Donegal (DGICA) 10-Q 7 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013	Nov. 01, 2013
		Common Class A [Member]	Common Class B [Member]
Document Information [Line Items]	'	'	'
Document Type	'10-Q	'	'
Amendment Flag	'false	'	'
Document Period End Date	30-Sep-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'Q3	'	'
Trading Symbol	'DGICA	'	'
Entity Registrant Name	'DONEGAL GROUP INC	'	'
Entity Central Index Key	'0000800457	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	20,681,588	5,576,775

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
Fixed maturities	'	'
Held to Maturity, at Amortized Cost	$30,208,111	$42,100,196
Available for sale, at fair value	669,808,544	694,509,821
Equity securities, available for sale, at fair value	13,399,532	8,757,258
Investments in affiliates	36,347,441	37,235,530
Short-term investments, at cost, which approximates fair value	38,680,145	23,826,227
Total investments	788,443,773	806,429,032
Cash	22,792,517	19,801,290
Accrued investment income	6,493,342	6,332,085
Premiums receivable	130,495,957	117,196,478
Reinsurance receivable	241,923,788	215,893,322
Deferred policy acquisition costs	44,601,415	40,121,697
Deferred tax asset, net	19,059,816	6,267,536
Prepaid reinsurance premiums	118,456,083	111,156,162
Property and equipment, net	5,979,283	5,953,833
Accounts receivable - securities	1,907,583	'
Federal income taxes recoverable	1,771,283	'
Goodwill	5,625,354	5,625,354
Other intangible assets	958,010	958,010
Other	1,137,309	1,154,388
Total assets	1,389,645,513	1,336,889,187
Liabilities	'	'
Unpaid losses and loss expenses	496,477,613	458,827,395
Unearned premiums	397,738,722	363,088,103
Accrued expenses	18,100,483	17,140,832
Reinsurance balances payable	14,537,456	13,941,337
Borrowings under lines of credit	64,500,000	52,000,000
Cash dividends declared to stockholders	'	3,066,532
Subordinated debentures	5,000,000	20,465,000
Federal income taxes payable	'	583,977
Due to affiliate	52,048	4,579,437
Drafts payable	1,466,446	863,589
Other	2,694,065	2,298,891
Total liabilities	1,000,566,833	936,855,093
Stockholders' Equity	'	'
Preferred stock, $.01 par value, authorized 2,000,000 shares; none issued	'	'
Additional paid-in capital	182,727,575	176,416,585
Accumulated other comprehensive (loss) income	-1,059,899	26,394,577
Retained earnings	219,914,119	209,670,214
Treasury stock	-12,773,217	-12,713,193
Total stockholders' equity	389,078,680	400,034,094
Total liabilities and stockholders' equity	1,389,645,513	1,336,889,187
Common Class A [Member]	'	'
Stockholders' Equity	'	'
Common stock value	213,610	209,419
Total stockholders' equity	213,610	209,419
Common Class B [Member]	'	'
Stockholders' Equity	'	'
Common stock value	56,492	56,492
Total stockholders' equity	$56,492	$56,492

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	'	'
Common Class A [Member]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	40,000,000	30,000,000
Common stock, shares issued	21,360,992	20,941,821
Common stock, shares outstanding	20,440,130	20,025,199
Common Class B [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_Inc

Consolidated Statements of Income (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:	'	'	'	'
Net premiums earned	$130,645,011	$120,916,960	$382,310,380	$353,177,873
Investment income, net of investment expenses	4,624,287	4,715,295	14,110,288	14,724,305
Net realized investment gains	349,164	1,312,137	2,943,710	5,150,450
Lease income	212,581	235,734	638,535	727,705
Installment payment fees	1,768,537	1,914,587	5,212,420	5,676,957
Equity in earnings of Donegal Financial Services Corporation	735,380	1,336,818	2,499,854	3,621,593
Total revenues	138,334,960	130,431,531	407,715,187	383,078,883
Expenses:	'	'	'	'
Net losses and loss expenses	84,882,734	82,105,094	259,935,100	245,099,666
Amortization of deferred policy acquisition costs	20,766,000	18,864,000	60,236,000	54,980,000
Other underwriting expenses	21,454,770	19,130,875	61,335,688	57,617,438
Policyholder dividends	456,675	401,531	1,272,530	800,015
Interest	431,899	584,109	1,252,747	1,785,108
Other expenses	828,674	473,240	3,223,467	1,961,158
Total expenses	128,820,752	121,558,849	387,255,532	362,243,385
Income before income tax expense	9,514,208	8,872,682	20,459,655	20,835,498
Income tax expense	1,860,474	2,033,298	3,701,498	3,962,900
Net income	$7,653,734	$6,839,384	$16,758,157	$16,872,598
Common Class A [Member]	'	'	'	'
Earnings per common share:	'	'	'	'
Common stock - basic and diluted	$0.30	$0.27	'	'
Common stock - basic	$0.30	$0.27	$0.66	$0.67
Common stock - diluted	$0.30	$0.27	$0.65	$0.66
Common Class B [Member]	'	'	'	'
Earnings per common share:	'	'	'	'
Common stock - basic and diluted	$0.27	$0.25	$0.60	$0.61
Common stock - basic	$0.27	$0.25	$0.60	$0.61
Common stock - diluted	$0.27	$0.25	$0.60	$0.61

Consolidated_Statements_of_Inc1

Consolidated Statements of Income (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net realized investment gains	$349,164	$1,312,137	$2,943,710	$5,150,450
Income tax expense	1,860,474	2,033,298	3,701,498	3,962,900
Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'
Net realized investment gains	349,164	0	2,943,710	0
Income tax expense	$118,715	$0	$1,000,861	$0

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive (Loss) Income (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net income	$7,653,734	$6,839,384	$16,758,157	$16,872,598
Unrealized (loss) gain on securities:	'	'	'	'
Unrealized holding (loss) income during the period, net of income tax (benefit) expense	-1,175,052	6,527,358	-25,511,627	11,096,463
Reclassification adjustment for gains included in net income, net of income tax	-230,449	-866,010	-1,942,849	-3,399,297
Other comprehensive (loss) income	-1,405,501	5,661,348	-27,454,476	7,697,166
Comprehensive (loss) income	$6,248,233	$12,500,732	($10,696,319)	$24,569,764

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive (Loss) Income (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Income tax on unrealized holding during the period	($638,094)	$3,494,545	($13,782,319)	$5,895,784
Income tax on reclassification adjustment for gains	$118,715	$446,127	$1,000,861	$1,751,153

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Common Class A [Member]	Common Class B [Member]
Beginning balance at Dec. 31, 2012	$400,034,094	$176,416,585	$26,394,577	$209,670,214	($12,713,193)	$209,419	$56,492
Beginning balance, shares at Dec. 31, 2012	'	'	'	'	'	20,941,821	5,649,240
Issuance of common stock (stock compensation plans)	6,058,319	6,054,128	'	'	'	4,191	'
Issuance of common stock (stock compensation plans), shares	'	'	'	'	'	419,171	'
Net income	16,758,157	'	'	16,758,157	'	'	'
Cash dividends declared	-6,466,257	'	'	-6,466,257	'	'	'
Grant of stock options	'	47,995	'	-47,995	'	'	'
Tax benefit on exercise of stock options	208,867	208,867	'	'	'	'	'
Repurchase of treasury shares	-60,024	'	'	'	-60,024	'	'
Other comprehensive loss	-27,454,476	'	-27,454,476	'	'	'	'
Ending balance at Sep. 30, 2013	$389,078,680	$182,727,575	($1,059,899)	$219,914,119	($12,773,217)	$213,610	$56,492
Ending balance, shares at Sep. 30, 2013	'	'	'	'	'	21,360,992	5,649,240

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities:	'	'
Net income	$16,758,157	$16,872,598
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	2,438,386	3,305,664
Net realized investment gains	-2,943,710	-5,150,450
Equity in earnings of Donegal Financial Services Corporation	-2,499,854	-3,621,593
Changes in assets and liabilities:	'	'
Losses and loss expenses	37,650,218	4,246,743
Unearned premiums	34,650,619	36,813,848
Premiums receivable	-13,299,479	-16,620,561
Deferred acquisition costs	-4,479,718	-4,544,020
Deferred income taxes	1,990,901	3,343,578
Reinsurance receivable	-26,030,466	911,821
Prepaid reinsurance premiums	-7,299,921	-8,236,346
Accrued investment income	-161,257	117,431
Due to affiliate	-4,527,389	-6,182,139
Reinsurance balances payable	596,119	-2,602,978
Current income taxes	-2,355,260	-1,014,356
Accrued expenses	959,651	-3,703,503
Other, net	1,015,118	-441,632
Net adjustments	15,703,958	-3,378,493
Net cash provided by operating activities	32,462,115	13,494,105
Cash Flows from Investing Activities:	'	'
Purchases of fixed maturities, available for sale	-132,694,023	-174,925,183
Purchases of equity securities, available for sale	-12,605,485	-17,768,362
Maturity of fixed maturities:	'	'
Held to maturity	11,697,169	14,351,317
Available for sale	42,631,930	86,783,677
Sales of fixed maturities, available for sale	74,570,305	68,049,639
Sales of equity securities, available for sale	8,299,617	22,235,533
Net purchases of property and equipment	-617,902	-61,731
Net decrease (increase) in investment in affiliates	465,000	-100,000
Net (purchases) sales of short-term investments	-14,853,918	7,675,768
Net cash (used in) provided by investing activities	-23,107,307	6,240,658
Cash Flows from Financing Activities:	'	'
Cash dividends paid	-9,532,789	-9,137,357
Issuance of common stock	6,194,232	2,357,890
Purchase of treasury stock	-60,024	-1,349,380
Payments on subordinated debentures	-15,465,000	'
Payments on line of credit	-9,000,000	-6,000,000
Borrowings under lines of credit	21,500,000	1,190,694
Net cash used in financing activities	-6,363,581	-12,938,153
Net increase in cash	2,991,227	6,796,610
Cash at beginning of period	19,801,290	13,245,378
Cash at end of period	22,792,517	20,041,988
Cash paid during period - Interest	1,189,584	1,620,551
Net cash paid during period - Taxes	$3,850,000	$1,626,965

Organization

Organization	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Organization	'
	1 -	Organization
	Donegal Mutual Insurance Company (“Donegal Mutual”) organized us as an insurance holding company on August 26, 1986. Our insurance subsidiaries, Atlantic States Insurance Company (“Atlantic States”), Southern Insurance Company of Virginia (“Southern”), Le Mars Insurance Company (“Le Mars”), the Peninsula Insurance Group (“Peninsula”), which consists of Peninsula Indemnity Company and The Peninsula Insurance Company, Sheboygan Falls Insurance Company (“Sheboygan”) and Michigan Insurance Company (“MICO”), write personal and commercial lines of property and casualty coverages exclusively through a network of independent insurance agents in certain Mid-Atlantic, Midwestern, New England and Southern states. We also own 48.2% of the outstanding stock of Donegal Financial Services Corporation (“DFSC”), a grandfathered unitary savings and loan holding company that owns Union Community Bank (“UCB”). UCB completed its conversion from a federal savings bank to a state savings bank in the second quarter of 2013. UCB has 13 banking offices, all of which are located in Lancaster County, Pennsylvania. Donegal Mutual owns the remaining 51.8% of the outstanding stock of DFSC.
	We have four segments: our investment function, our personal lines of insurance, our commercial lines of insurance and our investment in DFSC. The personal lines products of our insurance subsidiaries consist primarily of homeowners and private passenger automobile policies. The commercial lines products of our insurance subsidiaries consist primarily of commercial automobile, commercial multi-peril and workers’ compensation policies.
	At September 30, 2013, Donegal Mutual held approximately 38% of our outstanding Class A common stock and approximately 76% of our outstanding Class B common stock. This ownership provides Donegal Mutual with approximately 66% of the total voting power of the two outstanding classes of our common stock. Our insurance subsidiaries and Donegal Mutual have interrelated operations that arise from a pooling agreement and other intercompany agreements and transactions. While each company maintains its separate corporate existence, our insurance subsidiaries and Donegal Mutual conduct business together as the Donegal Insurance Group. As such, Donegal Mutual and our insurance subsidiaries share the same business philosophy, the same management, the same employees and the same facilities and offer the same types of insurance products.
	Atlantic States, our largest subsidiary, participates in a pooling agreement with Donegal Mutual. Under the pooling agreement, 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 our underwriting profitability objectives. The products our insurance subsidiaries and Donegal Mutual market are generally complementary, thereby allowing the Donegal Insurance Group to offer a broader range of products to a given market and to expand the Donegal Insurance Group’s ability to service an entire personal lines or commercial lines account. Distinctions within the products Donegal Mutual and our insurance subsidiaries offer generally relate to specific risk profiles targeted within similar classes of business, such as preferred tier versus standard tier products, but we do not allocate all of the standard risk gradients to either company. Therefore, the underwriting profitability of the business the individual companies write directly will vary. However, because the underwriting pool homogenizes the risk characteristics of all business Donegal Mutual and Atlantic States write directly, Donegal Mutual and Atlantic States share the underwriting results in proportion to their respective participation in the pool. Pooled business represents the predominant percentage of the net underwriting activity of both Donegal Mutual and Atlantic States.
	On February 23, 2009, our board of directors authorized a share repurchase program pursuant to which we may purchase up to 300,000 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 (the “SEC”) and in privately negotiated transactions. We purchased 4,240 and 92,364 shares of our Class A common stock under this program during the nine months ended September 30, 2013 and 2012, respectively. We have purchased a total of 275,932 shares of our Class A common stock under this program from its inception through September 30, 2013.
	On July 18, 2013, our board of directors authorized a share repurchase program pursuant to which we have the authority to purchase up to 500,000 additional shares of our Class A common stock at prices prevailing from time to time in the open market subject to the provisions of applicable rules of the SEC and in privately negotiated transactions. We did not purchase any shares of our Class A common stock under this program during the nine-month period ended September 30, 2013.
	At our annual meeting of stockholders on April 18, 2013, our stockholders approved an amendment to our certificate of incorporation that increased the number of shares of our Class A common stock we have the authority to issue from 30.0 million shares to 40.0 million shares.

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basis of Presentation	'
	2 -	Basis of Presentation
	Our financial information for the interim periods included in this Form 10-Q Report is unaudited; however, such information reflects all adjustments, consisting only of normal recurring adjustments that, in the opinion of our management, are necessary for a fair presentation of our financial position, results of operations and cash flows for those interim periods. Our results of operations for the nine months ended September 30, 2013 are not necessarily indicative of the results of operations we expect for the year ending December 31, 2013.
	You should read these interim financial statements in conjunction with the financial statements and the notes to our financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2012.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
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 must also 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 method to compute our earnings per common share. The two-class method is an earnings allocation formula that determines earnings per share separately for each class of common stock based on dividends we have declared and an allocation of our remaining 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 each class of our common stock:
			Three Months Ended September 30,
			2013				2012
			Class A		Class B		Class A		Class B
			(in thousands, except per share data)
	Basic and diluted net income per share:
	Numerator:
	Allocation of net income		$	6,133	$	1,521	$	5,465	$	1,374
	Denominator:
	Weighted-average shares outstanding			20,383,165		5,576,775		20,041,620		5,576,775
	Basic net income per share		$	0.3	$	0.27	$	0.27	$	0.25
	Diluted net income per share:
	Numerator:
	Allocation of net income		$	6,133	$	1,521	$	5,465	$	1,374
	Denominator:
	Number of shares used in basic computation			20,383,165		5,576,775		20,041,620		5,576,775
	Weighted-average shares effect of dilutive securities
	Add: Director and employee stock options			224,446		—		268,476		—
	Number of shares used in per share computations			20,607,611		5,576,775		20,310,096		5,576,775
	Diluted net income per share		$	0.3	$	0.27	$	0.27	$	0.25
			Nine Months Ended September 30,
			2013				2012
			Class A		Class B		Class A		Class B
			(in thousands, except per share data)
	Basic and diluted net income per share:
	Numerator:
	Allocation of net income		$	13,414	$	3,344	$	13,478	$	3,395
	Denominator:
	Weighted-average shares outstanding			20,246,449		5,576,775		20,026,652		5,576,775
	Basic net income per share		$	0.66	$	0.6	$	0.67	$	0.61
	Diluted net income per share:
	Numerator:
	Allocation of net income		$	13,414	$	3,344	$	13,478	$	3,395
	Denominator:
	Number of shares used in basic computation			20,246,449		5,576,775		20,026,652		5,576,775
	Weighted-average shares effect of dilutive securities
	Add: Director and employee stock options			305,377		—		310,117		—
	Number of shares used in per share computations			20,551,826		5,576,775		20,336,769		5,576,775
	Diluted net income per share		$	0.65	$	0.6	$	0.66	$	0.61
	We did not include outstanding options to purchase the following number of shares of Class A common stock in our computation of diluted earnings per share because the exercise price of the options was greater than the average market price of our Class A common stock during the applicable period:
			Three Months Ended September 30,				Nine Months Ended September 30,
			2013		2012		2013		2012
	Number of Class A shares excluded			1,559,267		1,222,000		1,209,000		1,219,000

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2013
Insurance [Abstract]	'
Reinsurance	'
	4 -	Reinsurance
	Atlantic States and Donegal Mutual have participated in a pooling agreement since 1986 under which each company places all of its direct written business into the pool, and Atlantic States and Donegal Mutual then share the underwriting results of the pool in accordance with the terms of the pooling agreement. Atlantic States has an 80% share of the results of the pool, and Donegal Mutual has a 20% share of the results of the pool.
	Our insurance subsidiaries and Donegal Mutual purchase certain third-party reinsurance on a combined basis. Le Mars, MICO, Peninsula and Sheboygan also purchase separate third-party reinsurance that provides coverage that is commensurate with their relative size and exposures. Our insurance subsidiaries use several different reinsurers, all of which, consistent with requirements of our insurance subsidiaries and Donegal Mutual, have an A.M. Best rating of A- (Excellent) or better or, with respect to foreign reinsurers, have a financial condition that, in the opinion of our management, is equivalent to a company with at least an A- rating from A.M. Best. The following information describes the external reinsurance our insurance subsidiaries have in place at September 30, 2013:
		•	excess of loss reinsurance, under which losses are automatically reinsured, through a series of reinsurance agreements, over a set retention (generally $1.0 million), and
		•	catastrophe reinsurance, under which Donegal Mutual, Atlantic States and Southern recover, through a series of reinsurance agreements, 100% of an accumulation of many losses resulting from a single event, including natural disasters, over a set retention (generally $5.0 million) and after exceeding an annual aggregate deductible (generally $5.0 million) up to aggregate losses of $145.0 million per occurrence.
	Our insurance subsidiaries and Donegal Mutual also purchase facultative reinsurance to cover exposures from losses that exceed the limits their third-party reinsurance agreements provide.
	MICO maintains a quota-share reinsurance agreement with third-party reinsurers to reduce its net exposures. Effective January 1, 2013, the quota-share reinsurance percentage was 30%.
	In addition to the pooling agreement and third-party reinsurance, our insurance subsidiaries have various reinsurance agreements with Donegal Mutual.
	Other than the changes we discuss above, we have made no significant changes to our third-party reinsurance or the reinsurance agreements between our insurance subsidiaries and Donegal Mutual during the nine months ended September 30, 2013.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Investments	'
	5 -	Investments
	The amortized cost and estimated fair values of our fixed maturities and equity securities at September 30, 2013 were as follows:
			Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
					Gains		Losses		Value
			(in thousands)
	Held to Maturity
	Obligations of states and political subdivisions		$	30,102	$	670	$	—	$	30,772
	Residential mortgage-backed securities			106		6		—		112
	Totals		$	30,208	$	676	$	—	$	30,884
			Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
					Gains		Losses		Value
			(in thousands)
	Available for Sale
	U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	74,697	$	207	$	3,247	$	71,657
	Obligations of states and political subdivisions			398,591		14,872		10,509		402,954
	Corporate securities			56,173		1,121		1,177		56,117
	Residential mortgage-backed securities			140,039		1,630		2,588		139,081
	Fixed maturities			669,500		17,830		17,521		669,809
	Equity securities			13,520		165		285		13,400
	Totals		$	683,020	$	17,995	$	17,806	$	683,209
	At September 30, 2013, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $329.9 million and an amortized cost of $323.7 million. Our holdings at September 30, 2013 also included special revenue bonds with an aggregate fair value of $103.8 million and an amortized cost of $105.0 million. With respect to both categories of these bonds, we held no securities of any issuer that comprised more than 10% of the category at September 30, 2013. Education bonds and water and sewer utility bonds represented 55% and 22%, respectively, of our total investments in special revenue bonds based on their carrying values at September 30, 2013. Many of the issuers of the special revenue bonds we held at September 30, 2013 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.
	The amortized cost and estimated fair values of our fixed maturities and equity securities at December 31, 2012 were as follows:
			Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
					Gains		Losses		Value
			(in thousands)
	Held to Maturity
	U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	1,000	$	12	$	—	$	1,012
	Obligations of states and political subdivisions			40,909		1,609		—		42,518
	Residential mortgage-backed securities			191		15		—		206
	Totals		$	42,100	$	1,636	$	—	$	43,736
			Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
					Gains		Losses		Value
			(in thousands)
	Available for Sale
	U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	70,254	$	1,101	$	44	$	71,311
	Obligations of states and political subdivisions			385,372		32,221		606		416,987
	Corporate securities			73,942		3,523		109		77,356
	Residential mortgage-backed securities			125,606		3,316		66		128,856
	Fixed maturities			655,174		40,161		825		694,510
	Equity securities			8,663		201		107		8,757
	Totals		$	663,837	$	40,362	$	932	$	703,267
	At December 31, 2012, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $358.5 million and an amortized cost of $332.4 million. Our holdings at December 31, 2012 also included special revenue bonds with an aggregate fair value of $101.0 million and an amortized cost of $93.9 million. With respect to both categories, we held no securities of any issuer that comprised more than 10% of the category at December 31, 2012. Education bonds and water and sewer utility bonds represented 54% and 19%, respectively, of our total investments in special revenue bonds based on their carrying values at December 31, 2012. Many of the issuers of the special revenue bonds we held at December 31, 2012 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 show below the amortized cost and estimated fair value of our fixed maturities at September 30, 2013 by contractual maturity. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
			Amortized Cost		Estimated Fair
					Value
			(in thousands)
	Held to maturity
	Due in one year or less		$	—	$	—
	Due after one year through five years			25,158		25,709
	Due after five years through ten years			4,944		5,063
	Due after ten years			—		—
	Residential mortgage-backed securities			106		112
	Total held to maturity		$	30,208	$	30,884
	Available for sale
	Due in one year or less		$	9,006	$	9,124
	Due after one year through five years			38,779		39,835
	Due after five years through ten years			210,203		212,654
	Due after ten years			271,473		269,115
	Residential mortgage-backed securities			140,039		139,081
	Total available for sale		$	669,500	$	669,809
	Gross realized gains and losses from investments before applicable income taxes were as follows:
			Three Months Ended September 30,				Nine Months Ended September 30,
			2013		2012		2013		2012
		(in thousands)
Gross realized gains:
Fixed maturities		$	390	$	1,249	$	2,730	$	4,944
Equity securities			352		215		1,093		1,003
			742		1,464		3,823		5,947
Gross realized losses:
Fixed maturities			304		36		328		42
Equity securities			89		116		551		755
			393		152		879		797
Net realized gains		$	349	$	1,312	$	2,944	$	5,150
We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at September 30, 2013 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		$	55,647	$	3,139	$	1,421	$	108
Obligations of states and political subdivisions			102,382		10,199		2,176		310
Corporate securities			20,611		1,059		1,995		118
Residential mortgage-backed securities			63,787		2,301		5,296		287
Equity securities			4,232		261		328		24
Totals		$	246,659	$	16,959	$	11,216	$	847
We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2012 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		$	12,308	$	44	$	—	$	—
Obligations of states and political subdivisions			22,134		606		—		—
Corporate securities			12,272		79		2,959		30
Residential mortgage-backed securities			22,492		66		—		—
Equity securities			2,226		107		—		—
Totals		$	71,432	$	902	$	2,959	$	30
Of our total fixed maturity securities with an unrealized loss at September 30, 2013, we classified 183 securities with a fair value of $253.3 million and an unrealized loss of $17.5 million as available-for-sale and carried them at fair value on our balance sheet.
Of our total fixed maturity securities with an unrealized loss at December 31, 2012, we classified 46 securities with a fair value of $72.2 million and an unrealized loss of $825,168 as available-for-sale and carried them at fair value on our balance sheet.
We have no direct exposure to sub-prime residential mortgage-backed securities and hold no collateralized debt obligations. Substantially all of the unrealized losses in our fixed maturity investment portfolio have resulted from increased market interest rates and the related impact on our fixed maturity investment valuations. 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, when we consider the decline in value of an individual investment to be other than temporary, we write the investment down to its fair value, and we reflect the amount of the write-down as a realized loss in our results of operations. We individually monitor all investments for other-than-temporary declines in value. Generally, if an individual equity security has depreciated in value by more than 20% of its original cost, and has been in an unrealized loss position for more than six months, we assume the decline in value is other than temporary. We held nine equity securities that were in an unrealized loss position at September 30, 2013. Based upon our analysis of general market conditions and underlying factors impacting these equity securities, we consider these declines in value to be temporary. With respect to a debt security that is in an unrealized loss position, we first assess if we intend to sell the debt security. If we 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 it is more likely than not that we will be required to sell the debt security prior to recovery, we recognize an impairment loss in our results of operations. If 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. To determine whether a credit loss has occurred, we compare the amortized cost of the debt security to the present value of the cash flows we expect to receive. If we expect a cash flow shortfall, we consider a credit loss to have occurred. If we consider a credit loss to have 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 whether the fair value of the investment is significantly below its cost, whether the financial condition of the issuer of the security has deteriorated, the occurrence of industry, company and geographic events that have negatively impacted the value of the security and rating agency downgrades. We determined that no investments with fair values below cost had declined on an other-than-temporary basis during the first nine months of 2013 and 2012, respectively.
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.
We account for investments in our affiliates using the equity method of accounting. Under this method, we record our investment at cost, with adjustments for our share of our affiliates’ earnings and losses as well as changes in the equity of our affiliates due to unrealized gains and losses. Our investments in affiliates include our 48.2% ownership interest in DFSC. We include our share of DFSC’s net income in our results of operations. We have compiled the following summary financial information for DFSC at September 30, 2013 and December 31, 2012 and for the three and nine months ended September 30, 2013 and 2012, respectively, from the financial statements of DFSC. The financial information of DFSC at September 30, 2013 and for the three and nine months then ended is unaudited.
		September 30,		December 31,
		2013		2012
		(in thousands)
Balance sheets:
Total assets		$	514,409	$	509,670
Total liabilities		$	439,107	$	433,490
Stockholders’ equity			75,302		76,180
Total liabilities and stockholders’ equity		$	514,409	$	509,670
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
		(in thousands)
Income statements:
Net income		$	1,525	$	2,771	$	5,184	$	7,510

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
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”). Financial data by segment is as follows:
			Three Months Ended September 30,
			2013			2012
			(in thousands)
	Revenues:
	Premiums earned
	Commercial lines		$	52,040		$	44,921
	Personal lines			78,605			75,996
	GAAP premiums earned			130,645			120,917
	Net investment income			4,624			4,715
	Realized investment gains			349			1,312
	Equity in earnings of DFSC			735			1,337
	Other			1,982			2,151
	Total revenues		$	138,335		$	130,432
	Income before income taxes:
	Underwriting income (loss):
	Commercial lines		$	2,537		$	2,507
	Personal lines			(961	)		(3,980	)
	SAP underwriting income (loss)			1,576			(1,473	)
	GAAP adjustments			1,509			1,888
	GAAP underwriting income			3,085			415
	Net investment income			4,624			4,715
	Realized investment gains			349			1,312
	Equity in earnings of DFSC			735			1,337
	Other			721			1,094
	Income before income taxes		$	9,514		$	8,873
			Nine Months Ended September 30,
			2013			2012
			(in thousands)
	Revenues:
	Premiums earned
	Commercial lines		$	149,283		$	128,704
	Personal lines			233,027			224,479
	Net premiums earned			382,310			353,183
	GAAP adjustments			—			(5	)
	GAAP premiums earned			382,310			353,178
	Net investment income			14,110			14,724
	Realized investment gains			2,944			5,150
	Equity in earnings of DFSC			2,500			3,622
	Other			5,851			6,405
	Total revenues		$	407,715		$	383,079
	Income before income taxes:
	Underwriting income (loss):
	Commercial lines		$	(2,133	)	$	4,827
	Personal lines			(4,185	)		(16,554	)
	SAP underwriting loss			(6,318	)		(11,727	)
	GAAP adjustments			5,849			6,408
	GAAP underwriting loss			(469	)		(5,319	)
	Net investment income			14,110			14,724
	Realized investment gains			2,944			5,150
	Equity in earnings of DFSC			2,500			3,622
	Other			1,375			2,659
	Income before income taxes		$	20,460		$	20,836

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Borrowings	'
	7 -	Borrowings
	Lines of Credit
	In June 2013, we renewed our existing credit agreement with Manufacturers and Traders Trust Company (“M&T”) relating to a $60.0 million unsecured, revolving line of credit. The line of credit expires in July 2016. We have the right to request a one-year extension of the credit agreement as of each anniversary date of the agreement. At September 30, 2013, we had $49.5 million in outstanding borrowings and had the ability to borrow an additional $10.5 million at interest rates equal to M&T’s current prime rate or the then current LIBOR rate plus 2.25%. The interest rate on our outstanding borrowings is adjustable quarterly. At September 30, 2013, the interest rate on our outstanding borrowings was 2.43%. We pay a fee of 0.2% per annum on the loan commitment amount regardless of usage. The credit agreement requires our compliance with certain covenants. These covenants include minimum levels of our net worth, leverage ratio, statutory surplus and the A.M. Best ratings of our insurance subsidiaries. We complied with all requirements of the credit agreement during the nine months ended September 30, 2013.
	MICO is a member of the Federal Home Loan Bank (“FHLB”) of Indianapolis. Through its membership, MICO has the ability to issue debt to the FHLB of Indianapolis in exchange for cash advances. MICO had no outstanding borrowings with the FHLB of Indianapolis at December 31, 2012 or September 30, 2013. The table below presents the amount of FHLB of Indianapolis stock MICO purchased, collateral pledged and assets related to MICO’s membership at September 30, 2013.
	FHLB stock purchased and owned as part of the agreement		$	252,100
	Collateral pledged, at par (carrying value $2,904,980)			3,700,000
	Borrowing capacity currently available			2,514,048
	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 the first quarter of 2013, Atlantic States issued secured debt in the principal amount of $15.0 million to the FHLB of Pittsburgh in exchange for cash advances in the amount of $15.0 million. The interest rate on the advances was .24% at September 30, 2013. Atlantic States then loaned $15.0 million to us. We used the proceeds of our loan from Atlantic States to fund our prepayment of our subordinated debentures, as we discuss below. Atlantic States had no outstanding borrowings with the FHLB of Pittsburgh at December 31, 2012. 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, 2013.
	FHLB stock purchased and owned as part of the agreement		$	870,300
	Collateral pledged, at par (carrying value $15,837,274)			19,000,000
	Borrowing capacity currently available			837,274
	Subordinated Debentures
	On October 29, 2003, we received $10.0 million in net proceeds from the issuance of subordinated debentures. The debentures had a maturity date of October 29, 2033 and were callable at our option, at par. The debentures carried an interest rate equal to the three-month LIBOR rate plus 3.85%. On January 28, 2013, we prepaid these subordinated debentures in full and liquidated our investment in the statutory trust.
	On May 24, 2004, we received $5.0 million in net proceeds from the issuance of subordinated debentures. The debentures had a maturity date of May 24, 2034 and were callable at our option, at par. The debentures carried an interest rate equal to the three-month LIBOR rate plus 3.85%. On February 25, 2013, we prepaid these subordinated debentures in full and liquidated our investment in the statutory trust.
	In January 2002, West Bend Mutual Insurance Company (“West Bend”), the prior owner of MICO, purchased a $5.0 million surplus note from MICO at face value to increase MICO’s statutory surplus. On December 1, 2010, Donegal Mutual purchased the surplus note from West Bend at face value. The surplus note carries an interest rate of 5.00%, and any repayment of principal or payment of interest on the surplus note requires prior approval of the Michigan Department of Insurance and Financial Services.

ShareBased_Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased 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 such expense in our consolidated statements of income. 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 $155,069 and $121,189 for the three months ended September 30, 2013 and 2012, respectively, with a corresponding income tax benefit of $54,274 and $42,416, respectively. We charged compensation expense for our stock compensation plans against income before income taxes of $482,897 and $360,915 for the nine months ended September 30, 2013 and 2012, respectively, with a corresponding income tax benefit of $169,014 and $126,320, respectively. At September 30, 2013, we had $669,154 of unrecognized compensation expense related to nonvested share-based compensation granted under our stock compensation plans. We expect to recognize this cost over a weighted average period of 0.9 years.
	We received cash from option exercises under all stock compensation plans for the three months ended September 30, 2013 and 2012 of $910,838 and $187,025, respectively. We received cash from option exercises under all stock compensation plans for the nine months ended September 30, 2013 and 2012 of $4.5 million and $1.0 million, respectively. We realized actual tax benefits for the tax deductions from option exercises of share-based compensation of $21,986 and $10,475 for the three months ended September 30, 2013 and 2012, respectively. We realized actual tax benefits for the tax deductions from option exercises of share-based compensation of $208,867 and $49,517 for the nine months ended September 30, 2013 and 2012, respectively.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
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 residential mortgage-backed securities.
	We present our investments in available-for-sale fixed maturity and equity securities at estimated fair value. The estimated fair value of a security may differ from the amount that could be realized if we sold the security in a forced transaction. In addition, the valuation of fixed maturity investments is more subjective when markets are less liquid, increasing the potential that the estimated fair value does not reflect the price at which an actual transaction would occur. We utilize nationally recognized independent pricing services to estimate fair values or obtain market quotations for substantially all of our fixed maturity and equity investments. We generally obtain one price per security. These pricing services utilize market quotations for fixed maturity and equity securities that have quoted prices in active markets. For fixed maturity securities that generally do not trade on a daily basis, the pricing services prepare estimates of fair value measurements based predominantly on observable market inputs. The pricing services do not use broker quotes in determining the fair values of our investments. Our investment personnel review the estimates of fair value the pricing services provide to determine if the estimates we obtain are representative of fair values based upon our investment personnel’s general knowledge of the market, their research findings related to unusual fluctuations in value and their comparison of such values to execution prices for similar securities. Our investment personnel regularly monitor the market, current trading ranges for similar securities and the pricing of specific investments. Our investment personnel review all pricing estimates that we receive from the pricing services against their expectations with respect to pricing based on fair market curves, security ratings, coupon rates, security type and recent trading activity. Our investment personnel review documentation with respect to the pricing services’ pricing methodology that they obtain periodically to determine if the primary pricing sources, market inputs and pricing frequency for various security types are reasonable. At September 30, 2013 and December 31, 2012, we received one estimate per security from one of the pricing services, and we priced substantially all of our Level 1 and Level 2 investments using those prices. In our review of the estimates the pricing services provided at September 30, 2013 and December 31, 2012, we did not identify any discrepancies, and we did not make any adjustments to the estimates the pricing services provided.
	We present our cash and short-term investments at estimated fair value. We classify these items as Level 1.
	The carrying values in the balance sheet for premium receivables and reinsurance receivables and payables for premiums and paid losses and loss expenses approximate their fair values. The carrying amounts reported in the balance sheet for our subordinated debentures and borrowings under lines of credit approximate their fair values. We classify these items as Level 3.
	We evaluate our assets and liabilities on a recurring basis 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 fixed maturity and equity securities at September 30, 2013:
					Fair Value Measurements Using
			Fair Value		Quoted		Significant Other		Significant
					Prices in  Active		Observable Inputs		Unobservable
					Markets for		(Level 2)		Inputs  (Level 3)
					Identical Assets
					(Level 1)
			(in thousands)
	U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	71,657	$	—	$	71,657	$	—
	Obligations of states and political subdivisions			402,954		—		402,954		—
	Corporate securities			56,116		—		56,116		—
	Residential mortgage-backed securities			139,082		—		139,082		—
	Equity securities			13,400		7,994		5,406		—
	Totals		$	683,209	$	7,994	$	675,215	$	—
	We did not transfer any investments between Levels 1 and 2 during the nine months ended September 30, 2013.
	The following table presents our fair value measurements for our investments in available-for-sale fixed maturity and equity securities at December 31, 2012:
					Fair Value Measurements Using
			Fair Value		Quoted		Significant Other		Significant
					Prices in  Active		Observable  Inputs		Unobservable
					Markets for		(Level 2)		Inputs (Level 3)
					Identical Assets
					(Level 1)
			(in thousands)
	U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	71,311	$	—	$	71,311	$	—
	Obligations of states and political subdivisions			416,987		—		416,987		—
	Corporate securities			77,356		—		77,356		—
	Residential mortgage-backed securities			128,856		—		128,856		—
	Equity securities			8,757		5,366		3,391		—
	Totals		$	703,267	$	5,366	$	697,901	$	—

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	10 -	Income Taxes
	At September 30, 2013 and December 31, 2012, respectively, we had no material unrecognized tax benefits or accrued interest and penalties. Tax years 2010 through 2012 remained open for examination at September 30, 2013. We provide a valuation allowance when we believe it is more likely than not that we will not realize some portion of our tax asset. We established a valuation allowance of $440,778 related to a portion of the net operating loss carryforward of Le Mars at January 1, 2004. We have determined that we are not required to establish a valuation allowance for the other net deferred tax assets of $38.9 million and $37.6 million at September 30, 2013 and December 31, 2012, 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. We also have a net operating loss carryforward of $5.1 million related to Le Mars, which will begin to expire in 2020 if not previously utilized. This carryforward is subject to an annual limitation in the amount that we can use in any one year of approximately $376,000. We also have an alternative minimum tax credit carryforward of $8.0 million with an indefinite life.

Impact_of_New_Accounting_Stand

Impact of New Accounting Standards	9 Months Ended
	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]	'
Impact of New Accounting Standards	'
	11 -	Impact of New Accounting Standards
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued guidance that requires an entity to provide information about amounts it reclassifies out of accumulated other comprehensive income. If GAAP requires an entity to reclassify amounts out of accumulated other comprehensive income to net income in their entirety in the same reporting period, the guidance requires an entity to present significant amounts it reclassifies out of accumulated other comprehensive income by the respective line items of net income, either on the face of the statement where the entity presents net income or in the notes to the entity’s financial statements,. For other amounts that GAAP does not require an entity to reclassify to net income in their entirety, the guidance requires an entity to cross-reference such amounts to other disclosures GAAP requires that provide additional detail about those amounts. The guidance is effective for interim and annual reporting periods after December 15, 2012. We adopted this new guidance as of January 1, 2013. Our adoption of this new guidance did not impact our financial position, results of operations or cash flows.
	In July 2013, the FASB issued a new standard that requires an entity to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss carryforward or similar tax loss or tax credit carryforward, rather than as a liability, when the uncertain tax position would reduce the net operating loss or other carryforward under the tax law of the applicable jurisdiction and when the entity intends to use the deferred tax asset for that purpose. The new standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this new standard in 2014 will not impact our financial position, results of operations or cash flows.

Impact_of_New_Accounting_Stand1

Impact of New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]	'
Other comprehensive income	'
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued guidance that requires an entity to provide information about amounts it reclassifies out of accumulated other comprehensive income. If GAAP requires an entity to reclassify amounts out of accumulated other comprehensive income to net income in their entirety in the same reporting period, the guidance requires an entity to present significant amounts it reclassifies out of accumulated other comprehensive income by the respective line items of net income, either on the face of the statement where the entity presents net income or in the notes to the entity’s financial statements,. For other amounts that GAAP does not require an entity to reclassify to net income in their entirety, the guidance requires an entity to cross-reference such amounts to other disclosures GAAP requires that provide additional detail about those amounts. The guidance is effective for interim and annual reporting periods after December 15, 2012. We adopted this new guidance as of January 1, 2013. Our adoption of this new guidance did not impact our financial position, results of operations or cash flows.
	In July 2013, the FASB issued a new standard that requires an entity to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss carryforward or similar tax loss or tax credit carryforward, rather than as a liability, when the uncertain tax position would reduce the net operating loss or other carryforward under the tax law of the applicable jurisdiction and when the entity intends to use the deferred tax asset for that purpose. The new standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this new standard in 2014 will not impact our financial position, results of operations or cash flows.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
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 each class of our common stock:
		Three Months Ended September 30,
		2013				2012
		Class A		Class B		Class A		Class B
		(in thousands, except per share data)
	Basic and diluted net income per share:
	Numerator:
	Allocation of net income	$	6,133	$	1,521	$	5,465	$	1,374
	Denominator:
	Weighted-average shares outstanding		20,383,165		5,576,775		20,041,620		5,576,775
	Basic net income per share	$	0.3	$	0.27	$	0.27	$	0.25
	Diluted net income per share:
	Numerator:
	Allocation of net income	$	6,133	$	1,521	$	5,465	$	1,374
	Denominator:
	Number of shares used in basic computation		20,383,165		5,576,775		20,041,620		5,576,775
	Weighted-average shares effect of dilutive securities
	Add: Director and employee stock options		224,446		—		268,476		—
	Number of shares used in per share computations		20,607,611		5,576,775		20,310,096		5,576,775
	Diluted net income per share	$	0.3	$	0.27	$	0.27	$	0.25
		Nine Months Ended September 30,
		2013				2012
		Class A		Class B		Class A		Class B
		(in thousands, except per share data)
	Basic and diluted net income per share:
	Numerator:
	Allocation of net income	$	13,414	$	3,344	$	13,478	$	3,395
	Denominator:
	Weighted-average shares outstanding		20,246,449		5,576,775		20,026,652		5,576,775
	Basic net income per share	$	0.66	$	0.6	$	0.67	$	0.61
	Diluted net income per share:
	Numerator:
	Allocation of net income	$	13,414	$	3,344	$	13,478	$	3,395
	Denominator:
	Number of shares used in basic computation		20,246,449		5,576,775		20,026,652		5,576,775
	Weighted-average shares effect of dilutive securities
	Add: Director and employee stock options		305,377		—		310,117		—
	Number of shares used in per share computations		20,551,826		5,576,775		20,336,769		5,576,775
	Diluted net income per share	$	0.65	$	0.6	$	0.66	$	0.61
Reconciliation of Diluted Shares Outstanding	'
	We did not include outstanding options to purchase the following number of shares of Class A common stock in our computation of diluted earnings per share because the exercise price of the options was greater than the average market price of our Class A common stock during the applicable period:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
	Number of Class A shares excluded		1,559,267		1,222,000		1,209,000		1,219,000

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities	'
	The amortized cost and estimated fair values of our fixed maturities and equity securities at September 30, 2013 were as follows:
		Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
				Gains		Losses		Value
		(in thousands)
	Held to Maturity
	Obligations of states and political subdivisions	$	30,102	$	670	$	—	$	30,772
	Residential mortgage-backed securities		106		6		—		112
	Totals	$	30,208	$	676	$	—	$	30,884
		Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
				Gains		Losses		Value
		(in thousands)
	Available for Sale
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	74,697	$	207	$	3,247	$	71,657
	Obligations of states and political subdivisions		398,591		14,872		10,509		402,954
	Corporate securities		56,173		1,121		1,177		56,117
	Residential mortgage-backed securities		140,039		1,630		2,588		139,081
	Fixed maturities		669,500		17,830		17,521		669,809
	Equity securities		13,520		165		285		13,400
	Totals	$	683,020	$	17,995	$	17,806	$	683,209
	The amortized cost and estimated fair values of our fixed maturities and equity securities at December 31, 2012 were as follows:
		Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
				Gains		Losses		Value
		(in thousands)
	Held to Maturity
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	1,000	$	12	$	—	$	1,012
	Obligations of states and political subdivisions		40,909		1,609		—		42,518
	Residential mortgage-backed securities		191		15		—		206
	Totals	$	42,100	$	1,636	$	—	$	43,736
		Amortized Cost		Gross Unrealized		Gross Unrealized		Estimated Fair
				Gains		Losses		Value
		(in thousands)
	Available for Sale
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	70,254	$	1,101	$	44	$	71,311
	Obligations of states and political subdivisions		385,372		32,221		606		416,987
	Corporate securities		73,942		3,523		109		77,356
	Residential mortgage-backed securities		125,606		3,316		66		128,856
	Fixed maturities		655,174		40,161		825		694,510
	Equity securities		8,663		201		107		8,757
	Totals	$	663,837	$	40,362	$	932	$	703,267
Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity	'
	We show below the amortized cost and estimated fair value of our fixed maturities at September 30, 2013 by contractual maturity. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
		Amortized Cost		Estimated Fair
				Value
		(in thousands)
	Held to maturity
	Due in one year or less	$	—	$	—
	Due after one year through five years		25,158		25,709
	Due after five years through ten years		4,944		5,063
	Due after ten years		—		—
	Residential mortgage-backed securities		106		112
	Total held to maturity	$	30,208	$	30,884
	Available for sale
	Due in one year or less	$	9,006	$	9,124
	Due after one year through five years		38,779		39,835
	Due after five years through ten years		210,203		212,654
	Due after ten years		271,473		269,115
	Residential mortgage-backed securities		140,039		139,081
	Total available for sale	$	669,500	$	669,809
Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes	'
	Gross realized gains and losses from investments before applicable income taxes were as follows:
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
		(in thousands)
	Gross realized gains:
	Fixed maturities	$	390	$	1,249	$	2,730	$	4,944
	Equity securities		352		215		1,093		1,003
			742		1,464		3,823		5,947
	Gross realized losses:
	Fixed maturities		304		36		328		42
	Equity securities		89		116		551		755
			393		152		879		797
	Net realized gains	$	349	$	1,312	$	2,944	$	5,150
Summary of Fixed Maturities and Equity Securities with Unrealized Losses	'
	We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at September 30, 2013 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	$	55,647	$	3,139	$	1,421	$	108
	Obligations of states and political subdivisions		102,382		10,199		2,176		310
	Corporate securities		20,611		1,059		1,995		118
	Residential mortgage-backed securities		63,787		2,301		5,296		287
	Equity securities		4,232		261		328		24
	Totals	$	246,659	$	16,959	$	11,216	$	847
	We held fixed maturities and equity securities with unrealized losses representing declines that we considered temporary at December 31, 2012 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	$	12,308	$	44	$	—	$	—
	Obligations of states and political subdivisions		22,134		606		—		—
	Corporate securities		12,272		79		2,959		30
	Residential mortgage-backed securities		22,492		66		—		—
	Equity securities		2,226		107		—		—
	Totals	$	71,432	$	902	$	2,959	$	30
Summary of Financial Information	'
	The financial information of DFSC at September 30, 2013 and for the three and nine months then ended is unaudited.
		September 30,		December 31,
		2013		2012
		(in thousands)
	Balance sheets:
	Total assets	$	514,409	$	509,670
	Total liabilities	$	439,107	$	433,490
	Stockholders’ equity		75,302		76,180
	Total liabilities and stockholders’ equity	$	514,409	$	509,670
		Three Months Ended September 30,				Nine Months Ended September 30,
		2013		2012		2013		2012
		(in thousands)
	Income statements:
	Net income	$	1,525	$	2,771	$	5,184	$	7,510

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Summary of Financial Data by Segment	'
	Financial data by segment is as follows:
		Three Months Ended September 30,
		2013			2012
		(in thousands)
	Revenues:
	Premiums earned
	Commercial lines	$	52,040		$	44,921
	Personal lines		78,605			75,996
	GAAP premiums earned		130,645			120,917
	Net investment income		4,624			4,715
	Realized investment gains		349			1,312
	Equity in earnings of DFSC		735			1,337
	Other		1,982			2,151
	Total revenues	$	138,335		$	130,432
	Income before income taxes:
	Underwriting income (loss):
	Commercial lines	$	2,537		$	2,507
	Personal lines		(961	)		(3,980	)
	SAP underwriting income (loss)		1,576			(1,473	)
	GAAP adjustments		1,509			1,888
	GAAP underwriting income		3,085			415
	Net investment income		4,624			4,715
	Realized investment gains		349			1,312
	Equity in earnings of DFSC		735			1,337
	Other		721			1,094
	Income before income taxes	$	9,514		$	8,873
		Nine Months Ended September 30,
		2013			2012
		(in thousands)
	Revenues:
	Premiums earned
	Commercial lines	$	149,283		$	128,704
	Personal lines		233,027			224,479
	Net premiums earned		382,310			353,183
	GAAP adjustments		—			(5	)
	GAAP premiums earned		382,310			353,178
	Net investment income		14,110			14,724
	Realized investment gains		2,944			5,150
	Equity in earnings of DFSC		2,500			3,622
	Other		5,851			6,405
	Total revenues	$	407,715		$	383,079
	Income before income taxes:
	Underwriting income (loss):
	Commercial lines	$	(2,133	)	$	4,827
	Personal lines		(4,185	)		(16,554	)
	SAP underwriting loss		(6,318	)		(11,727	)
	GAAP adjustments		5,849			6,408
	GAAP underwriting loss		(469	)		(5,319	)
	Net investment income		14,110			14,724
	Realized investment gains		2,944			5,150
	Equity in earnings of DFSC		2,500			3,622
	Other		1,375			2,659
	Income before income taxes	$	20,460		$	20,836

Borrowings_Tables

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement	'
	The table below presents the amount of FHLB of Indianapolis stock MICO purchased, collateral pledged and assets related to MICO’s membership at September 30, 2013.
	FHLB stock purchased and owned as part of the agreement	$	252,100
	Collateral pledged, at par (carrying value $2,904,980)		3,700,000
	Borrowing capacity currently available		2,514,048
	FHLB stock purchased and owned as part of the agreement	$	870,300
	Collateral pledged, at par (carrying value $15,837,274)		19,000,000
	Borrowing capacity currently available		837,274

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
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 fixed maturity and equity securities at September 30, 2013:
				Fair Value Measurements Using
		Fair Value		Quoted		Significant Other		Significant
				Prices in  Active		Observable Inputs		Unobservable
				Markets for		(Level 2)		Inputs  (Level 3)
				Identical Assets
				(Level 1)
		(in thousands)
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	71,657	$	—	$	71,657	$	—
	Obligations of states and political subdivisions		402,954		—		402,954		—
	Corporate securities		56,116		—		56,116		—
	Residential mortgage-backed securities		139,082		—		139,082		—
	Equity securities		13,400		7,994		5,406		—
	Totals	$	683,209	$	7,994	$	675,215	$	—
	The following table presents our fair value measurements for our investments in available-for-sale fixed maturity and equity securities at December 31, 2012:
				Fair Value Measurements Using
		Fair Value		Quoted		Significant Other		Significant
				Prices in  Active		Observable  Inputs		Unobservable
				Markets for		(Level 2)		Inputs (Level 3)
				Identical Assets
				(Level 1)
		(in thousands)
	U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	71,311	$	—	$	71,311	$	—
	Obligations of states and political subdivisions		416,987		—		416,987		—
	Corporate securities		77,356		—		77,356		—
	Residential mortgage-backed securities		128,856		—		128,856		—
	Equity securities		8,757		5,366		3,391		—
	Totals	$	703,267	$	5,366	$	697,901	$	—

Organization_Additional_Inform

Organization - Additional Information (Detail)

9 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jul. 18, 2013

Dec. 31, 2012

Feb. 23, 2009

Apr. 18, 2013

Apr. 18, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Office

Subsidiaries [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class B [Member]

Common Class B [Member]

Segment

Minimum [Member]

Maximum [Member]

Subsidiaries [Member]

Subsidiaries [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding stock percentage

48.20%

'

'

'

'

'

'

'

'

'

'

'

Number of banking offices

13

'

'

'

'

'

'

'

'

'

'

'

Stock ownership percentage owned by third party

51.80%

'

'

'

'

'

'

'

'

'

'

'

Number of operating segments

4

'

'

'

'

'

'

'

'

'

'

'

Stock ownership percentage held by major shareholder

'

'

38.00%

'

'

'

'

'

'

'

76.00%

'

Voting power percentage of outstanding common stock

66.00%

'

'

'

'

'

'

'

'

'

'

'

Percentage of share in results of pooled business

'

80.00%

'

'

'

'

'

'

'

'

'

'

Percentage of share in results of pooled business owned by third party

20.00%

'

'

'

'

'

'

'

'

'

'

'

Number of common stock shares purchased

'

'

'

500,000

'

300,000

'

'

'

'

'

'

Common stock shares purchased

'

'

275,932

'

'

'

'

'

4,240

92,364

'

'

Increase in number of shares

'

'

40,000,000

'

30,000,000

'

30,000,000

40,000,000

'

'

10,000,000

10,000,000

Earnings_Per_Share_Additional_

Earnings Per Share - Additional Information (Detail) (Common Class A [Member])	9 Months Ended
	Sep. 30, 2013
Common Class A [Member]	'
Class of Stock [Line Items]	'
Common stock payable interest rate	10.00%

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 $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Common Class A [Member]	'	'	'	'
Numerator:	'	'	'	'
Allocation of net income	$6,133	$5,465	$13,414	$13,478
Denominator:	'	'	'	'
Weighted-average shares outstanding	20,383,165	20,041,620	20,246,449	20,026,652
Basic net income per share	$0.30	$0.27	$0.66	$0.67
Numerator:	'	'	'	'
Allocation of net income	6,133	5,465	13,414	13,478
Denominator:	'	'	'	'
Number of shares used in basic computation	20,383,165	20,041,620	20,246,449	20,026,652
Weighted-average shares effect of dilutive securities	'	'	'	'
Add: Director and employee stock options	224,446	268,476	305,377	310,117
Number of shares used in per share computations	20,607,611	20,310,096	20,551,826	20,336,769
Diluted net income per share	$0.30	$0.27	$0.65	$0.66
Common Class B [Member]	'	'	'	'
Numerator:	'	'	'	'
Allocation of net income	1,521	1,374	3,344	3,395
Denominator:	'	'	'	'
Weighted-average shares outstanding	5,576,775	5,576,775	5,576,775	5,576,775
Basic net income per share	$0.27	$0.25	$0.60	$0.61
Numerator:	'	'	'	'
Allocation of net income	$1,521	$1,374	$3,344	$3,395
Denominator:	'	'	'	'
Number of shares used in basic computation	5,576,775	5,576,775	5,576,775	5,576,775
Weighted-average shares effect of dilutive securities	'	'	'	'
Add: Director and employee stock options	'	'	'	'
Number of shares used in per share computations	5,576,775	5,576,775	5,576,775	5,576,775
Diluted net income per share	$0.27	$0.25	$0.60	$0.61

Earnings_Per_Share_Reconciliat

Earnings Per Share - Reconciliation of Diluted Shares Outstanding (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Number of Class A shares excluded	1,559,267	1,222,000	1,209,000	1,219,000

Reinsurance_Additional_Informa

Reinsurance - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Ceded Credit Risk [Line Items]	'
Percentage of share in results of pooled business subsidiary	80.00%
Percentage of share in results of pooled business owned by third party	20.00%
Excess of loss reinsured under an agreement	$1
Percentage of accumulation of losses	100.00%
Natural disasters, over a set retention	5
Quota share reinsurance percentage	30.00%
Donegal Mutual [Member]	'
Ceded Credit Risk [Line Items]	'
Maximum amount of loss coverage under reinsurance agreement of property catastrophe	$145

Investments_Summary_of_Amortiz

Investments - Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]	'	'
Held to Maturity, at Amortized Cost	$30,208,111	$42,100,196
Held to Maturity, Gross Unrealized Gains	676,000	1,636,000
Held to Maturity, Gross Unrealized Losses	'	'
Total held to maturity, Estimated Fair Value	30,884,000	43,736,000
Available for Sale, Amortized Cost	683,020,000	663,837,000
Available for Sale, Gross Unrealized Gains	17,995,000	40,362,000
Available for Sale, Gross Unrealized Losses	17,806,000	932,000
Available for Sale, Estimated Fair Value	683,209,000	703,267,000
U.S. Treasury securities and obligations of U.S. government corporations and agencies [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Held to Maturity, at Amortized Cost	'	1,000,000
Held to Maturity, Gross Unrealized Gains	'	12,000
Held to Maturity, Gross Unrealized Losses	'	'
Total held to maturity, Estimated Fair Value	'	1,012,000
Available for Sale, Amortized Cost	74,697,000	70,254,000
Available for Sale, Gross Unrealized Gains	207,000	1,101,000
Available for Sale, Gross Unrealized Losses	3,247,000	44,000
Available for Sale, Estimated Fair Value	71,657,000	71,311,000
Obligations of states and political subdivisions [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Held to Maturity, at Amortized Cost	30,102,000	40,909,000
Held to Maturity, Gross Unrealized Gains	670,000	1,609,000
Held to Maturity, Gross Unrealized Losses	'	'
Total held to maturity, Estimated Fair Value	30,772,000	42,518,000
Available for Sale, Amortized Cost	398,591,000	385,372,000
Available for Sale, Gross Unrealized Gains	14,872,000	32,221,000
Available for Sale, Gross Unrealized Losses	10,509,000	606,000
Available for Sale, Estimated Fair Value	402,954,000	416,987,000
Corporate securities [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Available for Sale, Amortized Cost	56,173,000	73,942,000
Available for Sale, Gross Unrealized Gains	1,121,000	3,523,000
Available for Sale, Gross Unrealized Losses	1,177,000	109,000
Available for Sale, Estimated Fair Value	56,117,000	77,356,000
Residential mortgage-backed securities [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Held to Maturity, at Amortized Cost	106,000	191,000
Held to Maturity, Gross Unrealized Gains	6,000	15,000
Held to Maturity, Gross Unrealized Losses	'	'
Total held to maturity, Estimated Fair Value	112,000	206,000
Available for Sale, Amortized Cost	140,039,000	125,606,000
Available for Sale, Gross Unrealized Gains	1,630,000	3,316,000
Available for Sale, Gross Unrealized Losses	2,588,000	66,000
Available for Sale, Estimated Fair Value	139,081,000	128,856,000
Fixed maturities [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Available for Sale, Amortized Cost	669,500,000	655,174,000
Available for Sale, Gross Unrealized Gains	17,830,000	40,161,000
Available for Sale, Gross Unrealized Losses	17,521,000	825,000
Available for Sale, Estimated Fair Value	669,809,000	694,510,000
Equity securities [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Available for Sale, Amortized Cost	13,520,000	8,663,000
Available for Sale, Gross Unrealized Gains	165,000	201,000
Available for Sale, Gross Unrealized Losses	285,000	107,000
Available for Sale, Estimated Fair Value	$13,400,000	$8,757,000

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
	Securities	Securities
Schedule of Investments [Line Items]	'	'
Percentage of which the company held security of any issuer	10.00%	10.00%
Number of fixed maturity securities classified as available for sale	183	46
Fair value of fixed maturity securities classified as available for sale	$253,300,000	$72,200,000
Unrealized loss of fixed maturity securities classified as available for sale	17,500,000	825,168
Percentage decrease in value of individual equity security to assume other than temporary decline in value	20.00%	'
Time period for which individual security should be in unrealized position of twenty percentage or more to assume it as other than temporary decline	'More than six months	'
Percentage of ownership interest	48.20%	'
Equity securities [Member]	'	'
Schedule of Investments [Line Items]	'	'
Number of fixed maturity securities classified as available for sale	9	'
General obligation bonds [Member] | Obligations of states and political subdivisions [Member]	'	'
Schedule of Investments [Line Items]	'	'
Aggregate fair value of bond held	329,900,000	358,500,000
Amortized cost of bond held	323,700,000	332,400,000
Special revenue bond [Member]	'	'
Schedule of Investments [Line Items]	'	'
Aggregate fair value of bond held	103,800,000	101,000,000
Amortized cost of bond held	$105,000,000	$93,900,000
Education Bond [Member]	'	'
Schedule of Investments [Line Items]	'	'
Percentage of investments in special revenue bonds	55.00%	54.00%
Water and Sewer Utility Bonds [Member]	'	'
Schedule of Investments [Line Items]	'	'
Percentage of investments in special revenue bonds	22.00%	19.00%

Investments_Summary_of_Amortiz1

Investments - Summary of Amortized Cost and Estimated Fair Value of Fixed Maturities by Contractual Maturity (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Held to maturity	'	'
Due in one year or less, Amortized Cost	'	'
Due after one year through five years, Amortized Cost	25,158,000	'
Due after five years through ten years, Amortized Cost	4,944,000	'
Due after ten years, Amortized Cost	'	'
Residential mortgage-backed securities, Amortized Cost	106,000	'
Total held to maturity, Amortized Cost	30,208,111	42,100,196
Due in one year or less, Estimated Fair Value	9,006,000	'
Due after one year through five years, Estimated Fair Value	38,779,000	'
Due after five years through ten years, Estimated Fair Value	210,203,000	'
Due after ten years, Estimated Fair Value	271,473,000	'
Residential mortgage-backed securities, Estimated Fair Value	140,039,000	'
Total held to maturity, Estimated Fair Value	30,884,000	43,736,000
Available for sale	'	'
Due in one year or less, Amortized Cost	'	'
Due after one year through five years, Amortized Cost	25,709,000	'
Due after five years through ten years, Amortized Cost	5,063,000	'
Due after ten years, Amortized Cost	'	'
Residential mortgage-backed securities, Amortized Cost	112,000	'
Total available for sale, Amortized Cost	30,884,000	'
Due in one year or less, Estimated Fair Value	9,124,000	'
Due after one year through five years, Estimated Fair Value	39,835,000	'
Due after five years through ten years, Estimated Fair Value	212,654,000	'
Due after ten years, Estimated Fair Value	269,115,000	'
Residential mortgage-backed securities, Estimated Fair Value	139,081,000	'
Total available for sale, Estimated Fair Value	$669,808,544	$694,509,821

Investments_Summary_of_Gross_R

Investments - Summary of Gross Realized Gains and Losses from Investments before Applicable Income Taxes (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Gain (Loss) on Investments [Line Items]	'	'	'	'
Gross realized gains	$742,000	$1,464,000	$3,823,000	$5,947,000
Gross realized losses	393,000	152,000	879,000	797,000
Net realized investment gains	349,164	1,312,137	2,943,710	5,150,450
Fixed maturities [Member]	'	'	'	'
Gain (Loss) on Investments [Line Items]	'	'	'	'
Gross realized gains	390,000	1,249,000	2,730,000	4,944,000
Gross realized losses	304,000	36,000	328,000	42,000
Equity securities [Member]	'	'	'	'
Gain (Loss) on Investments [Line Items]	'	'	'	'
Gross realized gains	352,000	215,000	1,093,000	1,003,000
Gross realized losses	$89,000	$116,000	$551,000	$755,000

Investments_Summary_of_Fixed_M

Investments - Summary of Fixed Maturities and Equity Securities with Unrealized Losses (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	$246,659	$71,432
Less Than 12 Months, Unrealized Losses	16,959	902
More Than 12 Months, Fair Value	11,216	2,959
More Than 12 Months, Unrealized Losses	847	30
U.S. Treasury securities and obligations of U.S. government corporations and agencies [Member]	'	'
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	55,647	12,308
Less Than 12 Months, Unrealized Losses	3,139	44
More Than 12 Months, Fair Value	1,421	'
More Than 12 Months, Unrealized Losses	108	'
Obligations of states and political subdivisions [Member]	'	'
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	102,382	22,134
Less Than 12 Months, Unrealized Losses	10,199	606
More Than 12 Months, Fair Value	2,176	'
More Than 12 Months, Unrealized Losses	310	'
Corporate securities [Member]	'	'
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	20,611	12,272
Less Than 12 Months, Unrealized Losses	1,059	79
More Than 12 Months, Fair Value	1,995	2,959
More Than 12 Months, Unrealized Losses	118	30
Residential mortgage-backed securities [Member]	'	'
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	63,787	22,492
Less Than 12 Months, Unrealized Losses	2,301	66
More Than 12 Months, Fair Value	5,296	'
More Than 12 Months, Unrealized Losses	287	'
Equity securities [Member]	'	'
Schedule Of Fixed Maturities And Equity Securities With Unrealized Losses [Line Items]	'	'
Less Than 12 Months, Fair Value	4,232	2,226
Less Than 12 Months, Unrealized Losses	261	107
More Than 12 Months, Fair Value	328	'
More Than 12 Months, Unrealized Losses	$24	'

Investments_Summary_of_Financi

Investments - Summary of Financial Information (Detail) (Donegal Financial Services Corporation [Member], USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Donegal Financial Services Corporation [Member]	'	'	'	'	'
Balance sheets:	'	'	'	'	'
Total assets	$514,409	'	$514,409	'	$509,670
Total liabilities	439,107	'	439,107	'	433,490
Stockholders' equity	75,302	'	75,302	'	76,180
Total liabilities and stockholders' equity	514,409	'	514,409	'	509,670
Income statements:	'	'	'	'	'
Net income	$1,525	$2,771	$5,184	$7,510	'

Segment_Information_Summary_of

Segment Information - Summary of Financial Data by Segment (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:	'	'	'	'
Net premiums earned	$130,645,011	$120,916,960	$382,310,380	$353,177,873
GAAP adjustments	'	'	'	-5,000
GAAP premiums earned	130,645,000	120,917,000	382,310,000	353,178,000
Net investment income	4,624,287	4,715,295	14,110,288	14,724,305
Realized investment gains	349,164	1,312,137	2,943,710	5,150,450
Equity in earnings of DFSC	735,380	1,336,818	2,499,854	3,621,593
Other	1,982,000	2,151,000	5,851,000	6,405,000
Total revenues	138,334,960	130,431,531	407,715,187	383,078,883
Underwriting income (loss):	'	'	'	'
SAP underwriting income (loss)	1,576,000	-1,473,000	-6,318,000	-11,727,000
GAAP adjustments	1,509,000	1,888,000	5,849,000	6,408,000
GAAP underwriting income (loss)	3,085,000	415,000	-469,000	-5,319,000
Net investment income	4,624,000	4,715,000	14,110,000	14,724,000
Realized investment gains	349,164	1,312,137	2,943,710	5,150,450
Equity in earnings of DFSC	735,380	1,336,818	2,499,854	3,621,593
Other	721,000	1,094,000	1,375,000	2,659,000
Income before income tax expense	9,514,208	8,872,682	20,459,655	20,835,498
Operating Segments [Member] | Commercial Lines [Member]	'	'	'	'
Revenues:	'	'	'	'
Net premiums earned	52,040,000	44,921,000	149,283,000	128,704,000
Underwriting income (loss):	'	'	'	'
GAAP underwriting income (loss)	2,537,000	2,507,000	-2,133,000	4,827,000
Operating Segments [Member] | Personal Lines [Member]	'	'	'	'
Revenues:	'	'	'	'
Net premiums earned	78,605,000	75,996,000	233,027,000	224,479,000
Underwriting income (loss):	'	'	'	'
GAAP underwriting income (loss)	($961,000)	($3,980,000)	($4,185,000)	($16,554,000)

Borrowings_Additional_Informat

Borrowings - Additional Information (Detail) (USD $)

9 Months Ended

9 Months Ended

1 Months Ended

12 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

31-May-04

Oct. 31, 2003

Dec. 31, 2010

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Mar. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Jun. 30, 2013

Maximum [Member]

Subordinated Debentures 2033 [Member]

Subordinated Debentures 2034 [Member]

Subordinated Debentures [Member]

Subordinated Debentures [Member]

Subordinated Debentures [Member]

Subordinated Debentures [Member]

Subordinated Debentures [Member]

Lines of Credit [Member]

Atlantic States [Member]

Atlantic States [Member]

Atlantic States [Member]

West Bend Mutual Insurance Company [Member]

MICO [Member]

MICO [Member]

MICO [Member]

Manufacturers and Traders Trust Company [Member]

Three-month LIBOR rate plus 3.85% [Member]

Pittsburgh [Member]

Lines of Credit [Member]

Subordinated Debentures [Member]

Indianapolis [Member]

Indianapolis [Member]

Lines of Credit [Member]

Lines of Credit [Member]

Indianapolis [Member]

Line of Credit Facility [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Right to request for extension of credit agreement with Manufacturers and Traders Trust Company

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$2,514,048

$60,000,000

Line of credit that expires date

'

'

'

'

'

'

'

'

'

'2016-07

'

'

'

'

'

'

'

'

Outstanding borrowings

'

'

'

'

'

'

'

'

'

49,500,000

'

'

'

'

'

'

'

'

Line of credit facility remaining borrowing capacity

'

'

'

'

'

'

'

'

'

10,500,000

'

'

'

'

'

'

'

'

Line of credit, interest rate related to Libor rate description

'

'

'

'

'

'

'

'

'

'Interest rates equal to M&T's current prime rate or the then current LIBOR rate plus 2.25%

'

'

'

'

'

'

'

'

Debt instrument interest rate effective percentage

'

2.25%

'

'

'

'

'

3.85%

3.85%

'

'

'

'

'

'

'

'

'

Interest rate on borrowings

'

'

'

'

'

'

'

'

'

2.43%

'

'

'

'

'

'

'

'

Percentage commitment fee

0.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility, borrowing interest rate

'The credit agreement requires our compliance with certain covenants. These covenants include minimum levels of our net worth, leverage ratio, statutory surplus and the A.M. Best ratings of our insurance subsidiaries. We complied with all requirements of the credit agreement during the nine months ended September 30, 2013.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Federal home loan bank borrowing amount outstanding

'

'

'

'

'

'

'

'

'

'

'

0

'

'

0

0

'

'

Interest rate on advances

'

'

'

'

'

'

'

'

'

'

'

'

0.24%

'

'

'

'

'

Debt issued to FHLB in exchange of advance cash

'

'

'

'

'

'

'

'

'

'

15,000,000

'

'

'

'

'

'

'

Debt instrument, description

'On October 29, 2003, we received $10.0 million in net proceeds from the issuance of subordinated debentures. The debentures had a maturity date of October 29, 2033 and were callable at our option, at par. The debentures carried an interest rate equal to the three-month LIBOR rate plus 3.85%.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debentures, interest rate related to Libor rate description

'Interest rate equal to the three-month LIBOR rate plus 3.85%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving line of credit expiration date

29-Oct-33

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from the issuance of subordinated debentures

'

'

'

'

5,000,000

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Payment date of subordinated debentures and liquidated investment in the statutory trust

'

'

28-Jan-13

25-Feb-13

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debentures maturity date

24-May-34

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument basis spread on variable rate

'

'

'

'

'

'

5.00%

'

'

'

'

'

'

'

'

'

'

'

Purchase of surplus note

'

'

'

'

'

'

'

'

'

'

'

'

'

$5,000,000

'

'

'

'

Borrowings_Amount_of_FHLB_of_I

Borrowings - Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement (Detail) (Lines of Credit [Member], USD $)	Sep. 30, 2013
MICO [Member] | Indianapolis [Member]	'
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement	'
FHLB stock purchased and owned as part of the agreement	$252,100
Collateral pledged, at par (carrying value 2,904,980 for MICO and 15,837,274 for Atlantic States)	3,700,000
Borrowing capacity currently available	2,514,048
Atlantic States [Member] | Pittsburgh [Member]	'
Amount of FHLB of Indianapolis/Pittsburgh stock purchased, collateral pledged and assets related to MICO's/Atlantic States Agreement	'
FHLB stock purchased and owned as part of the agreement	870,300
Collateral pledged, at par (carrying value 2,904,980 for MICO and 15,837,274 for Atlantic States)	19,000,000
Borrowing capacity currently available	$837,274

Borrowings_Amount_of_FHLB_of_I1

Borrowings - Amount of FHLB of Indianapolis/Pittsburgh Stock Purchased, Collateral Pledged and Assets Related to MICO's/Atlantic States Agreement (Parenthetical) (Detail) (Lines of Credit [Member], USD $)	Sep. 30, 2013
Indianapolis [Member] | MICO [Member]	'
Line of Credit Facility [Line Items]	'
Collateral Pledged at carrying value	$2,904,980
Pittsburgh [Member] | Atlantic States [Member]	'
Line of Credit Facility [Line Items]	'
Collateral Pledged at carrying value	$15,837,274

ShareBased_Compensation_Additi

Share-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'	'	'
Compensation expenses in stock compensation plans	$155,069	$121,189	$482,897	$360,915
Income tax benefit of stock compensation plans	54,274	42,416	169,014	126,320
Unrecognized compensation expense related to nonvested share-based compensation	669,154	'	669,154	'
Weighted average period of unrecognized compensation cost	'10 months 24 days	'	'	'
Cash from stock option exercise	910,838	187,025	4,500,000	1,000,000
Tax benefit for tax deductions from option exercise	$21,986	$10,475	$208,867	$49,517

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Measurements for Investments in Available-for-Sale Fixed Maturity and Equity Securities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	$683,209	$703,267
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	683,209	703,267
Assets and liabilities on recurring basis [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	71,657	71,311
Assets and liabilities on recurring basis [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	402,954	416,987
Assets and liabilities on recurring basis [Member] | Corporate securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	56,116	77,356
Assets and liabilities on recurring basis [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	139,082	128,856
Assets and liabilities on recurring basis [Member] | Equity securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	13,400	8,757
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	7,994	5,366
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [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	'	'
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [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	'	'
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'
Assets and liabilities on recurring basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	7,994	5,366
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	675,215	697,901
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [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	71,657	71,311
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [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	402,954	416,987
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	56,116	77,356
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	139,082	128,856
Assets and liabilities on recurring basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Equity securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	5,406	3,391
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [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	'	'
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [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	'	'
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'
Assets and liabilities on recurring basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Equity securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Fair Value Disclosure	'	'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]	'	'
Material unrealized tax benefits	$0	$0
Deferred tax asset, net	38,900,000	37,600,000
Alternative minimum tax credit carryforward	8,000,000	'
Le Mars [Member]	'	'
Operating Loss Carryforwards [Line Items]	'	'
Valuation allowance related to the portion of operating loss carryforwards	440,778	'
Operating loss carryforwards	5,100,000	'
Operating loss carryforwards expiration period	'2020	'
Operating loss carryforwards annual limitations in amount on use	$376,000	'