ 2,372,650

Investments - Summary of Net In

Investments - Summary of Net Investment Income, Consisting Primarily of Interest and Dividends (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Marketable Securities [Line Items]
Investment income	$ 27,584,155	$ 26,478,162	$ 24,558,775
Investment expenses	(4,056,851)	(3,845,432)	(3,609,077)
Net investment income	23,527,304	22,632,730	20,949,698
Short-term investments [Member]
Marketable Securities [Line Items]
Investment income	407,580	115,763	181,154
Fixed Maturities [Member]
Marketable Securities [Line Items]
Investment income	26,143,924	25,066,582	23,636,468
Equity Securities [Member]
Marketable Securities [Line Items]
Investment income	999,335	1,187,814	707,703
Other [Member]
Marketable Securities [Line Items]
Investment income	$ 33,316	$ 108,003	$ 33,450

Investments - Summary of Gross

Investments - Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain (Loss) on Investments [Line Items]
Gross realized gains	$ 6,366,108	$ 3,539,656	$ 3,347,512
Gross realized losses	660,853	1,014,081	1,413,088
Net realized gains (losses)	5,705,255	2,525,575	1,934,424
Change in difference between fair value and cost of investments	3,905,577	(9,772,114)	(10,128,175)
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Gross realized gains	168,855	2,161,108	2,259,045
Gross realized losses	98,723	281,131	105,432
Change in difference between fair value and cost of investments	2,335,578	(12,932,470)	(10,787,772)
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Gross realized gains	6,197,253	1,378,548	1,088,467
Gross realized losses	562,130	732,950	1,307,656
Change in difference between fair value and cost of investments	$ 1,569,999	$ 3,160,356	$ 659,597

Investments - Summary of Fixed

Investments - Summary of Fixed Maturities and Equity Securities with Unrealized Losses (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 174,277,178	$ 332,842,702
Less Than 12 Months, Unrealized Losses	1,756,291	7,069,063
More Than 12 Months, Fair Value	203,736,737	5,834,053
More Than 12 Months, Unrealized Losses	4,955,013	483,582
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	24,024,445	37,729,947
Less Than 12 Months, Unrealized Losses	286,518	1,279,510
More Than 12 Months, Fair Value	33,987,229
More Than 12 Months, Unrealized Losses	990,759
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	10,223,383	40,739,099
Less Than 12 Months, Unrealized Losses	120,076	802,311
More Than 12 Months, Fair Value	14,127,415	710,280
More Than 12 Months, Unrealized Losses	294,557	8,936
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	35,203,959	80,181,238
Less Than 12 Months, Unrealized Losses	253,241	2,127,451
More Than 12 Months, Fair Value	31,560,591	4,706,945
More Than 12 Months, Unrealized Losses	1,003,047	472,044
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	100,533,516	168,771,543
Less Than 12 Months, Unrealized Losses	817,315	2,727,720
More Than 12 Months, Fair Value	124,061,502	416,828
More Than 12 Months, Unrealized Losses	2,666,650	2,602
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	4,291,875	5,420,875
Less Than 12 Months, Unrealized Losses	$ 279,141	$ 132,071

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurements for Investments in Available-for-Sale Fixed Maturity and Equity Securities (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 589,391,293	$ 562,162,782
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	44,049,424	38,588,024
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	132,117,170	186,082,885
Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	105,739,419	87,455,819
Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	257,040,037	202,948,212
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	50,445,243	47,087,842
Assets and Liabilities on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	589,391,293	562,162,782
Assets and Liabilities on Recurring Basis [Member] | Investments Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	13,709,122	11,165,505
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	575,682,171	550,997,277
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	44,049,424	38,588,024
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	132,117,170	186,082,885
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	105,739,419	87,455,819
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	257,040,037	202,948,212
Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	36,736,121	35,922,337
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets and Liabilities on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	36,736,121	35,922,337
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	36,736,121	35,922,337
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	36,736,121	35,922,337
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	538,946,050	515,074,940
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	538,946,050	515,074,940
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	44,049,424	38,588,024
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	132,117,170	186,082,885
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	105,739,419	87,455,819
Significant Other Observable Inputs (Level 2) [Member] | Assets and Liabilities on Recurring Basis [Member] | Total Investments in the Fair Value Hierarchy [Member] | Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 257,040,037	$ 202,948,212

Deferred Policy Acquisition C65

Deferred Policy Acquisition Costs - Changes in Insurance Subsidiaries' Deferred Policy Acquisition Costs (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Balance, January 1	$ 56,309,196	$ 52,108,388	$ 48,298,608
Acquisition costs deferred	119,045,664	112,076,808	103,322,780
Amortization charged to earnings	(115,065,000)	(107,876,000)	(99,513,000)
Balance, December 31	$ 60,289,860	$ 56,309,196	$ 52,108,388

Property and Equipment - Proper

Property and Equipment - Property and Equipment (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 21,463,856	$ 20,943,795
Accumulated depreciation	(14,183,441)	(14,275,306)
Property and equipment, Net	7,280,415	6,668,489
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	9,918,045	9,129,318
Automobiles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 779,357	1,334,385
Lease office equipment and automobiles range	5 years
Real Estate [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 7,971,590	7,685,228
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 2,794,864	$ 2,794,864
Lease office equipment and automobiles range	5 years
Minimum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	3 years
Minimum [Member] | Real Estate [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	5 years
Maximum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	15 years
Maximum [Member] | Real Estate [Member]
Property, Plant and Equipment [Line Items]
Lease office equipment and automobiles range	50 years

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 478,800	$ 742,861	$ 792,733

Liability for Losses and Loss68

Liability for Losses and Loss Expenses - Summary of Insurance Subsidiaries' Liability for Losses and Loss Expenses (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Liability for Claims and Claims Adjustment Expense [Abstract]
Balance at January 1	$ 606,664,590	$ 578,205,109	$ 538,258,406
Less reinsurance recoverable	(259,147,147)	(256,150,860)	(245,957,364)
Net balance at January 1	347,517,443	322,054,249	292,301,042
Incurred related to:
Current year	480,646,641	420,327,164	391,166,740
Prior years	6,621,413	2,988,739	7,200,134
Total incurred	487,268,054	423,315,903	398,366,874
Paid related to:
Current year	288,379,600	248,106,788	236,834,666
Prior years	163,005,427	149,745,921	131,779,001
Total paid	451,385,027	397,852,709	368,613,667
Net balance at December 31	383,400,470	347,517,443	322,054,249
Plus reinsurance recoverable	293,271,257	259,147,147	256,150,860
Balance at December 31	$ 676,671,727	$ 606,664,590	$ 578,205,109

Liability for Losses and Loss69

Liability for Losses and Loss Expenses - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Increase (Decrease) in liability for losses and loss expenses of prior years	$ 6,621,413	$ 2,988,739	$ 7,200,134
Percentage of 2010 development	1.90%	0.90%	2.50%

Liability for Losses and Loss70

Liability for Losses and Loss Expenses - Summary of Incurred and Paid Claims Development, Net of Reinsurance (Detail) $ in Thousands	Dec. 31, 2017USD ($)Claims	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)
Personal Automobile [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 1,314,137
Personal Automobile [Member] | 2008 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	100,915	$ 100,918	$ 100,923	$ 100,984	$ 100,819	$ 101,119	$ 101,388	$ 100,782	$ 101,937	$ 98,139
Total IBNR Plus Expected Development on Reported Claims	$ 9
Cumulative Number of Reported Claims | Claims	61
Personal Automobile [Member] | 2009 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 106,713	106,499	106,549	106,705	107,190	107,589	106,841	106,313	105,707
Total IBNR Plus Expected Development on Reported Claims	$ 15
Cumulative Number of Reported Claims | Claims	65
Personal Automobile [Member] | 2010 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 118,289	118,385	118,587	118,916	118,876	118,562	117,552	117,967
Total IBNR Plus Expected Development on Reported Claims	$ 45
Cumulative Number of Reported Claims | Claims	70
Personal Automobile [Member] | 2011 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 133,145	133,218	133,617	133,229	132,987	131,678	127,929
Total IBNR Plus Expected Development on Reported Claims	$ 97
Cumulative Number of Reported Claims | Claims	74
Personal Automobile [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 136,463	136,552	136,493	135,592	133,201	130,415
Total IBNR Plus Expected Development on Reported Claims	$ 249
Cumulative Number of Reported Claims | Claims	69
Personal Automobile [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 132,604	132,643	131,594	130,737	124,965
Total IBNR Plus Expected Development on Reported Claims	$ 438
Cumulative Number of Reported Claims | Claims	66
Personal Automobile [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 126,200	124,210	124,806	124,426
Total IBNR Plus Expected Development on Reported Claims	$ 905
Cumulative Number of Reported Claims | Claims	71
Personal Automobile [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 139,181	139,334	137,569
Total IBNR Plus Expected Development on Reported Claims	$ 2,713
Cumulative Number of Reported Claims | Claims	70
Personal Automobile [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 153,937	150,215
Total IBNR Plus Expected Development on Reported Claims	$ 7,327
Cumulative Number of Reported Claims | Claims	73
Personal Automobile [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 166,690
Total IBNR Plus Expected Development on Reported Claims	$ 26,640
Cumulative Number of Reported Claims | Claims	77
Homeowners [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 593,390
Homeowners [Member] | 2008 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 42,833	42,844	42,852	42,862	42,897	42,839	42,700	42,944	42,790	40,989
Cumulative Number of Reported Claims | Claims	18
Homeowners [Member] | 2009 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 50,435	50,433	50,419	50,405	50,137	49,998	50,333	50,621	51,054
Cumulative Number of Reported Claims | Claims	18
Homeowners [Member] | 2010 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 60,542	60,443	60,440	60,355	59,972	60,248	60,729	60,315
Cumulative Number of Reported Claims | Claims	25
Homeowners [Member] | 2011 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 70,479	70,351	70,297	70,381	70,436	70,461	71,256
Total IBNR Plus Expected Development on Reported Claims	$ (3)
Cumulative Number of Reported Claims | Claims	27
Homeowners [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 54,381	54,281	54,351	54,468	54,794	53,962
Total IBNR Plus Expected Development on Reported Claims	$ 44
Cumulative Number of Reported Claims | Claims	19
Homeowners [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 50,988	50,874	51,122	51,121	50,887
Total IBNR Plus Expected Development on Reported Claims	$ 47
Cumulative Number of Reported Claims | Claims	13
Homeowners [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 57,332	57,680	58,378	56,916
Total IBNR Plus Expected Development on Reported Claims	$ 6
Cumulative Number of Reported Claims | Claims	18
Homeowners [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 63,053	63,925	63,359
Total IBNR Plus Expected Development on Reported Claims	$ 157
Cumulative Number of Reported Claims | Claims	14
Homeowners [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 64,064	62,443
Total IBNR Plus Expected Development on Reported Claims	$ 833
Cumulative Number of Reported Claims | Claims	13
Homeowners [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 79,283
Total IBNR Plus Expected Development on Reported Claims	$ 4,166
Cumulative Number of Reported Claims | Claims	17
Commercial Automobile [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 375,212
Commercial Automobile [Member] | 2008 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 18,049	18,051	18,054	18,063	18,158	17,960	17,941	17,719	17,889	18,164
Cumulative Number of Reported Claims | Claims	6
Commercial Automobile [Member] | 2009 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 19,449	19,461	19,430	19,569	19,346	19,015	18,998	18,549	18,735
Total IBNR Plus Expected Development on Reported Claims	$ 3
Cumulative Number of Reported Claims | Claims	6
Commercial Automobile [Member] | 2010 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 21,713	21,746	21,756	21,490	21,477	20,695	19,913	19,315
Total IBNR Plus Expected Development on Reported Claims	$ 5
Cumulative Number of Reported Claims | Claims	7
Commercial Automobile [Member] | 2011 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 29,487	29,107	29,112	28,893	28,570	27,157	26,642
Total IBNR Plus Expected Development on Reported Claims	$ 1
Cumulative Number of Reported Claims | Claims	9
Commercial Automobile [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 31,648	31,278	31,435	30,606	27,720	26,557
Total IBNR Plus Expected Development on Reported Claims	$ 12
Cumulative Number of Reported Claims | Claims	8
Commercial Automobile [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 36,404	35,240	34,751	33,749	32,902
Total IBNR Plus Expected Development on Reported Claims	$ 196
Cumulative Number of Reported Claims | Claims	9
Commercial Automobile [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 48,213	47,326	44,544	42,760
Total IBNR Plus Expected Development on Reported Claims	$ 747
Cumulative Number of Reported Claims | Claims	11
Commercial Automobile [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 51,412	48,323	46,526
Total IBNR Plus Expected Development on Reported Claims	$ 2,639
Cumulative Number of Reported Claims | Claims	12
Commercial Automobile [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 57,353	54,302
Total IBNR Plus Expected Development on Reported Claims	$ 4,793
Cumulative Number of Reported Claims | Claims	13
Commercial Automobile [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 61,484
Total IBNR Plus Expected Development on Reported Claims	$ 17,554
Cumulative Number of Reported Claims | Claims	13
Commercial Multi-Peril [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 396,822
Commercial Multi-Peril [Member] | 2008 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 26,998	27,184	27,258	27,182	27,023	27,286	26,906	26,796	27,693	26,868
Cumulative Number of Reported Claims | Claims	5
Commercial Multi-Peril [Member] | 2009 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 27,508	27,484	27,625	27,959	27,739	27,357	27,357	26,454	26,712
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2010 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 29,779	29,463	29,453	29,373	29,169	29,390	29,656	28,745
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2011 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 38,105	38,270	37,385	37,576	35,942	35,411	33,054
Total IBNR Plus Expected Development on Reported Claims	$ 13
Cumulative Number of Reported Claims | Claims	7
Commercial Multi-Peril [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 36,214	35,755	34,117	32,449	30,716	29,789
Total IBNR Plus Expected Development on Reported Claims	$ 33
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 37,981	37,205	37,292	35,679	35,683
Total IBNR Plus Expected Development on Reported Claims	$ 155
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 52,336	51,843	50,135	48,204
Total IBNR Plus Expected Development on Reported Claims	$ 608
Cumulative Number of Reported Claims | Claims	7
Commercial Multi-Peril [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 44,728	43,874	42,070
Total IBNR Plus Expected Development on Reported Claims	$ 3,028
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 46,988	43,005
Total IBNR Plus Expected Development on Reported Claims	$ 4,991
Cumulative Number of Reported Claims | Claims	6
Commercial Multi-Peril [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 56,185
Total IBNR Plus Expected Development on Reported Claims	$ 13,847
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 393,629
Workers' Compensation [Member] | 2008 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	25,797	25,713	25,963	25,941	26,226	26,471	26,791	27,037	26,361	$ 24,034
Total IBNR Plus Expected Development on Reported Claims	$ 61
Cumulative Number of Reported Claims | Claims	5
Workers' Compensation [Member] | 2009 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 22,079	22,114	22,172	22,278	22,848	21,826	21,894	22,497	$ 21,571
Total IBNR Plus Expected Development on Reported Claims	$ 65
Cumulative Number of Reported Claims | Claims	4
Workers' Compensation [Member] | 2010 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 26,984	27,037	27,121	26,944	26,637	27,010	27,859	$ 27,304
Total IBNR Plus Expected Development on Reported Claims	$ 98
Cumulative Number of Reported Claims | Claims	5
Workers' Compensation [Member] | 2011 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 35,194	35,039	35,670	36,369	36,614	35,757	$ 32,490
Total IBNR Plus Expected Development on Reported Claims	$ 138
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2012 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 36,468	37,163	37,926	38,827	39,516	$ 39,142
Total IBNR Plus Expected Development on Reported Claims	$ 211
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2013 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 42,327	42,828	44,289	47,027	$ 46,325
Total IBNR Plus Expected Development on Reported Claims	$ 447
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2014 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 48,537	49,288	51,553	$ 51,508
Total IBNR Plus Expected Development on Reported Claims	$ 996
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2015 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 45,991	49,615	$ 53,332
Total IBNR Plus Expected Development on Reported Claims	$ 2,470
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2016 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 49,802	$ 58,814
Total IBNR Plus Expected Development on Reported Claims	$ 6,741
Cumulative Number of Reported Claims | Claims	6
Workers' Compensation [Member] | 2017 [Member]
Claims Development [Line Items]
Incurred Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 60,450
Total IBNR Plus Expected Development on Reported Claims	$ 21,116
Cumulative Number of Reported Claims | Claims	6

Liability for Losses and Loss71

Liability for Losses and Loss Expenses - Summary of Cumulative Claim Frequency and Total of Incurred but not Reported Claims plus Expected Development on Reported Claims Incurred (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Personal Automobile [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 1,212,999
All outstanding liabilities before 2008, net of reinsurance	540
Liabilities for claims and claims adjustment expenses, net of reinsurance	101,678
Personal Automobile [Member] | 2008 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	100,790	$ 100,778	$ 100,712	$ 100,642	$ 100,153	$ 99,110	$ 97,134	$ 93,325	$ 85,262	$ 66,648
Personal Automobile [Member] | 2009 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	106,477	106,017	105,922	105,577	104,779	102,332	97,349	89,089	69,585
Personal Automobile [Member] | 2010 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	118,054	117,978	117,812	116,748	113,243	107,662	96,749	75,889
Personal Automobile [Member] | 2011 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	132,714	132,479	131,319	127,545	121,621	110,249	87,191
Personal Automobile [Member] | 2012 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	134,581	133,428	130,862	124,652	111,941	87,517
Personal Automobile [Member] | 2013 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	130,026	125,946	120,118	109,051	84,241
Personal Automobile [Member] | 2014 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	120,491	114,893	104,736	85,377
Personal Automobile [Member] | 2015 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	128,395	116,303	93,611
Personal Automobile [Member] | 2016 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	129,507	102,433
Personal Automobile [Member] | 2017 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	111,964
Homeowners [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	577,461
All outstanding liabilities before 2008, net of reinsurance	15
Liabilities for claims and claims adjustment expenses, net of reinsurance	15,944
Homeowners [Member] | 2008 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	42,833	42,812	42,817	42,797	42,699	42,511	42,095	41,582	40,037	32,548
Homeowners [Member] | 2009 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	50,435	50,433	50,429	50,430	50,301	50,021	49,827	49,180	39,961
Homeowners [Member] | 2010 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	60,525	60,501	60,486	60,239	59,875	59,283	57,334	47,419
Homeowners [Member] | 2011 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	70,648	70,626	70,541	70,351	70,125	69,345	57,588
Homeowners [Member] | 2012 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	54,356	54,317	54,298	54,028	53,619	46,566
Homeowners [Member] | 2013 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	51,043	50,478	50,210	49,410	40,949
Homeowners [Member] | 2014 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	57,195	56,990	56,255	45,823
Homeowners [Member] | 2015 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	62,204	61,542	51,885
Homeowners [Member] | 2016 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	61,145	50,125
Homeowners [Member] | 2017 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	67,077
Commercial Automobile [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	305,328
All outstanding liabilities before 2008, net of reinsurance	10
Liabilities for claims and claims adjustment expenses, net of reinsurance	69,894
Commercial Automobile [Member] | 2008 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	18,049	18,051	18,051	18,052	17,548	17,110	16,077	14,115	12,330	9,204
Commercial Automobile [Member] | 2009 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	19,413	19,408	19,386	19,389	18,696	17,160	15,479	12,872	9,309
Commercial Automobile [Member] | 2010 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	21,549	21,482	21,014	20,804	19,030	16,426	14,180	10,778
Commercial Automobile [Member] | 2011 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	28,836	28,758	28,014	26,973	24,267	19,106	13,876
Commercial Automobile [Member] | 2012 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	30,402	29,873	27,417	23,718	20,240	13,642
Commercial Automobile [Member] | 2013 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	34,083	31,053	26,879	23,557	16,306
Commercial Automobile [Member] | 2014 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	44,374	39,436	31,089	22,707
Commercial Automobile [Member] | 2015 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	41,678	35,342	23,875
Commercial Automobile [Member] | 2016 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	38,237	27,033
Commercial Automobile [Member] | 2017 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	28,707
Commercial Multi-Peril [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	330,857
All outstanding liabilities before 2008, net of reinsurance	266
Liabilities for claims and claims adjustment expenses, net of reinsurance	66,231
Commercial Multi-Peril [Member] | 2008 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	26,996	27,017	26,956	26,760	25,983	25,154	24,161	22,991	21,645	16,128
Commercial Multi-Peril [Member] | 2009 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	27,409	27,357	27,287	26,780	26,212	24,977	21,560	19,356	13,675
Commercial Multi-Peril [Member] | 2010 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	29,632	28,906	28,681	27,768	26,832	24,749	22,017	17,007
Commercial Multi-Peril [Member] | 2011 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	38,240	37,759	36,722	33,526	30,286	24,767	18,773
Commercial Multi-Peril [Member] | 2012 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	35,331	33,327	29,370	26,634	23,384	16,666
Commercial Multi-Peril [Member] | 2013 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	35,104	33,614	29,159	26,216	19,875
Commercial Multi-Peril [Member] | 2014 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	47,021	40,936	35,520	27,920
Commercial Multi-Peril [Member] | 2015 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	34,323	29,419	21,837
Commercial Multi-Peril [Member] | 2016 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	29,402	19,660
Commercial Multi-Peril [Member] | 2017 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	27,399
Workers' Compensation [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	299,841
All outstanding liabilities before 2008, net of reinsurance	3,445
Liabilities for claims and claims adjustment expenses, net of reinsurance	97,233
Workers' Compensation [Member] | 2008 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	25,250	25,112	25,017	24,880	24,551	23,782	21,933	19,199	14,776	$ 6,562
Workers' Compensation [Member] | 2009 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	21,400	21,117	20,939	20,476	19,665	18,329	16,516	12,627	$ 6,490
Workers' Compensation [Member] | 2010 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	26,050	25,804	25,337	24,539	23,137	21,176	15,937	$ 8,066
Workers' Compensation [Member] | 2011 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	33,577	33,067	32,394	31,905	27,517	21,450	$ 9,157
Workers' Compensation [Member] | 2012 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	34,177	33,196	31,244	28,812	22,963	$ 11,097
Workers' Compensation [Member] | 2013 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	38,877	36,351	32,783	26,043	$ 13,052
Workers' Compensation [Member] | 2014 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	40,393	36,284	28,513	$ 13,932
Workers' Compensation [Member] | 2015 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	34,192	27,531	$ 13,071
Workers' Compensation [Member] | 2016 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	30,344	$ 14,709
Workers' Compensation [Member] | 2017 [Member]
Claims Development [Line Items]
Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance	$ 15,581

Liability for Losses and Loss72

Liability for Losses and Loss Expenses - Reconciliation of Net Incurred and Paid Claims Development Tables to Liability for Claims and Claim Adjustment Expenses (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Claims Development [Line Items]
Net outstanding liabilities	$ 356,384,000
Reinsurance recoverable	280,801,000
Unallocated loss adjustment expenses	39,487,000
Gross liability for unpaid losses and loss expenses	676,671,727	$ 606,664,590	$ 578,205,109	$ 538,258,406
Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	101,678,000
Reinsurance recoverable	94,091,000
Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	15,944,000
Reinsurance recoverable	11,465,000
Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	69,894,000
Reinsurance recoverable	45,201,000
Commercial Multi-Peril [Member]
Claims Development [Line Items]
Net outstanding liabilities	66,231,000
Reinsurance recoverable	40,685,000
Workers' Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	97,233,000
Reinsurance recoverable	85,528,000
Other Products and Service [Member]
Claims Development [Line Items]
Net outstanding liabilities	5,404,000
Reinsurance recoverable	$ 3,831,000

Liability for Losses and Loss73

Liability for Losses and Loss Expenses - Supplementary Information About Average Historical Claims Duration (Detail)	Dec. 31, 2017
Personal Automobile [Member]
Claims Development [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 1	65.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 2	17.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 3	8.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 4	4.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 5	2.50%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 6	0.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 7	0.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 8	0.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 9	0.20%
Homeowners [Member]
Claims Development [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 1	80.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 2	16.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 3	1.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 4	0.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 5	0.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 6	0.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 7	0.10%
Commercial Automobile [Member]
Claims Development [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 1	47.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 2	18.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 3	12.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 4	10.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 5	6.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 6	2.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 7	1.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 8	0.10%
Commercial Multi-Peril [Member]
Claims Development [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 1	50.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 2	17.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 3	9.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 4	9.00%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 5	5.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 6	3.30%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 7	1.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 8	1.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 9	0.20%
Workers' Compensation [Member]
Claims Development [Line Items]
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 1	28.40%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 2	31.10%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 3	16.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 4	8.90%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 5	5.20%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 6	2.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 7	1.60%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 8	0.70%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 9	0.80%
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance, Year 10	0.50%

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jul. 31, 2017
Line of Credit Facility [Line Items]
Line of credit expiration month and year	2020-07
Outstanding borrowings	$ 59,000,000	$ 69,000,000
Line of credit, interest rate description	Interest rates equal to M&T's current prime rate or the then-current LIBOR rate plus 2.25%.
Percentage commitment fee	0.25%
Interest paid	$ 250,000	250,000	$ 250,000
Manufacturers and Traders Trust Company [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings	24,000,000
Line of credit facility remaining borrowing capacity	$ 36,000,000
Interest rate on borrowings	3.82%
Line of credit covenant description	The credit agreement requires our compliance with certain covenants. These covenants include minimum levels of our net worth, leverage ratio, statutory surplus and the A.M. Best ratings of our insurance subsidiaries. We complied with all requirements of the credit agreement during 2017.
FHLB of Indianapolis [Member] | MICO [Member]
Line of Credit Facility [Line Items]
Outstanding advances	$ 0	$ 0
FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Right to request for extension of credit agreement with Manufacturers and Traders Trust Company	576,324
Outstanding advances	$ 35,000,000
Revolving Credit Facility [Member] | Manufacturers and Traders Trust Company [Member]
Line of Credit Facility [Line Items]
Right to request for extension of credit agreement with Manufacturers and Traders Trust Company				$ 60,000,000
Lines of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Debt instrument basis spread on variable rate	2.25%
Lines of Credit [Member] | FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Interest rate on advances	1.25%
Subordinated Debentures [Member]
Line of Credit Facility [Line Items]
Debt instrument stated interest rate	5.00%
Subordinated Debentures [Member] | West Bend Mutual Insurance Company [Member]
Line of Credit Facility [Line Items]
Surplus note	$ 5,000,000

Borrowings - Amount of FHLB of

Borrowings - Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement (Detail)	Dec. 31, 2017USD ($)
MICO [Member] | FHLB of Indianapolis [Member]
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement
FHLB stock purchased and owned as part of the agreement	$ 267,700
Collateral pledged, at par	2,850,000
Borrowing capacity currently available	2,592,075
Atlantic States [Member] | FHLB of Pittsburgh [Member]
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement
FHLB stock purchased and owned as part of the agreement	1,599,700
Collateral pledged, at par	37,322,954
Borrowing capacity currently available	$ 576,324

Borrowings - Amount of FHLB o76

Borrowings - Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement (Parenthetical) (Detail)	Dec. 31, 2017USD ($)
FHLB of Indianapolis [Member] | MICO [Member]
Line of Credit Facility [Line Items]
Collateral Pledged at carrying value	$ 2,751,398
FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Collateral Pledged at carrying value	$ 36,850,815

Reinsurance - Additional Inform

Reinsurance - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2010
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	$ 1,000,000
Percentage of accumulation of losses	100.00%
Catastrophe reinsurance, set retention amount	$ 5,000,000
Catastrophe reinsurance, deductible amount	1,000,000	$ 975,000	$ 1,500,000
Workers' compensation insurance	$ 10,000,000
Percentage of reinsurer coverage	25.00%
Quota share reinsurance percentage				75.00%
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	$ 5,000,000
Excess of loss treaties	50,000,000
Donegal Mutual [Member]
Ceded Credit Risk [Line Items]
Excess of loss reinsured under an agreement	500,000
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	$ 175,000,000

Reinsurance - Ceded Reinsurance

Reinsurance - Ceded Reinsurance Transactions with Unaffiliated Reinsurers (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums written	$ 320,956,412	$ 293,379,217	$ 269,363,012
Premiums earned	310,179,267	282,646,219	271,712,289
Prepaid reinsurance premiums	135,032,641	124,255,495
Unaffiliated Entity [Member]
Ceded Credit Risk [Line Items]
Premiums written	51,241,267	45,354,233	40,997,351
Premiums earned	49,633,348	44,318,542	49,758,371
Losses and loss expenses	44,575,268	18,588,114	30,722,807
Prepaid reinsurance premiums	11,213,665	9,605,746	8,570,055
Liability for losses and loss expenses	$ 116,689,871	$ 103,694,418	$ 113,023,942

Reinsurance - Total Ceded Reins

Reinsurance - Total Ceded Reinsurance Transactions with both Affiliated and Unaffiliated Reinsurers (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Premiums earned	$ 310,179,267	$ 282,646,219	$ 271,712,289
Prepaid reinsurance premiums	135,032,641	124,255,495
Affiliated Entity and Unaffiliated Entity [Member]
Ceded Credit Risk [Line Items]
Premiums earned	310,179,267	282,646,219	271,712,289
Losses and loss expenses	218,523,260	156,479,885	172,302,366
Prepaid reinsurance premiums	135,032,641	124,255,495	113,522,505
Liability for losses and loss expenses	$ 293,271,257	$ 259,147,147	$ 256,150,860

Reinsurance - Amounts Represent

Reinsurance - Amounts Represent Effect of Reinsurance on Premiums Written (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Premiums Written, Net [Abstract]
Direct	$ 584,007,351	$ 537,880,237	$ 492,073,587
Assumed	466,087,983	437,532,812	406,126,275
Ceded	(320,956,412)	(293,379,217)	(269,363,012)
Net premiums written	$ 729,138,922	$ 682,033,832	$ 628,836,850

Reinsurance - Amounts Represe81

Reinsurance - Amounts Represent Effect of Reinsurance on Premiums Earned (Detail) - USD ($)	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
Reinsurance Disclosures [Abstract]
Direct									$ 561,178,447	$ 515,721,745	$ 480,210,534
Assumed									451,515,575	423,129,271	397,142,483
Ceded									(310,179,267)	(282,646,219)	(271,712,289)
Net premiums earned	$ 181,059,920	$ 177,283,816	$ 175,014,872	$ 169,156,147	$ 168,977,030	$ 166,809,851	$ 161,942,637	$ 158,475,279	$ 702,514,755	$ 656,204,797	$ 605,640,728
Percentage of assumed premiums earned to net premiums earned									64.30%	64.50%	65.60%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Effective tax rate computed at the statutory federal rate		35.00%	35.00%	35.00%
Additional tax expense related to new corporate tax rate reform		$ 4,752,547
Reclassification of an alternative minimum tax credit carry forward		8,500,000	$ 7,357,733
Other deferred tax assets, net		23,100,000	43,100,000
Parent Company [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards		$ 77,100,000	72,000,000
Scenario, Forecast [Member]
Operating Loss Carryforwards [Line Items]
Effective tax rate computed at the statutory federal rate	21.00%
Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination		2,014
Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination		2,017
Le Mars [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards		$ 264,467	$ 440,778
Operating loss carryforwards		$ 3,300,000
Operating loss carryforwards expiration period		2,020
Operating loss carryforwards annual limitations in amount on use		$ 376,000

Income Taxes - Provision for In

Income Taxes - Provision for Income Tax (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current	$ (2,139,061)	$ 8,496,405	$ 5,621,367
Deferred	7,137,423	2,030,865	980,868
Federal income tax provision	$ 4,998,362	$ 10,527,270	$ 6,602,235

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Income Tax Rate (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income before income taxes	$ 12,114,462	$ 41,328,407	$ 27,592,268
Computed "expected" taxes	4,240,062	14,464,942	9,657,294
Tax-exempt interest	(3,241,530)	(3,951,926)	(4,806,855)
Proration	518,948	629,697	737,644
Effect of tax reform	4,752,547
Dividends received deduction	(508,409)	(691,616)	(701,658)
Tax benefit on exercise of options	(873,515)
Other, net	110,259	76,173	1,715,810
Federal income tax provision	$ 4,998,362	$ 10,527,270	$ 6,602,235

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Unearned premium	$ 15,511,854	$ 23,964,558
Loss reserves	4,164,246	6,460,683
Alternative minimum tax credit carryforward	8,500,000	7,357,733
Net unrealized losses	713,549	1,213,836
Other	2,300,595	3,307,286
Total gross deferred tax assets	100,506,229	115,624,741
Less valuation allowance	(77,396,473)	(72,490,012)
Net deferred tax assets	23,109,756	43,134,729
Deferred tax liabilities:
Deferred policy acquisition costs	12,660,871	19,708,220
Other	3,320,042	4,383,096
Total gross deferred tax liabilities	15,980,913	24,091,316
Net deferred tax asset	7,128,843	19,043,413
Le Mars [Member]
Deferred tax assets:
Net operating loss carryforward	683,979	1,271,411
Parent Company [Member]
Deferred tax assets:
Net state operating loss carryforward	$ 77,132,006	$ 72,049,234

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Dec. 22, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Jul. 18, 2013
Equity, Class of Treasury Stock [Line Items]
Minimum percentage of class A common stock declared dividend excess over class B dividend		10.00%
Common stock value purchased				$ 28,124,675
Premium paid on purchase of treasury stock				$ 5,780,000
Purchase agreement period	25 years
M &T Bank [Member]
Equity, Class of Treasury Stock [Line Items]
Existing line of credit amount	$ 33,000,000
Class A Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock shares purchased	2,000,000
Common stock value purchased	$ 33,000,000
Common stock per share on purchase	$ 16.50
Premium paid on purchase of treasury stock	$ 5,800,000
Treasury stock		3,002,588	3,002,588		3,002,588
Class A Common Stock [Member] | Stock Repurchase Program Two [Member]
Equity, Class of Treasury Stock [Line Items]
Authority to purchase shares						500,000
Common stock shares purchased		0	0	57,658	57,658
Class B Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Treasury stock		72,465	72,465		72,465

Stock Compensation Plans - Addi

Stock Compensation Plans - Additional Information (Detail) - USD ($)	Jan. 01, 2018	Jan. 03, 2017	Jan. 04, 2016	Jan. 02, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense in stock compensation plans					$ 2,000,000	$ 2,500,000	$ 2,600,000
Income tax benefit of stock compensation plans					692,164	864,210	896,753
Unrecognized compensation expense related to nonvested share-based compensation granted under the plan					$ 2,900,000	3,700,000
Weighted average period of unrecognized compensation expense					1 year 9 months 18 days
Cash from option exercises					$ 13,400,000	11,200,000	13,700,000
Tax benefit for tax deductions from option exercises					$ 873,515	$ 788,700	$ 437,474
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period of stock options							5 years
Restricted shares issued to directors							500
Weighted-average grant date fair value of options granted					$ 1.81	$ 1.94	$ 1.55
Fair value of risk-free interest rate					2.01%	2.23%	1.86%
Expected life					3 years	3 years	3 years
Expected volatility					19.00%	20.00%	23.00%
Expected dividend yield					3.00%	3.00%	4.00%
Shares available for future option grants					974,001
Equity Incentive Plan [Member] | Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance to employees of subsidiaries and affiliates under identical plan							4,500,000
Common stock available for issuance to directors and those of the subsidiaries and affiliates under identical plan							500,000
Equity Incentive Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional issued shares		9,000	8,500	7,200
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period of stock options					10 years
Common stock available for issuance to employees/directors and those of the subsidiaries and affiliates								300,000
Percentage of purchase price of shares					85.00%
Employee Stock Purchase Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional issued shares	20,662
Shares issued during period price per share	$ 13.34
Agency Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional issued shares					104,418	99,800	84,198
Common stock available for issuance to employees/directors and those of the subsidiaries and affiliates							350,000
Percentage of purchase price of shares					90.00%
Investment					$ 12,000
Number of trading days of subscription period					10 days

Stock Compensation Plans - Info

Stock Compensation Plans - Information Regarding Activity in Stock Option Plans (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Number of Options, Outstanding Beginning Balance	9,338,648	8,794,952	8,183,430
Number of Options, Granted	943,000	1,417,500	1,710,500
Number of Options, Exercised	(924,019)	(832,467)	(983,370)
Number of Options, Forfeited	(93,167)	(41,337)	(114,967)
Number of Options, Expired			(641)
Number of Options, Outstanding Ending Balance	9,264,462	9,338,648	8,794,952
Number of Options, Exercisable	6,946,677	6,347,470	5,250,338
Weighted-Average Exercise Price Per Share, Outstanding Beginning Balance	$ 14.95	$ 14.57	$ 14.69
Weighted-Average Exercise Price Per Share, Granted	17.58	16.44	13.64
Weighted-Average Exercise Price Per Share, Exercised	14.45	13.44	13.91
Weighted-Average Exercise Price Per Share, Forfeited	15.43	14.97	15.30
Weighted-Average Exercise Price Per Share, Expired			14
Weighted-Average Exercise Price Per Share, Outstanding Ending Balance	15.26	14.95	14.57
Weighted-Average Exercise Price Per Share, Exercisable	$ 14.90	$ 14.77	$ 14.42

Stock Compensation Plans - Summ

Stock Compensation Plans - Summary of Information about Stock Options Outstanding (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options Outstanding	9,264,462
Number of Options Exercisable	6,946,677	6,347,470	5,250,338
July 27, 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 12.50
Number of Options Outstanding	1,027,606
Weighted-Average Remaining Contractual Life	4 years
Number of Options Exercisable	1,027,606
December 20, 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 14.50
Number of Options Outstanding	1,062,319
Weighted-Average Remaining Contractual Life	5 years
Number of Options Exercisable	1,062,319
December 19, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 15.90
Number of Options Outstanding	2,102,006
Weighted-Average Remaining Contractual Life	6 years
Number of Options Exercisable	2,102,006
December 18, 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 15.80
Number of Options Outstanding	1,362,415
Weighted-Average Remaining Contractual Life	7 years
Number of Options Exercisable	1,362,415
December 17, 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 13.64
Number of Options Outstanding	1,404,174
Weighted-Average Remaining Contractual Life	3 years
Number of Options Exercisable	936,022
December 15, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 16.48
Number of Options Outstanding	1,368,942
Weighted-Average Remaining Contractual Life	4 years
Number of Options Exercisable	456,309
December 21, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price	$ 17.60
Number of Options Outstanding	937,000
Weighted-Average Remaining Contractual Life	5 years

Stock Compensation Plans - Su90

Stock Compensation Plans - Summary of Plan Activity (Detail) - $ / shares	Jul. 01, 2017	Jan. 01, 2017	Jul. 01, 2016	Jan. 01, 2016	Jul. 01, 2015	Jan. 01, 2015
Issue Date One [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price						$ 12.40
Shares Issued, Shares						17,662
Issue Date Two [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price					$ 12.95
Shares Issued, Shares					20,006
Issue Date Three [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price				$ 11.97
Shares Issued, Shares				18,387
Issue Date Four [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price			$ 11.83
Shares Issued, Shares			22,418
Issue Date Five [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price		$ 13.76
Shares Issued, Shares		18,512
Issue Date Six [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares Issued, Price	$ 13.52
Shares Issued, Shares	25,155

Statutory Net Income, Capital91

Statutory Net Income, Capital and Surplus and Dividend Restrictions - Statutory Net Income, Capital and Surplus and Dividend (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	$ 407,125,532	$ 421,752,063	$ 396,840,338
Statutory net (loss) income	1,677,549	26,926,349	22,311,517
Atlantic States [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	223,170,835	227,907,377	207,636,824
Statutory unassigned surplus	161,760,924	167,872,138	149,257,062
Statutory net (loss) income	(312,221)	15,750,876	13,352,784
Southern [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	54,503,581	63,331,001	61,742,861
Statutory unassigned surplus	2,914,532	11,881,309	10,459,840
Statutory net (loss) income	(3,375,434)	1,774,299	2,301,009
Le Mars [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	23,434,801	25,543,803	26,168,865
Statutory unassigned surplus	10,394,533	12,614,756	13,367,321
Statutory net (loss) income	(1,679,335)	603,226	(600,608)
Peninsula [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	39,396,818	41,977,034	41,838,137
Statutory unassigned surplus	21,148,253	23,826,681	23,813,003
Statutory net (loss) income	(841,119)	966,391	1,976,093
Sheboygan [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	13,823,118	13,129,143	13,254,117
Statutory unassigned surplus	554,498	914,773	1,107,421
Statutory net (loss) income	(46,116)	644,344	1,719,703
MICO [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	52,796,379	49,863,705	46,199,534
Statutory unassigned surplus	26,162,540	23,380,942	19,894,850
Statutory net (loss) income	$ 7,931,774	$ 7,187,213	$ 3,562,536

Statutory Net Income, Capital92

Statutory Net Income, Capital and Surplus and Dividend Restrictions - Additional Information (Detail)	Dec. 31, 2017USD ($)
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	$ 37,000,000
Atlantic States [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	22,300,000
Southern [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	5,500,000
Le Mars [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	2,300,000
Peninsula [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	1,600,000
Sheboygan [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	0
MICO [Member]
Statutory Accounting Practices [Line Items]
Amounts available for distribution as dividends	$ 5,300,000

Reconciliation of Statutory F93

Reconciliation of Statutory Filings to Amounts Reported Herein - Reconciliations of Statutory Net Income and Capital and Surplus (Detail) - USD ($)	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, 2014
Disclosure Text Block [Abstract]
Statutory net income of insurance subsidiaries									$ 1,677,549	$ 26,926,349	$ 22,311,517
Increases (decreases):
Deferred policy acquisition costs									3,980,664	4,200,808	3,809,780
Deferred federal income taxes									1,334,410	(2,030,865)	(168,395)
Salvage and subrogation recoverable									1,199,200	1,502,600	1,082,800
Consolidating eliminations and adjustments									(13,534,428)	(12,327,517)	(3,679,277)
Parent-only net income (loss)									12,458,705	12,529,762	(2,366,392)
Net income	$ (2,778,644)	$ 7,108,574	$ (2,318,648)	$ 5,104,818	$ 5,554,166	$ 4,813,404	$ 8,584,654	$ 11,848,913	7,116,100	30,801,137	20,990,033
Statutory capital and surplus of insurance subsidiaries	407,125,532				421,752,063				407,125,532	421,752,063	396,840,338
Increases (decreases):
Deferred policy acquisition costs	60,289,860				56,309,196				60,289,860	56,309,196	52,108,388	$ 48,298,608
Deferred federal income taxes	(14,422,511)				(20,843,506)				(14,422,511)	(20,843,506)	(16,930,202)
Salvage and subrogation recoverable	17,976,600				16,777,400				17,976,600	16,777,400	15,274,800
Non-admitted assets and other adjustments, net	1,960,089				1,689,814				1,960,089	1,689,814	2,441,591
Fixed maturities	(8,748,140)				(7,271,932)				(8,748,140)	(7,271,932)	957,401
Parent-only equity and other adjustments	(15,485,326)				(29,797,715)				(15,485,326)	(29,797,715)	(42,303,748)
Total stockholders' equity	$ 448,696,104				$ 438,615,320				$ 448,696,104	$ 438,615,320	$ 408,388,568	$ 416,134,643

Supplementary Cash Flow Infor94

Supplementary Cash Flow Information - Net Income Taxes and Interest Paid (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Income taxes	$ 3,050,000	$ 7,305,000	$ 7,100,000
Interest	$ 1,341,706	$ 1,377,247	$ 870,675

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017shares
Equity [Abstract]
Minimum percentage of class A common stock declared dividend excess over class B dividend	10.00%
Options excluded from diluted earnings per share	937,000

Earnings Per Share - Summary of

Earnings Per Share - Summary of Reconciliation of Numerators and Denominators Used in Basic and Diluted Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Class A Common Stock [Member]
Basic and diluted earnings per share:
Allocation of net income									$ 5,879	$ 24,885	$ 17,155
Number of shares used in basic computation									21,799	20,917	22,046
Weighted-average effect of dilutive securities
Add: Director and employee stock options									843	613	348
Number of shares used in per share computations									22,642	21,530	22,394
Weighted-average shares outstanding									21,799	20,917	22,046
Numerator:
Allocation of net income									$ 5,879	$ 24,885	$ 17,155
Denominator:
Weighted-average shares outstanding									21,799	20,917	22,046
Basic earnings per share	$ (0.10)	$ 0.27	$ (0.09)	$ 0.19	$ 0.21	$ 0.19	$ 0.33	$ 0.46	$ 0.27	$ 1.19	$ 0.78
Denominator:
Diluted earnings per share	(0.10)	0.26	(0.08)	0.18	0.20	0.18	0.32	0.46	$ 0.26	$ 1.16	$ 0.77
Class B Common Stock [Member]
Basic and diluted earnings per share:
Allocation of net income									$ 1,237	$ 5,916	$ 3,835
Number of shares used in basic computation									5,577	5,577	5,577
Weighted-average effect of dilutive securities
Weighted-average shares outstanding									5,577	5,577	5,577
Basic and diluted earnings per share	$ (0.11)	$ 0.24	$ (0.08)	$ 0.17	$ 0.18	$ 0.16	$ 0.30	$ 0.42	$ 0.22	$ 1.06	$ 0.69
Denominator:
Weighted-average shares outstanding									5,577	5,577	5,577
Basic earnings per share									$ 0.22	$ 1.06	$ 0.69
Denominator:
Diluted earnings per share									$ 0.22	$ 1.06	$ 0.69

Condensed Financial Informati97

Condensed Financial Information of Parent Company - Summary of Condensed Balance Sheets (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Short-term investments	$ 11,049,915	$ 9,371,007
Cash	37,833,435	24,587,214	$ 28,139,144	$ 35,578,509
Property and equipment	7,280,415	6,668,489
Other	1,483,769	1,137,863
Total assets	1,737,919,778	1,623,131,037
Liabilities
Cash dividends declared to stockholders	3,841,820	3,622,821
Borrowings under lines of credit	59,000,000	69,000,000
Other	1,789,283	1,556,859
Total liabilities	1,289,223,674	1,184,515,717
Stockholders' equity	448,696,104	438,615,320	408,388,568	416,134,643
Total liabilities and stockholders' equity	1,737,919,778	1,623,131,037
Parent Company [Member]
Assets
Investment in subsidiaries/affiliates (equity method)	509,011,000	510,731,000
Short-term investments	29,000	30,000
Cash	3,237,000	1,820,000	$ 1,153,000	$ 1,543,000
Property and equipment	994,000	342,000
Other	1,479,000	1,010,000
Total assets	514,750,000	513,933,000
Liabilities
Cash dividends declared to stockholders	3,842,000	3,623,000
Borrowings under lines of credit	59,000,000	69,000,000
Other	3,212,000	2,695,000
Total liabilities	66,054,000	75,318,000
Stockholders' equity	448,696,000	438,615,000
Total liabilities and stockholders' equity	$ 514,750,000	$ 513,933,000

Condensed Financial Informati98

Condensed Financial Information of Parent Company - Summary of Condensed Statements of Income and Comprehensive Income (Detail) - USD ($)	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
Revenues
Total revenues	$ 190,758,831	$ 185,716,027	$ 183,580,716	$ 178,970,963	$ 177,196,114	$ 175,311,263	$ 169,846,867	$ 166,068,776	$ 739,026,537	$ 688,423,020	$ 636,387,263
Expenses
Premium paid on purchase of treasury stock											5,780,000
Interest									1,593,437	1,657,647	1,111,441
Total expenses	130,442,303	114,386,379	128,005,914	114,433,458	113,368,960	111,174,963	103,193,915	95,578,065	726,912,075	647,094,613	608,794,995
Income (loss) before income tax benefit and equity in undistributed net (loss) income of subsidiaries									12,114,462	41,328,407	27,592,268
Income tax benefit									(4,998,362)	(10,527,270)	(6,602,235)
Net income	(2,778,644)	7,108,574	(2,318,648)	5,104,818	5,554,166	4,813,404	8,584,654	11,848,913	7,116,100	30,801,137	20,990,033
Statements of Comprehensive Income
Net income	$ (2,778,644)	$ 7,108,574	$ (2,318,648)	$ 5,104,818	$ 5,554,166	$ 4,813,404	$ 8,584,654	$ 11,848,913	7,116,100	30,801,137	20,990,033
Other comprehensive income (loss), net of tax
Unrealized gain (loss) - subsidiaries									3,811,151	(1,386,391)	(3,322,149)
Comprehensive income									7,161,783	27,773,122	16,410,508
Parent Company [Member]
Revenues
Dividends from subsidiaries									13,000,000	13,000,000	3,875,000
Other									2,131,000	1,759,000	2,028,000
Total revenues									15,131,000	14,759,000	5,903,000
Expenses
Operating expenses									1,433,000	1,413,000	2,451,000
Premium paid on purchase of treasury stock											5,780,000
Interest									1,929,000	1,747,000	1,066,000
Total expenses									3,362,000	3,160,000	9,297,000
Income (loss) before income tax benefit and equity in undistributed net (loss) income of subsidiaries									11,769,000	11,599,000	(3,394,000)
Income tax benefit									690,000	931,000	1,028,000
Income (loss) before equity in undistributed net (loss) income of subsidiaries									12,459,000	12,530,000	(2,366,000)
Equity in undistributed net (loss) income of subsidiaries									(5,343,000)	18,271,000	23,356,000
Net income									7,116,000	30,801,000	20,990,000
Statements of Comprehensive Income
Net income									7,116,000	30,801,000	20,990,000
Other comprehensive income (loss), net of tax
Unrealized gain (loss) - subsidiaries									46,000	(3,028,000)	(4,579,000)
Other comprehensive income (loss), net of tax									46,000	(3,028,000)	(4,579,000)
Comprehensive income									$ 7,162,000	$ 27,773,000	$ 16,411,000

Condensed Financial Informati99

Condensed Financial Information of Parent Company - Summary of Condensed Statements of Cash Flows (Detail) - USD ($)	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
Cash Flows from Operating Activities:
Net income	$ (2,778,644)	$ 7,108,574	$ (2,318,648)	$ 5,104,818	$ 5,554,166	$ 4,813,404	$ 8,584,654	$ 11,848,913	$ 7,116,100	$ 30,801,137	$ 20,990,033
Adjustments:
Other									(113,482)	(22,628)	(2,235,228)
Net adjustments									73,884,098	29,228,985	47,197,840
Net cash provided (used) by operating activities									81,000,198	60,030,122	68,187,873
Cash flows from investing activities:
Net sale of short-term investments									(1,678,908)	4,061,475	6,861,166
Net cash used in investing activities									(58,443,382)	(51,318,346)	(76,064,266)
Cash Flows from Financing Activities:
Cash dividends paid									(14,822,052)	(14,085,934)	(14,455,167)
Issuance of common stock									15,511,457	13,822,228	15,516,870
Payments on line of credit									(10,000,000)	(12,000,000)	(9,500,000)
Borrowings under lines of credit											37,000,000
Purchase of treasury stock											(28,124,675)
Net cash (used in) provided by financing activities									(9,310,595)	(12,263,706)	437,028
Net increase (decrease) in cash									13,246,221	(3,551,930)	(7,439,365)
Cash at beginning of year				24,587,214				28,139,144	24,587,214	28,139,144	35,578,509
Cash at end of year	37,833,435				24,587,214				37,833,435	24,587,214	28,139,144
Parent Company [Member]
Cash Flows from Operating Activities:
Net income									7,116,000	30,801,000	20,990,000
Adjustments:
Equity in undistributed net (loss) income of subsidiaries									5,343,000	(18,271,000)	(23,356,000)
Other									(401,000)	(27,000)	539,000
Net adjustments									4,942,000	(18,298,000)	(22,817,000)
Net cash provided (used) by operating activities									12,058,000	12,503,000	(1,827,000)
Cash flows from investing activities:
Net sale of short-term investments									1,000	2,000	498,000
Net purchase of property and equipment									(788,000)	(11,000)	(23,000)
Investment in subsidiaries									(2,992,000)	(2,393,000)	(2,427,000)
Other									(1,000)
Net cash used in investing activities									(3,780,000)	(2,402,000)	(1,952,000)
Cash Flows from Financing Activities:
Cash dividends paid									(14,821,000)	(14,085,000)	(14,454,000)
Issuance of common stock									17,960,000	16,651,000	18,468,000
Payments on line of credit									(10,000,000)	(12,000,000)	(9,500,000)
Borrowings under lines of credit											37,000,000
Purchase of treasury stock											(28,125,000)
Net cash (used in) provided by financing activities									(6,861,000)	(9,434,000)	3,389,000
Net increase (decrease) in cash									1,417,000	667,000	(390,000)
Cash at beginning of year				$ 1,820,000				$ 1,153,000	1,820,000	1,153,000	1,543,000
Cash at end of year	$ 3,237,000				$ 1,820,000				$ 3,237,000	$ 1,820,000	$ 1,153,000

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Segment
Income Statement [Abstract]
Number of reportable segments	4

Segment Information - Summary o

Segment Information - Summary of Financial Data by Segment (Detail) - USD ($)	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
Premiums earned
Net premiums earned	$ 181,059,920	$ 177,283,816	$ 175,014,872	$ 169,156,147	$ 168,977,030	$ 166,809,851	$ 161,942,637	$ 158,475,279	$ 702,514,755	$ 656,204,797	$ 605,640,728
GAAP premiums earned									702,515,000	656,205,000	605,641,000
Net investment income									23,527,304	22,632,730	20,949,698
Realized investment gains									5,705,255	2,525,575	1,934,424
Equity in earnings of DFSC									1,621,605	1,086,157	1,277,229
Other									5,658,000	5,973,000	6,585,000
Total revenues	$ 190,758,831	$ 185,716,027	$ 183,580,716	$ 178,970,963	$ 177,196,114	$ 175,311,263	$ 169,846,867	$ 166,068,776	739,026,537	688,423,020	636,387,263
Underwriting (loss) income:
SAP underwriting (loss) income									(25,779,000)	7,539,000	2,845,000
GAAP adjustments									4,408,000	4,642,000	3,344,000
GAAP underwriting (loss) income									(21,371,000)	12,181,000	6,189,000
Net investment income									23,527,304	22,632,730	20,949,698
Realized investment gains									5,705,255	2,525,575	1,934,424
Equity in earnings of DFSC									1,621,605	1,086,157	1,277,229
Premium paid on purchase of treasury stock											(5,780,000)
Other									2,631,000	2,902,000	3,022,000
Income before income tax expense									12,114,462	41,328,407	27,592,268
Commercial Lines [Member]
Premiums earned
Net premiums earned									318,391,000	295,077,000	261,286,000
Underwriting (loss) income:
SAP underwriting (loss) income									13,263,000	18,284,000	9,259,000
Personal Lines [Member]
Premiums earned
Net premiums earned									384,124,000	361,128,000	344,355,000
Underwriting (loss) income:
SAP underwriting (loss) income									$ (39,042,000)	$ (10,745,000)	$ (6,414,000)

Guaranty Fund and Other Insu102

Guaranty Fund and Other Insurance-Related Assessments - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Guarantees [Abstract]
Insurance subsidiaries' liabilities for guaranty fund and other insurance	$ 1,600,000	$ 1,500,000
Surcharges collected by insurance subsidiaries	$ 562,799	$ 447,620

Interim Financial Data - Summar

Interim Financial Data - Summary of Interim Financial Data (Detail) - USD ($)	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
Summary of interim financial data
Net premiums earned	$ 181,059,920	$ 177,283,816	$ 175,014,872	$ 169,156,147	$ 168,977,030	$ 166,809,851	$ 161,942,637	$ 158,475,279	$ 702,514,755	$ 656,204,797	$ 605,640,728
Total revenues	190,758,831	185,716,027	183,580,716	178,970,963	177,196,114	175,311,263	169,846,867	166,068,776	739,026,537	688,423,020	636,387,263
Net losses and loss expenses	130,442,303	114,386,379	128,005,914	114,433,458	113,368,960	111,174,963	103,193,915	95,578,065	726,912,075	647,094,613	608,794,995
Net income (loss)	$ (2,778,644)	$ 7,108,574	$ (2,318,648)	$ 5,104,818	$ 5,554,166	$ 4,813,404	$ 8,584,654	$ 11,848,913	$ 7,116,100	$ 30,801,137	$ 20,990,033
Class A Common Stock [Member]
Net earnings (loss) per common share:
Earnings per share, Basic	$ (0.10)	$ 0.27	$ (0.09)	$ 0.19	$ 0.21	$ 0.19	$ 0.33	$ 0.46	$ 0.27	$ 1.19	$ 0.78
Earnings per share, Diluted	(0.10)	0.26	(0.08)	0.18	0.20	0.18	0.32	0.46	0.26	1.16	0.77
Class B Common Stock [Member]
Net earnings (loss) per common share:
Earnings per share, Basic									0.22	1.06	0.69
Earnings per share, Diluted									0.22	1.06	0.69
Common stock - basic and diluted	$ (0.11)	$ 0.24	$ (0.08)	$ 0.17	$ 0.18	$ 0.16	$ 0.30	$ 0.42	$ 0.22	$ 1.06	$ 0.69

Schedule III - Supplementary104

Schedule III - Supplementary Insurance Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplementary Insurance Information, by Segment [Line Items]
Net Premiums Earned	$ 702,515	$ 656,205	$ 605,641
Net Investment Income	23,527	22,633	20,950
Net Losses and Loss Expenses	487,268	423,316	398,367
Amortization of Deferred Policy Acquisition Costs	115,065	107,876	99,513
Other Underwriting Expenses	116,538	108,459	97,710
Net Premiums Written	729,139	682,034	628,837
Deferred Policy Acquisition Costs	60,290	56,309
Liability For Losses and Loss Expenses	676,672	606,665
Unearned Premiums	503,457	466,055
Other Policy Claims and Benefits Payable	0	0
Personal Lines [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net Premiums Earned	384,124	361,128	344,355
Net Losses and Loss Expenses	289,924	247,323	235,717
Amortization of Deferred Policy Acquisition Costs	62,916	59,367	56,581
Other Underwriting Expenses	63,721	59,688	55,556
Net Premiums Written	400,023	371,657	352,327
Deferred Policy Acquisition Costs	33,823	31,477
Liability For Losses and Loss Expenses	239,542	217,793
Unearned Premiums	282,439	260,525
Other Policy Claims and Benefits Payable	0	0
Commercial Lines [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net Premiums Earned	318,391	295,077	261,286
Net Losses and Loss Expenses	197,344	175,993	162,650
Amortization of Deferred Policy Acquisition Costs	52,149	48,509	42,932
Other Underwriting Expenses	52,817	48,771	42,154
Net Premiums Written	329,116	310,377	276,510
Deferred Policy Acquisition Costs	26,467	24,832
Liability For Losses and Loss Expenses	437,130	388,872
Unearned Premiums	221,018	205,530
Other Policy Claims and Benefits Payable	0	0
Investments [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net Investment Income	23,527	22,633	$ 20,950
Other Policy Claims and Benefits Payable	$ 0	$ 0