Donegal (DGICA) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Document Information [Line Items]
Document Type	10-Q
Entity Interactive Data Current	Yes
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Registrant Name	DONEGAL GROUP INC
Entity Central Index Key	0000800457
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Address, State or Province	PA
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		23,106,528
Title of 12(b) Security	Common Stock
Trading Symbol	DGICA
Security Exchange Name	NASDAQ
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		5,576,775
Title of 12(b) Security	Common Stock
Trading Symbol	DGICB
Security Exchange Name	NASDAQ

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Fixed maturities
Held to maturity, at amortized cost	$ 458,888,742	$ 402,798,518
Available for sale, at fair value	559,101,387	526,558,304
Equity securities, at fair value	52,098,509	43,667,009
Investment in affiliate		41,025,975
Short-term investments, at cost, which approximates fair value	8,626,324	16,748,760
Total investments	1,078,714,962	1,030,798,566
Cash	55,268,760	52,594,461
Accrued investment income	7,285,349	6,561,199
Premiums receivable	173,749,759	156,702,250
Reinsurance receivable	362,366,588	343,369,065
Deferred policy acquisition costs	63,685,811	60,615,127
Deferred tax asset, net	8,965,877	13,069,755
Prepaid reinsurance premiums	141,958,161	135,379,777
Property and equipment, net	4,622,446	4,690,704
Accounts receivable - securities	48,428	261,829
Federal income taxes receivable	15,766,182	19,032,604
Goodwill	5,625,354	5,625,354
Other intangible assets	958,010	958,010
Other	2,069,524	2,419,566
Total assets	1,921,085,211	1,832,078,267
Liabilities
Unpaid losses and loss expenses	864,534,338	814,665,224
Unearned premiums	528,037,212	506,528,606
Accrued expenses	26,964,878	25,442,146
Reinsurance balances payable	2,032,722	3,882,193
Borrowings under lines of credit	35,000,000	60,000,000
Cash dividends declared to stockholders		3,948,484
Subordinated debentures	5,000,000	5,000,000
Accounts payable - securities	1,956,151	1,003,810
Due to affiliate	7,015,832	10,874,540
Other	7,992,473	1,863,363
Total liabilities	1,478,533,606	1,433,208,366
Stockholders' Equity
Preferred stock, $.01 par value, authorized 2,000,000 shares; none issued
Additional paid-in capital	265,680,180	261,258,423
Accumulated other comprehensive income (loss)	418,394	(14,228,059)
Retained earnings	217,362,373	192,751,208
Treasury stock, at cost	(41,226,357)	(41,226,357)
Total stockholders' equity	442,551,605	398,869,901
Total liabilities and stockholders' equity	1,921,085,211	1,832,078,267
Class A Common Stock [Member]
Stockholders' Equity
Common stock value	260,523	258,194
Total stockholders' equity	260,523	258,194
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, 2019	Dec. 31, 2018
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	50,000,000	50,000,000
Common stock, shares issued	26,052,220	25,819,341
Common stock, shares outstanding	23,049,632	22,816,753
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 (Loss) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Net premiums earned	$ 189,821,058	$ 187,661,705	$ 566,657,613	$ 555,140,395
Investment income, net of investment expenses	7,389,749	6,620,491	21,727,904	19,341,012
Net investment gains (losses)	(369,041)	3,463,504	19,294,229	4,062,475
Lease income	110,598	119,934	333,852	365,930
Installment payment fees	1,057,536	1,305,778	3,204,130	3,959,936
Equity in earnings of Donegal Financial Services Corporation		732,768	295,000	2,152,738
Total revenues	198,009,900	199,904,180	611,512,728	585,022,486
Expenses:
Net losses and loss expenses	130,743,395	140,726,106	385,361,331	433,063,019
Amortization of deferred policy acquisition costs	31,304,000	31,110,000	92,821,000	91,354,000
Other underwriting expenses	26,516,518	24,528,860	85,409,737	82,343,932
Policyholder dividends	2,446,696	1,050,200	6,765,834	3,565,971
Interest	443,179	651,768	1,311,894	1,682,200
Other expenses, net	251,228	560,260	1,155,493	1,604,595
Total expenses	191,705,016	198,627,194	572,825,289	613,613,717
Income (loss) before income tax expense (benefit)	6,304,884	1,276,986	38,687,439	(28,591,231)
Income tax expense (benefit)	1,118,505	70,630	5,689,442	(10,829,654)
Net income (loss)	$ 5,186,379	$ 1,206,356	$ 32,997,997	$ (17,761,577)
Class A Common Stock [Member]
Earnings (loss) per common share:
Common stock - basic	$ 0.19	$ 0.04	$ 1.18	$ (0.64)
Common stock - diluted	0.18	0.04	1.17	(0.64)
Class B Common Stock [Member]
Earnings (loss) per common share:
Common stock - basic	0.16	0.04	1.06	(0.59)
Common stock - diluted	0.16	0.04	1.06	(0.59)
Common stock - basic and diluted	$ 0.16	$ 0.04	$ 1.06	$ (0.59)

Consolidated Statements of In_2

Consolidated Statements of Income (Loss) (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net investment gains (losses)	$ (369,041)	$ 3,463,504	$ 19,294,229	$ 4,062,475
Income tax expense (benefit)	1,118,505	70,630	5,689,442	(10,829,654)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net investment gains (losses)	102,311	(20,512)	154,725	(52,828)
Income tax expense (benefit)	$ 21,485	$ (4,308)	$ 32,492	$ (11,094)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 5,186,379	$ 1,206,356	$ 32,997,997	$ (17,761,577)
Unrealized gain (loss) on securities:
Unrealized holding gain (loss) during the period, net of income tax expense (benefit)	2,336,599	(2,293,154)	14,768,686	(11,382,714)
Reclassification adjustment for (gains) losses included in net income (loss), net of income tax expense (benefit)	(80,826)	16,204	(122,233)	41,734
Other comprehensive income (loss)	2,255,773	(2,276,950)	14,646,453	(11,340,980)
Comprehensive income (loss)	$ 7,442,152	$ (1,070,594)	$ 47,644,450	$ (29,102,557)

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Unrealized holding gain (loss) during the period, net of income tax expense (benefit) during the period	$ 621,120	$ (609,572)	$ 3,925,853	$ (3,025,784)
Income tax expense (benefit) on reclassification adjustment for gains	$ 21,485	$ (4,308)	$ 32,492	$ (11,094)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive (Loss) Income [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 (stock compensation plans)	422,610	422,318				$ 292
Issuance of common stock (stock compensation plans), shares						29,162
Share-based compensation	1,024,650	1,024,328				$ 322
Share-based compensation, shares						32,176
Net income (loss)	(18,178,078)			(18,178,078)
Cash dividends declared	(8,587)			(8,587)
Grant of stock options		187,444		(187,444)
Reclassification of equity unrealized gains			(4,918,655)	4,918,655
Other comprehensive income (loss)	(6,602,985)		(6,602,985)
Ending balance at Mar. 31, 2018	425,353,714	257,035,648	(14,205,915)	223,437,587	(41,226,357)	$ 256,259	$ 56,492
Ending balance, shares at Mar. 31, 2018						25,625,819	5,649,240
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
Net income (loss)	(17,761,577)
Other comprehensive income (loss)	(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
Beginning balance at Mar. 31, 2018	425,353,714	257,035,648	(14,205,915)	223,437,587	(41,226,357)	$ 256,259	$ 56,492
Beginning balance, shares at Mar. 31, 2018						25,625,819	5,649,240
Issuance of common stock (stock compensation plans)	960,773	960,139				$ 634
Issuance of common stock (stock compensation plans), shares						63,430
Share-based compensation	536,472	536,472
Net income (loss)	(789,855)			(789,855)
Cash dividends declared	(3,930,019)			(3,930,019)
Grant of stock options		133,656		(133,656)
Other comprehensive income (loss)	(2,461,046)		(2,461,046)
Ending balance at Jun. 30, 2018	419,670,039	258,665,915	(16,666,961)	218,584,057	(41,226,357)	$ 256,893	$ 56,492
Ending balance, shares at Jun. 30, 2018						25,689,249	5,649,240
Issuance of common stock (stock compensation plans)	321,627	321,349				$ 278
Issuance of common stock (stock compensation plans), shares						27,802
Share-based compensation	553,090	552,928				$ 162
Share-based compensation, shares						16,168
Net income (loss)	1,206,356			1,206,356
Cash dividends declared	(3,934,135)			(3,934,135)
Grant of stock options		126,870		(126,870)
Other comprehensive income (loss)	(2,276,950)		(2,276,949)
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
Beginning balance at Dec. 31, 2018	398,869,901	261,258,423	(14,228,059)	192,751,208	(41,226,357)	$ 258,194	$ 56,492
Beginning balance, shares at Dec. 31, 2018						25,819,341	5,649,240
Issuance of common stock (stock compensation plans)	404,055	403,722				$ 333
Issuance of common stock (stock compensation plans), shares						33,334
Share-based compensation	442,920	442,920
Net income (loss)	23,023,164			23,023,164
Cash dividends declared	(4,752)			(4,752)
Grant of stock options		144,226		(144,226)
Other comprehensive income (loss)	6,468,473		6,468,473
Ending balance at Mar. 31, 2019	429,203,761	262,249,291	(7,759,586)	215,625,394	(41,226,357)	$ 258,527	$ 56,492
Ending balance, shares at Mar. 31, 2019						25,852,675	5,649,240
Beginning balance at Dec. 31, 2018	398,869,901	261,258,423	(14,228,059)	192,751,208	(41,226,357)	$ 258,194	$ 56,492
Beginning balance, shares at Dec. 31, 2018						25,819,341	5,649,240
Net income (loss)	32,997,997
Other comprehensive income (loss)	14,646,453
Ending balance at Sep. 30, 2019	442,551,605	265,680,180	418,394	217,362,373	(41,226,357)	$ 260,523	$ 56,492
Ending balance, shares at Sep. 30, 2019						26,052,220	5,649,240
Beginning balance at Mar. 31, 2019	429,203,761	262,249,291	(7,759,586)	215,625,394	(41,226,357)	$ 258,527	$ 56,492
Beginning balance, shares at Mar. 31, 2019						25,852,675	5,649,240
Issuance of common stock (stock compensation plans)	752,914	752,354				$ 560
Issuance of common stock (stock compensation plans), shares						55,933
Share-based compensation	1,218,804	1,218,195				$ 609
Share-based compensation, shares						60,969
Net income (loss)	4,788,454			4,788,454
Cash dividends declared	(4,032,416)			(4,032,416)
Grant of stock options		100,485		(100,485)
Other comprehensive income (loss)	5,922,207		5,922,207
Ending balance at Jun. 30, 2019	437,853,724	264,320,325	(1,837,379)	216,280,947	(41,226,357)	$ 259,696	$ 56,492
Ending balance, shares at Jun. 30, 2019						25,969,577	5,649,240
Issuance of common stock (stock compensation plans)	280,614	280,385				$ 229
Issuance of common stock (stock compensation plans), shares						22,926
Share-based compensation	1,020,616	1,020,018				$ 598
Share-based compensation, shares						59,717
Net income (loss)	5,186,379			5,186,379
Cash dividends declared	(4,045,501)			(4,045,501)
Grant of stock options		59,452		(59,452)
Other comprehensive income (loss)	2,255,773		2,255,773
Ending balance at Sep. 30, 2019	$ 442,551,605	$ 265,680,180	$ 418,394	$ 217,362,373	$ (41,226,357)	$ 260,523	$ 56,492
Ending balance, shares at Sep. 30, 2019						26,052,220	5,649,240

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income (loss)	$ 32,997,997	$ (17,761,577)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, amortization and other non-cash items	4,299,566	5,288,171
Net investment gains	(19,294,229)	(4,062,475)
Equity in earnings of Donegal Financial Services Corporation	(295,000)	(2,152,738)
Changes in assets and liabilities:
Losses and loss expenses	49,869,114	103,307,950
Unearned premiums	21,508,606	27,087,130
Premiums receivable	(17,047,509)	87,668
Deferred acquisition costs	(3,070,684)	(4,277,025)
Deferred income taxes	210,518	83,985
Reinsurance receivable	(18,997,523)	(24,125,183)
Prepaid reinsurance premiums	(6,578,384)	(6,504,067)
Accrued investment income	(724,150)	(613,539)
Due to affiliate	(3,858,708)	(3,577,086)
Reinsurance balances payable	(1,849,471)	(924,413)
Current income taxes	3,266,422	(8,660,414)
Accrued expenses	1,522,732	(3,652,271)
Other, net	6,479,153	310,988
Net adjustments	15,440,453	77,616,681
Net cash provided by operating activities	48,438,450	59,855,104
Cash Flows from Investing Activities:
Purchases of fixed maturities, held to maturity	(69,297,759)	(42,834,707)
Purchases of fixed maturities, available for sale	(125,791,644)	(88,940,126)
Purchases of equity securities, available for sale	(19,055,851)	(11,255,867)
Maturity of fixed maturities:
Held to maturity	13,723,483	9,485,969
Available for sale	88,459,874	84,617,730
Sales of fixed maturities, available for sale	20,548,077	1,388,934
Sales of equity securities, available for sale	37,968,114	7,843,437
Net purchases of property and equipment	(147,005)	(132,290)
Net sales of short-term investments	8,122,436	5,953,868
Net cash used in investing activities	(11,547,502)	(33,873,052)
Cash Flows from Financing Activities:
Cash dividends paid	(12,031,153)	(11,714,561)
Issuance of common stock	2,814,504	2,157,730
Borrowings under line of credit		1,000,000
Payments on lines of credit	(25,000,000)
Net cash used in financing activities	(34,216,649)	(8,556,831)
Net increase in cash	2,674,299	17,425,221
Cash at beginning of period	52,594,461	37,833,435
Cash at end of period	55,268,760	55,258,656
Cash paid during period - Interest	321,585	$ 937,470
Net cash paid during period - Taxes	2,200,000
Donegal Financial Services Corporation [Member]
Maturity of fixed maturities:
Sale of investment	19,863,949
Dividends received	$ 14,058,824

Organization

Organization	9 Months Ended
	Sep. 30, 2019
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 Mid-Atlantic, At September 30, 2019, we had three segments: our investment function, our personal lines of insurance and our commercial lines of insurance. 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, 2019, Donegal Mutual held approximately 43% of our outstanding Class A common stock and approximately 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. In July 2018, we consolidated the branch office operations of Peninsula into our home office operations to achieve economies of scale and enhance service levels for policyholders of Peninsula. We recorded a restructuring charge for employee termination costs associated with the Peninsula consolidation of approximately $1.9 million and paid approximately $1.5 million of these costs in 2018. We paid approximately $195,000 of these costs in the first nine months of 2019 and had an accrual of approximately $195,000 remaining at September 30, 2019. We entered into a definitive purchase agreement for the sale of Peninsula’s branch office in 2018. The sale was completed in January 2019, and we received net proceeds of $1.2 million. We recorded an impairment charge of $1.1 million in other expenses in 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 December 31, 2018. We and Donegal Mutual sold DFSC to Northwest Bancshares, Inc. (“Northwest”) on March 8, 2019, resulting in proceeds valued at approximately $85.8 million in a combination of cash and Northwest common stock. Immediately prior to the closing of the merger, DFSC paid a dividend of approximately $29.2 million to us and Donegal Mutual. As the owner of 48.2% of DFSC’s common stock, we received a dividend payment from DFSC of approximately $14.1 million and consideration from Northwest that included a combination of cash in the amount of $20.5 million and Northwest common stock with a fair value at the closing date of $20.9 million. We recorded a gain of $12.7 million from the sale of DFSC in our results of operations for the first quarter of 2019. We sold the Northwest common stock that we received as part of the consideration during the first quarter of 2019. This transaction represented the culmination of a banking strategy that began with the formation of DFSC in 2000. 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, 2019 or 2018. We have purchased a total of 57,658 shares of our Class A common stock under this program from its inception through September 30, 2019.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
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, 2019
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 undistributed earnings using a participation percentage that reflects the dividend rights of each class. 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, 2019 2018 Class A Class B Class A Class B (in thousands, except per share data) Basic earnings per share: Numerator: Allocation of net income $ 4,269 $ 917 $ 1,006 $ 200 Denominator: Weighted-average shares outstanding 23,015 5,577 22,717 5,577 Basic earnings per share $ 0.19 $ 0.16 $ 0.04 $ 0.04 Diluted earnings per share: Numerator: Allocation of net income $ 4,269 $ 917 $ 1,006 $ 200 Denominator: Number of shares used in basic computation 23,015 5,577 22,717 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 277 — 178 — Number of shares used in diluted computation 23,292 5,577 22,895 5,577 Diluted earnings per share $ 0.18 $ 0.16 $ 0.04 $ 0.04 Nine Months Ended September 30, 2019 2018 Class A Class B Class A Class B (in thousands, except per share data) Basic earnings (loss) per share: Numerator: Allocation of net income (loss) $ 27,065 $ 5,933 $ (14,472 ) $ (3,290 ) Denominator: Weighted-average shares outstanding 22,933 5,577 22,673 5,577 Basic earnings (loss) per share $ 1.18 $ 1.06 $ (0.64 ) $ (0.59 ) Diluted earnings (loss) per share: Numerator: Allocation of net income (loss) $ 27,065 $ 5,933 $ (14,472 ) $ (3,290 ) Denominator: Number of shares used in basic computation 22,933 5,577 22,673 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 183 — — — Number of shares used in diluted computation 23,116 5,577 22,673 5,577 Diluted earnings (loss) per share $ 1.17 $ 1.06 $ (0.64 ) $ (0.59 ) We did not include outstanding options to purchase 5,330,525 shares and 5,531,561 shares of Class A common stock in our computation of diluted earnings per share for the three months and nine months ended September 30, 2019 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 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 no

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2019
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 implemented a combined third-party reinsurance program effective January 1, 2019. The coverage and parameters of the fully consolidated program are common to all of our insurance subsidiaries and Donegal Mutual. 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 the losses of Donegal Mutual and our insurance subsidiaries are automatically reinsured, through a series of contracts, over a set retention of $1.0 million for property losses and a retention of $2.0 million for casualty losses (including workers’ compensation losses); 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 of $10.0 million and after exceeding an annual aggregate deductible of $1.2 million up to aggregate losses of $190.0 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 a catastrophe reinsurance agreement with Donegal Mutual, under which each of our insurance subsidiaries recovers 100% of an accumulation of multiple losses resulting from a single event, including natural disasters, over a set retention of $2.0 million up to aggregate losses of $8.0 million per occurrence. The agreement also provides additional coverage for an accumulation of losses from a single event including a combination of our insurance subsidiaries over a combined retention of $5.0 million.

Investments

Investments	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investments	5 - Investments The amortized cost and estimated fair values of our fixed maturities at September 30, 2019 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 $ 91,485 $ 2,336 $ 47 $ 93,774 Obligations of states and political subdivisions 181,575 15,124 86 196,613 Corporate securities 151,654 8,281 353 159,582 Mortgage-backed securities 34,175 623 25 34,773 Totals $ 458,889 $ 26,364 $ 511 $ 484,742 Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 19,325 $ 128 $ 7 $ 19,446 Obligations of states and political subdivisions 57,178 1,990 3 59,165 Corporate securities 146,644 4,295 158 150,781 Mortgage-backed securities 327,645 2,902 838 329,709 Totals $ 550,792 $ 9,315 $ 1,006 $ 559,101 At September 30, 2019, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $170.9 million and an amortized cost of $160.4 million. Our holdings at September 30, 2019 also included special revenue bonds with an aggregate fair value of $84.9 million and an amortized cost of $78.4 million. With respect to both categories of those bonds at September 30, 2019, 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 45 The amortized cost and estimated fair values of our fixed maturities at December 31, 2018 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated Fair (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 76,222 $ 175 $ 1,087 $ 75,310 Obligations of states and political subdivisions 159,292 8,237 704 166,825 Corporate securities 127,010 396 4,391 123,015 Mortgage-backed securities 40,274 64 450 39,888 Totals $ 402,798 $ 8,872 $ 6,632 $ 405,038 Amortized Cost Gross Unrealized Gross Unrealized Estimated Fair (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 45,188 $ 25 $ 1,003 $ 44,210 Obligations of states and political subdivisions 73,761 1,762 307 75,216 Corporate securities 140,689 203 3,059 137,833 Mortgage-backed securities 275,475 149 6,325 269,299 Totals $ 535,113 $ 2,139 $ 10,694 $ 526,558 At December 31, 2018, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $157.7 million and an amortized cost of $152.2 million. Our holdings also included special revenue bonds with an aggregate fair value of $84.3 million and an amortized cost of $80.9 million. With respect to both categories of bonds, we held no securities of any issuer that comprised more than 10% of that category at December 31, 2018. Education bonds and water and sewer utility bonds represented 49% and 29%, respectively, of our total investments in special revenue bonds based on their carrying values at December 31, 2018. Many of the issuers of the special revenue bonds we held at December 31, 2018 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 $ 870,186 income ( ) We show below the amortized cost and estimated fair value of our fixed maturities at September 30, 2019 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 Fair (in thousands) Held to maturity Due in one year or less $ 22,801 $ 22,881 Due after one year through five years 72,894 75,680 Due after five years through ten years 179,648 189,376 Due after ten years 149,371 162,032 Mortgage-backed securities 34,175 34,773 Total held to maturity $ 458,889 $ 484,742 Available for sale Due in one year or less $ 16,975 $ 17,152 Due after one year through five years 90,226 92,564 Due after five years through ten years 100,580 103,705 Due after ten years 15,366 15,971 Mortgage-backed securities 327,645 329,709 Total available for sale $ 550,792 $ 559,101 The cost and estimated fair values of our equity securities at September 30, 2019 were as follows: Cost Gross Gains Gross Losses Estimated Fair Value (in thousands) Equity securities $ 43,407 $ 10,078 $ 1,386 $ 52,099 The cost and estimated fair values of our equity securities at December 31, 2018 were as follows: Cost Gross Gains Gross Losses Estimated Fair Value (in thousands) Equity securities $ 40,943 $ 4,818 $ 2,094 $ 43,667 Gross investment gains and losses before applicable income taxes for the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) (in thousands) Gross investment gains: Fixed maturities $ 107 $ 5 $ 479 $ 16 Equity securities 721 2,976 8,293 6,246 Investment in affiliate — — 12,662 — 828 2,981 21,434 6,262 Gross investment losses: Fixed maturities 4 25 324 70 Equity securities 1,193 (508 ) 1,816 2,130 1,197 (483 ) 2,140 2,200 Net investment (losses) $ (369 ) $ 3,464 $ 19,294 $ 4,062 We recognized $6.7 million of gains and $1.2 million of losses on equity securities we held at September 30, 2019 in net investment gains for the nine months ended September 30, 2019. We recognized $3.9 million of gains and $1.6 million of losses on equity securities held at September 30, 2018 in net 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, 2019 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 $ 3,466 $ 34 $ 6,429 $ 20 Obligations of states and political subdivisions 4,582 86 2,321 3 Corporate securities 14,152 179 25,113 332 Mortgage-backed securities 18,686 75 89,643 788 Totals $ 40,886 $ 374 $ 123,506 $ 1,143 We held fixed maturities with unrealized losses representing declines that we considered temporary at December 31, 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 $ 26,342 $ 166 $ 54,900 $ 1,924 Obligations of states and political subdivisions 28,322 477 21,560 534 Corporate securities 149,270 4,483 59,397 2,968 Mortgage-backed securities 82,594 913 181,379 5,862 Totals $ 286,528 $ 6,039 $ 317,236 $ 11,288 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 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 131 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.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2019
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, 2019 and 2018 is as follows: Three Months Ended September 30, 2019 2018 (in thousands) Revenues: Premiums earned: Commercial lines $ 98,324 $ 84,251 Personal lines 91,497 103,410 Premiums earned 189,821 187,661 Net investment income 7,390 6,620 Investment (losses) gains (369 ) 3,464 Equity in earnings of DFSC — 733 Other 1,168 1,426 Total revenues $ 198,010 $ 199,904 Income before income tax expense: Underwriting income (loss): Commercial lines $ 2,521 $ 2,125 Personal lines (3,312 ) (12,210 ) SAP underwriting loss (791 ) (10,085 ) GAAP adjustments (399 ) 332 GAAP underwriting loss (1,190 ) (9,753 ) Net investment income 7,390 6,620 Investment (losses) gains (369 ) 3,464 Equity in earnings of DFSC — 733 Other 474 213 Income before income tax expense $ 6,305 $ 1,277 Nine Months Ended September 30, 2019 2018 (in thousands) Revenues: Premiums earned: Commercial lines $ 284,593 $ 251,029 Personal lines 282,065 304,111 Premiums earned 566,658 555,140 Net investment income 21,728 19,341 Investment gains 19,294 4,062 Equity in earnings of DFSC 295 2,153 Other 3,538 4,326 Total revenues $ 611,513 $ 585,022 Income (loss) before income tax expense (benefit): Underwriting income (loss): Commercial lines $ 4,946 $ (17,935 ) Personal lines (10,077 ) (42,358 ) SAP underwriting loss (5,131 ) (60,293 ) GAAP adjustments 1,431 5,106 GAAP underwriting loss (3,700 ) (55,187 ) Net investment income 21,728 19,341 Investment gains 19,294 4,062 Equity in earnings of DFSC 295 2,153 Other 1,070 1,040 Income (loss) before income tax expense (benefit) $ 38,687 $ (28,591 )

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Borrowings	7 - Borrowings Lines of Credit In March 2019, we terminated our previous credit agreement with Manufacturers and Traders Trust Company (“M&T”) and entered into a new credit agreement with M&T. The new credit agreement relates to a $ 30.0 July 2020 30.0 interest rates equal to M&T’s current prime rate or the then-current LIBOR rate plus 2.25% The credit a 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. In August 2019, Atlantic States repaid a variable-rate cash advance of $35.0 million that was due in March 2020 and issued debt to the FHLB of Pittsburgh in exchange for a fixed-rate cash advance of $35.0 million that was outstanding at September 30, 2019. Atlantic States incurred a pre-payment penalty of $176,000 related to the early repayment of its previous cash advance. The new cash advance carries a fixed interest rate of 1.74% and is due in August 2024. 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, 2019. FHLB of Pittsburgh stock purchased and owned $ 1,639,200 Collateral pledged, at par (carrying value $ 37,535,059 37,635,763 Borrowing capacity currently available 1,428,241 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, 2019
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 $247,301 and $317,526 for the three months ended September 30, 2019 and 2018, respectively, with a corresponding income tax benefit of $51,933 and $66,680, respectively. We charged compensation expense related to our stock compensation plans against income before income taxes of $1.1 million and $1.4 million for the nine months ended September 30, 2019 and 2018, respectively, with a corresponding income tax benefit of $233,851 and $285,578, respectively. At September 30, 2019, we had $1.3 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 1.5 We received cash from option exercises under all stock compensation plans during the three months ended September 30, 2019 and 2018 of $772,969 217,112 2,516 for the three months ended September 30, 2019 and 2018, respectively . We received cash from option exercises under all stock compensation plans during the nine months ended September 30, 2019 and 2018 of $ 1.6 million 695,762

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
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 $ 19,446 $ — $ 19,446 $ — Obligations of states and political subdivisions 59,165 — 59,165 — Corporate securities 150,781 — 150,781 — Mortgage-backed securities 329,709 — 329,709 — Equity securities 52,099 49,746 2,353 — Total investments in the fair value hierarchy $ 611,200 $ 49,746 $ 561,454 $ — 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 $ 44,210 $ — $ 44,210 $ — Obligations of states and political subdivisions 75,216 — 75,216 — Corporate securities 137,833 — 137,833 — Mortgage-backed securities 269,299 — 269,299 — Equity securities 30,675 28,351 2,324 — Total investments in the fair value hierarchy 557,233 28,351 528,882 — Investment measured at net asset value 12,992 — — — Totals $ 570,225 $ 28,351 $ 528,882 $ —

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	10 - Income Taxes At September 30, 2019 and December 31, 2018, respectively, we had no material unrecognized tax benefits or accrued interest and penalties. Tax years 2016 through 2018 remained open for examination at September 30, 2019. 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 $8.1 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 $25.2 million and $32.4 million at September 30, 2019 and December 31, 2018, 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 $1.2 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, 2019
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, 2019 2018 (in thousands) Balance at January 1 $ 814,665 $ 676,672 Less reinsurance recoverable (339,267 ) (293,271 ) Net balance at January 1 475,398 383,401 Incurred related to: Current year 393,301 404,150 Prior years (7,940 ) 28,913 Total incurred 385,361 433,063 Paid related to: Current year 197,234 214,825 Prior years 157,691 140,806 Total paid 354,925 355,631 Net balance at end of period 505,834 460,833 Plus reinsurance recoverable 358,700 319,147 Balance at end of period $ 864,534 $ 779,980 Our insurance subsidiaries recognized a (decrease) increase in their liability for losses and loss expenses of prior years of ($7.9 million) 2018 at September 30, 2018. The 2018 development represented 7.5% of the December 31, 2017 net carried reserves and resulted primarily from higher-than-expected severity in the personal automobile and commercial automobile lines of business, offset by lower-than-expected severity in the workers’ compensation line of business, in accident years prior to 2018. The majority of the 2018 development related to increases in the liability for losses and loss expenses of prior years for Atlantic States and 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 their actuaries made no significant changes to that methodology during the nine months ended September 30, 2019. 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, 2019
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Standards	12 - Impact of New Accounting Standards 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. Our adoption of this guidance on January 1, 2019 did not have a significant impact on our financial position, results of operations or cash flows. In June 2016, the FASB issued guidance that amends previous guidance on the impairment of financial instruments by adding an impairment model that requires an entity to recognize expected credit losses as an allowance rather than impairments as credit losses are incurred. The intent of this guidance is to reduce complexity and result in a more timely recognition of expected credit losses. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. We 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 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. The adoption of this guidance on January 1, 2019 did not 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, 2019
Accounting Changes and Error Corrections [Abstract]
Impact of New Accounting Standards	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. Our adoption of this guidance on January 1, 2019 did not have a significant impact on our financial position, results of operations or cash flows. In June 2016, the FASB issued guidance that amends previous guidance on the impairment of financial instruments by adding an impairment model that requires an entity to recognize expected credit losses as an allowance rather than impairments as credit losses are incurred. The intent of this guidance is to reduce complexity and result in a more timely recognition of expected credit losses. The guidance is effective for annual and interim reporting periods beginning after December 15, 2019. We 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 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. The adoption of this guidance on January 1, 2019 did not 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, 2019
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, 2019 2018 Class A Class B Class A Class B (in thousands, except per share data) Basic earnings per share: Numerator: Allocation of net income $ 4,269 $ 917 $ 1,006 $ 200 Denominator: Weighted-average shares outstanding 23,015 5,577 22,717 5,577 Basic earnings per share $ 0.19 $ 0.16 $ 0.04 $ 0.04 Diluted earnings per share: Numerator: Allocation of net income $ 4,269 $ 917 $ 1,006 $ 200 Denominator: Number of shares used in basic computation 23,015 5,577 22,717 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 277 — 178 — Number of shares used in diluted computation 23,292 5,577 22,895 5,577 Diluted earnings per share $ 0.18 $ 0.16 $ 0.04 $ 0.04 Nine Months Ended September 30, 2019 2018 Class A Class B Class A Class B (in thousands, except per share data) Basic earnings (loss) per share: Numerator: Allocation of net income (loss) $ 27,065 $ 5,933 $ (14,472 ) $ (3,290 ) Denominator: Weighted-average shares outstanding 22,933 5,577 22,673 5,577 Basic earnings (loss) per share $ 1.18 $ 1.06 $ (0.64 ) $ (0.59 ) Diluted earnings (loss) per share: Numerator: Allocation of net income (loss) $ 27,065 $ 5,933 $ (14,472 ) $ (3,290 ) Denominator: Number of shares used in basic computation 22,933 5,577 22,673 5,577 Weighted-average shares effect of dilutive securities: Director and employee stock options 183 — — — Number of shares used in diluted computation 23,116 5,577 22,673 5,577 Diluted earnings (loss) per share $ 1.17 $ 1.06 $ (0.64 ) $ (0.59 )

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 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 $ 91,485 $ 2,336 $ 47 $ 93,774 Obligations of states and political subdivisions 181,575 15,124 86 196,613 Corporate securities 151,654 8,281 353 159,582 Mortgage-backed securities 34,175 623 25 34,773 Totals $ 458,889 $ 26,364 $ 511 $ 484,742 Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 19,325 $ 128 $ 7 $ 19,446 Obligations of states and political subdivisions 57,178 1,990 3 59,165 Corporate securities 146,644 4,295 158 150,781 Mortgage-backed securities 327,645 2,902 838 329,709 Totals $ 550,792 $ 9,315 $ 1,006 $ 559,101 The amortized cost and estimated fair values of our fixed maturities at December 31, 2018 were as follows: Amortized Cost Gross Unrealized Gross Unrealized Estimated Fair (in thousands) Held to Maturity U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 76,222 $ 175 $ 1,087 $ 75,310 Obligations of states and political subdivisions 159,292 8,237 704 166,825 Corporate securities 127,010 396 4,391 123,015 Mortgage-backed securities 40,274 64 450 39,888 Totals $ 402,798 $ 8,872 $ 6,632 $ 405,038 Amortized Cost Gross Unrealized Gross Unrealized Estimated Fair (in thousands) Available for Sale U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 45,188 $ 25 $ 1,003 $ 44,210 Obligations of states and political subdivisions 73,761 1,762 307 75,216 Corporate securities 140,689 203 3,059 137,833 Mortgage-backed securities 275,475 149 6,325 269,299 Totals $ 535,113 $ 2,139 $ 10,694 $ 526,558
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 Fair (in thousands) Held to maturity Due in one year or less $ 22,801 $ 22,881 Due after one year through five years 72,894 75,680 Due after five years through ten years 179,648 189,376 Due after ten years 149,371 162,032 Mortgage-backed securities 34,175 34,773 Total held to maturity $ 458,889 $ 484,742 Available for sale Due in one year or less $ 16,975 $ 17,152 Due after one year through five years 90,226 92,564 Due after five years through ten years 100,580 103,705 Due after ten years 15,366 15,971 Mortgage-backed securities 327,645 329,709 Total available for sale $ 550,792 $ 559,101
Summary of Cost and Estimated Fair Values of Equity Securities	The cost and estimated fair values of our equity securities at September 30, 2019 were as follows: Cost Gross Gains Gross Losses Estimated Fair Value (in thousands) Equity securities $ 43,407 $ 10,078 $ 1,386 $ 52,099 The cost and estimated fair values of our equity securities at December 31, 2018 were as follows: Cost Gross Gains Gross Losses Estimated Fair Value (in thousands) Equity securities $ 40,943 $ 4,818 $ 2,094 $ 43,667
Summary of Gross Investment Gains and Losses before Applicable Income Taxes	Gross investment gains and losses before applicable income taxes for the three and nine months ended September 30, 2019 and 2018 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (in thousands) (in thousands) Gross investment gains: Fixed maturities $ 107 $ 5 $ 479 $ 16 Equity securities 721 2,976 8,293 6,246 Investment in affiliate — — 12,662 — 828 2,981 21,434 6,262 Gross investment losses: Fixed maturities 4 25 324 70 Equity securities 1,193 (508 ) 1,816 2,130 1,197 (483 ) 2,140 2,200 Net investment (losses) $ (369 ) $ 3,464 $ 19,294 $ 4,062
Summary of Fixed Maturities with Unrealized Losses	We held fixed maturities with unrealized losses representing declines that we considered temporary at September 30, 2019 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 $ 3,466 $ 34 $ 6,429 $ 20 Obligations of states and political subdivisions 4,582 86 2,321 3 Corporate securities 14,152 179 25,113 332 Mortgage-backed securities 18,686 75 89,643 788 Totals $ 40,886 $ 374 $ 123,506 $ 1,143 We held fixed maturities with unrealized losses representing declines that we considered temporary at December 31, 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 $ 26,342 $ 166 $ 54,900 $ 1,924 Obligations of states and political subdivisions 28,322 477 21,560 534 Corporate securities 149,270 4,483 59,397 2,968 Mortgage-backed securities 82,594 913 181,379 5,862 Totals $ 286,528 $ 6,039 $ 317,236 $ 11,288

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Summary of Financial Data by Segment	Financial data by segment for the three and nine months ended September 30, 2019 and 2018 is as follows: Three Months Ended September 30, 2019 2018 (in thousands) Revenues: Premiums earned: Commercial lines $ 98,324 $ 84,251 Personal lines 91,497 103,410 Premiums earned 189,821 187,661 Net investment income 7,390 6,620 Investment (losses) gains (369 ) 3,464 Equity in earnings of DFSC — 733 Other 1,168 1,426 Total revenues $ 198,010 $ 199,904 Income before income tax expense: Underwriting income (loss): Commercial lines $ 2,521 $ 2,125 Personal lines (3,312 ) (12,210 ) SAP underwriting loss (791 ) (10,085 ) GAAP adjustments (399 ) 332 GAAP underwriting loss (1,190 ) (9,753 ) Net investment income 7,390 6,620 Investment (losses) gains (369 ) 3,464 Equity in earnings of DFSC — 733 Other 474 213 Income before income tax expense $ 6,305 $ 1,277 Nine Months Ended September 30, 2019 2018 (in thousands) Revenues: Premiums earned: Commercial lines $ 284,593 $ 251,029 Personal lines 282,065 304,111 Premiums earned 566,658 555,140 Net investment income 21,728 19,341 Investment gains 19,294 4,062 Equity in earnings of DFSC 295 2,153 Other 3,538 4,326 Total revenues $ 611,513 $ 585,022 Income (loss) before income tax expense (benefit): Underwriting income (loss): Commercial lines $ 4,946 $ (17,935 ) Personal lines (10,077 ) (42,358 ) SAP underwriting loss (5,131 ) (60,293 ) GAAP adjustments 1,431 5,106 GAAP underwriting loss (3,700 ) (55,187 ) Net investment income 21,728 19,341 Investment gains 19,294 4,062 Equity in earnings of DFSC 295 2,153 Other 1,070 1,040 Income (loss) before income tax expense (benefit) $ 38,687 $ (28,591 )

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2019
FHLB of Pittsburgh [Member]
Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement	The table below presents the amount of FHLB of Pittsburgh stock Atlantic States purchased, collateral pledged and assets related to Atlantic States’ membership in the FHLB of Pittsburgh at September 30, 2019. FHLB of Pittsburgh stock purchased and owned $ 1,639,200 Collateral pledged, at par (carrying value $ 37,535,059 37,635,763 Borrowing capacity currently available 1,428,241

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
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 $ 19,446 $ — $ 19,446 $ — Obligations of states and political subdivisions 59,165 — 59,165 — Corporate securities 150,781 — 150,781 — Mortgage-backed securities 329,709 — 329,709 — Equity securities 52,099 49,746 2,353 — Total investments in the fair value hierarchy $ 611,200 $ 49,746 $ 561,454 $ — 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 $ 44,210 $ — $ 44,210 $ — Obligations of states and political subdivisions 75,216 — 75,216 — Corporate securities 137,833 — 137,833 — Mortgage-backed securities 269,299 — 269,299 — Equity securities 30,675 28,351 2,324 — Total investments in the fair value hierarchy 557,233 28,351 528,882 — Investment measured at net asset value 12,992 — — — Totals $ 570,225 $ 28,351 $ 528,882 $ —

Liability for Losses and Loss_2

Liability for Losses and Loss Expenses (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 (in thousands) Balance at January 1 $ 814,665 $ 676,672 Less reinsurance recoverable (339,267 ) (293,271 ) Net balance at January 1 475,398 383,401 Incurred related to: Current year 393,301 404,150 Prior years (7,940 ) 28,913 Total incurred 385,361 433,063 Paid related to: Current year 197,234 214,825 Prior years 157,691 140,806 Total paid 354,925 355,631 Net balance at end of period 505,834 460,833 Plus reinsurance recoverable 358,700 319,147 Balance at end of period $ 864,534 $ 779,980

Organization - Additional Infor

Organization - Additional Information (Detail)	Mar. 08, 2019USD ($)	Jan. 31, 2019USD ($)	Sep. 30, 2019USD ($)Segment	Dec. 31, 2018USD ($)	Sep. 30, 2019shares	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			3
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			195,000	$ 1,500,000
Accrual of restructuring charge			$ 195,000
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]
Business Acquisition [Line Items]
Consideration from sale of business	$ 20,500,000
Consideration from sale of business fair value at closing date	20,900,000
DFSC and North West [Member] | Donegal Mutual Insurance Company [Member]
Business Acquisition [Line Items]
Consideration from sale of business	85,800,000
Proceeds from dividend	$ 29,200,000
Peninsula [Member]
Business Acquisition [Line Items]
Expected proceeds from sale of real estate		$ 1,200,000
Impairment charge related to real estate transaction				1,100,000
Fair value of real asset held for sale				$ 1,200,000
Donegal Financial Services Corporation [Member]
Business Acquisition [Line Items]
Outstanding stock ownership percentage			48.20%		48.20%
Gain (Loss) on Sale of Equity Investments			$ 12,700,000
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	$ 14,100,000
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
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	5,330,525	6,731,481	5,531,561	0

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Class A Common Stock [Member]
Numerator:
Allocation of net income (loss)	$ 4,269	$ 1,006	$ 27,065	$ (14,472)
Denominator:
Weighted-average shares outstanding	23,015	22,717	22,933	22,673
Basic earnings (loss) per share	$ 0.19	$ 0.04	$ 1.18	$ (0.64)
Numerator:
Allocation of net income (loss)	$ 4,269	$ 1,006	$ 27,065	$ (14,472)
Denominator:
Number of shares used in basic computation	23,015	22,717	22,933	22,673
Weighted-average shares effect of dilutive securities:
Director and employee stock options	277	178	183
Number of shares used in diluted computation	23,292	22,895	23,116	22,673
Diluted earnings (loss) per share	$ 0.18	$ 0.04	$ 1.17	$ (0.64)
Class B Common Stock [Member]
Numerator:
Allocation of net income (loss)	$ 917	$ 200	$ 5,933	$ (3,290)
Denominator:
Weighted-average shares outstanding	5,577	5,577	5,577	5,577
Basic earnings (loss) per share	$ 0.16	$ 0.04	$ 1.06	$ (0.59)
Numerator:
Allocation of net income (loss)	$ 917	$ 200	$ 5,933	$ (3,290)
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 earnings (loss) per share	$ 0.16	$ 0.04	$ 1.06	$ (0.59)

Reinsurance - Additional Inform

Reinsurance - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2019USD ($)
Ceded Credit Risk [Line Items]
Loss reinsurance, set retention amount for property losses	$ 1,000,000
Loss reinsurance, set retention amount for casualty losses	$ 2,000,000
Third Party Reinsurance [Member]
Ceded Credit Risk [Line Items]
Percentage of accumulation of losses	100.00%
Catastrophe reinsurance, set retention amount	$ 10,000,000
Catastrophe reinsurance, deductible amount	1,200,000
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	$ 190,000,000
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%
Percentage of accumulation of losses	100.00%
Catastrophe reinsurance, set retention amount	$ 2,000,000
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	8,000,000
Additional coverage amount	$ 5,000,000

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Estimated Fair Values of Fixed Maturities (Detail) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	$ 458,888,742	$ 402,798,518
Held to Maturity, Gross Unrealized Gains	26,364,000	8,872,000
Held to Maturity, Gross Unrealized Losses	511,000	6,632,000
Total held to maturity, Estimated Fair Value	484,742,000	405,038,000
Available for Sale, Amortized Cost	550,792,000	535,113,000
Available for Sale, Gross Unrealized Gains	9,315,000	2,139,000
Available for Sale, Gross Unrealized Losses	1,006,000	10,694,000
Available for Sale, Estimated Fair Value	559,101,000	526,558,000
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	91,485,000	76,222,000
Held to Maturity, Gross Unrealized Gains	2,336,000	175,000
Held to Maturity, Gross Unrealized Losses	47,000	1,087,000
Total held to maturity, Estimated Fair Value	93,774,000	75,310,000
Available for Sale, Amortized Cost	19,325,000	45,188,000
Available for Sale, Gross Unrealized Gains	128,000	25,000
Available for Sale, Gross Unrealized Losses	7,000	1,003,000
Available for Sale, Estimated Fair Value	19,446,000	44,210,000
Obligations of States and Political Subdivisions [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	181,575,000	159,292,000
Held to Maturity, Gross Unrealized Gains	15,124,000	8,237,000
Held to Maturity, Gross Unrealized Losses	86,000	704,000
Total held to maturity, Estimated Fair Value	196,613,000	166,825,000
Available for Sale, Amortized Cost	57,178,000	73,761,000
Available for Sale, Gross Unrealized Gains	1,990,000	1,762,000
Available for Sale, Gross Unrealized Losses	3,000	307,000
Available for Sale, Estimated Fair Value	59,165,000	75,216,000
Corporate Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	151,654,000	127,010,000
Held to Maturity, Gross Unrealized Gains	8,281,000	396,000
Held to Maturity, Gross Unrealized Losses	353,000	4,391,000
Total held to maturity, Estimated Fair Value	159,582,000	123,015,000
Available for Sale, Amortized Cost	146,644,000	140,689,000
Available for Sale, Gross Unrealized Gains	4,295,000	203,000
Available for Sale, Gross Unrealized Losses	158,000	3,059,000
Available for Sale, Estimated Fair Value	150,781,000	137,833,000
Mortgage-Backed Securities [Member]
Schedule of Equity Method Investments [Line Items]
Total held to maturity, Amortized Cost	34,175,000	40,274,000
Held to Maturity, Gross Unrealized Gains	623,000	64,000
Held to Maturity, Gross Unrealized Losses	25,000	450,000
Total held to maturity, Estimated Fair Value	34,773,000	39,888,000
Available for Sale, Amortized Cost	327,645,000	275,475,000
Available for Sale, Gross Unrealized Gains	2,902,000	149,000
Available for Sale, Gross Unrealized Losses	838,000	6,325,000
Available for Sale, Estimated Fair Value	$ 329,709,000	$ 269,299,000

Investments - Additional Inform

Investments - Additional Information (Detail)	Nov. 30, 2013USD ($)	Sep. 30, 2019USD ($)Securities	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule of Investments [Line Items]
Net unrealized losses arising prior to reclassification date	$ 15,100,000
Amortization of unrealized losses recorded in accumulated other comprehensive income (loss)		$ 870,186	$ 912,229
Accumulated other comprehensive loss		418,394		$ (14,228,059)
Gain on equity securities		6,700,000	3,900,000
Loss on equity securities		1,200,000	$ 1,600,000
Obligations of States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		170,900,000		157,700,000
Amortized cost of bond held		160,400,000		152,200,000
Special Revenue Bonds [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		84,900,000		84,300,000
Amortized cost of bond held		$ 78,400,000		$ 80,900,000
Education Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		45.00%		49.00%
Water and Sewer Utility Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		34.00%		29.00%
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale | Securities		131
Accumulated Net Unrealized Investment Losses [Member]
Schedule of Investments [Line Items]
Accumulated other comprehensive loss		$ (7,800,000)		$ (8,600,000)
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, 2019	Dec. 31, 2018
Held to maturity
Due in one year or less, Amortized Cost	$ 22,801,000
Due after one year through five years, Amortized Cost	72,894,000
Due after five years through ten years, Amortized Cost	179,648,000
Due after ten years, Amortized Cost	149,371,000
Mortgage-backed securities, Amortized Cost	34,175,000
Total held to maturity, Amortized Cost	458,888,742	$ 402,798,518
Available for sale
Due in one year or less, Amortized Cost	16,975,000
Due after one year through five years, Amortized Cost	90,226,000
Due after five years through ten years, Amortized Cost	100,580,000
Due after ten years, Amortized Cost	15,366,000
Mortgage-backed securities, Amortized Cost	327,645,000
Total available for sale, Amortized Cost	550,792,000
Held to maturity
Due in one year or less, Estimated Fair Value	22,881,000
Due after one year through five years, Estimated Fair Value	75,680,000
Due after five years through ten years, Estimated Fair Value	189,376,000
Due after ten years, Estimated Fair Value	162,032,000
Mortgage-backed securities, Estimated Fair Value	34,773,000
Total held to maturity, Estimated Fair Value	484,742,000	405,038,000
Available for sale
Due in one year or less, Estimated Fair Value	17,152,000
Due after one year through five years, Estimated Fair Value	92,564,000
Due after five years through ten years, Estimated Fair Value	103,705,000
Due after ten years, Estimated Fair Value	15,971,000
Mortgage-backed securities, Estimated Fair Value	329,709,000
Total available for sale, Estimated Fair Value	$ 559,101,387	$ 526,558,304

Investments - Summary of Cost a

Investments - Summary of Cost and Estimated Fair Value of Equity Securities (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Cost	$ 43,407,000	$ 40,943,000
Gross Gains	10,078,000	4,818,000
Gross Losses	1,386,000	2,094,000
Estimated Fair Value	$ 52,098,509	$ 43,667,009

Investments - Summary of Gross

Investments - Summary of Gross Investment Gains and Losses before Applicable Income Taxes (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Gain (Loss) on Securities [Line Items]
Gross investment gains	$ 828,000	$ 2,981,000	$ 21,434,000	$ 6,262,000
Gross investment losses	1,197,000	(483,000)	2,140,000	2,200,000
Net investment (losses) gains	(369,041)	3,463,504	19,294,229	4,062,475
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	107,000	5,000	479,000	16,000
Gross investment losses	4,000	25,000	324,000	70,000
Investments In Affiliates [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	0		12,662,000
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	721,000	2,976,000	8,293,000	6,246,000
Gross investment losses	$ 1,193,000	$ (508,000)	$ 1,816,000	$ 2,130,000

Investments - Summary of Fixed

Investments - Summary of Fixed Maturities with Unrealized Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	$ 40,886	$ 286,528
Less Than 12 Months, Unrealized Losses	374	6,039
More Than 12 Months, Fair Value	123,506	317,236
More Than 12 Months, Unrealized Losses	1,143	11,288
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	3,466	26,342
Less Than 12 Months, Unrealized Losses	34	166
More Than 12 Months, Fair Value	6,429	54,900
More Than 12 Months, Unrealized Losses	20	1,924
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	4,582	28,322
Less Than 12 Months, Unrealized Losses	86	477
More Than 12 Months, Fair Value	2,321	21,560
More Than 12 Months, Unrealized Losses	3	534
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	14,152	149,270
Less Than 12 Months, Unrealized Losses	179	4,483
More Than 12 Months, Fair Value	25,113	59,397
More Than 12 Months, Unrealized Losses	332	2,968
Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	18,686	82,594
Less Than 12 Months, Unrealized Losses	75	913
More Than 12 Months, Fair Value	89,643	181,379
More Than 12 Months, Unrealized Losses	$ 788	$ 5,862

Segment Information - Summary o

Segment Information - Summary of Financial Data by Segment (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Premiums earned:
Premiums earned	$ 189,821,058	$ 187,661,705	$ 566,657,613	$ 555,140,395
Net investment income	7,389,749	6,620,491	21,727,904	19,341,012
Investment (losses) gains	(369,041)	3,463,504	19,294,229	4,062,475
Equity in earnings of DFSC		732,768	295,000	2,152,738
Other	1,168,000	1,426,000	3,538,000	4,326,000
Total revenues	198,009,900	199,904,180	611,512,728	585,022,486
Underwriting income (loss):
SAP underwriting income (loss)	(791,000)	(10,085,000)	(5,131,000)	(60,293,000)
GAAP adjustments	(399,000)	332,000	1,431,000	5,106,000
GAAP underwriting income (loss)	(1,190,000)	(9,753,000)	(3,700,000)	(55,187,000)
Net investment income	7,389,749	6,620,491	21,727,904	19,341,012
Investment (losses) gains	(369,041)	3,463,504	19,294,229	4,062,475
Equity in earnings of DFSC		732,768	295,000	2,152,738
Other	474,000	213,000	1,070,000	1,040,000
Income (loss) before income tax expense (benefit)	6,304,884	1,276,986	38,687,439	(28,591,231)
Commercial Lines [Member]
Premiums earned:
Premiums earned	98,324,000	84,251,000	284,593,000	251,029,000
Underwriting income (loss):
SAP underwriting income (loss)	2,521,000	2,125,000	4,946,000	(17,935,000)
Personal Lines [Member]
Premiums earned:
Premiums earned	91,497,000	103,410,000	282,065,000	304,111,000
Underwriting income (loss):
SAP underwriting income (loss)	$ (3,312,000)	$ (12,210,000)	$ (10,077,000)	$ (42,358,000)

Borrowings - Additional Informa

Borrowings - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2019USD ($)
Line of Credit Facility [Line Items]
Line of credit expiration month and year	2020-07
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	0.15%
Manufacturers and Traders Trust Company [Member]
Line of Credit Facility [Line Items]
Line of credit facility remaining borrowing capacity	$ 30,000,000
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. In addition, Atlantic States has guaranteed our payment obligations under the new credit agreement. We complied with all requirements of the credit agreement during the nine months ended September 30, 2019.
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	$ 1,428,241
Outstanding advances	35,000,000
Federal home loan bank, fixed rate advances	35,000,000
Pre-Payment of Penalty	176,000
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	$ 30,000,000
Lines of Credit [Member] | FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Interest rate on advances	1.74%
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, 2019USD ($)
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement
FHLB stock purchased and owned	$ 1,639,200
Collateral pledged, at par	37,635,763
Borrowing capacity currently available	$ 1,428,241

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, 2019USD ($)
FHLB of Pittsburgh [Member] | Atlantic States [Member]
Line of Credit Facility [Line Items]
Collateral Pledged at carrying value	$ 37,535,059

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation expense in stock compensation plans	$ 247,301	$ 317,526	$ 1,100,000	$ 1,400,000
Income tax benefit of stock compensation plans	51,933	66,680	233,851	285,578
Unrecognized compensation expense related to nonvested share-based compensation granted under the plan	1,300,000		$ 1,300,000
Weighted average period of unrecognized compensation expense			1 year 6 months
Cash from option exercises	772,969	217,112	$ 1,600,000	695,762
Tax benefit for tax deductions related to option exercises	$ 22,414	$ 2,516	$ 38,376	$ 21,319

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, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	$ 559,101	$ 526,558
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	19,446	44,210
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	59,165	75,216
Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	150,781	137,833
Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value Disclosure	329,709	269,299
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		570,225
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		12,992
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	611,200	557,233
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	19,446	44,210
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	59,165	75,216
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	150,781	137,833
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	329,709	269,299
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	52,099	30,675
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		28,351
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	49,746	28,351
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	49,746	28,351
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		528,882
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	561,454	528,882
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	19,446	44,210
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	59,165	75,216
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	150,781	137,833
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	329,709	269,299
Significant Other Observable Inputs (Level 2) [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	$ 2,353	$ 2,324

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Other deferred tax assets, net	$ 25,200,000	$ 32,400,000
Parent Company [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	$ 8,100,000
Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2016
Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2018
Le Mars [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	$ 264,467
Operating loss carryforwards	$ 1,200,000
Operating loss carryforwards expiration period	2020
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, 2019	Sep. 30, 2018
Liability for Claims and Claims Adjustment Expense [Abstract]
Balance at January 1	$ 814,665,224	$ 676,672,000
Less reinsurance recoverable	(339,267,000)	(293,271,000)
Net balance at January 1	475,398,000	383,401,000
Incurred related to:
Current year	393,301,000	404,150,000
Prior years	(7,940,000)	28,913,000
Total incurred	385,361,000	433,063,000
Paid related to:
Current year	197,234,000	214,825,000
Prior years	157,691,000	140,806,000
Total paid	354,925,000	355,631,000
Net balance at end of period	505,834,000	460,833,000
Plus reinsurance recoverable	358,700,000	319,147,000
Balance at end of period	$ 864,534,338	$ 779,980,000

Liability for Losses and Loss_4

Liability for Losses and Loss Expenses - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
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	$ (7,940)	$ 28,913
Percentage of 2010 development	1.70%	7.50%
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