Selective Insurance (SIGI) 10-Q 30 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 15, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Entity Registrant Name	SELECTIVE INSURANCE GROUP INC
Entity Central Index Key	230557
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock , Shares Outstanding		56,948,239

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
ASSETS
Fixed income securities, held-to-maturity – at carrying value (fair value: $311,093 – 2015; $333,961 – 2014)	$296,557	$318,137
Fixed income securities, available-for-sale – at fair value (amortized cost: $4,059,034 – 2015; $3,975,786 – 2014)	4,174,242	4,066,122
Equity securities, available-for-sale – at fair value (cost: $199,617 – 2015; $159,011 – 2014)	211,571	191,400
Short-term investments (at cost which approximates fair value)	124,376	131,972
Other investments	95,020	99,203
Total investments	4,901,766	4,806,834
Cash	14,804	23,959
Interest and dividends due or accrued	38,416	38,901
Premiums receivable, net of allowance for uncollectible accounts of: $4,201 – 2015; $4,137 – 2014	596,888	558,778
Reinsurance recoverables, net	574,982	581,548
Prepaid reinsurance premiums	141,941	146,993
Deferred federal income tax	92,061	98,449
Property and equipment – at cost, net of accumulated depreciation and amortization of: $175,896 – 2015; $172,183 – 2014	61,855	59,416
Deferred policy acquisition costs	191,956	185,608
Goodwill	7,849	7,849
Other assets	78,627	73,215
Total assets	6,701,145	6,581,550
Liabilities And Stockholders' Equity
Reserve for loss and loss expenses	3,516,268	3,477,870
Unearned premiums	1,132,733	1,095,819
Notes payable	394,301	379,297
Current federal income tax	10,627	3,921
Accrued salaries and benefits	142,092	158,382
Other liabilities	189,186	190,675
Total liabilities	5,385,207	5,305,964
Stockholders' Equity:
Preferred stock of $0 par value per share: Authorized shares: 5,000,000; no shares issued or outstanding	0	0
Common stock of $2 par value per share Authorized shares: 360,000,000 Issued: 100,430,480 – 2015; 99,947,933 – 2014	200,861	199,896
Additional paid-in capital	312,930	305,385
Retained earnings	1,345,035	1,313,440
Accumulated other comprehensive income	23,615	19,788
Treasury stock - at cost (shares: 43,482,438 – 2015; 43,353,181 – 2014)	-566,503	-562,923
Total stockholders' equity	1,315,938	1,275,586
Commitments and contingencies
Total liabilities and stockholders' equity	$6,701,145	$6,581,550

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Fixed income securities, held-to-maturity, fair value	$311,093	$333,961
Fixed income securities, available-for-sale, amortized cost	4,059,034	3,975,786
Equity securities, available-for-sale, cost	199,617	159,011
Premiums receivable, allowance for uncollectible accounts	4,201	4,137
Property and equipment - at cost, accumulated depreciation and amortization	$175,896	$172,183
Preferred stock, par value per share	$0	$0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$2	$2
Common stock, shares authorized	360,000,000	360,000,000
Common stock, shares issued	100,430,480	99,947,933
Treasury stock - at cost, shares	43,482,438	43,353,181

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Net premiums earned	$476,123	$456,495
Net investment income earned	26,917	35,534
Net realized gains:
Net realized investment gains	20,977	8,181
Other-than-temporary impairments	-2,094	-963
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0
Total net realized gains	18,883	7,218
Other income	1,969	9,824
Total revenues	523,892	509,071
Expenses:
Loss and loss expense incurred	284,999	320,546
Policy acquisition costs	164,723	149,266
Interest expense	5,479	5,561
Other expenses	12,401	8,614
Total expenses	467,602	483,987
Income before federal income tax	56,290	25,084
Federal income tax expense:
Current	12,254	6,538
Deferred	4,328	572
Total federal income tax expense	16,582	7,110
Net income	$39,708	$17,974
Earnings per share:
Basic net income	$0.70	$0.32
Diluted net income	$0.69	$0.31
Dividends to stockholders	$0.14	$0.13

Consolidation_Statements_of_Co

Consolidation Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net income	$39,708	$17,974
Unrealized holding gains arising during period	15,586	21,426
Amount reclassified into net income: Held-to-maturity securities	-170	-296
Amount reclassified into net income: Non-credit other-than-temporary impairments	232	0
Amount reclassified into net income: Realized gains on available for sale securities	-12,932	-4,699
Total unrealized gains on investment securities	2,716	16,431
Amount reclassified into net income: Net actuarial loss	1,111	247
Total defined benefit pension and post-retirement plans	1,111	247
Other comprehensive income	3,827	16,678
Comprehensive income	$43,535	$34,652

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income [Member]	Treasury stock [Member]
In Thousands
Beginning of year at Dec. 31, 2013		$198,240	$288,182	$1,202,015	$24,851	($559,360)
Dividend reinvestment plan (shares: 13,533 – 2015; 15,283 - 2014)		31	320
Stock purchase and compensation plans (shares: 469,014 - 2015; 401,179 - 2014)		802	5,863
Net income	17,974			17,974
Dividends to stockholders ($0.14 per share - 2015; $0.13 per share - 2014)				-7,412
Other comprehensive income	16,678				16,678
Acquisition of treasury stock (shares: 129,257 - 2015; 118,876 - 2014)						-2,653
End of period at Mar. 31, 2014	1,185,531	199,073	294,365	1,212,577	41,529	-562,013
Beginning of year at Dec. 31, 2014	1,275,586	199,896	305,385	1,313,440	19,788	-562,923
Dividend reinvestment plan (shares: 13,533 – 2015; 15,283 - 2014)		27	346
Stock purchase and compensation plans (shares: 469,014 - 2015; 401,179 - 2014)		938	7,199
Net income	39,708			39,708
Dividends to stockholders ($0.14 per share - 2015; $0.13 per share - 2014)				-8,113
Other comprehensive income	3,827				3,827
Acquisition of treasury stock (shares: 129,257 - 2015; 118,876 - 2014)						-3,580
End of period at Mar. 31, 2015	$1,315,938	$200,861	$312,930	$1,345,035	$23,615	($566,503)

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Dividend reinvestment plan, shares	13,533	15,283
Stock purchase and compensation plans, shares	469,014	401,179
Dividends to stockholders, per share	$0.14	$0.13
Acquisition of treasury stock, shares	129,257	118,876
Preferred stock, par value per share	$0	$0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Series A Preferred Stock [Member]
Preferred stock, par value per share	$0	$0
Preferred stock, shares authorized	300,000	300,000

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flow (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Activities
Net income	$39,708	$17,974
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	14,041	10,578
Sale of renewal rights	0	-8,000
Stock-based compensation expense	3,681	4,176
Undistributed losses (gains) of equity method investments	3,541	-33
Net realized gains	-18,883	-7,218
Changes in assets and liabilities:
Increase in reserve for loss and loss expenses, net of reinsurance recoverables	44,964	58,938
Increase in unearned premiums, net of prepaid reinsurance	41,966	20,254
Decrease in net federal income taxes	11,034	4,332
Increase in premiums receivable	-38,110	-29,042
Increase in deferred policy acquisition costs	-6,348	-4,697
Decrease in interest and dividends due or accrued	510	414
Decrease in accrued salaries and benefits	-16,290	-21,869
Decrease in accrued insurance expenses	-24,255	-26,957
Increase in other assets and other liabilities	5,015	16,914
Net adjustments	20,866	17,790
Net cash provided by operating activities	60,574	35,764
Investing Activities
Purchase of fixed income securities, available-for-sale	-238,000	-182,809
Purchase of equity securities, available-for-sale	-150,500	-61,360
Purchase of other investments	-1,724	-4,615
Purchase of short-term investments	-333,550	-398,348
Sale of fixed income securities, available-for-sale	9,305	1,302
Sale of short-term investments	341,146	434,865
Redemption and maturities of fixed income securities, held-to-maturity	20,720	9,396
Redemption and maturities of fixed income securities, available-for-sale	145,661	104,358
Sale of equity securities, available-for-sale	129,052	61,523
Distributions from other investments	5,845	5,704
Purchase of property and equipment	-4,064	-5,699
Sale of renewal rights	0	8,000
Net cash used in investing activities	-76,109	-27,683
Financing Activities
Dividends to stockholders	-7,591	-6,948
Acquisition of treasury stock	-3,580	-2,653
Net proceeds from stock purchase and compensation plans	2,271	1,261
Proceeds from borrowings	15,000	0
Excess tax benefits from share-based payment arrangements	1,398	770
Repayments of capital lease obligations	-1,118	-459
Net cash provided by (used in) financing activities	6,380	-8,029
Net (decrease) increase in cash	-9,155	52
Cash, beginning of year	23,959	193
Cash, end of period	$14,804	$245

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Basis of Presentation And Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	As used herein, the "Company,” “we,” “us,” or “our” refers to Selective Insurance Group, Inc. (the "Parent"), and its subsidiaries, except as expressly indicated or unless the context otherwise requires. Our interim unaudited consolidated financial statements (“Financial Statements”) have been prepared by us in conformity with: (i) U.S. generally accepted accounting principles (“GAAP”); and (ii) the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) regarding interim financial reporting. The preparation of the Financial Statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported financial statement balances, as well as the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. All significant intercompany accounts and transactions between the Parent and its subsidiaries are eliminated in consolidation.
	Certain amounts in the prior years' Financial Statements and related notes have been reclassified to conform to the 2015 presentation. Such reclassifications had no effect on our net income, stockholders' equity, or cash flows.
	Our Financial Statements reflect all adjustments that, in our opinion, are normal, recurring, and necessary for a fair presentation of our results of operations and financial condition. Our Financial Statements cover the first quarters ended March 31, 2015 (“First Quarter 2015”) and March 31, 2014 (“First Quarter 2014”) and do not include all of the information and disclosures required by GAAP and the SEC for audited annual financial statements. Results of operations for any interim period are not necessarily indicative of results for a full year. Consequently, our Financial Statements should be read in conjunction with the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2014 (“2014 Annual Report”) filed with the SEC.

Accounting_Pronouncements

Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Pronouncements	Accounting Pronouncements
	In June 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period (“ASU 2014-12”). ASU 2014-12 requires that performance targets that affect vesting and could be achieved after the requisite service period be treated as performance conditions. The effective date for ASU 2014-12 is for interim and annual periods beginning after December 15, 2015. The adoption of ASU 2014-12 will not affect us, as we are currently recording expense consistent with the requirements of this accounting update.
	In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”). ASU 2014-15 provides guidance about: (i) management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern; and (ii) the content of related footnote disclosures. ASU 2014-15 is effective for annual periods ending after December 15, 2016, and interim periods beginning in 2017. Early application is permitted. The adoption of this ASU is not expected to impact the Company.
	In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis (“ASU 2015-02”). ASU 2015-02 amends the current consolidation guidance, focusing mainly on the investment management industry, although entities across all industries will be impacted. The main provisions in this update affect the following areas: (i) limited partnerships and similar legal entities; (ii) the evaluation of fees paid to a decision maker or a service provider as a variable interest; (iii) the effect of fee arrangements on the primary beneficiary determination; (iv) the effect of related parties on the primary beneficiary determination; and (v) certain investment funds. ASU 2015-02 is effective for interim and annual reporting periods beginning after December 15, 2015. While we are currently evaluating ASU 2015-02, we do not expect a material impact on our financial condition or results of operations from the adoption of this guidance.

Statements_of_Cash_Flow

Statements of Cash Flow	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Information [Abstract]
Statements of Cash Flow	Statements of Cash Flow
	Supplemental cash flow information for First Quarter 2015 and First Quarter 2014 is as follows:
		Quarter ended March 31,
	($ in thousands)	2015		2014
	Cash paid during the period for:
	Interest	$	2,887	2,973
	Federal income tax	4,000		2,000
	Non-cash items:
	Tax-free exchange of fixed income securities, available-for-sale ("AFS")	8,586		—
	Tax-free exchange of fixed income securities, held-to-maturity ("HTM")	—		15
	Corporate actions related to equity securities, AFS1	389		—
	Assets acquired under capital lease arrangements	2,428		1,419
	1Examples of such corporate actions include non-cash acquisitions and stock splits.
	Included in "Other assets" on the Consolidated Balance Sheet was $6.0 million at March 31, 2015 and $6.1 million at March 31, 2014 of cash received from the National Flood Insurance Program ("NFIP"), which is restricted to pay flood claims under the Write Your Own ("WYO") program.

Investments

Investments	3 Months Ended
	Mar. 31, 2015
Investments [Abstract]
Investments	Investments
	(a) The amortized cost, net unrealized gains and losses, carrying value, unrecognized holding gains and losses, and fair value of HTM fixed income securities as of March 31, 2015 and December 31, 2014 were as follows:
	March 31, 2015
	($ in thousands)	Amortized			Net		Carrying			Unrecognized		Unrecognized Holding		Fair
		Cost			Unrealized Gains		Value			Holding		Losses		Value
					(Losses)					Gains
	Foreign government	$	5,292		25		5,317			21		—		5,338
	Obligations of states and political subdivisions	264,788			1,706		266,494			10,536		—		277,030
	Corporate securities	18,532			(269	)	18,263			2,936		—		21,199
	Asset-backed securities (“ABS”)	2,483			(378	)	2,105			375		—		2,480
	Commercial mortgage-backed securities (“CMBS”)	4,764			(386	)	4,378			668		—		5,046
	Total HTM fixed income securities	$	295,859		698		296,557			14,536		—		311,093
	December 31, 2014
	($ in thousands)	Amortized			Net		Carrying			Unrecognized		Unrecognized Holding		Fair
		Cost			Unrealized Gains		Value			Holding		Losses		Value
					(Losses)					Gains
	Foreign government	$	5,292		47		5,339			55		—		5,394
	Obligations of states and political subdivisions	285,301			2,071		287,372			11,760		—		299,132
	Corporate securities	18,899			(273	)	18,626			2,796		—		21,422
	ABS	2,818			(455	)	2,363			460		—		2,823
	CMBS	4,869			(432	)	4,437			753		—		5,190
	Total HTM fixed income securities	$	317,179		958		318,137			15,824		—		333,961
	Unrecognized holding gains and losses of HTM securities are not reflected in the Financial Statements, as they represent fair value fluctuations from the later of: (i) the date a security is designated as HTM; or (ii) the date that an other-than-temporary impairment (“OTTI”) charge is recognized on an HTM security, through the date of the balance sheet. Our HTM securities had an average duration of 1.7 years as of March 31, 2015.
	(b) The cost/amortized cost, unrealized gains and losses, and fair value of AFS securities as of March 31, 2015 and December 31, 2014 were as follows:
	March 31, 2015
	($ in thousands)	Cost/			Unrealized		Unrealized			Fair
		Amortized			Gains		Losses			Value
		Cost
	U.S. government and government agencies	$	112,146		7,342		(2	)		119,486
	Foreign government	27,030			885		—			27,915
	Obligations of states and political subdivisions	1,254,037			40,872		(534	)		1,294,375
	Corporate securities	1,770,747			55,057		(1,539	)		1,824,265
	ABS	184,278			1,214		(105	)		185,387
	CMBS1	197,304			3,335		(128	)		200,511
	Residential mortgage-backed	513,492			9,991		(1,180	)		522,303
	securities (“RMBS”)2
	AFS fixed income securities	4,059,034			118,696		(3,488	)		4,174,242
	AFS equity securities	199,617			15,223		(3,269	)		211,571
	Total AFS securities	$	4,258,651		133,919		(6,757	)		4,385,813
	December 31, 2014
	($ in thousands)	Cost/			Unrealized		Unrealized			Fair
		Amortized			Gains		Losses			Value
		Cost
	U.S. government and government agencies	$	116,666		7,592		(128	)		124,130
	Foreign government	27,035			796		—			27,831
	Obligations of states and political subdivisions	1,208,776			38,217		(729	)		1,246,264
	Corporate securities	1,763,427			42,188		(5,809	)		1,799,806
	ABS	176,837			760		(373	)		177,224
	CMBS1	177,932			2,438		(777	)		179,593
	RMBS2	505,113			8,587		(2,426	)		511,274
	AFS fixed income securities	3,975,786			100,578		(10,242	)		4,066,122
	AFS equity securities	159,011			32,725		(336	)		191,400
	Total AFS securities	$	4,134,797		133,303		(10,578	)		4,257,522
	1 CMBS includes government guaranteed agency securities with a fair value of $12.9 million at March 31, 2015 and $13.2 million at December 31, 2014.
	2 RMBS includes government guaranteed agency securities with a fair value of $29.2 million at March 31, 2015 and $32.4 million at December 31, 2014.
	Unrealized gains and losses of AFS securities represent fair value fluctuations from the later of: (i) the date a security is designated as AFS; or (ii) the date that an OTTI charge is recognized on an AFS security, through the date of the balance sheet. These unrealized gains and losses are recorded in Accumulated other comprehensive income ("AOCI") on the Consolidated Balance Sheets.
	(c) The following tables summarize, for all securities in a net unrealized/unrecognized loss position at March 31, 2015 and December 31, 2014, the fair value and pre-tax net unrealized/unrecognized loss by asset class and by length of time those securities have been in a net loss position:
	March 31, 2015	Less than 12 months					12 months or longer
	($ in thousands)	Fair Value			Unrealized		Fair Value			Unrealized
					Losses1					Losses1
	AFS securities
	U.S. government and government agencies	$	—		—		398			(2	)
	Obligations of states and political subdivisions	75,935			(534	)	—			—
	Corporate securities	93,912			(821	)	50,858			(718	)
ABS	25,684			(16	)	14,353			(89	)
CMBS	24,664			(55	)	15,682			(73	)
RMBS	50,977			(189	)	75,521			(991	)
Total fixed income securities	271,172			(1,615	)	156,812			(1,873	)
Equity securities	100,209			(3,269	)	—			—
Subtotal	$	371,381		(4,884	)	156,812			(1,873	)
	Less than 12 months								12 months or longer
($ in thousands)	Fair			Unrealized		Unrecognized			Fair		Unrealized		Unrecognized
	Value			Losses1		Gains2			Value		Losses1		Gains2
HTM securities
Obligations of states and political subdivisions	197			(2	)	1			—		—		—
ABS	—			—		—			2,003		(379	)	361
Subtotal	$	197		(2	)	1			2,003		(379	)	361
Total AFS and HTM	$	371,578		(4,886	)	1			158,815		(2,252	)	361
December 31, 2014	Less than 12 months					12 months or longer
($ in thousands)	Fair			Unrealized		Fair Value			Unrealized
	Value			Losses1					Losses1
AFS securities
U.S. government and government agencies	$	7,567		(13	)	10,866			(115	)
Obligations of states and political subdivisions	47,510			(105	)	64,018			(624	)
Corporate securities	276,648			(1,734	)	153,613			(4,075	)
ABS	113,202			(178	)	15,618			(195	)
CMBS	12,799			(34	)	59,219			(743	)
RMBS	3,399			(8	)	138,724			(2,418	)
Total fixed income securities	461,125			(2,072	)	442,058			(8,170	)
Equity securities	5,262			(336	)	—			—
Subtotal	$	466,387		(2,408	)	442,058			(8,170	)
	Less than 12 months								12 months or longer
($ in thousands)	Fair			Unrealized		Unrecognized			Fair		Unrealized		Unrecognized
	Value			Losses1		Gains2			Value		Losses1		Gains2
HTM securities
Obligations of states and political subdivisions	$	196		(3	)	1			—		—		—
ABS	—			—		—			2,235		(455	)	439
Subtotal	196			(3	)	1			2,235		(455	)	439
Total AFS and HTM	$	466,583		(2,411	)	1			444,293		(8,625	)	439
1 Gross unrealized losses include non-OTTI unrealized amounts and OTTI losses recognized in AOCI.  In addition, this column includes remaining unrealized gain or loss amounts on securities that were transferred to an HTM designation in the first quarter of 2009 for those securities that are in a net unrealized/unrecognized loss position.
2 Unrecognized gains represent fair value fluctuations from the later of:  (i) the date a security is designated as HTM; or (ii) the date that an OTTI charge is recognized on an HTM security.
The table below provides our net unrealized/unrecognized loss positions by impairment severity as of March 31, 2015 compared to December 31, 2014:
($ in thousands)
March 31, 2015					December 31, 2014
Number of	% of Market/Book	Unrealized/			Number of	% of	Unrealized/
Issues		Unrecognized Loss			Issues	Market/Book	Unrecognized Loss
189	80% - 99%	$	6,776		350	80% - 99%	$	10,596
—	60% - 79%	—			—	60% - 79%	—
—	40% - 59%	—			—	40% - 59%	—
—	20% - 39%	—			—	20% - 39%	—
—	0% - 19%	—			—	0% - 19%	—
		$	6,776				$	10,596
The improvement in the number of securities in a loss position in our portfolio and the related loss amounts was mainly driven by a lower interest rate environment. During First Quarter 2015, interest rates on the 10-year U.S. Treasury Note fell by 25 basis points. This interest rate movement had a positive impact on the valuation of our fixed income securities portfolio, thus decreasing the number of securities in a loss position and the corresponding dollar amount of unrealized losses. For a discussion regarding the impact of interest rate movements on our fixed income securities portfolio, refer to Item 7A. "Quantitative and Qualitative Disclosures About Market Risk." in our 2014 Annual Report. Partially offsetting the improvement in fixed income securities was an increase in unrealized losses on our equity portfolio. Unrealized losses of $3.3 million on this portfolio related to 28 securities with an average impairment severity of 3% of cost. The temporary dislocation in market value on these securities was driven by energy and utility-related holdings that are expected to recover in the near term.
We do not intend to sell any of the securities in the tables above, nor do we believe we will be required to sell any of these securities. We have also reviewed these securities under our OTTI policy, as described in Note 2. “Summary of Significant Accounting Policies” within Item 8. “Financial Statements and Supplementary Data.” of our 2014 Annual Report, and have concluded that they are temporarily impaired. This conclusion reflects our current judgment as to the financial position and future prospects of the entity that issued the investment security and underlying collateral. If our judgment about an individual security changes in the future, we may ultimately record a credit loss after having originally concluded that one did not exist, which could have a material impact on our net income and financial position in future periods.
(d) Fixed income securities at March 31, 2015, by contractual maturity, are shown below. Mortgage-backed securities ("MBS") are included in the maturity tables using the estimated average life of each security. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations, with or without call or prepayment penalties.
Listed below are the contractual maturities of HTM fixed income securities at March 31, 2015:
($ in thousands)	Carrying Value			Fair Value
Due in one year or less	$	124,997		126,670
Due after one year through five years	160,671			171,337
Due after five years through 10 years	10,889			13,086
Total HTM fixed income securities	$	296,557		311,093
Listed below are the contractual maturities of AFS fixed income securities at March 31, 2015:
($ in thousands)	Fair Value
Due in one year or less	$	416,983
Due after one year through five years	2,067,679
Due after five years through 10 years	1,605,398
Due after 10 years	84,182
Total AFS fixed income securities	$	4,174,242
(e) The following table summarizes our other investment portfolio by strategy and the remaining commitment amount associated with each strategy:
Other Investments	Carrying Value					March 31,
						2015
($ in thousands)	March 31,			December 31,		Remaining Commitment
	2015			2014
Alternative Investments
Secondary private equity	$	20,208		21,807		7,040
Private equity	17,519			20,126		8,879
Energy/power generation	12,393			14,445		21,905
Real estate	11,986			11,452		10,016
Mezzanine financing	8,363			9,853		13,598
Distressed debt	7,569			8,679		2,982
Venture capital	6,236			6,606		350
Total alternative investments	84,274			92,968		64,770
Other securities	10,746			6,235		2,001
Total other investments	$	95,020		99,203		66,771
For a description of our seven alternative investment strategies, as well as information regarding redemption, restrictions, and fund liquidations, refer to Note 5. “Investments” in Item 8. “Financial Statements and Supplementary Data.” of our 2014 Annual Report.
The following table sets forth gross summarized financial information for our other investments portfolio, including the portion not owned by us. The investments are carried under the equity method of accounting. The last line of the table below reflects our share of the aggregate income, which is the portion included in our Financial Statements. As the majority of these investments report results to us on a one quarter lag, the summarized financial statement information for the three-month periods ended December 31 is as follows:
Income Statement Information	Quarter ended December 31,
($ in millions)	2014			2013
Net investment income	$	77		65.1
Realized gains	160.5			63.3
Net change in unrealized (depreciation) appreciation	(518.0		)	505.9
Net (loss) income	$	(280.5	)	634.3
Selective’s insurance subsidiaries’ other investments (loss) income	$	(3.5	)	5.2
(f) We have pledged certain AFS fixed income securities as collateral related to: (i) our outstanding borrowing of $60 million with the Federal Home Loan Bank of Indianapolis ("FHLBI"); and (ii) our reinsurance obligations related to our 2011 acquisition of our excess and surplus lines ("E&S") book of business. In addition, certain securities were on deposit with various state and regulatory agencies to comply with insurance laws. We retain all rights regarding all securities pledged as collateral.
The following table summarizes the market value of these securities at March 31, 2015:
($ in millions)	FHLBI Collateral			Reinsurance Collateral		State and Regulatory Deposits			Total
U.S. government and government agencies	$	7.7		—		25.2			32.9
Obligations of states and political subdivisions	—			5		—			5
Corporate securities	—			4.8		—			4.8
ABS	—			1		—			1
CMBS	1.7			—		—			1.7
RMBS	54.6			2.2		—			56.8
Total pledged as collateral	$	64		13		25.2			102.2
(g) The components of pre-tax net investment income earned for the periods indicated were as follows:
	Quarter ended March 31,
($ in thousands)	2015			2014
Fixed income securities	$	30,967		31,028
Equity securities	1,792			1,449
Short-term investments	25			19
Other investments	(3,540		)	5,218
Investment expenses	(2,327		)	(2,180	)
Net investment income earned	$	26,917		35,534
(h) The following tables summarize OTTI by asset type for the periods indicated:
First Quarter 2015	Gross			Included in Other Comprehensive Income ("OCI")		Recognized in
($ in thousands)						Earnings
AFS fixed income securities
Corporate securities	$	1,009		—		1,009
RMBS	1			—		1
Total AFS fixed income securities	1,010			—		1,010
AFS equity securities	$	1,084		—		1,084
OTTI losses	$	2,094		—		2,094
First Quarter 2014	Gross			Included in OCI		Recognized in Earnings
($ in thousands)
AFS securities
Equity securities	$	963		—		963
OTTI losses	$	963		—		963
For a discussion of our evaluation for OTTI of fixed income securities, short-term investments, equity securities, and other investments, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2014 Annual Report.
The following table set forth, for the periods indicated, credit loss impairments on fixed income securities for which a portion of the OTTI charge was recognized in OCI, and the corresponding changes in such amounts:
	Quarter ended March 31,
($ in thousands)	2015			2014
Balance, beginning of period	$	5,444		7,488
Addition for the amount related to credit loss for which an OTTI was not previously recognized	—			—
Reductions for securities sold during the period	(4,431		)	—
Reductions for securities for which the amount previously recognized in OCI was recognized in earnings because of intention or potential requirement to sell before recovery of amortized cost	—			—
Additional increases to the amount related to credit loss for which an OTTI was previously recognized	—			—
Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	—			—
Balance, end of period	1,013			7,488
(i) The components of net realized gains, excluding OTTI charges, for the periods indicated were as follows:
	Quarter ended March 31,
($ in thousands)	2015			2014
HTM fixed income securities
Gains	$	—		—
Losses	(1		)	(11	)
AFS fixed income securities
Gains	1,502			158
Losses	(112		)	(112	)
AFS equity securities
Gains	21,318			8,317
Losses	(1,076		)	(171	)
Other investments
Gains	—			—
Losses	(654		)	—
Total net realized gains (excluding OTTI charges)	$	20,977		8,181
Realized gains and losses on the sale of investments are determined on the basis of the cost of the specific investments sold. Proceeds from the sale of AFS securities were $138.4 million in First Quarter 2015 and $62.8 million in First Quarter 2014. The $21.0 million in net realized gains in First Quarter 2015 were primarily related to the sale of AFS equity securities due to a change in our dividend equity strategy from a quantitative, model-driven stock selection strategy to a fundamentally-based stock selection approach that incorporates an assessment of the sustainability and growth rate of a company’s dividends and future cash flow. The $8.2 million in net realized gains in First Quarter 2014 was primarily related to the sale of AFS equity securities due to the quantitative rebalancing of our dividend yield strategy holdings.

Indebtedness

Indebtedness	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Indebtedness	NOTE 5. Indebtedness
	Of our ten insurance subsidiaries ("Insurance Subsidiaries"), we have two domiciled in Indiana ("Indiana Subsidiaries") that are members of the FHLBI. In January 2015, the Indiana Subsidiaries borrowed $15 million in the aggregate from the FHLBI for general corporate purposes. The unpaid principal amount accrues interest of 0.63%, which is paid on the 15th of every month. The principal amount is due on July 22, 2016. For a summary of the Indiana Subsidiaries' borrowings from the FHLBI, refer to Note 10. "Indebtedness" in Item 8. "Financial Statements and Supplementary Data." of our 2014 Annual Report.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	The following table presents the carrying amounts and estimated fair values of our financial instruments as of March 31, 2015 and December 31, 2014:
			March 31, 2015			December 31, 2014
	($ in thousands)		Carrying Amount		Fair	Carrying Amount	Fair
					Value		Value
	Financial Assets
	Fixed income securities:
	HTM		$	296,557	311,093	318,137	333,961
	AFS		4,174,242		4,174,242	4,066,122	4,066,122
	Equity securities, AFS		211,571		211,571	191,400	191,400
	Short-term investments		124,376		124,376	131,972	131,972
	Financial Liabilities
	Notes payable:
	0.63% borrowings from FHLBI		15,000		14,994	—	—
	1.25% borrowings from FHLBI		45,000		45,338	45,000	45,244
	7.25% Senior Notes		49,896		60,407	49,896	59,181
	6.70% Senior Notes		99,405		117,389	99,401	114,845
	5.875% Senior Notes		185,000		189,440	185,000	185,000
	Total notes payable		$	394,301	427,568	379,297	404,270
	The fair values of our financial assets and liabilities are generated using various valuation techniques and are placed into the fair value hierarchy considering the following: (i) the highest priority is given to quoted prices in active markets for identical assets (Level 1); (ii) the next highest priority is given to quoted prices in markets that are not active or inputs that are observable either directly or indirectly, including quoted prices for similar assets in markets that are not active and other inputs that can be derived principally from, or corroborated by, observable market data for substantially the full term of the assets (Level 2); and (iii) the lowest priority is given to unobservable inputs supported by little or no market activity and that reflect our assumptions about the exit price, including assumptions that market participants would use in pricing the asset (Level 3). An asset or liability's classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. Transfers between levels in the fair value hierarchy are recognized at the end of the reporting period.
	For a discussion of the techniques used to value our financial assets and liabilities, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2014 Annual Report.
	The following tables provide quantitative disclosures of our financial assets that were measured at fair value at March 31, 2015 and December 31, 2014:
	March 31, 2015				Fair Value Measurements Using
	($ in thousands)		Assets		Quoted Prices in	Significant Other	Significant Unobservable
			Measured at		Active Markets for	Observable	Inputs
			Fair Value		Identical Assets/	Inputs	(Level 3)
			at 3/31/2015		Liabilities (Level 1)1	(Level 2)1
	Description
	Measured on a recurring basis:
	AFS:
	U.S. government and government agencies		$	119,486	52,977	66,509	—
	Foreign government		27,915		—	27,915	—
	Obligations of states and political subdivisions		1,294,375		—	1,294,375	—
	Corporate securities		1,824,265		—	1,824,265	—
	ABS		185,387		—	185,387	—
	CMBS		200,511		—	200,511	—
	RMBS		522,303		—	522,303	—
	Total AFS fixed income securities		4,174,242		52,977	4,121,265	—
	Equity securities		211,571		208,671	—	2,900
	Total AFS Securities		4,385,813		261,648	4,121,265	2,900
	Short-term investments		124,376		124,376	—	—
	Total assets measured at fair value		$	4,510,189	386,024	4,121,265	2,900
	1	There were no transfers of securities between Level 1 and Level 2.
	December 31, 2014				Fair Value Measurements Using
	($ in thousands)		Assets		Quoted Prices in	Significant	Significant Unobservable
			Measured at		Active Markets for	Other Observable	Inputs
			Fair Value		Identical Assets/Liabilities	Inputs	(Level 3)
			at 12/31/14		(Level 1)1	(Level 2)1
	Description
	Measured on a recurring basis:
	AFS:
	U.S. government and government agencies		$	124,130	53,199	70,931	—
	Foreign government		27,831		—	27,831	—
	Obligations of states and political subdivisions		1,246,264		—	1,246,264	—
	Corporate securities		1,799,806		—	1,799,806	—
	ABS		177,224		—	177,224	—
	CMBS		179,593		—	179,593	—
	RMBS		511,274		—	511,274	—
	Total AFS fixed income securities		4,066,122		53,199	4,012,923	—
	Equity securities		191,400		188,500	—	2,900
	Total AFS Securities		4,257,522		241,699	4,012,923	2,900
	Short-term investments		131,972		131,972	—	—
	Total assets measured at fair value		$	4,389,494	373,671	4,012,923	2,900
	1	There were no transfers of securities between Level 1 and Level 2.
The $2.9 million fair value of securities measured using Level 3 prices remained unchanged during First Quarter 2015 and full year 2014. The price for the securities, which were measured using Level 3 inputs at March 31, 2015 and December 31, 2014, was obtained through statements provided by the issuer, which we review for reasonabless.
The following tables provide quantitative information regarding our financial assets and liabilities that were disclosed at fair value at March 31, 2015 and December 31, 2014:
March 31, 2015				Fair Value Measurements Using
($ in thousands)		Assets/		Quoted Prices in	Significant Other	Significant
		Liabilities		Active Markets for	Observable	Unobservable
		Disclosed at		Identical Assets/	Inputs	Inputs
		Fair Value at 3/31/2015		Liabilities	(Level 2)	(Level 3)
				(Level 1)
Financial Assets
HTM:
Foreign government		$	5,338	—	5,338	—
Obligations of states and political subdivisions		277,030		—	277,030	—
Corporate securities		21,199		—	21,199	—
ABS		2,480		—	2,480	—
CMBS		5,046		—	5,046	—
Total HTM fixed income securities		$	311,093	—	311,093	—
Financial Liabilities
Notes payable:
0.63% borrowings from FHLBI		$	14,994	—	14,994	—
1.25% borrowings from FHLBI		45,338		—	45,338	—
7.25% Senior Notes		60,407		—	60,407	—
6.70% Senior Notes		117,389		—	117,389	—
5.875% Senior Notes		189,440		189,440	—	—
Total notes payable		$	427,568	189,440	238,128	—
December 31, 2014				Fair Value Measurements Using
($ in thousands)		Assets/		Quoted Prices in	Significant Other	Significant
		Liabilities		Active Markets for	Observable	Unobservable
		Disclosed at		Identical Assets/	Inputs	Inputs
		Fair Value at 12/31/2014		Liabilities	(Level 2)	(Level 3)
				(Level 1)
Financial Assets
HTM:
Foreign government		$	5,394	—	5,394	—
Obligations of states and political subdivisions		299,132		—	299,132	—
Corporate securities		21,422		—	21,422	—
ABS		2,823		—	2,823	—
CMBS		5,190		—	5,190	—
Total HTM fixed income securities		$	333,961	—	333,961	—
Financial Liabilities
Notes payable:
1.25% borrowings from FHLBI		$	45,244	—	45,244	—
7.25% Senior Notes		59,181		—	59,181	—
6.70% Senior Notes		114,845		—	114,845	—
5.875% Senior Notes		185,000		185,000	—	—
Total notes payable		$	404,270	185,000	219,270	—

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2015
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance
	The following table contains a listing of direct, assumed, and ceded reinsurance amounts for premiums written, premiums earned, and loss and loss expenses incurred for the periods indicated. For more information concerning reinsurance, refer to
	Note 8. “Reinsurance” in Item 8. “Financial Statements and Supplementary Data.” of our 2014 Annual Report.
		Quarter ended March 31,
	($ in thousands)	2015			2014
	Premiums written:
	Direct	$	598,783		557,891
	Assumed	6,081			7,850
	Ceded	(86,776		)	(88,991	)
	Net	$	518,088		476,750
	Premiums earned:
	Direct	$	562,042		536,700
	Assumed	5,908			10,185
	Ceded	(91,827		)	(90,390	)
	Net	$	476,123		456,495
	Loss and loss expense incurred:
	Direct	$	312,246		358,349
	Assumed	4,662			7,479
	Ceded	(31,909		)	(45,282	)
	Net	$	284,999		320,546
	Ceded premiums and losses related to our participation in the NFIP, under which 100% of our flood premiums, losses, and loss expenses are ceded to the NFIP, are as follows:
	Ceded to NFIP	Quarter ended March 31,
	($ in thousands)	2015			2014
	Ceded premiums written	$	(53,842	)	(57,303	)
	Ceded premiums earned	(58,998		)	(58,286	)
	Ceded loss and loss expense incurred	(6,249		)	(7,379	)

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information
	Selective Insurance Group, Inc., through its Insurance Subsidiaries, offers property and casualty insurance products in the standard and E&S marketplaces. We classify our business into four reportable segments, which are as follows:
	•	Standard Commercial Lines - comprised of insurance products and services provided in the standard marketplace to
	commercial enterprises, which are typically businesses, non-profit organizations, and local government agencies.
	•	Standard Personal Lines - comprised of insurance products and services, including flood insurance coverage, provided primarily to individuals acquiring coverage in the standard marketplace.
	•	E&S Lines - comprised of insurance products and services provided to customers who have not obtained coverage in
	the standard marketplace.
	•	Investments - invests the premiums collected by our Standard Commercial Lines, Standard Personal Lines, and E&S
	Lines, our earnings and amounts generated through our capital management strategies, which may include the issuance of debt and equity securities.
	In the fourth quarter of 2014, we revised our reporting segments from our previously-reported Standard Insurance Operations segment to Standard Commercial Lines and Standard Personal Lines. For information regarding this change, see Note 11. "Segment Information" in Item 8. "Financial Statements and Supplementary Data." of our 2014 Annual Report.
	In computing the results of each segment, we do not make adjustments for interest expense or net general corporate expenses. While we do not fully allocate taxes to all segments, we do allocate taxes to our Investments segment as we manage that segment on after-tax results. We do not maintain separate investment portfolios for the segments and therefore, do not allocate assets to the segments.
	In First Quarter 2014, we sold the renewal rights to our $37 million self-insured group, or "SIG," book of business within the Standard Commercial Lines segment. We decided to opportunistically sell this small and specialized book of pooled business as a significant portion of the business was produced outside of our standard lines footprint, and proved difficult to grow. As this was a renewal rights sale, we will continue to service policies that were in force at the date of the sale. We continue to remain active in the municipal and public school marketplace for individual risks that procure traditional insurance programs rather than pooling arrangements. The proceeds from this sale, which amounted to $8 million, are included in "Miscellaneous income" within the table below as a component of Standard Commercial Lines revenue.
	The following summaries present revenues (net investment income and net realized gains on investments in the case of the Investments segment) and pre-tax income for the individual segments:
	Revenue by Segment		Quarter ended
			March 31,
	($ in thousands)		2015			2014
	Standard Commercial Lines:
	Net premiums earned:
	Commercial automobile		$	86,355		82,216
	Workers compensation		68,477			69,413
	General liability		114,971			108,818
	Commercial property		64,563			60,186
	Businessowners’ policies		22,699			20,869
	Bonds		5,000			4,756
	Other		3,468			3,183
	Miscellaneous income		1,669			8,914
	Total Standard Commercial Lines revenue		367,202			358,355
	Standard Personal Lines:
	Net premiums earned:
	Personal automobile		37,010			38,226
	Homeowners		33,721			33,298
	Other		1,748			3,294
	Miscellaneous income		300			905
	Total Standard Personal Lines revenue		72,779			75,723
	E&S Lines:
	Net premiums earned:
	General liability		26,726			21,931
	Commercial property		9,655			9,117
	Commercial automobile		1,730			1,188
	Total E&S Lines revenue		38,111			32,236
	Investments:
	Net investment income		26,917			35,534
	Net realized investment gains		18,883			7,218
	Total Investments revenue		45,800			42,752
	Total segments revenue		523,892			509,066
	Other income		—			5
	Total revenues		$	523,892		509,071
	Income Before Federal Income Tax		Quarter ended March 31,
	($ in thousands)		2015			2014
	Standard Commercial Lines:
	Underwriting gain (loss)		$	30,036		(3,630	)
	GAAP combined ratio		91.8		%	101	%
	Statutory combined ratio		89.7		%	100.3	%
	Standard Personal Lines:
	Underwriting loss		$	(2,466	)	(2,360	)
	GAAP combined ratio		103.4		%	103.2	%
	Statutory combined ratio		105.1		%	104.5	%
	E&S Insurance Operations:
	Underwriting (loss) gain		$	(1,549	)	975
	GAAP combined ratio		104.1		%	97	%
	Statutory combined ratio		102.1		%	97.9	%
	Investments:
	Net investment income		$	26,917		35,534
	Net realized investment gains		18,883			7,218
Total investment income, before federal income tax		45,800			42,752
Tax on investment income		12,318			11,575
Total investment income, after federal income tax		33,482			31,177
Reconciliation of Segment Results to Income		Quarter ended
Before Federal Income Tax		March 31,
($ in thousands)		2015			2014
Underwriting gain (loss), before federal income tax
Standard Commercial Lines		$	30,036		(3,630		)
Standard Personal Lines		(2,466		)	(2,360		)
E&S Lines		(1,549		)	975
Investment income, before federal income tax		45,800			42,752
Total all segments		71,821			37,737
Interest expense		(5,479		)	(5,561		)
General corporate and other expenses		(10,052		)	(7,092		)
Income before federal income tax		$	56,290		$	25,084

Retirement_Plans

Retirement Plans	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Retirement Plans	Retirement Plans
	The following table shows the net periodic benefit cost related to the Retirement Income Plan for Selective Insurance Company of America (“Retirement Income Plan”) and the life insurance benefits provided to eligible Selective Insurance Company of America retirees (referred to as the "Retirement Life Plan"). For more information concerning these plans, refer to Note 15. “Retirement Plans” in Item 8. “Financial Statements and Supplementary Data.” of our 2014 Annual Report.
		Retirement Income Plan							Retirement Life Plan
		Quarter ended March 31,							Quarter ended March 31,
	($ in thousands)	2015				2014			2015		2014
	Components of Net Periodic Benefit Cost:
	Net Periodic Benefit Cost:
	Service cost	$	1,964			1,627			—		—
	Interest cost	3,502				3,254			63		73
	Expected return on plan assets	(3,991		)		(3,919	)		—		—
	Amortization of unrecognized net actuarial loss	1,695				367			14		13
	Total net periodic cost	$	3,170			1,329			77		86
		Retirement Income Plan					Retirement Life Plan
		Quarter ended March 31,					Quarter ended March 31,
		2015			2014		2015			2014
	Weighted-Average Expense Assumptions:
	Discount rate	4.29	%		5.16		4.08	%		4.85
	Expected return on plan assets	6.27			6.92		—			—
	Rate of compensation increase	4			4		—			—
	We presently anticipate contributing $11.9 million to the Retirement Income Plan in 2015, $3.2 million of which has been funded as of March 31, 2015.

Comprehensive_Income

Comprehensive Income	3 Months Ended
	Mar. 31, 2015
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income	Comprehensive Income
	The components of comprehensive income, both gross and net of tax, for First Quarter 2015 and First Quarter 2014 are as follows:
	First Quarter 2015
	($ in thousands)		Gross				Tax		Net
	Net income		$	56,290			16,582		39,708
	Components of OCI:
	Unrealized gains on investment securities:
	Unrealized holding gains during the period		23,977				8,391		15,586
	Amounts reclassified into net income:
	HTM securities		(261		)		(91	)	(170	)
	Non-credit OTTI		357				125		232
	Realized gains on AFS securities		(19,895		)		(6,963	)	(12,932	)
	Net unrealized gains		4,178				1,462		2,716
	Defined benefit pension and post-retirement plans:
	Amounts reclassified into net income:
	Net actuarial loss		1,709				598		1,111
	Defined benefit pension and post-retirement plans		1,709				598		1,111
	Other comprehensive income		5,887				2,060		3,827
	Comprehensive income		$	62,177			18,642		43,535
	First Quarter 2014
	($ in thousands)		Gross				Tax		Net
	Net income		$	25,084			7,110		17,974
	Components of OCI:
	Unrealized gains on investment securities:
	Unrealized holding gains during the period		32,964				11,538		21,426
	Amounts reclassified into net income:
	HTM securities		(456		)		(160	)	(296	)
	Realized gains on AFS securities		(7,229		)		(2,530	)	(4,699	)
	Net unrealized gains		25,279				8,848		16,431
	Defined benefit pension and post-retirement plans:
	Amounts reclassified into net income:
	Net actuarial loss		380				133		247
	Defined benefit pension and post-retirement plans		380				133		247
	Other comprehensive income		25,659				8,981		16,678
	Comprehensive income		$	50,743			16,091		34,652
	The balances of, and changes in, each component of AOCI (net of taxes) as of March 31, 2015 are as follows:
	March 31, 2015
			Net Unrealized (Loss) Gain on Investment Securities										Defined Benefit
	($ in thousands)		OTTI				HTM		All		Investments		Pension and Post-Retirement Plans		Total AOCI
			Related				Related		Other		Subtotal
	Balance, December 31, 2014		$	(514	)		623		80,284		80,393		(60,605	)	19,788
	OCI before reclassifications		—				—		15,586		15,586		—		15,586
	Amounts reclassified from AOCI		232				(170	)	(12,932	)	(12,870	)	1,111		(11,759	)
	Net current period OCI		232				(170	)	2,654		2,716		1,111		3,827
	Balance, March 31, 2015		$	(282	)		453		82,938		83,109		(59,494	)	23,615
	The reclassifications out of AOCI are as follows:
		Quarter ended
		March 31,
	($ in thousands)	2015			2014			Affected Line Item in the Unaudited Consolidated Statement of Income
	OTTI related
	Non-credit OTTI on disposed securities	357			—			Net realized gains
		357			—			Income before federal income tax
		(125	)		—			Total federal income tax expense
		232			—			Net income
	HTM related
	Unrealized losses on HTM disposals	50			24			Net realized gains
	Amortization of net unrealized gains on HTM securities	(311	)		(480	)		Net investment income earned
		(261	)		(456	)		Income before federal income tax
		91			160			Total federal income tax expense
		(170	)		(296	)		Net income
	Realized gains and losses on AFS and OTTI
	Realized gains on AFS disposals and OTTI	(19,895	)		(7,229	)		Net realized gains
		(19,895	)		(7,229	)		Income before federal income tax
		6,963			2,530			Total federal income tax expense
	(12,932	)		(4,699	)		Net income
Defined benefit pension and post-retirement life plans
Net actuarial loss	371			87			Loss and loss expense incurred
	1,338			293			Policy acquisition costs
Total defined benefit pension and post-retirement life	1,709			380			Income before federal income tax
	(598	)		(133	)		Total federal income tax expense
	1,111			247			Net income
Total reclassifications for the period	(11,759	)		(4,748	)		Net income

Litigation

Litigation	3 Months Ended
	Mar. 31, 2015
Loss Contingency, Information about Litigation Matters [Abstract]
Litigation	Litigation
	In the ordinary course of conducting business, we are named as defendants in various legal proceedings. Most of these proceedings are claims litigation involving our Insurance Subsidiaries as either: (i) liability insurers defending or providing indemnity for third-party claims brought against our customers; or (ii) insurers defending first-party coverage claims brought against them. We account for such activity through the establishment of unpaid loss and loss expense reserves. We expect that the ultimate liability, if any, with respect to such ordinary course claims litigation, after consideration of provisions made for potential losses and costs of defense, will not be material to our consolidated financial condition, results of operations, or cash flows.
	Our Insurance Subsidiaries are also from time to time involved in other legal actions, some of which assert claims for substantial amounts. These actions include, among others, putative class actions seeking certification of a state or national class. Such putative class actions have alleged, for example, improper reimbursement of medical providers paid under workers compensation and personal and commercial automobile insurance policies. Our Insurance Subsidiaries also are involved from time to time in individual actions in which extra-contractual damages, punitive damages, or penalties are sought, such as claims alleging bad faith in the handling of insurance claims. We believe that we have valid defenses to these cases. We expect that the ultimate liability, if any, with respect to such lawsuits, after consideration of provisions made for estimated losses, will not be material to our consolidated financial condition. Nonetheless, given the large or indeterminate amounts sought in certain of these actions, and the inherent unpredictability of litigation, an adverse outcome in certain matters could, from time to time, have a material adverse effect on our consolidated results of operations or cash flows in particular quarterly or annual periods. As of March 31, 2015, we do not believe the Company was involved in any legal action that could have a material adverse effect on our consolidated financial position, results of operations, or cash flows.

Statements_of_Cash_Flow_Tables

Statements of Cash Flow (Tables)	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures
		Quarter ended March 31,
	($ in thousands)	2015		2014
	Cash paid during the period for:
	Interest	$	2,887	2,973
	Federal income tax	4,000		2,000
	Non-cash items:
	Tax-free exchange of fixed income securities, available-for-sale ("AFS")	8,586		—
	Tax-free exchange of fixed income securities, held-to-maturity ("HTM")	—		15
	Corporate actions related to equity securities, AFS1	389		—
	Assets acquired under capital lease arrangements	2,428		1,419
	1Examples of such corporate actions include non-cash acquisitions and stock splits.

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2015
Investments [Line Items]
Schedule of Held-to-maturity Securities
	March 31, 2015
	($ in thousands)	Amortized			Net		Carrying			Unrecognized		Unrecognized Holding		Fair
		Cost			Unrealized Gains		Value			Holding		Losses		Value
					(Losses)					Gains
	Foreign government	$	5,292		25		5,317			21		—		5,338
	Obligations of states and political subdivisions	264,788			1,706		266,494			10,536		—		277,030
	Corporate securities	18,532			(269	)	18,263			2,936		—		21,199
	Asset-backed securities (“ABS”)	2,483			(378	)	2,105			375		—		2,480
	Commercial mortgage-backed securities (“CMBS”)	4,764			(386	)	4,378			668		—		5,046
	Total HTM fixed income securities	$	295,859		698		296,557			14,536		—		311,093
	December 31, 2014
	($ in thousands)	Amortized			Net		Carrying			Unrecognized		Unrecognized Holding		Fair
		Cost			Unrealized Gains		Value			Holding		Losses		Value
					(Losses)					Gains
	Foreign government	$	5,292		47		5,339			55		—		5,394
	Obligations of states and political subdivisions	285,301			2,071		287,372			11,760		—		299,132
	Corporate securities	18,899			(273	)	18,626			2,796		—		21,422
	ABS	2,818			(455	)	2,363			460		—		2,823
	CMBS	4,869			(432	)	4,437			753		—		5,190
	Total HTM fixed income securities	$	317,179		958		318,137			15,824		—		333,961
Schedule Of Available For Sale Securities
	March 31, 2015
	($ in thousands)	Cost/			Unrealized		Unrealized			Fair
		Amortized			Gains		Losses			Value
		Cost
	U.S. government and government agencies	$	112,146		7,342		(2	)		119,486
	Foreign government	27,030			885		—			27,915
	Obligations of states and political subdivisions	1,254,037			40,872		(534	)		1,294,375
	Corporate securities	1,770,747			55,057		(1,539	)		1,824,265
	ABS	184,278			1,214		(105	)		185,387
	CMBS1	197,304			3,335		(128	)		200,511
	Residential mortgage-backed	513,492			9,991		(1,180	)		522,303
	securities (“RMBS”)2
	AFS fixed income securities	4,059,034			118,696		(3,488	)		4,174,242
	AFS equity securities	199,617			15,223		(3,269	)		211,571
	Total AFS securities	$	4,258,651		133,919		(6,757	)		4,385,813
	December 31, 2014
	($ in thousands)	Cost/			Unrealized		Unrealized			Fair
		Amortized			Gains		Losses			Value
		Cost
	U.S. government and government agencies	$	116,666		7,592		(128	)		124,130
	Foreign government	27,035			796		—			27,831
	Obligations of states and political subdivisions	1,208,776			38,217		(729	)		1,246,264
	Corporate securities	1,763,427			42,188		(5,809	)		1,799,806
	ABS	176,837			760		(373	)		177,224
	CMBS1	177,932			2,438		(777	)		179,593
	RMBS2	505,113			8,587		(2,426	)		511,274
	AFS fixed income securities	3,975,786			100,578		(10,242	)		4,066,122
	AFS equity securities	159,011			32,725		(336	)		191,400
	Total AFS securities	$	4,134,797		133,303		(10,578	)		4,257,522
	1 CMBS includes government guaranteed agency securities with a fair value of $12.9 million at March 31, 2015 and $13.2 million at December 31, 2014.
	2 RMBS includes government guaranteed agency securities with a fair value of $29.2 million at March 31, 2015 and $32.4 million at December 31, 2014.
Schedule of Fair Value and Gross Pre-Tax Net Unrealized/Unrecognized Loss of Securities by Length of Time
	March 31, 2015	Less than 12 months					12 months or longer
	($ in thousands)	Fair Value			Unrealized		Fair Value			Unrealized
					Losses1					Losses1
	AFS securities
	U.S. government and government agencies	$	—		—		398			(2	)
	Obligations of states and political subdivisions	75,935			(534	)	—			—
	Corporate securities	93,912			(821	)	50,858			(718	)
	ABS	25,684			(16	)	14,353			(89	)
	CMBS	24,664			(55	)	15,682			(73	)
	RMBS	50,977			(189	)	75,521			(991	)
	Total fixed income securities	271,172			(1,615	)	156,812			(1,873	)
	Equity securities	100,209			(3,269	)	—			—
	Subtotal	$	371,381		(4,884	)	156,812			(1,873	)
		Less than 12 months								12 months or longer
	($ in thousands)	Fair			Unrealized		Unrecognized			Fair		Unrealized		Unrecognized
		Value			Losses1		Gains2			Value		Losses1		Gains2
	HTM securities
	Obligations of states and political subdivisions	197			(2	)	1			—		—		—
	ABS	—			—		—			2,003		(379	)	361
	Subtotal	$	197		(2	)	1			2,003		(379	)	361
	Total AFS and HTM	$	371,578		(4,886	)	1			158,815		(2,252	)	361
	December 31, 2014	Less than 12 months					12 months or longer
	($ in thousands)	Fair			Unrealized		Fair Value			Unrealized
		Value			Losses1					Losses1
	AFS securities
	U.S. government and government agencies	$	7,567		(13	)	10,866			(115	)
	Obligations of states and political subdivisions	47,510			(105	)	64,018			(624	)
	Corporate securities	276,648			(1,734	)	153,613			(4,075	)
	ABS	113,202			(178	)	15,618			(195	)
	CMBS	12,799			(34	)	59,219			(743	)
	RMBS	3,399			(8	)	138,724			(2,418	)
	Total fixed income securities	461,125			(2,072	)	442,058			(8,170	)
	Equity securities	5,262			(336	)	—			—
	Subtotal	$	466,387		(2,408	)	442,058			(8,170	)
		Less than 12 months								12 months or longer
	($ in thousands)	Fair			Unrealized		Unrecognized			Fair		Unrealized		Unrecognized
		Value			Losses1		Gains2			Value		Losses1		Gains2
	HTM securities
	Obligations of states and political subdivisions	$	196		(3	)	1			—		—		—
	ABS	—			—		—			2,235		(455	)	439
	Subtotal	196			(3	)	1			2,235		(455	)	439
	Total AFS and HTM	$	466,583		(2,411	)	1			444,293		(8,625	)	439
	1 Gross unrealized losses include non-OTTI unrealized amounts and OTTI losses recognized in AOCI.  In addition, this column includes remaining unrealized gain or loss amounts on securities that were transferred to an HTM designation in the first quarter of 2009 for those securities that are in a net unrealized/unrecognized loss position.
	2 Unrecognized gains represent fair value fluctuations from the later of:  (i) the date a security is designated as HTM; or (ii) the date that an OTTI charge is recognized on an HTM security.
Schedule Of The Number Of Securities In An Unrealized Unrecognized Loss Position
	($ in thousands)
	March 31, 2015					December 31, 2014
	Number of	% of Market/Book	Unrealized/			Number of	% of	Unrealized/
	Issues		Unrecognized Loss			Issues	Market/Book	Unrecognized Loss
	189	80% - 99%	$	6,776		350	80% - 99%	$	10,596
	—	60% - 79%	—			—	60% - 79%	—
	—	40% - 59%	—			—	40% - 59%	—
	—	20% - 39%	—			—	20% - 39%	—
	—	0% - 19%	—			—	0% - 19%	—
			$	6,776				$	10,596
Schedule Of Other Investment Portfolio By Strategy And Remaining Commitment Amount Associated With Each Strategy
	Other Investments	Carrying Value					March 31,
							2015
	($ in thousands)	March 31,			December 31,		Remaining Commitment
		2015			2014
	Alternative Investments
	Secondary private equity	$	20,208		21,807		7,040
	Private equity	17,519			20,126		8,879
	Energy/power generation	12,393			14,445		21,905
	Real estate	11,986			11,452		10,016
	Mezzanine financing	8,363			9,853		13,598
	Distressed debt	7,569			8,679		2,982
	Venture capital	6,236			6,606		350
	Total alternative investments	84,274			92,968		64,770
	Other securities	10,746			6,235		2,001
	Total other investments	$	95,020		99,203		66,771
Schedule Of Aggregated Summarized Income Statement Financial Information For Partnerships In Our Alternative Investment Portfolio
	Income Statement Information	Quarter ended December 31,
	($ in millions)	2014			2013
	Net investment income	$	77		65.1
	Realized gains	160.5			63.3
	Net change in unrealized (depreciation) appreciation	(518.0		)	505.9
	Net (loss) income	$	(280.5	)	634.3
	Selective’s insurance subsidiaries’ other investments (loss) income	$	(3.5	)	5.2
Schedule Of Securities Pledged As Collateral
	($ in millions)	FHLBI Collateral			Reinsurance Collateral		State and Regulatory Deposits			Total
	U.S. government and government agencies	$	7.7		—		25.2			32.9
	Obligations of states and political subdivisions	—			5		—			5
	Corporate securities	—			4.8		—			4.8
	ABS	—			1		—			1
	CMBS	1.7			—		—			1.7
	RMBS	54.6			2.2		—			56.8
	Total pledged as collateral	$	64		13		25.2			102.2
Schedule of Net Investment Income Earned
		Quarter ended March 31,
	($ in thousands)	2015			2014
	Fixed income securities	$	30,967		31,028
	Equity securities	1,792			1,449
	Short-term investments	25			19
	Other investments	(3,540		)	5,218
	Investment expenses	(2,327		)	(2,180	)
	Net investment income earned	$	26,917		35,534
Schedule of OTTI By Asset Type
	First Quarter 2015	Gross			Included in Other Comprehensive Income ("OCI")		Recognized in
	($ in thousands)						Earnings
	AFS fixed income securities
	Corporate securities	$	1,009		—		1,009
	RMBS	1			—		1
	Total AFS fixed income securities	1,010			—		1,010
	AFS equity securities	$	1,084		—		1,084
	OTTI losses	$	2,094		—		2,094
	First Quarter 2014	Gross			Included in OCI		Recognized in Earnings
	($ in thousands)
	AFS securities
	Equity securities	$	963		—		963
	OTTI losses	$	963		—		963
Schedule of Gross Credit Loss Impairments on Fixed Maturity Securities for Which a Portion of the OTTI Charge was Recognized in OCI
		Quarter ended March 31,
	($ in thousands)	2015			2014
	Balance, beginning of period	$	5,444		7,488
	Addition for the amount related to credit loss for which an OTTI was not previously recognized	—			—
	Reductions for securities sold during the period	(4,431		)	—
	Reductions for securities for which the amount previously recognized in OCI was recognized in earnings because of intention or potential requirement to sell before recovery of amortized cost	—			—
	Additional increases to the amount related to credit loss for which an OTTI was previously recognized	—			—
	Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	—			—
	Balance, end of period	1,013			7,488
Schedule of Components of Net Realized Gains Excluding OTTI Charges
		Quarter ended March 31,
	($ in thousands)	2015			2014
	HTM fixed income securities
	Gains	$	—		—
	Losses	(1		)	(11	)
	AFS fixed income securities
	Gains	1,502			158
	Losses	(112		)	(112	)
	AFS equity securities
	Gains	21,318			8,317
	Losses	(1,076		)	(171	)
	Other investments
	Gains	—			—
	Losses	(654		)	—
	Total net realized gains (excluding OTTI charges)	$	20,977		8,181
Held To Maturity Fixed Income Securities [Member]
Investments [Line Items]
Schedule Of Fixed Maturity Securities By Contractual Maturities
	($ in thousands)	Carrying Value			Fair Value
	Due in one year or less	$	124,997		126,670
	Due after one year through five years	160,671			171,337
	Due after five years through 10 years	10,889			13,086
	Total HTM fixed income securities	$	296,557		311,093
AFS Fixed Income Securities [Member]
Investments [Line Items]
Schedule Of Fixed Maturity Securities By Contractual Maturities
	($ in thousands)	Fair Value
	Due in one year or less	$	416,983
	Due after one year through five years	2,067,679
	Due after five years through 10 years	1,605,398
	Due after 10 years	84,182
	Total AFS fixed income securities	$	4,174,242

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of The Carrying Amounts and Estimated Fair Values of Financial Instruments
			March 31, 2015			December 31, 2014
	($ in thousands)		Carrying Amount		Fair	Carrying Amount	Fair
					Value		Value
	Financial Assets
	Fixed income securities:
	HTM		$	296,557	311,093	318,137	333,961
	AFS		4,174,242		4,174,242	4,066,122	4,066,122
	Equity securities, AFS		211,571		211,571	191,400	191,400
	Short-term investments		124,376		124,376	131,972	131,972
	Financial Liabilities
	Notes payable:
	0.63% borrowings from FHLBI		15,000		14,994	—	—
	1.25% borrowings from FHLBI		45,000		45,338	45,000	45,244
	7.25% Senior Notes		49,896		60,407	49,896	59,181
	6.70% Senior Notes		99,405		117,389	99,401	114,845
	5.875% Senior Notes		185,000		189,440	185,000	185,000
	Total notes payable		$	394,301	427,568	379,297	404,270
Schedule of Quantitative Disclosures of Our Financial Assets That Were Measured At Fair Value
	March 31, 2015				Fair Value Measurements Using
	($ in thousands)		Assets		Quoted Prices in	Significant Other	Significant Unobservable
			Measured at		Active Markets for	Observable	Inputs
			Fair Value		Identical Assets/	Inputs	(Level 3)
			at 3/31/2015		Liabilities (Level 1)1	(Level 2)1
	Description
	Measured on a recurring basis:
	AFS:
	U.S. government and government agencies		$	119,486	52,977	66,509	—
	Foreign government		27,915		—	27,915	—
	Obligations of states and political subdivisions		1,294,375		—	1,294,375	—
	Corporate securities		1,824,265		—	1,824,265	—
	ABS		185,387		—	185,387	—
	CMBS		200,511		—	200,511	—
	RMBS		522,303		—	522,303	—
	Total AFS fixed income securities		4,174,242		52,977	4,121,265	—
	Equity securities		211,571		208,671	—	2,900
	Total AFS Securities		4,385,813		261,648	4,121,265	2,900
	Short-term investments		124,376		124,376	—	—
	Total assets measured at fair value		$	4,510,189	386,024	4,121,265	2,900
	1	There were no transfers of securities between Level 1 and Level 2.
	December 31, 2014				Fair Value Measurements Using
	($ in thousands)		Assets		Quoted Prices in	Significant	Significant Unobservable
			Measured at		Active Markets for	Other Observable	Inputs
			Fair Value		Identical Assets/Liabilities	Inputs	(Level 3)
			at 12/31/14		(Level 1)1	(Level 2)1
	Description
	Measured on a recurring basis:
	AFS:
	U.S. government and government agencies		$	124,130	53,199	70,931	—
	Foreign government		27,831		—	27,831	—
	Obligations of states and political subdivisions		1,246,264		—	1,246,264	—
	Corporate securities		1,799,806		—	1,799,806	—
	ABS		177,224		—	177,224	—
	CMBS		179,593		—	179,593	—
	RMBS		511,274		—	511,274	—
	Total AFS fixed income securities		4,066,122		53,199	4,012,923	—
	Equity securities		191,400		188,500	—	2,900
	Total AFS Securities		4,257,522		241,699	4,012,923	2,900
	Short-term investments		131,972		131,972	—	—
	Total assets measured at fair value		$	4,389,494	373,671	4,012,923	2,900
	1	There were no transfers of securities between Level 1 and Level 2.
Schedule of Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value	:
	March 31, 2015				Fair Value Measurements Using
	($ in thousands)		Assets/		Quoted Prices in	Significant Other	Significant
			Liabilities		Active Markets for	Observable	Unobservable
			Disclosed at		Identical Assets/	Inputs	Inputs
			Fair Value at 3/31/2015		Liabilities	(Level 2)	(Level 3)
					(Level 1)
	Financial Assets
	HTM:
	Foreign government		$	5,338	—	5,338	—
	Obligations of states and political subdivisions		277,030		—	277,030	—
	Corporate securities		21,199		—	21,199	—
	ABS		2,480		—	2,480	—
	CMBS		5,046		—	5,046	—
	Total HTM fixed income securities		$	311,093	—	311,093	—
	Financial Liabilities
	Notes payable:
	0.63% borrowings from FHLBI		$	14,994	—	14,994	—
	1.25% borrowings from FHLBI		45,338		—	45,338	—
	7.25% Senior Notes		60,407		—	60,407	—
	6.70% Senior Notes		117,389		—	117,389	—
	5.875% Senior Notes		189,440		189,440	—	—
	Total notes payable		$	427,568	189,440	238,128	—
	December 31, 2014				Fair Value Measurements Using
	($ in thousands)		Assets/		Quoted Prices in	Significant Other	Significant
			Liabilities		Active Markets for	Observable	Unobservable
			Disclosed at		Identical Assets/	Inputs	Inputs
			Fair Value at 12/31/2014		Liabilities	(Level 2)	(Level 3)
					(Level 1)
	Financial Assets
	HTM:
	Foreign government		$	5,394	—	5,394	—
	Obligations of states and political subdivisions		299,132		—	299,132	—
	Corporate securities		21,422		—	21,422	—
	ABS		2,823		—	2,823	—
	CMBS		5,190		—	5,190	—
	Total HTM fixed income securities		$	333,961	—	333,961	—
	Financial Liabilities
	Notes payable:
	1.25% borrowings from FHLBI		$	45,244	—	45,244	—
	7.25% Senior Notes		59,181		—	59,181	—
	6.70% Senior Notes		114,845		—	114,845	—
	5.875% Senior Notes		185,000		185,000	—	—
	Total notes payable		$	404,270	185,000	219,270	—

Reinsurance_Tables

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2015
Reinsurance Disclosures [Abstract]
Schedule of List Of Direct, Assumed, And Ceded Reinsurance Amounts
		Quarter ended March 31,
	($ in thousands)	2015			2014
	Premiums written:
	Direct	$	598,783		557,891
	Assumed	6,081			7,850
	Ceded	(86,776		)	(88,991	)
	Net	$	518,088		476,750
	Premiums earned:
	Direct	$	562,042		536,700
	Assumed	5,908			10,185
	Ceded	(91,827		)	(90,390	)
	Net	$	476,123		456,495
	Loss and loss expense incurred:
	Direct	$	312,246		358,349
	Assumed	4,662			7,479
	Ceded	(31,909		)	(45,282	)
	Net	$	284,999		320,546
Schedule of Ceded Premiums and Losses Related to Flood Operations
	Ceded to NFIP	Quarter ended March 31,
	($ in thousands)	2015			2014
	Ceded premiums written	$	(53,842	)	(57,303	)
	Ceded premiums earned	(58,998		)	(58,286	)
	Ceded loss and loss expense incurred	(6,249		)	(7,379	)

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Schedule Of Revenue By Segment
	Revenue by Segment	Quarter ended
		March 31,
	($ in thousands)	2015			2014
	Standard Commercial Lines:
	Net premiums earned:
	Commercial automobile	$	86,355		82,216
	Workers compensation	68,477			69,413
	General liability	114,971			108,818
	Commercial property	64,563			60,186
	Businessowners’ policies	22,699			20,869
	Bonds	5,000			4,756
	Other	3,468			3,183
	Miscellaneous income	1,669			8,914
	Total Standard Commercial Lines revenue	367,202			358,355
	Standard Personal Lines:
	Net premiums earned:
	Personal automobile	37,010			38,226
	Homeowners	33,721			33,298
	Other	1,748			3,294
	Miscellaneous income	300			905
	Total Standard Personal Lines revenue	72,779			75,723
	E&S Lines:
	Net premiums earned:
	General liability	26,726			21,931
	Commercial property	9,655			9,117
	Commercial automobile	1,730			1,188
	Total E&S Lines revenue	38,111			32,236
	Investments:
	Net investment income	26,917			35,534
	Net realized investment gains	18,883			7,218
	Total Investments revenue	45,800			42,752
	Total segments revenue	523,892			509,066
	Other income	—			5
	Total revenues	$	523,892		509,071
Schedule of Income Before Federal Income Tax
	Income Before Federal Income Tax	Quarter ended March 31,
	($ in thousands)	2015			2014
	Standard Commercial Lines:
	Underwriting gain (loss)	$	30,036		(3,630	)
	GAAP combined ratio	91.8		%	101	%
	Statutory combined ratio	89.7		%	100.3	%
	Standard Personal Lines:
	Underwriting loss	$	(2,466	)	(2,360	)
	GAAP combined ratio	103.4		%	103.2	%
	Statutory combined ratio	105.1		%	104.5	%
	E&S Insurance Operations:
	Underwriting (loss) gain	$	(1,549	)	975
	GAAP combined ratio	104.1		%	97	%
	Statutory combined ratio	102.1		%	97.9	%
	Investments:
	Net investment income	$	26,917		35,534
	Net realized investment gains	18,883			7,218
	Total investment income, before federal income tax	45,800			42,752
	Tax on investment income	12,318			11,575
	Total investment income, after federal income tax	33,482			31,177
Schedule of Reconciliation of Segment Results to Income Before Federal Income Tax
	Reconciliation of Segment Results to Income	Quarter ended
	Before Federal Income Tax	March 31,
	($ in thousands)	2015			2014
	Underwriting gain (loss), before federal income tax
	Standard Commercial Lines	$	30,036		(3,630		)
	Standard Personal Lines	(2,466		)	(2,360		)
	E&S Lines	(1,549		)	975
	Investment income, before federal income tax	45,800			42,752
	Total all segments	71,821			37,737
	Interest expense	(5,479		)	(5,561		)
	General corporate and other expenses	(10,052		)	(7,092		)
	Income before federal income tax	$	56,290		$	25,084

Retirement_Plans_Table

Retirement Plans (Table)	3 Months Ended
	Mar. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Schedule of Components Of Net Periodic Benefit Cost And Other Amounts Recognized In Other Comprehensive Income
		Retirement Income Plan							Retirement Life Plan
		Quarter ended March 31,							Quarter ended March 31,
	($ in thousands)	2015				2014			2015		2014
	Components of Net Periodic Benefit Cost:
	Net Periodic Benefit Cost:
	Service cost	$	1,964			1,627			—		—
	Interest cost	3,502				3,254			63		73
	Expected return on plan assets	(3,991		)		(3,919	)		—		—
	Amortization of unrecognized net actuarial loss	1,695				367			14		13
	Total net periodic cost	$	3,170			1,329			77		86
Schedule Of Weighted-Average Expense Assumptions
		Retirement Income Plan					Retirement Life Plan
		Quarter ended March 31,					Quarter ended March 31,
		2015			2014		2015			2014
	Weighted-Average Expense Assumptions:
	Discount rate	4.29	%		5.16		4.08	%		4.85
	Expected return on plan assets	6.27			6.92		—			—
	Rate of compensation increase	4			4		—			—

Comprehensive_Income_Tables

Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2015
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Components of Comprehensive Income-Gross and Net of Tax
	First Quarter 2015
	($ in thousands)		Gross				Tax		Net
	Net income		$	56,290			16,582		39,708
	Components of OCI:
	Unrealized gains on investment securities:
	Unrealized holding gains during the period		23,977				8,391		15,586
	Amounts reclassified into net income:
	HTM securities		(261		)		(91	)	(170	)
	Non-credit OTTI		357				125		232
	Realized gains on AFS securities		(19,895		)		(6,963	)	(12,932	)
	Net unrealized gains		4,178				1,462		2,716
	Defined benefit pension and post-retirement plans:
	Amounts reclassified into net income:
	Net actuarial loss		1,709				598		1,111
	Defined benefit pension and post-retirement plans		1,709				598		1,111
	Other comprehensive income		5,887				2,060		3,827
	Comprehensive income		$	62,177			18,642		43,535
	First Quarter 2014
	($ in thousands)		Gross				Tax		Net
	Net income		$	25,084			7,110		17,974
	Components of OCI:
	Unrealized gains on investment securities:
	Unrealized holding gains during the period		32,964				11,538		21,426
	Amounts reclassified into net income:
	HTM securities		(456		)		(160	)	(296	)
	Realized gains on AFS securities		(7,229		)		(2,530	)	(4,699	)
	Net unrealized gains		25,279				8,848		16,431
	Defined benefit pension and post-retirement plans:
	Amounts reclassified into net income:
	Net actuarial loss		380				133		247
	Defined benefit pension and post-retirement plans		380				133		247
	Other comprehensive income		25,659				8,981		16,678
	Comprehensive income		$	50,743			16,091		34,652
Schedule of Components of Accumulated Other Comprehensive Income
	March 31, 2015
			Net Unrealized (Loss) Gain on Investment Securities										Defined Benefit
	($ in thousands)		OTTI				HTM		All		Investments		Pension and Post-Retirement Plans		Total AOCI
			Related				Related		Other		Subtotal
	Balance, December 31, 2014		$	(514	)		623		80,284		80,393		(60,605	)	19,788
	OCI before reclassifications		—				—		15,586		15,586		—		15,586
	Amounts reclassified from AOCI		232				(170	)	(12,932	)	(12,870	)	1,111		(11,759	)
	Net current period OCI		232				(170	)	2,654		2,716		1,111		3,827
	Balance, March 31, 2015		$	(282	)		453		82,938		83,109		(59,494	)	23,615
Schedule of Reclassifications Out Of Accumulated Other Comprehensive Income
		Quarter ended
		March 31,
	($ in thousands)	2015			2014			Affected Line Item in the Unaudited Consolidated Statement of Income
	OTTI related
	Non-credit OTTI on disposed securities	357			—			Net realized gains
		357			—			Income before federal income tax
		(125	)		—			Total federal income tax expense
		232			—			Net income
	HTM related
	Unrealized losses on HTM disposals	50			24			Net realized gains
	Amortization of net unrealized gains on HTM securities	(311	)		(480	)		Net investment income earned
		(261	)		(456	)		Income before federal income tax
		91			160			Total federal income tax expense
		(170	)		(296	)		Net income
	Realized gains and losses on AFS and OTTI
	Realized gains on AFS disposals and OTTI	(19,895	)		(7,229	)		Net realized gains
		(19,895	)		(7,229	)		Income before federal income tax
		6,963			2,530			Total federal income tax expense
		(12,932	)		(4,699	)		Net income
	Defined benefit pension and post-retirement life plans
	Net actuarial loss	371			87			Loss and loss expense incurred
		1,338			293			Policy acquisition costs
	Total defined benefit pension and post-retirement life	1,709			380			Income before federal income tax
		(598	)		(133	)		Total federal income tax expense
		1,111			247			Net income
	Total reclassifications for the period	(11,759	)		(4,748	)		Net income

Statements_of_Cash_Flow_Cash_F

Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Interest	$2,887,000		$2,973,000
Federal income tax	4,000,000		2,000,000
Corporate Actions Related To Equity Securities, AFS	389,000	[1]	0	[1]
Assets acquired under capital lease arrangements	2,428,000		1,419,000
AFS Fixed Maturity Securities [Member]
Tax-free exchange of fixed maturity security	8,586,000		0
Held-to-maturity Securities [Member]
Tax-free exchange of fixed maturity security	0		15,000
National Flood Insurance Program [Member]
Restricted Cash	$6,000,000		$6,100,000
[1]	1Examples of such corporate actions include non-cash acquisitions and stock splits.

Investments_HeldToMaturity_Sec

Investments (Held-To-Maturity Securities Disclosure) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$295,859	$317,179
Net Unrealized Gains (Losses)	698	958
Carrying Value	296,557	318,137
Unrecognized Holding Gains	14,536	15,824
Unrecognized Holding Losses	0	0
HTM, Fair Value	311,093	333,961
Held To Maturity securities average duration	1 year 8 months 8 days
Foreign Government [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	5,292	5,292
Net Unrealized Gains (Losses)	25	47
Carrying Value	5,317	5,339
Unrecognized Holding Gains	21	55
Unrecognized Holding Losses	0	0
HTM, Fair Value	5,338	5,394
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	264,788	285,301
Net Unrealized Gains (Losses)	1,706	2,071
Carrying Value	266,494	287,372
Unrecognized Holding Gains	10,536	11,760
Unrecognized Holding Losses	0	0
HTM, Fair Value	277,030	299,132
Corporate Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	18,532	18,899
Net Unrealized Gains (Losses)	-269	-273
Carrying Value	18,263	18,626
Unrecognized Holding Gains	2,936	2,796
Unrecognized Holding Losses	0	0
HTM, Fair Value	21,199	21,422
Asset-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,483	2,818
Net Unrealized Gains (Losses)	-378	-455
Carrying Value	2,105	2,363
Unrecognized Holding Gains	375	460
Unrecognized Holding Losses	0	0
HTM, Fair Value	2,480	2,823
Commercial Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	4,764	4,869
Net Unrealized Gains (Losses)	-386	-432
Carrying Value	4,378	4,437
Unrecognized Holding Gains	668	753
Unrecognized Holding Losses	0	0
HTM, Fair Value	$5,046	$5,190

Investments_AvailableForSale_S

Investments (Available-For-Sale Securities Disclosure) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	$4,258,651,000		$4,134,797,000
Unrealized Gains	133,919,000		133,303,000
Unrealized Losses	-6,757,000		-10,578,000
Total AFS securities	4,385,813,000		4,257,522,000
AFS Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	4,059,034,000		3,975,786,000
Unrealized Gains	118,696,000		100,578,000
Unrealized Losses	-3,488,000		-10,242,000
Total AFS securities	4,174,242,000		4,066,122,000
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	112,146,000		116,666,000
Unrealized Gains	7,342,000		7,592,000
Unrealized Losses	-2,000		-128,000
Total AFS securities	119,486,000		124,130,000
AFS Fixed Income Securities [Member] | Foreign Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	27,030,000		27,035,000
Unrealized Gains	885,000		796,000
Unrealized Losses	0		0
Total AFS securities	27,915,000		27,831,000
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	1,254,037,000		1,208,776,000
Unrealized Gains	40,872,000		38,217,000
Unrealized Losses	-534,000		-729,000
Total AFS securities	1,294,375,000		1,246,264,000
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	1,770,747,000		1,763,427,000
Unrealized Gains	55,057,000		42,188,000
Unrealized Losses	-1,539,000		-5,809,000
Total AFS securities	1,824,265,000		1,799,806,000
AFS Fixed Income Securities [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	184,278,000		176,837,000
Unrealized Gains	1,214,000		760,000
Unrealized Losses	-105,000		-373,000
Total AFS securities	185,387,000		177,224,000
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	197,304,000	[1]	177,932,000	[1]
Unrealized Gains	3,335,000	[1]	2,438,000	[1]
Unrealized Losses	-128,000	[1]	-777,000	[1]
Total AFS securities	200,511,000	[1]	179,593,000	[1]
Government guaranteed agency securities fair value	12,900,000		13,200,000
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	513,492,000	[2]	505,113,000	[2]
Unrealized Gains	9,991,000	[2]	8,587,000	[2]
Unrealized Losses	-1,180,000	[2]	-2,426,000	[2]
Total AFS securities	522,303,000	[2]	511,274,000	[2]
Government guaranteed agency securities fair value	29,200,000		32,400,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	199,617,000		159,011,000
Unrealized Gains	15,223,000		32,725,000
Unrealized Losses	-3,269,000		-336,000
Total AFS securities	$211,571,000		$191,400,000
[1]	CMBS includes government guaranteed agency securities with a fair value of $12.9 million at March 31, 2015 and $13.2 million at December 31, 2014.
[2]	RMBS includes government guaranteed agency securities with a fair value of $29.2 million at March 31, 2015 and $32.4 million at December 31, 2014.

Investments_Fair_Value_and_Gro

Investments (Fair Value and Gross Pre-Tax Net Unrealized Unrecognized Loss of Securities By Length of Time) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
AFS Fair Value, Less than 12 months	$371,381		$466,387
AFS Unrealized Losses, Less than 12 months	-4,884	[1]	-2,408	[1]
AFS Fair Value, 12 months or longer	156,812		442,058
AFS Unrealized Losses, 12 months or longer	-1,873	[1]	-8,170	[1]
HTM Fair Value, Less than 12 months	197		196
HTM Unrealized Losses, Less than 12 months	-2	[1]	-3	[1]
HTM Unrecognized Gains, Less than 12 months	1	[2]	1	[2]
HTM Fair Value, 12 months or longer	2,003		2,235
HTM Unrealized Losses, 12 months or longer	-379	[1]	-455	[1]
HTM Unrecognized Gains, 12 months or longer	361	[2]	439	[2]
Total AFS and HTM Fair Value, Less than 12 months	371,578		466,583
Total AFS and HTM Unrealized Losses, Less than 12 months	-4,886	[1]	-2,411	[1]
Total AFS and HTM Securities Unrecognized Gains, Less Than 12 Months	1	[2]	1	[2]
Total AFS and HTM Fair Value, 12 months or longer	158,815		444,293
Total AFS and HTM Unrealized Losses, 12 months or longer	-2,252	[1]	-8,625	[1]
Total AFS and HTM Securities Unrecognized Gains, 12 months or longer	361	[2]	439	[2]
Obligations of States and Political Subdivisions [Member]
HTM Fair Value, Less than 12 months	197		196
HTM Unrealized Losses, Less than 12 months	-2	[1]	-3	[1]
HTM Unrecognized Gains, Less than 12 months	1	[2]	1	[2]
HTM Fair Value, 12 months or longer	0		0
HTM Unrealized Losses, 12 months or longer	0	[1]	0	[1]
HTM Unrecognized Gains, 12 months or longer	0	[2]	0	[2]
Asset-Backed Securities [Member]
HTM Fair Value, Less than 12 months	0		0
HTM Unrealized Losses, Less than 12 months	0	[1]	0	[1]
HTM Unrecognized Gains, Less than 12 months	0	[2]	0	[2]
HTM Fair Value, 12 months or longer	2,003		2,235
HTM Unrealized Losses, 12 months or longer	-379	[1]	-455	[1]
HTM Unrecognized Gains, 12 months or longer	361	[2]	439	[2]
AFS Fixed Income Securities [Member]
AFS Fair Value, Less than 12 months	271,172		461,125
AFS Unrealized Losses, Less than 12 months	-1,615	[1]	-2,072	[1]
AFS Fair Value, 12 months or longer	156,812		442,058
AFS Unrealized Losses, 12 months or longer	-1,873	[1]	-8,170	[1]
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member]
AFS Fair Value, Less than 12 months	0		7,567
AFS Unrealized Losses, Less than 12 months	0	[1]	-13	[1]
AFS Fair Value, 12 months or longer	398		10,866
AFS Unrealized Losses, 12 months or longer	-2	[1]	-115	[1]
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
AFS Fair Value, Less than 12 months	75,935		47,510
AFS Unrealized Losses, Less than 12 months	-534	[1]	-105	[1]
AFS Fair Value, 12 months or longer	0		64,018
AFS Unrealized Losses, 12 months or longer	0	[1]	-624	[1]
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
AFS Fair Value, Less than 12 months	93,912		276,648
AFS Unrealized Losses, Less than 12 months	-821	[1]	-1,734	[1]
AFS Fair Value, 12 months or longer	50,858		153,613
AFS Unrealized Losses, 12 months or longer	-718	[1]	-4,075	[1]
AFS Fixed Income Securities [Member] | Asset-Backed Securities [Member]
AFS Fair Value, Less than 12 months	25,684		113,202
AFS Unrealized Losses, Less than 12 months	-16	[1]	-178	[1]
AFS Fair Value, 12 months or longer	14,353		15,618
AFS Unrealized Losses, 12 months or longer	-89	[1]	-195	[1]
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 months	24,664		12,799
AFS Unrealized Losses, Less than 12 months	-55	[1]	-34	[1]
AFS Fair Value, 12 months or longer	15,682		59,219
AFS Unrealized Losses, 12 months or longer	-73	[1]	-743	[1]
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 months	50,977		3,399
AFS Unrealized Losses, Less than 12 months	-189	[1]	-8	[1]
AFS Fair Value, 12 months or longer	75,521		138,724
AFS Unrealized Losses, 12 months or longer	-991	[1]	-2,418	[1]
Equity Securities [Member]
AFS Fair Value, Less than 12 months	100,209		5,262
AFS Unrealized Losses, Less than 12 months	-3,269	[1]	-336	[1]
AFS Fair Value, 12 months or longer	0		0
AFS Unrealized Losses, 12 months or longer	$0	[1]	$0	[1]
[1]	Gross unrealized losses include non-OTTI unrealized amounts and OTTI losses recognized in AOCI. In addition, this column includes remaining unrealized gain or loss amounts on securities that were transferred to an HTM designation in the first quarter of 2009 for those securities that are in a net unrealized/unrecognized loss position.
[2]	Unrecognized gains represent fair value fluctuations from the later of: (i) the date a security is designated as HTM; or (ii) the date that an OTTI charge is recognized on an HTM security.

Investments_Number_of_Securiti

Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Unrealized Unrecognized Loss	6,776,000	$10,596,000
Eighty Percent to Ninety-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	189	350
Unrealized Unrecognized Loss	6,776,000	10,596,000
Sixty Percent to Seventy-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	0	0
Unrealized Unrecognized Loss	0	0
Forty Percent to Fifty-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	0	0
Unrealized Unrecognized Loss	0	0
Twenty Percent to Thirty-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	0	0
Unrealized Unrecognized Loss	0	0
Zero Percent to Nineteen Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	0	0
Unrealized Unrecognized Loss	0	0
10 year U.S. Treasury Note [Member]
Schedule of Available-for-sale Securities [Line Items]
Decrease of Yield on 10-year U.S. Treasury Note	25
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position	28
Unrealized Loss on Securities	3,300,000
Percentage Decline In Fair Value Cost	3.00%

Investments_HTM_Fixed_Income_S

Investments (HTM Fixed Income Securities by Contractual Maturity) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investments [Abstract]
Due in one year or less carrying value	$124,997
Due after one year through five years carrying value	160,671
Due after five years through 10 years carrying value	10,889
Carrying Value	296,557	318,137
Due in one year or less fair value	126,670
Due after one year through five years fair value	171,337
Due after five years through 10 years fair value	13,086
HTM, Fair Value	$311,093	$333,961

Investments_AFS_Fixed_Income_s

Investments (AFS Fixed Income securities by Contractual Maturity) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Investments [Abstract]
Due in one year or less fair value	$416,983
Due after one year through five years fair value	2,067,679
Due after five years through 10 years fair value	1,605,398
Due after 10 years fair value	84,182
Total AFS fixed income securities	$4,174,242	$4,066,122

Investments_Other_Investment_P

Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Carrying Value	$95,020	$99,203
Other Investments [Member]
Carrying Value	95,020	99,203
Remaining Commitment	66,771
Alternative Investments [Member]
Carrying Value	84,274	92,968
Remaining Commitment	64,770
Secondary Private Equity Member | Alternative Investments [Member]
Carrying Value	20,208	21,807
Remaining Commitment	7,040
Private Equity [Member] | Alternative Investments [Member]
Carrying Value	17,519	20,126
Remaining Commitment	8,879
Energy Power Generation [Member] | Alternative Investments [Member]
Carrying Value	12,393	14,445
Remaining Commitment	21,905
Real Estate Strategy [Member] | Alternative Investments [Member]
Carrying Value	11,986	11,452
Remaining Commitment	10,016
Mezzanine Financing [Member] | Alternative Investments [Member]
Carrying Value	8,363	9,853
Remaining Commitment	13,598
Distressed debt [Member] | Alternative Investments [Member]
Carrying Value	7,569	8,679
Remaining Commitment	2,982
Venture Capital [Member] | Alternative Investments [Member]
Carrying Value	6,236	6,606
Remaining Commitment	350
Other Securities [Member]
Carrying Value	10,746	6,235
Remaining Commitment	$2,001

Investments_Aggregated_Income_

Investments (Aggregated Income Statement Summarized Financial Information for Partnerhips in our Alternative Investment Portfolio) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$26,917,000	$35,534,000
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned	-3,500,000	5,200,000
Investments accounted for under the equity method [Member]
Schedule of Equity Method Investments [Line Items]
Net Investment Income			77,000,000	65,100,000
Realized gains			160,500,000	63,300,000
Net change in unrealized (depreciation) appreciation			-518,000,000	505,900,000
Net income (loss)			($280,500,000)	$634,300,000

Investments_Investments_Pledge

Investments (Investments Pledged as Collateral) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	$64
Securities Pledged As Collateral For Reinsurance Obligations	13
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	25.2
Securities Pledged As Collateral	102.2
Outstanding Borrowing With The Federal Home Loan Bank Of Indianapolis	60
U.S. Government and Government Agencies [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	7.7
Securities Pledged As Collateral For Reinsurance Obligations	0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	25.2
Securities Pledged As Collateral	32.9
Obligations of States and Political Subdivisions [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	0
Securities Pledged As Collateral For Reinsurance Obligations	5
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	5
Corporate Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	0
Securities Pledged As Collateral For Reinsurance Obligations	4.8
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	4.8
Asset-Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	0
Securities Pledged As Collateral For Reinsurance Obligations	1
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	1
Commercial Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	1.7
Securities Pledged As Collateral For Reinsurance Obligations	0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	1.7
Residential Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLBI Collateral	54.6
Securities Pledged As Collateral For Reinsurance Obligations	2.2
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	$56.80

Investments_Net_Investment_Inc

Investments (Net Investment Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net Investment Income [Line Items]
Net investment income earned	$26,917	$35,534
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	30,967	31,028
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	1,792	1,449
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	25	19
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	-3,540	5,218
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	($2,327)	($2,180)

Investments_OTTI_by_Asset_Type

Investments (OTTI by Asset Type) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
OTTI Losses Gross	$2,094	$963
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0
OTTI Losses Recognized in Earnings	2,094	963
Residential Mortgage Backed Securities [Member] | AFS Fixed Income Securities [Member]
OTTI Losses Gross	1
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0
OTTI Losses Recognized in Earnings	1
AFS Fixed Income Securities [Member]
OTTI Losses Gross	1,010
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0
OTTI Losses Recognized in Earnings	1,010
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
OTTI Losses Gross	1,009
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0
OTTI Losses Recognized in Earnings	1,009
Total AFS Securities [Member] | Equity Securities [Member]
OTTI Losses Gross	1,084	963
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0
OTTI Losses Recognized in Earnings	$1,084	$963

Investments_Gross_Credit_Loss_

Investments (Gross Credit Loss Impairments of Fixed Maturity Securities for Which a Portion of the OTTI Charge was Recognized in OCI) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments [Abstract]
Balance, beginning of period	$5,444	$7,488
Addition for the amount related to credit loss for which an OTTI was not previously recognized	0	0
Reductions for securities sold during the period	-4,431	0
Reductions for securities for which the amount previously recognized in OCI was recognized in earnings because of intention or potential requirement to sell before recovery of amortized cost	0	0
Additional increases to the amount related to credit loss for which an OTTI was previously recognized	0	0
Accretion of credit loss impairments previously recognized due to an increase in cash flows expected to be collected	0	0
Balance, end of period	$1,013	$7,488

Investments_Components_Of_Net_

Investments (Components Of Net Realized Gains, Excluding OTTI Charges) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
HTM fixed income securities Gains	$0	$0
HTM fixed income securities Losses	-1,000	-11,000
Other investments Gains	0	0
Other Investments Losses	-654,000	0
Total other net realized investment gains	20,977,000	8,181,000
Proceeds From Sale Of Available For Sale Securities	138,400,000	62,800,000
Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
AFS securities Gains	1,502,000	158,000
AFS securities Losses	-112,000	-112,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
AFS securities Gains	21,318,000	8,317,000
AFS securities Losses	($1,076,000)	($171,000)

Indebtedness_Details

Indebtedness (Details) (Point sixty three Percent Borrowing From Federal Home Loan Bank [Member], USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
Point sixty three Percent Borrowing From Federal Home Loan Bank [Member]
Debt Instrument [Line Items]
FHLBI Borrowing	$15

Fair_Value_Measurements_Carryi

Fair Value Measurements (Carrying Value and Estimated Fair Value of Financial Instruments) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Held-to-maturity Securities	$296,557	$318,137
Available-for-sale Securities	4,174,242	4,066,122
Equity securities, AFS	211,571	191,400
Short-term investments	124,376	131,972
Notes payable	394,301	379,297
Carrying Amount [Member]
Held-to-maturity Securities	296,557	318,137
Available-for-sale Securities	4,174,242	4,066,122
Equity securities, AFS	211,571	191,400
Short-term investments	124,376	131,972
Notes payable	394,301	379,297
Carrying Amount [Member] | Point sixty three Percent Borrowing From Federal Home Loan Bank [Member]
Notes payable	15,000	0
Carrying Amount [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Notes payable	45,000	45,000
Carrying Amount [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Notes payable	49,896	49,896
Carrying Amount [Member] | Six Point Seventy Percent Senior Notes [Member]
Notes payable	99,405	99,401
Carrying Amount [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Notes payable	185,000	185,000
Fair Value [Member]
Held-to-maturity Securities	311,093	333,961
Available-for-sale Securities	4,174,242	4,066,122
Equity securities, AFS	211,571	191,400
Short-term investments	124,376	131,972
Notes payable	427,568	404,270
Fair Value [Member] | Point sixty three Percent Borrowing From Federal Home Loan Bank [Member]
Notes payable	14,994	0
Fair Value [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Notes payable	45,338	45,244
Fair Value [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Notes payable	60,407	59,181
Fair Value [Member] | Six Point Seventy Percent Senior Notes [Member]
Notes payable	117,389	114,845
Fair Value [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Notes payable	$189,440	$185,000

Fair_Value_Measurements_Quanti

Fair Value Measurements (Quantitative Disclosures of Fair Value Assets) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Available-for-sale Securities, Debt Securities	$4,174,242		$4,066,122
Equity securities, AFS	211,571		191,400
Total AFS securities	4,385,813		4,257,522
Short-term investments	124,376		131,972
Fair Value [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	4,174,242		4,066,122
Equity securities, AFS	211,571		191,400
Total AFS securities	4,385,813		4,257,522
Short-term investments	124,376		131,972
Total assets measured at fair value	4,510,189		4,389,494
Fair Value [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	119,486		124,130
Fair Value [Member] | Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	27,915		27,831
Fair Value [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	1,294,375		1,246,264
Fair Value [Member] | Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	1,824,265		1,799,806
Fair Value [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	185,387		177,224
Fair Value [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	200,511		179,593
Fair Value [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	522,303		511,274
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	52,977	[1]	53,199	[1]
Equity securities, AFS	208,671	[1]	188,500	[1]
Total AFS securities	261,648	[1]	241,699	[1]
Short-term investments	124,376	[1]	131,972	[1]
Total assets measured at fair value	386,024	[1]	373,671	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	52,977	[1]	53,199	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0	[1]	0	[1]
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	4,121,265	[1]	4,012,923	[1]
Equity securities, AFS	0	[1]	0	[1]
Total AFS securities	4,121,265	[1]	4,012,923	[1]
Short-term investments	0	[1]	0	[1]
Total assets measured at fair value	4,121,265	[1]	4,012,923	[1]
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	66,509	[1]	70,931	[1]
Significant Other Observable Inputs (Level 2) [Member] | Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	27,915	[1]	27,831	[1]
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	1,294,375	[1]	1,246,264	[1]
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	1,824,265	[1]	1,799,806	[1]
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	185,387	[1]	177,224	[1]
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	200,511	[1]	179,593	[1]
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	522,303	[1]	511,274	[1]
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Equity securities, AFS	2,900		2,900
Total AFS securities	2,900		2,900
Short-term investments	0		0
Total assets measured at fair value	2,900		2,900
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	0		0
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	$0		$0
[1]	1 There were no transfers of securities between Level 1 and Level 2.

Fair_Value_Measurements_Quanti1

Fair Value Measurements (Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	$296,557	$318,137
Notes payable	394,301	379,297
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	311,093	333,961
Notes payable	427,568	404,270
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Notes payable	189,440	185,000
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	311,093	333,961
Notes payable	238,128	219,270
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Notes payable	0	0
Foreign Government [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	5,338	5,394
Foreign Government [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Foreign Government [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	5,338	5,394
Foreign Government [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Obligations of States and Political Subdivisions [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	277,030	299,132
Obligations of States and Political Subdivisions [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Obligations of States and Political Subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	277,030	299,132
Obligations of States and Political Subdivisions [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Corporate Securities [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	21,199	21,422
Corporate Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	21,199	21,422
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Asset-Backed Securities [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	2,480	2,823
Asset-Backed Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Asset-Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	2,480	2,823
Asset-Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	5,046	5,190
Commercial Mortgage Backed Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Commercial Mortgage Backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	5,046	5,190
Commercial Mortgage Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities	0	0
Point sixty three Percent Borrowing From Federal Home Loan Bank [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	14,994
Point sixty three Percent Borrowing From Federal Home Loan Bank [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0
Point sixty three Percent Borrowing From Federal Home Loan Bank [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	14,994
Point sixty three Percent Borrowing From Federal Home Loan Bank [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0
One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	45,338	45,244
One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	45,338	45,244
One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Seven Point Twenty Five Percent Senior Notes [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	60,407	59,181
Seven Point Twenty Five Percent Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Seven Point Twenty Five Percent Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	60,407	59,181
Seven Point Twenty Five Percent Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Six Point Seventy Percent Senior Notes [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	117,389	114,845
Six Point Seventy Percent Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Six Point Seventy Percent Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	117,389	114,845
Six Point Seventy Percent Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Five Point Eight Hundred Seventy Five Senior Notes [Member] | Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	189,440	185,000
Five Point Eight Hundred Seventy Five Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	189,440	185,000
Five Point Eight Hundred Seventy Five Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	0	0
Five Point Eight Hundred Seventy Five Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable	$0	$0

Reinsurance_List_of_Direct_Ass

Reinsurance (List of Direct, Assumed, and Ceded Reinsurance Amounts) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Premiums written:
Direct	$598,783	$557,891
Assumed	6,081	7,850
Ceded premiums written	-86,776	-88,991
Net	518,088	476,750
Premiums earned:
Direct	562,042	536,700
Assumed	5,908	10,185
Ceded premiums earned	-91,827	-90,390
Net	476,123	456,495
Loss and loss expense incurred:
Direct	312,246	358,349
Assumed	4,662	7,479
Ceded loss and loss expense incurred	-31,909	-45,282
Net	$284,999	$320,546
Percentage of NFIP claims ceded by federal government	100.00%

Reinsurance_Ceded_Premiums_and

Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Ceded premiums written	($86,776)	($88,991)
Ceded premiums earned	-91,827	-90,390
Ceded loss and loss expense incurred	-31,909	-45,282
National Flood Insurance Program [Member]
Ceded premiums written	-53,842	-57,303
Ceded premiums earned	-58,998	-58,286
Ceded loss and loss expense incurred	($6,249)	($7,379)

Segment_Information_Narrative_

Segment Information Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Number of Operating Segments	4
Gross premiums of self-insured pooled group renewal book of business sold		$37,000,000
Proceeds from sale of renewal rights	$0	$8,000,000

Segment_Information_Revenue_by

Segment Information (Revenue by Segment) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Total net premiums earned	$476,123	$456,495
Investment Income, Net	26,917	35,534
Other income	1,969	9,824
Net realized investment gains	18,883	7,218
Total investment revenues	45,800	42,752
Total revenues	523,892	509,071
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	523,892	509,066
Other Income [Member]
Segment Reporting Information [Line Items]
Other income	0	5
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	86,355	82,216
Standard Commercial Lines [Member] | Workers Compensation [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	68,477	69,413
Standard Commercial Lines [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	114,971	108,818
Standard Commercial Lines [Member] | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	64,563	60,186
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	22,699	20,869
Standard Commercial Lines [Member] | Bonds Segment [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	5,000	4,756
Standard Commercial Lines [Member] | Other Commercial [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	3,468	3,183
Standard Commercial Lines [Member] | Miscellaneous Income [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	1,669	8,914
Standard Commercial Lines [Member] | Total Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	367,202	358,355
Standard Personal Lines [Member] | Miscellaneous Income [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	300	905
Standard Personal Lines [Member] | Personal Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	37,010	38,226
Standard Personal Lines [Member] | Homeowners [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	33,721	33,298
Standard Personal Lines [Member] | Other Personal [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	1,748	3,294
Standard Personal Lines [Member] | Total Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	72,779	75,723
Excess And Surplus Operations [Member] | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	1,730	1,188
Excess And Surplus Operations [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	26,726	21,931
Excess And Surplus Operations [Member] | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	9,655	9,117
Excess And Surplus Operations [Member] | Total Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	$38,111	$32,236

Segment_Information_Income_Bef

Segment Information (Income Before Federal Income Tax) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net investment income earned	$26,917	$35,534
Net realized investment gains	18,883	7,218
Total investment revenues	45,800	42,752
Tax on investment income	12,318	11,575
Total investment income after federal income tax	33,482	31,177
Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	30,036	-3,630
GAAP combined ratio	91.80%	101.00%
Statutory combined ratio	89.70%	100.30%
Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	-2,466	-2,360
GAAP combined ratio	103.40%	103.20%
Statutory combined ratio	105.10%	104.50%
Excess And Surplus Operations [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	($1,549)	$975
GAAP combined ratio	104.10%	97.00%
Statutory combined ratio	102.10%	97.90%

Segment_Information_Reconcilia

Segment Information (Reconciliation of Segment Results to Income Before Federal Income Tax (Details)) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Investment income, before federal income tax	$45,800	$42,752
Interest expense	-5,479	-5,561
General corporate and other expenses	-10,052	-7,092
Income before federal income tax	56,290	25,084
Standard Commercial Lines [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	30,036	-3,630
Standard Personal Lines [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	-2,466	-2,360
Excess And Surplus Operations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	-1,549	975
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total all segments	$71,821	$37,737

Retirement_Plans_Components_of

Retirement Plans (Components of Net Periodic Benefit Cost and Other Amount Recognized in Other Comprehensive Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Retirement Income Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$1,964	$1,627
Interest cost	3,502	3,254
Expected return on plan assets	-3,991	-3,919
Amortization of unrecognized net actuarial loss	1,695	367
Total net periodic cost	3,170	1,329
Retirement Life Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0
Interest cost	63	73
Expected return on plan assets	0	0
Amortization of unrecognized net actuarial loss	14	13
Total net periodic cost	$77	$86

Retirement_Plans_WeightedAvera

Retirement Plans (Weighted-Average Expense Assumptions) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Retirement Income Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.29%	5.16%
Expected return on plan assets	6.27%	6.92%
Rate of compensation increase	4.00%	4.00%
Contributions by Employer	$3.20
Retirement Income Plan [Member] | Scenario, Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated contribution from the employer	$11.90
Retirement Life Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.08%	4.85%
Expected return on plan assets	0.00%	0.00%
Rate of compensation increase	0.00%	0.00%

Comprehensive_Income_Component

Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net income, Gross	$56,290	$25,084
Unrealized holding gains during the period, Gross	23,977	32,964
Amounts reclassified into net income: HTM securities, Gross	-261	-456
Amounts reclassified into net income: non-credit OTTI	357
Realized gains on AFS securities, Gross	-19,895	-7,229
Net unrealized gains, Gross	4,178	25,279
Amount reclassified into Net Income: Net actuarial loss, Gross	1,709	380
Defined pension and other post-retirement benefit plans, gross	1,709	380
Other comprehensive income, Gross	5,887	25,659
Net income, Tax	16,582	7,110
Unrealized holding gains during the period, Tax	8,391	11,538
HTM securities, Tax	-91	-160
Non-credit OTTI, Tax	125
Realized gains on AFS securities, Tax	-6,963	-2,530
Net unrealized gains, Tax	1,462	8,848
Amount reclassified into Net Income: Net actuarial loss, Tax	598	133
Defined pension and other post-retirement benefit plans, tax	598	133
Other comprehensive income, Tax	2,060	8,981
Comprehensive Income Tax	18,642	16,091
Net income	39,708	17,974
Unrealized holding gains arising during period	15,586	21,426
HTM Securities	-170	-296
Amounts reclassified into Net Income: Non-credit other-than-temporary impairments	232	0
Realized gains on available for sale securities	-12,932	-4,699
Total unrealized gains on investment securities	2,716	16,431
Amount reclassified into Net Income: Net actuarial loss	1,111	247
Total defined benefit pension and post-retirement plans	1,111	247
Other comprehensive income	3,827	16,678
Comprehensive Income Loss Before Tax	62,177	50,743
Comprehensive income	$43,535	$34,652

Comprehensive_Income_Component1

Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	$19,788
Amounts reclassified into Net Income: Non-credit other-than-temporary impairments	232	0
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans	0
Amounts reclassified from AOCI, HTM Related	-170	-296
Amounts reclassified from AOCI, All Other	-12,932	-4,699
Other comprehensive income	3,827	16,678
Other Comprehensive Income, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	1,111	247
Ending Balance, March, 2015	23,615
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	80,284
OCI before reclassifications	15,586
Other comprehensive income	2,654
Ending Balance, March, 2015	82,938
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	80,393
OCI before reclassifications	15,586
Amounts reclassified from AOCI	-12,870
Other comprehensive income	2,716
Ending Balance, March, 2015	83,109
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	-514
OCI before reclassifications	0
Other comprehensive income	232
Ending Balance, March, 2015	-282
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	623
OCI before reclassifications	0
Other comprehensive income	-170
Ending Balance, March, 2015	453
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	-60,605
Other Comprehensive Income, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	1,111
Ending Balance, March, 2015	-59,494
Accumulated other comprehensive income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014	19,788
OCI before reclassifications	15,586
Amounts reclassified from AOCI	-11,759
Other comprehensive income	3,827	16,678
Ending Balance, March, 2015	$23,615

Comprehensive_Income_Reclassif

Comprehensive Income (Reclassification out of AOCI) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Amounts reclassified into net income: non-credit OTTI	$357
Non-credit OTTI, Tax	-125
Amounts reclassified into Net Income: Non-credit other-than-temporary impairments	232	0
Reclassification of net unrealized gains on HTM securities including disposals and amortization	-261	-456
Total HTM Related, Tax	91	160
Amounts reclassified from AOCI, HTM Related	-170	-296
Realized gains on AFS disposals and OTTI	-19,895	-7,229
Total realized gains on AFS disposals and OTTI	6,963	2,530
Amounts reclassified into net income: realized gains on available for sale securities	-12,932	-4,699
Amount reclassified into Net Income: Net actuarial loss, Gross	1,709	380
Defined pension and other post-retirement benefit plans, tax	-598	-133
Total defined benefit pension and post-retirement plans	1,111	247
Investment Income [Member]
Amortization of net unrealized gains on HTM securities	-311	-480
Income Before Federal Income Tax [Member]
Amounts reclassified into net income: non-credit OTTI	357	0
Reclassification of net unrealized gains on HTM securities including disposals and amortization	-261	-456
Realized gains on AFS disposals and OTTI	-19,895	-7,229
Amount reclassified into Net Income: Net actuarial loss, Gross	1,709	380
Total Federal Income Tax Expense [Member]
Non-credit OTTI, Tax	-125	0
Total HTM Related, Tax	91	160
Total realized gains on AFS disposals and OTTI	6,963	2,530
Defined pension and other post-retirement benefit plans, tax	-598	-133
Net Income Financial Statement Line Item [Member]
Amounts reclassified into Net Income: Non-credit other-than-temporary impairments	232	0
Amounts reclassified from AOCI, HTM Related	-170	-296
Amounts reclassified into net income: realized gains on available for sale securities	-12,932	-4,699
Total defined benefit pension and post-retirement plans	1,111	247
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-11,759	-4,748
Net Realized Investment Gains [Member]
Unrealized gains and losses on HTM disposals	50	24
Realized gains on AFS disposals and OTTI	-19,895	-7,229
Net Realized Investment Gains [Member] | Non-credit OTTI on Disposed Securities [Member]
Amounts reclassified into net income: non-credit OTTI	357	0
Loss And Loss Expense Incurred [Member]
Amount reclassified into Net Income: Net actuarial loss, Gross	371	87
Policy acquisition costs [Member]
Amount reclassified into Net Income: Net actuarial loss, Gross	$1,338	$293