Donegal (DGICA) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	DGICA
Entity Registrant Name	DONEGAL GROUP INC
Entity Central Index Key	800,457
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		22,788,003
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,576,775

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Fixed maturities
Held to maturity, at amortized cost	$ 400,233,054	$ 366,655,077
Available for sale, at fair value	525,027,434	538,946,050
Equity securities, at fair value	57,972,976	50,445,243
Investment in affiliate	39,960,649	38,773,420
Short-term investments, at cost, which approximates fair value	5,096,047	11,049,915
Total investments	1,028,290,160	1,005,869,705
Cash	55,258,656	37,833,435
Accrued investment income	7,166,660	6,553,121
Premiums receivable	160,318,764	160,406,432
Reinsurance receivable	322,467,746	298,342,563
Deferred policy acquisition costs	64,566,885	60,289,860
Deferred tax asset, net	10,059,549	7,128,843
Prepaid reinsurance premiums	141,536,708	135,032,641
Property and equipment, net	4,825,788	7,280,415
Accounts receivable-securities	1,101,615	180,525
Federal income taxes receivable	19,595,519	10,935,105
Goodwill	5,625,354	5,625,354
Other intangible assets	958,010	958,010
Other	2,475,943	1,483,769
Total assets	1,824,247,357	1,737,919,778
Liabilities
Unpaid losses and loss expenses	779,979,677	676,671,727
Unearned premiums	530,543,671	503,456,541
Accrued expenses	24,381,505	28,033,776
Reinsurance balances payable	3,191,746	4,116,159
Borrowings under lines of credit	60,000,000	59,000,000
Cash dividends declared to stockholders		3,841,820
Subordinated debentures	5,000,000	5,000,000
Due to affiliate	3,737,282	7,314,368
Other	1,873,448	1,789,283
Total liabilities	1,408,707,329	1,289,223,674
Stockholders' Equity
Preferred stock, $.01 par value, authorized 2,000,000 shares; none issued
Additional paid-in capital	259,667,062	255,401,558
Accumulated other comprehensive loss	(18,943,910)	(2,684,275)
Retained earnings	215,729,408	236,893,041
Treasury stock, at cost	(41,226,357)	(41,226,357)
Total stockholders' equity	415,540,028	448,696,104
Total liabilities and stockholders' equity	1,824,247,357	1,737,919,778
Class A Common Stock [Member]
Stockholders' Equity
Common stock value	257,333	255,645
Total stockholders' equity	257,333	255,645
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) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
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	25,733,219	25,564,481
Common stock, shares outstanding	22,730,631	22,561,893
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 - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Net premiums earned	$ 187,661,705	$ 177,283,816	$ 555,140,395	$ 521,454,835
Investment income, net of investment expenses	6,620,491	5,979,834	19,341,012	17,385,103
Net realized investment gains	3,463,504	561,429	4,062,475	4,207,710
Lease income	119,934	113,409	365,930	383,183
Installment payment fees	1,305,778	1,373,892	3,959,936	3,813,663
Equity in earnings of Donegal Financial Services Corporation	732,768	403,647	2,152,738	1,023,212
Total revenues	199,904,180	185,716,027	585,022,486	548,267,706
Expenses:
Net losses and loss expenses	140,726,106	114,386,379	433,063,019	356,825,751
Amortization of deferred policy acquisition costs	31,110,000	29,008,000	91,354,000	85,391,000
Other underwriting expenses	24,528,860	31,790,251	82,343,932	88,538,755
Policyholder dividends	1,050,200	1,376,115	3,565,971	3,422,672
Interest	651,768	466,262	1,682,200	1,212,895
Other expenses, net	560,260	176,970	1,604,595	1,036,223
Total expenses	198,627,194	177,203,977	613,613,717	536,427,296
(Loss) income before income tax (benefit) expense	1,276,986	8,512,050	(28,591,231)	11,840,410
Income tax (benefit) expense	70,630	1,403,476	(10,829,654)	1,945,666
Net (loss) income	$ 1,206,356	$ 7,108,574	$ (17,761,577)	$ 9,894,744
Class A Common Stock [Member]
(Loss) earnings per common share:
Common stock - basic	$ 0.04	$ 0.27	$ (0.64)	$ 0.37
Common stock - diluted	0.04	0.26	(0.64)	0.36
Class B Common Stock [Member]
(Loss) earnings per common share:
Common stock - basic	0.04	0.24	(0.59)	0.33
Common stock - diluted	0.04	0.24	(0.59)	0.33
Common stock - basic and diluted	$ 0.04	$ 0.24	$ (0.59)	$ 0.33

Consolidated Statements of In_2

Consolidated Statements of Income (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net realized investment gains	$ 3,463,504	$ 561,429	$ 4,062,475	$ 4,207,710
Income tax (benefit) expense	70,630	1,403,476	(10,829,654)	1,945,666
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net realized investment gains	(20,512)	561,429	(52,828)	4,207,710
Income tax (benefit) expense	$ (4,308)	$ 196,500	$ (11,094)	$ 1,472,698

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ 1,206,356	$ 7,108,574	$ (17,761,577)	$ 9,894,744
Unrealized (loss) gain on securities:
Unrealized holding (loss) gain during the period, net of income tax (benefit) expense	(2,293,154)	1,042,317	(11,382,714)	4,115,189
Reclassification adjustment for losses (gains) included in net (loss) income, net of income tax (benefit) expense	16,204	(364,929)	41,734	(2,735,012)
Other comprehensive (loss) income	(2,276,950)	677,388	(11,340,980)	1,380,177
Comprehensive (loss) income	$ (1,070,594)	$ 7,785,962	$ (29,102,557)	$ 11,274,921

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Income tax (benefit) expense on unrealized holding (loss) gain during the period	$ (609,572)	$ 561,247	$ (3,025,784)	$ 2,215,869
Income tax (benefit) expense on reclassification adjustment for losses (gains)	$ (4,308)	$ 196,500	$ (11,094)	$ 1,472,698

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2018 - USD ($)	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member]
Beginning balance at Dec. 31, 2017	$ 448,696,104	$ 255,401,558	$ (2,684,275)	$ 236,893,041	$ (41,226,357)	$ 255,645	$ 56,492
Beginning balance, shares at Dec. 31, 2017						25,564,481	5,649,240
Issuance of common stock	1,705,010	1,703,806				$ 1,204
Issuance of common stock, shares						120,394
Share-based compensation	2,114,212	2,113,728				$ 484
Share-based compensation, shares						48,344
Net (loss) income	(17,761,577)			(17,761,577)
Cash dividends declared	(7,872,741)			(7,872,741)
Grant of stock options		447,970		(447,970)
Reclassification of equity unrealized gains			(4,918,655)	4,918,655
Other comprehensive (loss) income	(11,340,980)		(11,340,980)
Ending balance at Sep. 30, 2018	$ 415,540,028	$ 259,667,062	$ (18,943,910)	$ 215,729,408	$ (41,226,357)	$ 257,333	$ 56,492
Ending balance, shares at Sep. 30, 2018						25,733,219	5,649,240

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows from Operating Activities:
Net (loss) income	$ (17,761,577)	$ 9,894,744
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, amortization and other non-cash items	5,288,171	4,791,010
Net realized investment gains	(4,062,475)	(4,207,710)
Equity in earnings of Donegal Financial Services Corporation	(2,152,738)	(1,023,212)
Changes in assets and liabilities:
Losses and loss expenses	103,307,950	37,685,539
Unearned premiums	27,087,130	49,850,687
Premiums receivable	87,668	(4,035,543)
Deferred acquisition costs	(4,277,025)	(5,568,430)
Deferred income taxes	83,985	(113,508)
Reinsurance receivable	(24,125,183)	(20,551,553)
Prepaid reinsurance premiums	(6,504,067)	(13,554,734)
Accrued investment income	(613,539)	(656,215)
Due to affiliate	(3,577,086)	14,960,562
Reinsurance balances payable	(924,413)	1,312,472
Current income taxes	(8,660,414)	(995,307)
Accrued expenses	(3,652,271)	(5,018,331)
Other, net	310,988	(101,676)
Net adjustments	77,616,681	52,774,051
Net cash provided by operating activities	59,855,104	62,668,795
Cash Flows from Investing Activities:
Purchases of fixed maturities, held to maturity	(42,834,707)	(43,710,213)
Purchases of fixed maturities, available for sale	(88,940,126)	(105,011,666)
Purchases of equity securities, available for sale	(11,255,867)	(9,030,858)
Maturity of fixed maturities:
Held to maturity	9,485,969	14,580,714
Available for sale	84,617,730	75,856,616
Sales of fixed maturities, available for sale	1,388,934	9,634,968
Sales of equity securities, available for sale	7,843,437	10,782,859
Net purchases of property and equipment	(132,290)	(740,608)
Net sales (purchases) of short-term investments	5,953,868	(1,360,359)
Net cash used in investing activities	(33,873,052)	(48,998,547)
Cash Flows from Financing Activities:
Cash dividends paid	(11,714,561)	(11,079,326)
Issuance of common stock	2,157,730	4,363,003
Borrowings under line of credit	1,000,000
Net cash used in financing activities	(8,556,831)	(6,716,323)
Net increase in cash	17,425,221	6,953,925
Cash at beginning of period	37,833,435	24,587,214
Cash at end of period	55,258,656	31,541,139
Cash paid during period - Interest	$ 937,470	1,016,678
Net cash paid during period - Taxes		$ 3,050,000

Organization

Organization	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1 - Organization 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 property and casualty insurance exclusively through 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 September 30, 2018, Donegal Mutual held approximately 43% of our outstanding Class A common stock and approximately 84% 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, Donegal Mutual and our insurance subsidiaries 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 entire personal lines or commercial lines accounts. Distinctions within the products Donegal Mutual and our insurance subsidiaries offer relate generally to specific risk profiles targeted within similar classes of business, such as preferred tier products versus standard tier products, but we do not allocate all of the standard risk gradients to any specific company within the Donegal Insurance Group. Therefore, the underwriting profitability of the business the individual companies write directly will vary. However, because 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 underwriting pool. Donegal Mutual completed the merger of Mountain States Mutual Casualty Company (“Mountain States”) with and into Donegal Mutual effective May 25, 2017. Donegal Mutual was the surviving company in the merger, and Mountain States’ insurance subsidiaries, Mountain States Indemnity Company and Mountain States Commercial Insurance Company, became insurance subsidiaries of Donegal Mutual upon completion of the merger. Upon completion of the merger, Donegal Mutual assumed all of the policy obligations of Mountain States and began to market its products together with those of its insurance subsidiaries as the Mountain States Insurance Group in four Southwestern states. For an indefinite period of time, Donegal Mutual will exclude the business of the Mountain States Insurance Group from the pooling agreement with Atlantic States. As a result, our consolidated results of operations exclude the results of Donegal Mutual’s operations in those Southwestern states. On April 3, 2018, we announced plans to consolidate the branch office operations of Peninsula into our home office operations effective July 2, 2018 to achieve economies of scale and enhance service levels for policyholders of Peninsula. We recorded a restructuring charge in the second quarter of 2018 for employee termination costs associated with the Peninsula consolidation of approximately $1.9 million. We paid approximately $835,000 of these costs in the third quarter of 2018 and had an accrual of approximately $1.1 million remaining at September 30, 2018. We entered into a definitive purchase arrangement for the sale of Peninsula’s branch office real estate, and expect to receive net proceeds of $1.2 million during the fourth quarter of 2018. We recorded an impairment charge of $1.0 million in other expenses in the third quarter of 2018 related to this real estate transaction and included the $1.2 million fair value of the real estate we held for sale in other assets at September 30, 2018. On June 11, 2018, we and Donegal Mutual entered into an agreement whereby DFSC will merge with and into Northwest Bancshares, Inc. (“Northwest”) in exchange for payment by Northwest to us and Donegal Mutual of approximately $85.0 million in a combination of cash and Northwest common stock. Immediately prior to the closing of the transaction, DFSC will pay a dividend of approximately $30.0 million to us and Donegal Mutual. As the owner of 48.2% of DFSC’s common stock, we will receive a dividend payment from DFSC of approximately $14.5 million and consideration from Northwest that will range in value from $38.9 million to $43.0 million. Subject to receipt of various regulatory approvals and satisfaction of other customary closing conditions, we anticipate that the transaction will close during the first quarter of 2019. 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 shares of our Class A common stock at prices prevailing from time to time in the open market subject to the provisions of applicable rules of the Securities and Exchange Commission (“SEC”) and in privately negotiated transactions. We did not purchase any shares of our Class A common stock under this program during the nine months ended September 30, 2018 or 2017. We have purchased a total of 57,658 shares of our Class A common stock under this program from its inception through September 30, 2018.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	2 - Basis of Presentation Our financial information for the interim periods included in this Form 10-Q 10-Q We recommend you read the interim financial statements we include in this Form 10-Q 10-K

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	3 - Earnings Per Share We have two classes of common stock, which we refer to as our Class A common stock and our Class B common stock. Our certificate of incorporation provides that whenever our board of directors declares a dividend on our Class B common stock, our board of directors shall simultaneously declare a dividend on our Class A common stock that is payable to the holders of our Class A common stock at the same time and as of the same record date at a rate that is at least 10% greater than the rate at which our board of directors declared a dividend on our Class B common stock. Accordingly, we use the two-class two-class Three Months Ended September 30, 2018 2017 Class A Class B Class A Class B (in thousands, except per share data) Basic income per share: Numerator: Allocation of net income $ 1,006 $ 200 $ 5,787 $ 1,322 Denominator: Weighted-average shares outstanding 22,717 5,577 21,756 5,577 Basic income per share $ 0.04 $ 0.04 $ 0.27 $ 0.24 Diluted income per share: Numerator: Allocation of net income $ 1,006 $ 200 $ 5,787 $ 1,322 Denominator: Number of shares used in basic computation 22,717 5,577 21,756 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 178 — 461 — Number of shares used in diluted computation 22,895 5,577 22,217 5,577 Diluted income per share $ 0.04 $ 0.04 $ 0.26 $ 0.24 Nine Months Ended September 30, 2018 2017 Class A Class B Class A Class B (in thousands, except per share data) Basic (loss) earnings per share: Numerator: Allocation of net (loss) income $ (14,472 ) $ (3,290 ) $ 8,066 $ 1,829 Denominator: Weighted-average shares outstanding 22,673 5,577 21,669 5,577 Basic (loss) earnings per share $ (0.64 ) $ (0.59 ) $ 0.37 $ 0.33 Diluted (loss) earnings per share: Numerator: Allocation of net (loss) income $ (14,472 ) $ (3,290 ) $ 8,066 $ 1,829 Denominator: Number of shares used in basic computation 22,673 5,577 21,669 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options — — 778 — Number of shares used in diluted computation 22,673 5,577 22,447 5,577 Diluted (loss) earnings per share $ (0.64 ) $ (0.59 ) $ 0.36 $ 0.33 We did not include outstanding options to purchase 6,731,481 shares of Class A common stock in our computation of diluted earnings per share for the three months ended September 30, 2018 because the exercise price of the options exceeded the average market price of our Class A common stock during the period. We did not include any effect of dilutive securities in the computation of diluted earnings per share for the nine months ended September 30, 2018 because we sustained a net loss for this period. We did not include outstanding options to purchase 5,178,629 and 1,382,400 shares of Class A common stock in our computation of diluted earnings per share for the three and nine months ended September 30, 2017 because the exercise price of the options exceeded the average market price of our Class A common stock during the applicable periods.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2018
Insurance [Abstract]
Reinsurance	4 - Reinsurance Atlantic States and Donegal Mutual have participated in a pooling agreement since 1986 under which they pool substantially all of their direct premiums written, and Atlantic States and Donegal Mutual then share the underwriting results of the pool in accordance with the terms of the pooling agreement. 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. Our insurance subsidiaries and Donegal Mutual purchase certain third-party reinsurance on a combined basis. Le Mars, MICO, Peninsula and Sheboygan also separately purchase third-party reinsurance that provides that insurance subsidiary with reinsurance coverage that we believe is commensurate with its respective size and risk exposures. Our insurance subsidiaries use several different reinsurers, all of which have an A.M. Best rating of A- A- • excess of loss reinsurance, under which Donegal Mutual and our insurance subsidiaries recover, through a series of reinsurance agreements, losses over a set retention (generally $1.0 million), and • catastrophe reinsurance, under which Donegal Mutual and our insurance subsidiaries recover, through a series of reinsurance agreements, 100% of an accumulation of many losses resulting from a single event, including natural disasters, over a set retention (generally $5.0 million) and after exceeding an annual aggregate deductible (generally $5.0 million) up to aggregate losses of $170.0 million per occurrence. Our insurance subsidiaries and Donegal Mutual also purchase facultative reinsurance to cover exposures in excess of the covered limits of their third-party reinsurance agreements. In addition to the pooling agreement and third-party reinsurance, our insurance subsidiaries have various reinsurance agreements with Donegal Mutual. Effective March 1, 2018, Donegal Mutual and certain of our insurance subsidiaries modified their third-party reinsurance coverage related to umbrella liability policies to increase the maximum loss retention of Donegal Mutual and our insurance subsidiaries from $250,000 to $1.0 million. Donegal Mutual and certain of our insurance subsidiaries also made various adjustments to the terms of their intercompany catastrophe reinsurance agreements effective January 1, 2018. We have made no other significant changes to our third-party reinsurance or the reinsurance agreements between our insurance subsidiaries and Donegal Mutual during the nine months ended September 30, 2018.

Investments

Investments	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	5 - Investments The amortized cost and estimated fair values of our fixed maturities at September 30, 2018 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 76,078 $ 5 $ 2,120 $ 73,963 Obligations of states and political subdivisions 156,055 6,890 1,721 161,224 Corporate securities 125,879 258 4,338 121,799 Mortgage-backed securities 42,221 — 1,033 41,188 Totals $ 400,233 $ 7,153 $ 9,212 $ 398,174 Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,192 $ 4 $ 1,668 $ 42,528 Obligations of states and political subdivisions 81,704 1,696 726 82,674 Corporate securities 135,889 178 3,285 132,782 Mortgage-backed securities 276,973 37 9,967 267,043 Totals $ 538,758 $ 1,915 $ 15,646 $ 525,027 At September 30, 2018, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $163.4 million and an amortized cost of $159.7 million. Our holdings at September 30, 2018 also included special revenue bonds with an aggregate fair value of $80.5 million and an amortized cost of $78.1 million. With respect to both categories of those bonds at September 30, 2018, we held no securities of any issuer that comprised more than 10% of our holdings of either bond category. Education bonds and water and sewer utility bonds represented 54% and 27%, respectively, of our total investments in special revenue bonds based on the carrying values of these investments at September 30, 2018. Many of the issuers of the special revenue bonds we held at September 30, 2018 have the authority to impose ad valorem taxes. In that respect, many of the special revenue bonds we held at September 30, 2018 are similar to general obligation bonds. The amortized cost and estimated fair values of our fixed maturities at December 31, 2017 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 71,736 $ 804 $ 547 $ 71,993 Obligations of states and political subdivisions 137,581 11,162 112 148,631 Corporate securities 108,025 2,860 731 110,154 Mortgage-backed securities 49,313 516 157 49,672 Totals $ 366,655 $ 15,342 $ 1,547 $ 380,450 Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,759 $ 20 $ 730 $ 44,049 Obligations of states and political subdivisions 128,478 3,942 303 132,117 Corporate securities 105,254 1,011 526 105,739 Mortgage-backed securities 259,923 445 3,327 257,041 Totals $ 538,414 $ 5,418 $ 4,886 $ 538,946 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 at December 31, 2017 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 those bonds at December 31, 2017, we held no securities of any issuer that comprised more than 10% of that category. 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. We made reclassifications from available for sale to held to maturity of certain fixed maturities at fair value on November 30, 2013. We segregated within accumulated other comprehensive loss the net unrealized losses of $15.1 million arising prior to the November 30, 2013 reclassifications. We are amortizing this balance over the remaining life of the related securities as an adjustment to yield in a manner consistent with the accretion of discount on the same fixed maturities. We recorded amortization of $912,229 and $909,044 in other comprehensive (loss) income during the nine months ended September 30, 2018 and 2017, respectively. At September 30, 2018 and December 31, 2017, net unrealized losses of $8.9 million and $9.8 million, respectively, remained within accumulated other comprehensive loss. We show below the amortized cost and estimated fair value of our fixed maturities at September 30, 2018 by contractual maturity. Expected maturities may differ from contractual maturities because issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Cost Estimated (in thousands) Held to maturity Due in one year or less $ 8,783 $ 8,768 Due after one year through five years 70,790 70,505 Due after five years through ten years 136,673 135,068 Due after ten years 141,766 142,645 Mortgage-backed securities 42,221 41,188 Total held to maturity $ 400,233 $ 398,174 Available for sale Due in one year or less $ 39,265 $ 39,465 Due after one year through five years 86,468 85,156 Due after five years through ten years 116,791 114,026 Due after ten years 19,261 19,337 Mortgage-backed securities 276,973 267,043 Total available for sale $ 538,758 $ 525,027 The cost and estimated fair values of our equity securities at September 30, 2018 were as follows: Cost Gross Gains Gross Losses Estimated (in thousands) Equity securities $ 49,416 $ 9,207 $ 650 $ 57,973 The cost and estimated fair values of our equity securities at December 31, 2017 were as follows: Cost Gross Gains Gross Losses Estimated (in thousands) Equity securities $ 44,219 $ 6,505 $ 279 $ 50,445 Gross realized gains and losses from investments before applicable income taxes for the three and nine months ended September 30, 2018 and 2017 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) (in thousands) Gross realized gains: Fixed maturities $ 5 $ 87 $ 16 $ 138 Equity securities 2,976 513 6,246 4,142 2,981 600 6,262 4,280 Gross realized losses: Fixed maturities 25 39 70 69 Equity securities (508 ) — 2,130 3 (483 ) 39 2,200 72 Net realized gains $ 3,464 $ 561 $ 4,062 $ 4,208 We recognized $3.9 million of gains and $1.6 million of losses on equity securities held at September 30, 2018 in net realized investment gains for the nine months ended September 30, 2018. We held fixed maturities with unrealized losses representing declines that we considered temporary at September 30, 2018 as follows: Less Than 12 Months More Than 12 Months Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 65,701 $ 1,017 $ 48,064 $ 2,771 Obligations of states and political subdivisions 58,935 1,586 16,385 861 Corporate securities 179,587 5,150 39,074 2,473 Mortgage-backed securities 144,615 3,200 159,788 7,800 Totals $ 448,838 $ 10,953 $ 263,311 $ 13,905 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 More Than 12 Months Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 24,024 $ 287 $ 33,987 $ 990 Obligations of states and political subdivisions 10,223 120 14,127 295 Corporate securities 35,204 253 31,561 1,004 Mortgage-backed securities 100,534 817 124,062 2,667 Equity securities 4,292 279 — — Totals $ 174,277 $ 1,756 $ 203,737 $ 4,956 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 measure investments at fair value and, beginning January 1, 2018, we recognize changes in fair value in our results of operations. 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 the 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 with respect to that security. 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, issuer or geographic events that have negatively impacted the value of a security and rating agency downgrades. We held 565 debt securities that were in an unrealized loss position at September 30, 2018. 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 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 on mortgage-backed debt securities using anticipated prepayments. Our investment in affiliate represents our 48.2% ownership interest in DFSC. 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 the equity of DFSC due to 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 September 30, 2018 and December 31, 2017 and for the three and nine months ended September 30, 2018 and 2017, respectively, from the financial statements of DFSC. The financial information of DFSC at September 30, 2018 and 2017 and for the three and nine months then ended is unaudited. September 30, December 31, (in thousands) Balance sheets: Total assets $ 543,086 $ 567,935 Total liabilities $ 460,292 $ 487,604 Stockholders’ equity 82,794 80,331 Total liabilities and stockholders’ equity $ 543,086 $ 567,935 Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) (in thousands) Income statements: Net income $ 1,519 $ 837 $ 4,464 $ 2,122

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Information	6 - Segment Information We evaluate the performance of our personal lines and commercial lines segments based upon the underwriting results of our insurance subsidiaries using statutory accounting principles (“SAP”) that various state insurance departments prescribe or permit. Our management uses SAP to measure the performance of our insurance subsidiaries instead of United States generally accepted accounting principles (“GAAP”). SAP financial measures are considered non-GAAP Financial data by segment for the three and nine months ended September 30, 2018 and 2017 is as follows: Three Months Ended September 30, 2018 2017 (in thousands) Revenues: Premiums earned: Commercial lines $ 84,251 $ 80,724 Personal lines 103,410 96,560 Premiums earned 187,661 177,284 Net investment income 6,620 5,980 Realized investment gains 3,464 561 Equity in earnings of DFSC 733 404 Other 1,426 1,487 Total revenues $ 199,904 $ 185,716 Income before income tax expense: Underwriting (loss) income: Commercial lines $ 2,125 $ 8,998 Personal lines (12,210 ) (8,919 ) SAP underwriting (loss) income (10,085 ) 79 GAAP adjustments 332 644 GAAP underwriting (loss) income (9,753 ) 723 Net investment income 6,620 5,980 Realized investment gains 3,464 561 Equity in earnings of DFSC 733 404 Other 213 844 Income before income tax expense $ 1,277 $ 8,512 Nine Months Ended September 30, 2018 2017 (in thousands) Revenues: Premiums earned: Commercial lines $ 251,029 $ 236,437 Personal lines 304,111 285,018 Premiums earned 555,140 521,455 Net investment income 19,341 17,385 Realized investment gains 4,062 4,208 Equity in earnings of DFSC 2,153 1,023 Other 4,326 4,197 Total revenues $ 585,022 $ 548,268 (Loss) income before income tax (benefit) expense: Underwriting (loss) income: Commercial lines $ (17,935 ) $ 12,670 Personal lines (42,358 ) (31,816 ) SAP underwriting loss (60,293 ) (19,146 ) GAAP adjustments 5,106 6,423 GAAP underwriting loss (55,187 ) (12,723 ) Net investment income 19,341 17,385 Realized investment gains 4,062 4,208 Equity in earnings of DFSC 2,153 1,023 Other 1,040 1,947 (Loss) income before income tax (benefit) expense $ (28,591 ) $ 11,840

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Borrowings	7 - Borrowings Lines of Credit In July 2018, 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 expires in July 2021. We have the right to request a one-year 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 September 30, 2018. The interest rate on the advances was 2.32% at September 30, 2018. 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 September 30, 2018. FHLB of Pittsburgh stock purchased and owned $ 1,631,800 Collateral pledged, at par (carrying value $40,947,302) 41,858,302 Borrowing capacity currently available 3,817,595 MICO is a member of the Federal Home Loan Bank (“FHLB”) of Indianapolis. During the second quarter of 2018, MICO terminated its line of credit with the FHLB of Indianapolis. Subordinated Debentures Donegal Mutual holds a $5.0 million surplus note that MICO issued to increase MICO’s statutory surplus. The surplus note carries an interest rate of 5.00%, and any repayment of principal or payment of interest on the surplus note requires prior approval of the Michigan Department of Insurance and Financial Services.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	8 - Share-Based Compensation We measure all share-based payments to employees, including grants of stock options, and use a fair-value-based method for the recording of related compensation 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, the expected term, the dividend yield and the expected volatility. We charged compensation expense related to our stock compensation plans against income before income taxes of $317,526 and $411,450 for the three months ended September 30, 2018 and 2017, respectively, with a corresponding income tax benefit of $66,680 and $144,008, respectively. We charged compensation expense related to our stock compensation plans against income before income taxes of $1.4 million and $1.6 million for the nine months ended September 30, 2018 and 2017, respectively, with a corresponding income tax benefit of $285,578 and $564,075, respectively. At September 30, 2018, we had $1.4 million of unrecognized compensation expense related to nonvested share-based compensation granted under our stock compensation plans that we expect to recognize over a weighted average period of approximately 1.4years. We received cash from option exercises under all stock compensation plans during the three months ended September 30, 2018 and 2017 of $217,112 and $765,127, respectively. We received cash from option exercises under all stock compensation plans during the nine months ended September 30, 2018 and 2017 of $695,762 and $2.9 million, respectively. We realized actual tax benefits for the tax deductions related to those option exercises of $2,516 and $42,411 for the three months ended September 30, 2018 and 2017, respectively. We realized actual tax benefits for the tax deductions related to those option exercises of $21,319 and $220,767 for the nine months ended September 30, 2018 and 2017, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	9 - Fair Value Measurements We account for financial assets using a framework that establishes a hierarchy that ranks the quality and reliability of the inputs, or assumptions, we use 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 and include these investments in Level 2 of the fair value hierarchy. 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. We classify these items as Level 1. The carrying values we report 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 we report in our balance sheets 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 to determine the appropriate level at which to classify them for each reporting period. 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 (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 42,528 $ — $ 42,528 $ — Obligations of states and political subdivisions 82,674 — 82,674 — Corporate securities 132,782 — 132,782 — Mortgage-backed securities 267,043 — 267,043 — Equity securities 42,228 42,228 — — Total investments in the fair value hierarchy 567,255 42,228 525,027 — Investment measured at net asset value 15,745 — — — Totals $ 583,000 $ 42,228 $ 525,027 $ — We did not transfer any investments between Levels 1 and 2 during the nine months ended September 30, 2018. 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 (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,049 $ — $ 44,049 $ — Obligations of states and political subdivisions 132,117 — 132,117 — Corporate securities 105,739 — 105,739 — Mortgage-backed securities 257,041 — 257,041 — Equity securities 36,736 36,736 — — Total investments in the fair value hierarchy 575,682 36,736 538,946 — Investment measured at net asset value 13,709 — — — Totals $ 589,391 $ 36,736 $ 538,946 $ —

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	10 - Income Taxes At September 30, 2018 and December 31, 2017, respectively, we had no material unrecognized tax benefits or accrued interest and penalties. Tax years 2015 through 2018 remained open for examination at September 30, 2018. We provide a valuation allowance when we believe it is more likely than not that we will not realize some portion of our tax assets. We established a valuation allowance of $264,467 related to a portion of the net operating loss carryforward of Le Mars at January 1, 2004 and a valuation allowance of $77.1 million for our net state operating loss carryforward. We have determined that we are not required to establish a valuation allowance for our other deferred tax assets of $30.0 million and $23.1 million at September 30, 2018 and December 31, 2017, respectively, because it is more likely than not that we will realize these deferred tax assets through reversals of existing temporary differences, future taxable income and the implementation of tax planning strategies. Our deferred tax assets include a net operating loss carryforward of $2.0 million related to Le Mars, which will begin to expire in 2020 if not previously utilized. This carryforward is subject to an annual limitation of approximately $376,000.

Liability for Losses and Loss E

Liability for Losses and Loss Expenses	9 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Liability for Losses and Loss Expenses	11 - 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 for losses and loss expenses 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 estimated future liabilities for losses and loss expenses have exceeded their actual liabilities for losses and loss expenses. Changes in our insurance subsidiaries’ estimate of their liability for losses and loss expenses generally reflect actual payments and their evaluation of information received subsequent to the prior reporting period. We summarize activity in our insurance subsidiaries’ liability for losses and loss expenses as follows: Nine Months Ended September 30, 2018 2017 (in thousands) Balance at January 1 $ 676,672 $ 606,665 Less reinsurance recoverable (293,271 ) (259,147 ) Net balance at January 1 383,401 347,518 Incurred related to: Current year 404,150 351,812 Prior years 28,913 5,014 Total incurred 433,063 356,826 Paid related to: Current year 214,825 201,849 Prior years 140,806 133,587 Total paid 355,631 335,436 Net balance at end of period 460,833 368,908 Plus reinsurance recoverable 319,147 275,442 Balance at end of period $ 779,980 $ 644,350 Our insurance subsidiaries recognized an increase in their liability for losses and loss expenses of prior years of $28.9 million and $5.0 million for the nine months ended September 30, 2018 and 2017, respectively. Our insurance subsidiaries made no significant changes in their reserving philosophy or claims management personnel, and our insurance subsidiaries have made no significant offsetting changes in estimates that increased or decreased their loss and loss expense reserves in those periods. During the first quarter of 2018, our insurance subsidiaries received new information on previously-reported commercial automobile and personal automobile claims that led our insurance subsidiaries to conclude that their prior actuarial assumptions did not fully anticipate recent changes in severity and reporting trends. Our insurance subsidiaries have encountered increasing difficulties in projecting the ultimate severity of automobile losses over recent accident years, which our insurance subsidiaries attribute to worsening litigation trends and an increased delay in the reporting to our insurance subsidiaries of information with respect to the severity of claims. As a result, our insurance subsidiaries’ actuaries have increased their projections of the ultimate cost of our insurance subsidiaries’ prior-year commercial automobile and personal automobile losses, and our insurance subsidiaries added $13.0 million to their reserves for personal automobile and $19.1 million to their reserves for commercial automobile for accident years prior to 2018. Modest adverse development related to higher-than-expected severity in the homeowners and commercial multi-peril lines of business was offset by lower-than-expected severity in the workers’ compensation line of business in accident years prior to 2018. The 2018 development represented 7.5% of the December 31, 2017 net carried reserves. The majority of the 2018 development related to increases in the liability for losses and loss expenses of prior years for Atlantic States and Southern. The 2017 development represented 1.4% of the December 31, 2016 net carried reserves and resulted primarily from higher-than-expected severity in the commercial multi-peril and commercial automobile liabilitylines 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. 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 the material lines of business of our insurance subsidiaries 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, the IBNR reserves of our insurance subsidiaries 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, other than the reserve strengthening actions we describe above, their actuaries made no significant changes to that methodology during the nine months ended September 30, 2018. 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 and 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 the 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 and 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 at 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 predict loss frequency accurately 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.

Impact of New Accounting Standa

Impact of New Accounting Standards	9 Months Ended
	Sep. 30, 2018
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Standards	12 - 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 replaced most existing GAAP revenue recognition guidance, the scope of the guidance excludes insurance contracts. The new standard was 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 this 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 was effective for annual and interim reporting periods beginning after December 15, 2017. As a result of the adoption of this guidance on January 1, 2018, we transferred $4.9 million of net unrealized gains from accumulated other comprehensive income (“AOCI”) to retained earnings. We recognized $3.9 million of gains and $1.6 million of losses on equity securities held at September 30, 2018 in net realized investment gains for the nine months ended September 30, 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 are in the process of evaluating the impact of the adoption of this guidance on our financial position, results of operations and 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 are in the process of evaluating the impact of the adoption of this guidance on our financial position, results of operations and cash flows. In January 2017, the FASB issued guidance that simplifies the measurement of goodwill by modifying the goodwill impairment test previous guidance required. The guidance requires an entity to perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize impairment for the amount by which the reporting unit’s carrying amount exceeds its fair value. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019 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 February 2018, the FASB issued updated guidance that allows entities to reclassify the stranded tax effects in 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. In August 2018, the FASB issued guidance that modifies disclosure requirements related to fair value measurements. The guidance removes the requirements to disclose the amounts of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019 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.

Impact of New Accounting Stan_2

Impact of New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
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 replaced most existing GAAP revenue recognition guidance, the scope of the guidance excludes insurance contracts. The new standard was 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 this 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 was effective for annual and interim reporting periods beginning after December 15, 2017. As a result of the adoption of this guidance on January 1, 2018, we transferred $4.9 million of net unrealized gains from accumulated other comprehensive income (“AOCI”) to retained earnings. We recognized $3.9 million of gains and $1.6 million of losses on equity securities held at September 30, 2018 in net realized investment gains for the nine months ended September 30, 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 are in the process of evaluating the impact of the adoption of this guidance on our financial position, results of operations and 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 are in the process of evaluating the impact of the adoption of this guidance on our financial position, results of operations and cash flows. In January 2017, the FASB issued guidance that simplifies the measurement of goodwill by modifying the goodwill impairment test previous guidance required. The guidance requires an entity to perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount and recognize impairment for the amount by which the reporting unit’s carrying amount exceeds its fair value. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019 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 February 2018, the FASB issued updated guidance that allows entities to reclassify the stranded tax effects in 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. In August 2018, the FASB issued guidance that modifies disclosure requirements related to fair value measurements. The guidance removes the requirements to disclose the amounts of, and reasons for, transfers between Level 1 and Level 2 of the fair value hierarchy. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019 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.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Summary of Reconciliation of Numerators and Denominators Used in Basic and Diluted Per Share Computations	The table below presents for the periods indicated a reconciliation of the numerators and denominators we used to compute basic and diluted net income per share for our Class A common stock and our Class B common stock: Three Months Ended September 30, 2018 2017 Class A Class B Class A Class B (in thousands, except per share data) Basic income per share: Numerator: Allocation of net income $ 1,006 $ 200 $ 5,787 $ 1,322 Denominator: Weighted-average shares outstanding 22,717 5,577 21,756 5,577 Basic income per share $ 0.04 $ 0.04 $ 0.27 $ 0.24 Diluted income per share: Numerator: Allocation of net income $ 1,006 $ 200 $ 5,787 $ 1,322 Denominator: Number of shares used in basic computation 22,717 5,577 21,756 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 178 — 461 — Number of shares used in diluted computation 22,895 5,577 22,217 5,577 Diluted income per share $ 0.04 $ 0.04 $ 0.26 $ 0.24 Nine Months Ended September 30, 2018 2017 Class A Class B Class A Class B (in thousands, except per share data) Basic (loss) earnings per share: Numerator: Allocation of net (loss) income $ (14,472 ) $ (3,290 ) $ 8,066 $ 1,829 Denominator: Weighted-average shares outstanding 22,673 5,577 21,669 5,577 Basic (loss) earnings per share $ (0.64 ) $ (0.59 ) $ 0.37 $ 0.33 Diluted (loss) earnings per share: Numerator: Allocation of net (loss) income $ (14,472 ) $ (3,290 ) $ 8,066 $ 1,829 Denominator: Number of shares used in basic computation 22,673 5,577 21,669 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options — — 778 — Number of shares used in diluted computation 22,673 5,577 22,447 5,577 Diluted (loss) earnings per share $ (0.64 ) $ (0.59 ) $ 0.36 $ 0.33

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Values of Fixed Maturities	The amortized cost and estimated fair values of our fixed maturities at September 30, 2018 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 76,078 $ 5 $ 2,120 $ 73,963 Obligations of states and political subdivisions 156,055 6,890 1,721 161,224 Corporate securities 125,879 258 4,338 121,799 Mortgage-backed securities 42,221 — 1,033 41,188 Totals $ 400,233 $ 7,153 $ 9,212 $ 398,174 Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,192 $ 4 $ 1,668 $ 42,528 Obligations of states and political subdivisions 81,704 1,696 726 82,674 Corporate securities 135,889 178 3,285 132,782 Mortgage-backed securities 276,973 37 9,967 267,043 Totals $ 538,758 $ 1,915 $ 15,646 $ 525,027 The amortized cost and estimated fair values of our fixed maturities at December 31, 2017 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 71,736 $ 804 $ 547 $ 71,993 Obligations of states and political subdivisions 137,581 11,162 112 148,631 Corporate securities 108,025 2,860 731 110,154 Mortgage-backed securities 49,313 516 157 49,672 Totals $ 366,655 $ 15,342 $ 1,547 $ 380,450 Amortized Cost Gross Unrealized Gross Unrealized Estimated (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,759 $ 20 $ 730 $ 44,049 Obligations of states and political subdivisions 128,478 3,942 303 132,117 Corporate securities 105,254 1,011 526 105,739 Mortgage-backed securities 259,923 445 3,327 257,041 Totals $ 538,414 $ 5,418 $ 4,886 $ 538,946
Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity	Expected maturities may differ from contractual maturities because issuers of the securities may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Cost Estimated (in thousands) Held to maturity Due in one year or less $ 8,783 $ 8,768 Due after one year through five years 70,790 70,505 Due after five years through ten years 136,673 135,068 Due after ten years 141,766 142,645 Mortgage-backed securities 42,221 41,188 Total held to maturity $ 400,233 $ 398,174 Available for sale Due in one year or less $ 39,265 $ 39,465 Due after one year through five years 86,468 85,156 Due after five years through ten years 116,791 114,026 Due after ten years 19,261 19,337 Mortgage-backed securities 276,973 267,043 Total available for sale $ 538,758 $ 525,027
Summary of Cost and Estimated Fair Values of Equity Securities	The cost and estimated fair values of our equity securities at September 30, 2018 were as follows: Cost Gross Gains Gross Losses Estimated (in thousands) Equity securities $ 49,416 $ 9,207 $ 650 $ 57,973 The cost and estimated fair values of our equity securities at December 31, 2017 were as follows: Cost Gross Gains Gross Losses Estimated (in thousands) Equity securities $ 44,219 $ 6,505 $ 279 $ 50,445
Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes	Gross realized gains and losses from investments before applicable income taxes for the three and nine months ended September 30, 2018 and 2017 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) (in thousands) Gross realized gains: Fixed maturities $ 5 $ 87 $ 16 $ 138 Equity securities 2,976 513 6,246 4,142 2,981 600 6,262 4,280 Gross realized losses: Fixed maturities 25 39 70 69 Equity securities (508 ) — 2,130 3 (483 ) 39 2,200 72 Net realized gains $ 3,464 $ 561 $ 4,062 $ 4,208
Summary of Fixed Maturities and Equity Securities with Unrealized Losses	We held fixed maturities with unrealized losses representing declines that we considered temporary at September 30, 2018 as follows: Less Than 12 Months More Than 12 Months Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 65,701 $ 1,017 $ 48,064 $ 2,771 Obligations of states and political subdivisions 58,935 1,586 16,385 861 Corporate securities 179,587 5,150 39,074 2,473 Mortgage-backed securities 144,615 3,200 159,788 7,800 Totals $ 448,838 $ 10,953 $ 263,311 $ 13,905 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 More Than 12 Months Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 24,024 $ 287 $ 33,987 $ 990 Obligations of states and political subdivisions 10,223 120 14,127 295 Corporate securities 35,204 253 31,561 1,004 Mortgage-backed securities 100,534 817 124,062 2,667 Equity securities 4,292 279 — — Totals $ 174,277 $ 1,756 $ 203,737 $ 4,956
Summary of Financial Information	We have compiled the following summary financial information for DFSC at September 30, 2018 and December 31, 2017 and for the three and nine months ended September 30, 2018 and 2017, respectively, from the financial statements of DFSC. The financial information of DFSC at September 30, 2018 and 2017 and for the three and nine months then ended is unaudited. September 30, December 31, (in thousands) Balance sheets: Total assets $ 543,086 $ 567,935 Total liabilities $ 460,292 $ 487,604 Stockholders’ equity 82,794 80,331 Total liabilities and stockholders’ equity $ 543,086 $ 567,935 Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (in thousands) (in thousands) Income statements: Net income $ 1,519 $ 837 $ 4,464 $ 2,122

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Summary of Financial Data by Segment	Financial data by segment for the three and nine months ended September 30, 2018 and 2017 is as follows: Three Months Ended September 30, 2018 2017 (in thousands) Revenues: Premiums earned: Commercial lines $ 84,251 $ 80,724 Personal lines 103,410 96,560 Premiums earned 187,661 177,284 Net investment income 6,620 5,980 Realized investment gains 3,464 561 Equity in earnings of DFSC 733 404 Other 1,426 1,487 Total revenues $ 199,904 $ 185,716 Income before income tax expense: Underwriting (loss) income: Commercial lines $ 2,125 $ 8,998 Personal lines (12,210 ) (8,919 ) SAP underwriting (loss) income (10,085 ) 79 GAAP adjustments 332 644 GAAP underwriting (loss) income (9,753 ) 723 Net investment income 6,620 5,980 Realized investment gains 3,464 561 Equity in earnings of DFSC 733 404 Other 213 844 Income before income tax expense $ 1,277 $ 8,512 Nine Months Ended September 30, 2018 2017 (in thousands) Revenues: Premiums earned: Commercial lines $ 251,029 $ 236,437 Personal lines 304,111 285,018 Premiums earned 555,140 521,455 Net investment income 19,341 17,385 Realized investment gains 4,062 4,208 Equity in earnings of DFSC 2,153 1,023 Other 4,326 4,197 Total revenues $ 585,022 $ 548,268 (Loss) income before income tax (benefit) expense: Underwriting (loss) income: Commercial lines $ (17,935 ) $ 12,670 Personal lines (42,358 ) (31,816 ) SAP underwriting loss (60,293 ) (19,146 ) GAAP adjustments 5,106 6,423 GAAP underwriting loss (55,187 ) (12,723 ) Net investment income 19,341 17,385 Realized investment gains 4,062 4,208 Equity in earnings of DFSC 2,153 1,023 Other 1,040 1,947 (Loss) income before income tax (benefit) expense $ (28,591 ) $ 11,840

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2018
FHLB of Pittsburgh [Member]
Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement	September 30, 2018. 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 September 30, 2018. FHLB of Pittsburgh stock purchased and owned $ 1,631,800 Collateral pledged, at par (carrying value $40,947,302) 41,858,302 Borrowing capacity currently available 3,817,595

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
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 Significant Significant (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 42,528 $ — $ 42,528 $ — Obligations of states and political subdivisions 82,674 — 82,674 — Corporate securities 132,782 — 132,782 — Mortgage-backed securities 267,043 — 267,043 — Equity securities 42,228 42,228 — — Total investments in the fair value hierarchy 567,255 42,228 525,027 — Investment measured at net asset value 15,745 — — — Totals $ 583,000 $ 42,228 $ 525,027 $ — We did not transfer any investments between Levels 1 and 2 during the nine months ended September 30, 2018. 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 (in thousands) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 44,049 $ — $ 44,049 $ — Obligations of states and political subdivisions 132,117 — 132,117 — Corporate securities 105,739 — 105,739 — Mortgage-backed securities 257,041 — 257,041 — Equity securities 36,736 36,736 — — Total investments in the fair value hierarchy 575,682 36,736 538,946 — Investment measured at net asset value 13,709 — — — Totals $ 589,391 $ 36,736 $ 538,946 $ —

Liability for Losses and Loss_2

Liability for Losses and Loss Expenses (Tables)	9 Months Ended
	Sep. 30, 2018
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: Nine Months Ended September 30, 2018 2017 (in thousands) Balance at January 1 $ 676,672 $ 606,665 Less reinsurance recoverable (293,271 ) (259,147 ) Net balance at January 1 383,401 347,518 Incurred related to: Current year 404,150 351,812 Prior years 28,913 5,014 Total incurred 433,063 356,826 Paid related to: Current year 214,825 201,849 Prior years 140,806 133,587 Total paid 355,631 335,436 Net balance at end of period 460,833 368,908 Plus reinsurance recoverable 319,147 275,442 Balance at end of period $ 779,980 $ 644,350

Organization - Additional Infor

Organization - Additional Information (Detail)	Jun. 11, 2018USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)Segment	Sep. 30, 2018USD ($)shares	Jul. 18, 2013shares
Business Acquisition [Line Items]
Operations commenced date				Aug. 26, 1986
Stock ownership percentage owned by third party				51.80%
Number of operating segments | Segment				4
Voting power percentage of outstanding common stock				72.00%
Restructuring charge for employee termination costs				$ 1,900,000
Restructuring charges paid for employee termination costs				835,000
Accrual of restructuring charge				$ 1,100,000
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%
DFSC and North West [Member] | Donegal Mutual Insurance Company [Member]
Business Acquisition [Line Items]
Consideration from sale of business	$ 85,000,000
Proceeds from dividend	$ 30,000,000
Peninsula [Member]
Business Acquisition [Line Items]
Impairment charge related to real estate transaction			$ 1,000,000
Fair value of real asset held for sale			$ 1,200,000	$ 1,200,000	$ 1,200,000
Peninsula [Member] | Scenario, Forecast [Member]
Business Acquisition [Line Items]
Expected proceeds from sale of real estate		$ 1,200,000
Donegal Financial Services Corporation [Member]
Business Acquisition [Line Items]
Outstanding stock ownership percentage			48.20%	48.20%	48.20%
Donegal Financial Services Corporation [Member] | DFSC and North West [Member]
Business Acquisition [Line Items]
Outstanding stock ownership percentage	48.20%
Dividend payment to be received	$ 14,500,000
Donegal Financial Services Corporation [Member] | DFSC and North West [Member] | Minimum [Member]
Business Acquisition [Line Items]
Consideration from sale of business and dividend	38,900,000
Donegal Financial Services Corporation [Member] | DFSC and North West [Member] | Maximum [Member]
Business Acquisition [Line Items]
Consideration from sale of business and dividend	$ 43,000,000
Class A Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder				43.00%
Class A Common Stock [Member] | Stock Repurchase Program Two [Member]
Business Acquisition [Line Items]
Authority to purchase shares | shares						500,000
Common stock shares purchased | shares					57,658
Class B Common Stock [Member]
Business Acquisition [Line Items]
Stock ownership percentage held by major shareholder				84.00%

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Minimum percentage of class A common stock declared dividend excess over class B dividend			10.00%
Options excluded from diluted earnings per share	6,731,481	5,178,629		1,382,400

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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Class A Common Stock [Member]
Numerator:
Allocation of net (loss) income	$ 1,006	$ 5,787	$ (14,472)	$ 8,066
Denominator:
Weighted-average shares outstanding	22,717	21,756	22,673	21,669
Basic (loss) earnings per share	$ 0.04	$ 0.27	$ (0.64)	$ 0.37
Numerator:
Allocation of net (loss) income	$ 1,006	$ 5,787	$ (14,472)	$ 8,066
Denominator:
Number of shares used in basic computation	22,717	21,756	22,673	21,669
Weighted-average shares effect of dilutive securities:
Director and employee stock options	178	461		778
Number of shares used in diluted computation	22,895	22,217	22,673	22,447
Diluted (loss) earnings per share	$ 0.04	$ 0.26	$ (0.64)	$ 0.36
Class B Common Stock [Member]
Numerator:
Allocation of net (loss) income	$ 200	$ 1,322	$ (3,290)	$ 1,829
Denominator:
Weighted-average shares outstanding	5,577	5,577	5,577	5,577
Basic (loss) earnings per share	$ 0.04	$ 0.24	$ (0.59)	$ 0.33
Numerator:
Allocation of net (loss) income	$ 200	$ 1,322	$ (3,290)	$ 1,829
Denominator:
Number of shares used in basic computation	5,577	5,577	5,577	5,577
Weighted-average shares effect of dilutive securities:
Number of shares used in diluted computation	5,577	5,577	5,577	5,577
Diluted (loss) earnings per share	$ 0.04	$ 0.24	$ (0.59)	$ 0.33

Reinsurance - Additional Inform

Reinsurance - Additional Information (Detail) - USD ($)	Mar. 01, 2018	Sep. 30, 2018
Ceded Credit Risk [Line Items]
Loss reinsurance, set retention amount		$ 1,000,000
Percentage of accumulation of losses		100.00%
Catastrophe reinsurance, set retention amount		$ 5,000,000
Catastrophe reinsurance, deductible amount		$ 5,000,000
Increase loss retention of reinsurance coverage	$ 250,000
Maximum [Member]
Ceded Credit Risk [Line Items]
Increase loss retention of reinsurance coverage	$ 1,000,000
Atlantic States [Member]
Ceded Credit Risk [Line Items]
Percentage of share in results of pooled business subsidiary		80.00%
Donegal Mutual [Member]
Ceded Credit Risk [Line Items]
Percentage of share in results of pooled business owned by third party		20.00%
Maximum amount of loss coverage under reinsurance agreement of property catastrophe		$ 170,000,000

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Estimated Fair Values of Fixed Maturities (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	$ 400,233,054	$ 366,655,077
Held to Maturity, Gross Unrealized Gains	7,153,000	15,342,000
Held to Maturity, Gross Unrealized Losses	9,212,000	1,547,000
Total held to maturity, Estimated Fair Value	398,174,000	380,450,000
Available for Sale, Amortized Cost	538,758,000	538,414,000
Available for Sale, Gross Unrealized Gains	1,915,000	5,418,000
Available for Sale, Gross Unrealized Losses	15,646,000	4,886,000
Available for Sale, Estimated Fair Value	525,027,000	538,946,000
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	76,078,000	71,736,000
Held to Maturity, Gross Unrealized Gains	5,000	804,000
Held to Maturity, Gross Unrealized Losses	2,120,000	547,000
Total held to maturity, Estimated Fair Value	73,963,000	71,993,000
Available for Sale, Amortized Cost	44,192,000	44,759,000
Available for Sale, Gross Unrealized Gains	4,000	20,000
Available for Sale, Gross Unrealized Losses	1,668,000	730,000
Available for Sale, Estimated Fair Value	42,528,000	44,049,000
Obligations of States and Political Subdivisions [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	156,055,000	137,581,000
Held to Maturity, Gross Unrealized Gains	6,890,000	11,162,000
Held to Maturity, Gross Unrealized Losses	1,721,000	112,000
Total held to maturity, Estimated Fair Value	161,224,000	148,631,000
Available for Sale, Amortized Cost	81,704,000	128,478,000
Available for Sale, Gross Unrealized Gains	1,696,000	3,942,000
Available for Sale, Gross Unrealized Losses	726,000	303,000
Available for Sale, Estimated Fair Value	82,674,000	132,117,000
Corporate Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	125,879,000	108,025,000
Held to Maturity, Gross Unrealized Gains	258,000	2,860,000
Held to Maturity, Gross Unrealized Losses	4,338,000	731,000
Total held to maturity, Estimated Fair Value	121,799,000	110,154,000
Available for Sale, Amortized Cost	135,889,000	105,254,000
Available for Sale, Gross Unrealized Gains	178,000	1,011,000
Available for Sale, Gross Unrealized Losses	3,285,000	526,000
Available for Sale, Estimated Fair Value	132,782,000	105,739,000
Mortgage-Backed Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	42,221,000	49,313,000
Held to Maturity, Gross Unrealized Gains		516,000
Held to Maturity, Gross Unrealized Losses	1,033,000	157,000
Total held to maturity, Estimated Fair Value	41,188,000	49,672,000
Available for Sale, Amortized Cost	276,973,000	259,923,000
Available for Sale, Gross Unrealized Gains	37,000	445,000
Available for Sale, Gross Unrealized Losses	9,967,000	3,327,000
Available for Sale, Estimated Fair Value	$ 267,043,000	$ 257,041,000

Investments - Additional Inform

Investments - Additional Information (Detail)	Nov. 30, 2013USD ($)	Sep. 30, 2018USD ($)Securities	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
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 (loss) income		$ 912,229	$ 909,044
Accumulated other comprehensive loss		$ (18,943,910)		$ (2,684,275)
Donegal Financial Services Corporation [Member]
Schedule of Investments [Line Items]
Percentage of ownership interest		48.20%
Obligations of States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		$ 163,400,000		190,700,000
Amortized cost of bond held		159,700,000		181,400,000
Special Revenue Bonds [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		80,500,000		90,000,000
Amortized cost of bond held		$ 78,100,000		$ 84,700,000
Education Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		54.00%		53.00%
Water and Sewer Utility Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		27.00%		26.00%
Equity Securities [Member]
Schedule of Investments [Line Items]
Net realized gain on investment		$ 3,900,000
Net realized loss on investment		$ 1,600,000
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale | Securities		565
Accumulated Net Unrealized Investment Losses [Member]
Schedule of Investments [Line Items]
Accumulated other comprehensive loss		$ (8,900,000)		$ (9,800,000)
Minimum [Member]
Schedule of Investments [Line Items]
Percentage of which the company held security of any issuer		10.00%		10.00%

Investments - Summary of Amor_2

Investments - Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Held to maturity
Due in one year or less, Amortized Cost	$ 8,783,000
Due after one year through five years, Amortized Cost	70,790,000
Due after five years through ten years, Amortized Cost	136,673,000
Due after ten years, Amortized Cost	141,766,000
Mortgage-backed securities, Amortized Cost	42,221,000
Total held to maturity, Amortized Cost	400,233,054	$ 366,655,077
Available for sale
Due in one year or less, Amortized Cost	39,265,000
Due after one year through five years, Amortized Cost	86,468,000
Due after five years through ten years, Amortized Cost	116,791,000
Due after ten years, Amortized Cost	19,261,000
Mortgage-backed securities, Amortized Cost	276,973,000
Total available for sale, Amortized Cost	538,758,000
Held to maturity
Due in one year or less, Estimated Fair Value	8,768,000
Due after one year through five years, Estimated Fair Value	70,505,000
Due after five years through ten years, Estimated Fair Value	135,068,000
Due after ten years, Estimated Fair Value	142,645,000
Mortgage-backed securities, Estimated Fair Value	41,188,000
Total held to maturity, Estimated Fair Value	398,174,000	380,450,000
Available for sale
Due in one year or less, Estimated Fair Value	39,465,000
Due after one year through five years, Estimated Fair Value	85,156,000
Due after five years through ten years, Estimated Fair Value	114,026,000
Due after ten years, Estimated Fair Value	19,337,000
Mortgage-backed securities, Estimated Fair Value	267,043,000
Total available for sale, Estimated Fair Value	$ 525,027,434	$ 538,946,050

Investment - Summary of Cost an

Investment - Summary of Cost and Estimated Fair Value of Equity Securities (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Cost	$ 49,416,000	$ 44,219,000
Gross Gains	9,207,000	6,505,000
Gross Losses	650,000	279,000
Estimated Fair Value	$ 57,972,976	$ 50,445,243

Investments - Summary of Gross

Investments - Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gain (Loss) on Securities [Line Items]
Gross realized gains	$ 2,981,000	$ 600,000	$ 6,262,000	$ 4,280,000
Gross realized losses	(483,000)	39,000	2,200,000	72,000
Net realized gains	3,463,504	561,429	4,062,475	4,207,710
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Gross realized gains	5,000	87,000	16,000	138,000
Gross realized losses	25,000	39,000	70,000	69,000
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Gross realized gains	2,976,000	$ 513,000	6,246,000	4,142,000
Gross realized losses	$ (508,000)		$ 2,130,000	$ 3,000

Investments - Summary of Fixed

Investments - Summary of Fixed Maturities and Equity Securities with Unrealized Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	$ 448,838	$ 174,277
Less Than 12 Months, Unrealized Losses	10,953	1,756
More Than 12 Months, Fair Value	263,311	203,737
More Than 12 Months, Unrealized Losses	13,905	4,956
U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	65,701	24,024
Less Than 12 Months, Unrealized Losses	1,017	287
More Than 12 Months, Fair Value	48,064	33,987
More Than 12 Months, Unrealized Losses	2,771	990
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	58,935	10,223
Less Than 12 Months, Unrealized Losses	1,586	120
More Than 12 Months, Fair Value	16,385	14,127
More Than 12 Months, Unrealized Losses	861	295
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	179,587	35,204
Less Than 12 Months, Unrealized Losses	5,150	253
More Than 12 Months, Fair Value	39,074	31,561
More Than 12 Months, Unrealized Losses	2,473	1,004
Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	144,615	100,534
Less Than 12 Months, Unrealized Losses	3,200	817
More Than 12 Months, Fair Value	159,788	124,062
More Than 12 Months, Unrealized Losses	$ 7,800	2,667
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value		4,292
Less Than 12 Months, Unrealized Losses		$ 279

Investments - Summary of Financ

Investments - Summary of Financial Information (Detail) - Donegal Financial Services Corporation [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Balance sheets:
Total assets	$ 543,086		$ 543,086		$ 567,935
Total liabilities	460,292		460,292		487,604
Stockholders' equity	82,794		82,794		80,331
Total liabilities and stockholders' equity	543,086		543,086		$ 567,935
Income statements:
Net income	$ 1,519	$ 837	$ 4,464	$ 2,122

Segment Information - Summary o

Segment Information - Summary of Financial Data by Segment (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Premiums earned:
Premiums earned	$ 187,661,705	$ 177,283,816	$ 555,140,395	$ 521,454,835
Net investment income	6,620,491	5,979,834	19,341,012	17,385,103
Realized investment gains	3,463,504	561,429	4,062,475	4,207,710
Equity in earnings of DFSC	732,768	403,647	2,152,738	1,023,212
Other	1,426,000	1,487,000	4,326,000	4,197,000
Total revenues	199,904,180	185,716,027	585,022,486	548,267,706
Underwriting (loss) income:
SAP underwriting (loss) income	(10,085,000)	79,000	(60,293,000)	(19,146,000)
GAAP adjustments	332,000	644,000	5,106,000	6,423,000
GAAP underwriting (loss) income	(9,753,000)	723,000	(55,187,000)	(12,723,000)
Net investment income	6,620,491	5,979,834	19,341,012	17,385,103
Realized investment gains	3,463,504	561,429	4,062,475	4,207,710
Equity in earnings of DFSC	732,768	403,647	2,152,738	1,023,212
Other	213,000	844,000	1,040,000	1,947,000
(Loss) income before income tax (benefit) expense	1,276,986	8,512,050	(28,591,231)	11,840,410
Commercial Lines [Member]
Premiums earned:
Premiums earned	84,251,000	80,724,000	251,029,000	236,437,000
Underwriting (loss) income:
SAP underwriting (loss) income	2,125,000	8,998,000	(17,935,000)	12,670,000
Personal Lines [Member]
Premiums earned:
Premiums earned	103,410,000	96,560,000	304,111,000	285,018,000
Underwriting (loss) income:
SAP underwriting (loss) income	$ (12,210,000)	$ (8,919,000)	$ (42,358,000)	$ (31,816,000)

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Jul. 31, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Line of credit expiration month and year	2021-07
Outstanding borrowings	$ 60,000,000		$ 59,000,000
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%
Manufacturers and Traders Trust Company [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings	$ 25,000,000
Line of credit facility remaining borrowing capacity	$ 35,000,000
Interest rate on borrowings	4.51%
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. With the exception of a requirement that we maintain a minimum interest coverage ratio, we complied with all requirements of the credit agreement during the nine months ended September 30, 2018.
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	$ 3,817,595
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	2.32%
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) - Atlantic States [Member] - FHLB of Pittsburgh [Member]	Sep. 30, 2018USD ($)
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement
FHLB stock purchased and owned	$ 1,631,800
Collateral pledged, at par	41,858,302
Borrowing capacity currently available	$ 3,817,595

Borrowings - Amount of FHLB o_2

Borrowings - Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement (Parenthetical) (Detail)	Sep. 30, 2018USD ($)
FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Collateral Pledged at carrying value	$ 40,947,302

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation expense in stock compensation plans	$ 317,526	$ 411,450	$ 1,400,000	$ 1,600,000
Income tax benefit of stock compensation plans	66,680	144,008	285,578	564,075
Unrecognized compensation expense related to nonvested share-based compensation granted under the plan	1,400,000		$ 1,400,000
Weighted average period of unrecognized compensation expense			1 year 4 months 24 days
Cash from option exercises	217,112	765,127	$ 695,762	2,900,000
Tax benefit for tax deductions related to option exercises	$ 2,516	$ 42,411	$ 21,319	$ 220,767

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurements for Investments in Available-for-Sale Fixed Maturity and Equity Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 525,027	$ 538,946
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	42,528	44,049
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	82,674	132,117
Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	132,782	105,739
Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	267,043	257,041
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	583,000	589,391
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	15,745	13,709
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	567,255	575,682
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	42,528	44,049
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	82,674	132,117
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	132,782	105,739
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	267,043	257,041
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	42,228	36,736
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	42,228	36,736
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	42,228	36,736
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	42,228	36,736
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	525,027	538,946
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	525,027	538,946
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	42,528	44,049
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	82,674	132,117
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	132,782	105,739
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	$ 267,043	$ 257,041

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Other deferred tax assets, net	$ 30,000,000	$ 23,100,000
Parent Company [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	$ 77,100,000
Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2,015
Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2,018
Le Mars [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	$ 264,467
Operating loss carryforwards	$ 2,000,000
Operating loss carryforwards expiration period	2,020
Operating loss carryforwards annual limitations in amount on use	$ 376,000

Liability for Losses and Loss_3

Liability for Losses and Loss Expenses - Summary of Insurance Subsidiaries' Liability for Losses and Loss Expenses (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Liability for Claims and Claims Adjustment Expense [Abstract]
Balance at January 1	$ 676,671,727	$ 606,665,000
Less reinsurance recoverable	(293,271,000)	(259,147,000)
Net balance at January 1	383,401,000	347,518,000
Incurred related to:
Current year	404,150,000	351,812,000
Prior years	28,913,000	5,014,000
Total incurred	433,063,000	356,826,000
Paid related to:
Current year	214,825,000	201,849,000
Prior years	140,806,000	133,587,000
Total paid	355,631,000	335,436,000
Net balance at end of period	460,833,000	368,908,000
Plus reinsurance recoverable	319,147,000	275,442,000
Balance at end of period	$ 779,979,677	$ 644,350,000

Liability for Losses and Loss_4

Liability for Losses and Loss Expenses - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (Decrease) in liability for losses and loss expenses of prior years	$ 28,913	$ 5,014
Percentage of 2010 development	7.50%	1.40%
Personal Automobile [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Reserve created for commercial automobile	$ 13,000
Commercial Automobile [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Reserve created for commercial automobile	$ 19,100

Impact of New Accounting Stan_3

Impact of New Accounting Standards - Additional Information (Detail) - USD ($) $ in Millions	Jan. 01, 2018	Sep. 30, 2018
Gain on equity securities		$ 3.9
Loss on equity securities		$ 1.6
Accounting Standards Update 2016-01 [Member] | Accumulated Net Unrealized Investment Losses [Member]
Reclassification from AOCI to retained earnings	$ 4.9