Selective Insurance (SIGI) 10-Q 28 Jul 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 15, 2016
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Entity Registrant Name	SELECTIVE INSURANCE GROUP INC
Entity Central Index Key	230,557
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock , Shares Outstanding		57,812,467

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
ASSETS
Fixed income securities, held-to-maturity – at carrying value (fair value: $167,061 – 2016; $209,544 – 2015)	$ 160,297	$ 201,354
Fixed income securities, available-for-sale – at fair value (amortized cost: $4,506,580 – 2016; $4,352,514 – 2015)	4,671,786	4,408,203
Equity securities, available-for-sale – at fair value (cost: $126,881 – 2016; $193,816 – 2015)	152,938	207,051
Short-term investments (at cost which approximates fair value)	205,451	194,819
Other investments	76,051	77,842
Total investments (Note 4)	5,266,523	5,089,269
Cash	1,530	898
Interest and dividends due or accrued	39,941	38,501
Premiums receivable, net of allowance for uncollectible accounts of: $4,624 – 2016; $4,422 – 2015	706,555	615,164
Reinsurance recoverables, net of allowance for uncollectible accounts of: $6,100 – 2016; $5,700 – 2015	592,423	561,968
Prepaid reinsurance premiums	145,520	140,889
Deferred federal income tax	47,696	92,696
Property and equipment – at cost, net of accumulated depreciation and amortization of: $193,997 – 2016; $188,548 – 2015	68,573	65,701
Deferred policy acquisition costs	228,554	213,159
Goodwill	7,849	7,849
Other assets	84,477	78,339
Total assets	7,189,641	6,904,433
Liabilities And Stockholders' Equity
Reserve for loss and loss expenses	3,590,169	3,517,728
Unearned premiums	1,263,450	1,169,710
Short-term debt	60,000	60,000
Long-term debt	328,433	328,192
Current federal income tax	8,670	7,442
Accrued salaries and benefits	118,733	167,336
Other liabilities	267,449	255,984
Total liabilities	5,636,904	5,506,392
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: 101,451,214 – 2016; 100,861,372 – 2015	202,903	201,723
Additional paid-in capital	340,109	326,656
Retained earnings	1,509,242	1,446,192
Accumulated other comprehensive income (loss) (Note 10)	72,007	(9,425)
Treasury stock - at cost (shares: 43,638,649 – 2016; 43,500,642 – 2015)	(571,524)	(567,105)
Total stockholders' equity	1,552,737	1,398,041
Commitments and contingencies
Total liabilities and stockholders' equity	$ 7,189,641	$ 6,904,433

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fixed income securities, held-to-maturity, fair value	$ 167,061	$ 209,544
Fixed income securities, available-for-sale, amortized cost	4,506,580	4,352,514
Equity securities, available-for-sale, cost	126,881	193,816
Premiums receivable, allowance for uncollectible accounts	4,624	4,422
Reinsurance recoverable, allowance for uncollectible accounts	6,100	5,700
Property and equipment - at cost, accumulated depreciation and amortization	$ 193,997	$ 188,548
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	101,451,214	100,861,372
Treasury stock - at cost, shares	43,638,649	43,500,642

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Net premiums earned	$ 531,932	$ 490,309	$ 1,054,390	$ 966,432
Net investment income earned	31,182	32,230	61,951	59,147
Net realized gains (losses):
Net realized investment gains	2,314	1,031	3,203	22,008
Other-than-temporary impairments	(559)	(4,451)	(4,152)	(6,545)
Other-than-temporary impairments on fixed maturity securities recognized in other comprehensive income	10	0	10	0
Total net realized gains (losses)	1,765	(3,420)	(939)	15,463
Other income	3,868	2,854	4,819	4,823
Total revenues	568,747	521,973	1,120,221	1,045,865
Expenses:
Loss and loss expense incurred	298,479	291,561	595,623	576,560
Policy acquisition costs	190,731	169,770	373,958	334,493
Interest expense	5,620	5,612	11,226	11,216
Other expenses	11,606	8,265	25,228	20,541
Total expenses	506,436	475,208	1,006,035	942,810
Income before federal income tax	62,311	46,765	114,186	103,055
Federal income tax expense:
Current	18,318	7,733	32,402	19,987
Deferred	392	5,264	1,151	9,592
Total federal income tax expense	18,710	12,997	33,553	29,579
Net income	$ 43,601	$ 33,768	$ 80,633	$ 73,476
Earnings per share:
Basic net income	$ 0.75	$ 0.59	$ 1.40	$ 1.29
Diluted net income	0.74	0.58	1.38	1.27
Dividends to stockholders	$ 0.15	$ 0.14	$ 0.30	$ 0.28

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income	$ 43,601	$ 33,768	$ 80,633	$ 73,476
Unrealized holding gains (losses) arising during period	36,188	(39,160)	78,917	(23,574)
Non-credit portion of other-than-temporary impairments recognized in other comprehensive income	(6)	0	(6)	0
Non-credit portion of other-than-temporary impairments recognized in other comprehensive income	0	0	0	232
Amount reclassified into net income: Held-to-maturity securities	(12)	(120)	(59)	(290)
Amount reclassified into net income: Realized (gains) losses on available-for-sale securities	(1,145)	2,225	609	(10,707)
Total unrealized gains (losses) on investment securities	35,025	(37,055)	79,461	(34,339)
Amount reclassified into net income: Net actuarial loss	985	1,111	1,971	2,222
Total defined benefit pension and post-retirement plans	985	1,111	1,971	2,222
Other comprehensive income (loss)	36,010	(35,944)	81,432	(32,117)
Comprehensive income (loss)	$ 79,611	$ (2,176)	$ 162,065	$ 41,359

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss) [Member]	Treasury stock [Member]
Beginning of year at Dec. 31, 2014		$ 199,896	$ 305,385	$ 1,313,440	$ 19,788	$ (562,923)
Dividend reinvestment plan (shares: 20,808 – 2016; 26,843 - 2015)		54	677
Stock purchase and compensation plans (shares: 569,034 - 2016; 611,076 - 2015)		1,222	11,233
Net income	$ 73,476			73,476
Dividends to stockholders ($0.30 per share - 2016; $0.28 per share - 2015)				(16,235)
Other comprehensive income (loss)	(32,117)				(32,117)
Acquisition of treasury stock (shares: 138,007 - 2016; 129,352 - 2015)						(3,583)
End of period at Jun. 30, 2015	1,310,313	201,172	317,295	1,370,681	(12,329)	(566,506)
Beginning of year at Dec. 31, 2015	1,398,041	201,723	326,656	1,446,192	(9,425)	(567,105)
Dividend reinvestment plan (shares: 20,808 – 2016; 26,843 - 2015)		42	696
Stock purchase and compensation plans (shares: 569,034 - 2016; 611,076 - 2015)		1,138	12,757
Net income	80,633			80,633
Dividends to stockholders ($0.30 per share - 2016; $0.28 per share - 2015)				(17,583)
Other comprehensive income (loss)	81,432				81,432
Acquisition of treasury stock (shares: 138,007 - 2016; 129,352 - 2015)						(4,419)
End of period at Jun. 30, 2016	$ 1,552,737	$ 202,903	$ 340,109	$ 1,509,242	$ 72,007	$ (571,524)

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Dividend reinvestment plan, shares			20,808	26,843
Stock purchase and compensation plans, shares			569,034	611,076
Dividends to stockholders, per share	$ 0.15	$ 0.14	$ 0.30	$ 0.28
Acquisition of treasury stock, shares			138,007	129,352
Preferred stock, par value per share	$ 0	$ 0	$ 0	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	0	0	0	0	0
Series A Preferred Stock [Member]
Preferred stock, par value per share	$ 0	$ 0	$ 0	$ 0
Preferred stock, shares authorized	300,000	300,000	300,000	300,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flow - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net income	$ 80,633	$ 73,476
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30,155	29,085
Stock-based compensation expense	7,203	6,049
Undistributed losses of equity method investments	1,677	2,117
Net realized losses (gains)	939	(15,463)
Changes in assets and liabilities:
Increase in reserve for loss and loss expenses, net of reinsurance recoverables	41,986	66,609
Increase in unearned premiums, net of prepaid reinsurance	89,109	83,789
Decrease in net federal income taxes	2,380	19,232
Increase in premiums receivable	(91,391)	(88,813)
Increase in deferred policy acquisition costs	(15,395)	(17,616)
(Increase) decrease in interest and dividends due or accrued	(1,030)	395
Decrease in accrued salaries and benefits	(48,603)	(18,171)
Increase in other assets	(3,877)	(743)
(Decrease) increase in other liabilities	(34,659)	25,651
Net adjustments	(21,506)	92,121
Net cash provided by operating activities	59,127	165,597
Investing Activities
Purchase of fixed income securities, available-for-sale	(411,538)	(463,758)
Purchase of fixed income securities, held-to-maturity	(4,235)	0
Purchase of equity securities, available-for-sale	(16,796)	(177,386)
Purchase of other investments	(17,734)	(2,947)
Purchase of short-term investments	(691,496)	(732,278)
Sale of fixed income securities, available-for-sale	22,114	22,323
Sale of short-term investments	680,865	695,901
Redemption and maturities of fixed income securities, held-to-maturity	44,615	68,704
Redemption and maturities of fixed income securities, available-for-sale	264,244	254,995
Sale of equity securities, available-for-sale	83,793	135,548
Distributions from other investments	13,380	17,840
Purchase of property and equipment	(8,187)	(7,591)
Net cash used in investing activities	(40,975)	(188,649)
Financing Activities
Dividends to stockholders	(16,569)	(15,211)
Acquisition of treasury stock	(4,419)	(3,583)
Net proceeds from stock purchase and compensation plans	4,368	4,037
Proceeds from borrowings	55,000	15,000
Repayments of borrowings	(55,000)	0
Excess tax benefits from share-based payment arrangements	1,761	1,549
Repayments of capital lease obligations	(2,661)	(2,331)
Net cash used in financing activities	(17,520)	(539)
Net increase in cash	632	(23,591)
Cash, beginning of year	898	23,959
Cash, end of period	$ 1,530	$ 368

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2016
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 U.S. generally accepted accounting principles (“GAAP”) and 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 our prior years' Financial Statements and related notes have been reclassified to conform to the 2016 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 second quarters ended June 30, 2016 (“ Second Quarter 2016 ”) and June 30, 2015 (“ Second Quarter 2015 ”) and the six-month periods ended June 30, 2016 (" Six Months 2016 ") and June 30, 2015 (" Six Months 2015 "). The Financial Statements 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, 2015 (“ 2015 Annual Report ”) filed with the SEC.

Accounting Pronouncements

Accounting Pronouncements	6 Months Ended
	Jun. 30, 2016
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 adoption of ASU 2014-12 in the first quarter of 2016 did not affect us, as we record expense consistent with the requirements of this accounting update. In February 2015, the FASB issued ASU 2015-02, Amendments to the Consolidation Analysis (“ASU 2015-02”). ASU 2015-02 affects 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. We adopted this guidance in the first quarter of 2016. Under the new guidance, our limited partnership and tax credit investments are variable interest entities ("VIEs"); however, we are not the primary beneficiary of any of these investments. As such, the adoption had no impact on our financial condition or results of operations. The required disclosures related to our VIEs are included in Note 4. “Investments” below. In April 2015, the FASB issued ASU 2015-05, Customer's Accounting for Fees Paid in a Cloud Computing Arrangement (“ASU 2015-05”). ASU 2015-05 provides guidance to customers with cloud computing arrangements that include a software license. If a cloud computing arrangement includes a software license, the customer's accounting for the software license element of the arrangement is consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer accounts for the arrangement as a service contract. We adopted this guidance in the first quarter of 2016, with prospective application. The impact of this adoption did not have a material effect on our financial condition or results of operations. In May 2015, the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) (“ASU 2015-07”). ASU 2015-07 provides that investments for which the practical expedient is used to measure fair value at net asset value per share ("NAV") must be removed from the fair value hierarchy. Instead, those investments must be included as a reconciling line item so that the total fair value amount of investments in the disclosure is consistent with the amount on the balance sheet. ASU 2015-07 also includes disclosure requirements for investments for which the NAV practical expedient was used to determine fair value. The adoption of this guidance in the first quarter of 2016 did not impact our financial condition or results of operations. Pronouncements to be effective in the future 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 is intended to define management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and provide related footnote disclosures. ASU 2014-15 is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. Early application is permitted. As the requirements of this literature are disclosure only, ASU 2014-15 will not impact our financial condition or results of operations. In May 2015, the FASB issued ASU 2015-09, Disclosures about Short-Duration Contracts (“ASU 2015-09”). ASU 2015-09 requires companies that issue short duration contracts to disclose additional information, including: (i) incurred and paid claims development tables; (ii) frequency and severity of claims; and (iii) information about material changes in judgments made in calculating the liability for unpaid claim adjustment expenses, including reasons for the change and the effects on the financial statements. ASU 2015-09 is effective for annual periods beginning after December 15, 2015, and interim periods within annual periods beginning after December 15, 2016. ASU 2015-09 is to be applied retrospectively by providing comparative disclosures for each period presented, except for those requirements that apply only to the current period. As the requirements of this literature are disclosure only, the application of this guidance will not impact our financial condition or results of operations. In January 2016, the FASB issued ASU 2016-01 Financial Instruments - Overall (Sub-topic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 provides guidance to improve certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. Specifically the guidance: (i) requires equity investments to be measured at fair value with changes in fair value recognized in earnings; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost; (iv) requires the use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and (v) clarifies that the need for a valuation allowance on a deferred tax asset related to an available-for-sale ("AFS") security should be evaluated with other deferred tax assets. ASU 2016-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Early application to financial statements of annual or interim periods that have not yet been issued are permitted as of the beginning of the year of adoption, otherwise early adoption of ASU 2016-01 is not permitted. We are currently evaluating the impact of this guidance on our financial condition and results of operations. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 requires all lessees to recognize a lease liability and a right-of-use asset, measured at the present value of the future minimum lease payments, at the lease commencement date. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim reporting periods within that fiscal year, with early adoption permitted. ASU 2016-02 requires the application of a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. While we are currently evaluating ASU 2016-02, we do not expect a material impact on our financial condition or results of operations from the adoption of this guidance. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-based Payment Accounting (“ASU 2016-09”). ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions including: (i) income tax consequences; (ii) classification of awards as either equity or liabilities; (iii) forfeitures assumptions; and (iv) cash flow classification. ASU 2016-09 is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. While we are currently evaluating ASU 2016-09, we do not expect a material impact on our financial condition or results of operations. In June 2016, the FASB issued ASU 2016-13 , Financial Instruments - Credit Losses (“ASU 2016-13”). ASU 2016-13 will change the way entities recognize impairment of financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining life of many financial assets, including, among others, held-to-maturity debt securities, trade receivables, and reinsurance receivables. ASU 2016-13 requires a valuation allowance to be calculated on these financial assets and that they be presented on the financial statements net of the valuation allowance. The valuation allowance is a measurement of expected losses that is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. This methodology is referred to as the current expected credit loss model. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those annual periods. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2018. We are currently evaluating the impact of this guidance on our financial condition and results of operations.

Statements of Cash Flow

Statements of Cash Flow	6 Months Ended
	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Statements of Cash Flow	Statements of Cash Flow Supplemental cash flow information is as follows: Six Months ended June 30, ($ in thousands) 2016 2015 Cash paid during the period for: Interest $ 10,986 10,947 Federal income tax 29,000 8,500 Non-cash items: Exchange of fixed income securities, AFS 17,702 17,120 Corporate actions related to equity securities, AFS 1 3,032 884 Assets acquired under capital lease arrangements 2,999 3,478 Non-cash purchase of property and equipment 577 — 1 Examples of such corporate actions include non-cash acquisitions and stock splits. Included in "Other assets" on the Consolidated Balance Sheet was $8.9 million at June 30, 2016 and $5.2 million at June 30, 2015 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	6 Months Ended
	Jun. 30, 2016
Investments [Abstract]
Investments	Investments (a) Information regarding our held-to-maturity ("HTM") fixed income securities as of June 30, 2016 and December 31, 2015 was as follows: June 30, 2016 ($ in thousands) Amortized Cost Net Unrealized Gains (Losses) Carrying Value Unrecognized Holding Gains Unrecognized Holding Losses Fair Value Obligations of states and political subdivisions $ 131,480 533 132,013 4,260 — 136,273 Corporate securities 23,995 (175 ) 23,820 2,286 — 26,106 Asset-backed securities (“ABS”) 126 — 126 — — 126 Commercial mortgage-backed securities (“CMBS”) 4,489 (151 ) 4,338 218 — 4,556 Total HTM fixed income securities $ 160,090 207 160,297 6,764 — 167,061 December 31, 2015 ($ in thousands) Amortized Cost Net Unrealized Gains (Losses) Carrying Value Unrecognized Holding Gains Unrecognized Holding Losses Fair Value Obligations of states and political subdivisions $ 175,269 848 176,117 5,763 — 181,880 Corporate securities 20,228 (185 ) 20,043 1,972 — 22,015 ABS 1,030 (120 ) 910 118 — 1,028 CMBS 4,527 (243 ) 4,284 337 — 4,621 Total HTM fixed income securities $ 201,054 300 201,354 8,190 — 209,544 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 1.8 years as of June 30, 2016 . (b) Information regarding our AFS securities as of June 30, 2016 and December 31, 2015 was as follows: June 30, 2016 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 91,933 4,237 — 96,170 Foreign government 8,635 424 — 9,059 Obligations of states and political subdivisions 1,379,548 82,604 — 1,462,152 Corporate securities 1,977,838 62,233 (1,963 ) 2,038,108 ABS 257,182 1,656 (127 ) 258,711 CMBS 249,603 6,484 (51 ) 256,036 Residential mortgage-backed securities (“RMBS”) 541,841 10,027 (318 ) 551,550 Total AFS fixed income securities 4,506,580 167,665 (2,459 ) 4,671,786 AFS equity securities: Common stock 114,099 26,343 (1,023 ) 139,419 Preferred stock 12,782 737 — 13,519 Total AFS equity securities 126,881 27,080 (1,023 ) 152,938 Total AFS securities $ 4,633,461 194,745 (3,482 ) 4,824,724 December 31, 2015 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 99,485 4,721 (91 ) 104,115 Foreign government 14,885 298 (2 ) 15,181 Obligations of states and political subdivisions 1,314,779 44,523 (160 ) 1,359,142 Corporate securities 1,892,296 23,407 (15,521 ) 1,900,182 ABS 244,541 531 (918 ) 244,154 CMBS 245,252 750 (2,410 ) 243,592 RMBS 541,276 4,274 (3,713 ) 541,837 Total AFS fixed income securities 4,352,514 78,504 (22,815 ) 4,408,203 AFS equity securities: Common stock 181,991 14,796 (1,998 ) 194,789 Preferred stock 11,825 477 (40 ) 12,262 Total AFS equity securities 193,816 15,273 (2,038 ) 207,051 Total AFS securities $ 4,546,330 93,777 (24,853 ) 4,615,254 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 (loss) ("AOCI") on the Consolidated Balance Sheets. (c) The following tables provide information regarding our AFS securities in a net unrealized/unrecognized loss position at June 30, 2016 and December 31, 2015 : June 30, 2016 Less than 12 months 12 months or longer ($ in thousands) Fair Value Unrealized Losses 1 Fair Value Unrealized Losses 1 AFS fixed income securities: Corporate securities $ 96,244 (822 ) 33,616 (1,141 ) ABS 46,992 (117 ) 4,665 (10 ) CMBS 6,348 (4 ) 10,451 (47 ) RMBS 6,835 (19 ) 50,134 (299 ) Total AFS fixed income securities 156,419 (962 ) 98,866 (1,497 ) AFS equity securities: Common stock 16,428 (1,023 ) — — Total AFS equity securities 16,428 (1,023 ) — — Total AFS $ 172,847 (1,985 ) 98,866 (1,497 ) December 31, 2015 Less than 12 months 12 months or longer ($ in thousands) Fair Value Unrealized Losses 1 Fair Value Unrealized Losses 1 AFS fixed income securities: U.S. government and government agencies $ 16,006 (87 ) 396 (4 ) Foreign government 1,067 (2 ) — — Obligations of states and political subdivisions 28,617 (160 ) — — Corporate securities 761,479 (12,671 ) 50,382 (2,850 ) ABS 197,477 (807 ) 12,022 (111 ) CMBS 146,944 (2,196 ) 15,385 (214 ) RMBS 264,914 (1,992 ) 63,395 (1,721 ) Total AFS fixed income securities 1,416,504 (17,915 ) 141,580 (4,900 ) AFS equity securities: Common stock 31,148 (1,998 ) — — Preferred stock 1,531 (40 ) — — Total AFS equity securities 32,679 (2,038 ) — — Total AFS $ 1,449,183 (19,953 ) 141,580 (4,900 ) 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. There were no net unrealized/unrecognized losses on our HTM portfolio as of June 30, 2016. The table below provides our net unrealized/unrecognized loss positions by impairment severity for AFS securities as of June 30, 2016 and for both AFS and HTM securities as of December 31, 2015 : ($ in thousands) June 30, 2016 December 31, 2015 Number of Issues % of Market/Book Unrealized/ Unrecognized Loss Number of Issues % of Market/Book Unrealized/ Unrecognized Loss 156 80% - 99% $ 3,482 606 80% - 99% $ 22,971 — 60% - 79% — 3 60% - 79% 1,888 — 40% - 59% — — 40% - 59% — — 20% - 39% — — 20% - 39% — — 0% - 19% — — 0% - 19% — $ 3,482 $ 24,859 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 2015 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 June 30, 2016 , 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 June 30, 2016 : ($ in thousands) Carrying Value Fair Value Due in one year or less $ 84,415 85,514 Due after one year through five years 65,616 69,914 Due after five years through 10 years 10,266 11,633 Total HTM fixed income securities $ 160,297 167,061 Listed below are the contractual maturities of AFS fixed income securities at June 30, 2016 : ($ in thousands) Fair Value Due in one year or less $ 482,867 Due after one year through five years 2,425,517 Due after five years through 10 years 1,647,615 Due after 10 years 115,787 Total AFS fixed income securities $ 4,671,786 (e) We evaluate the alternative investments and the tax credit investments that are included in our other investments portfolio to determine whether those investments are VIEs and if so, whether consolidation is required. A VIE is an entity that either has equity investors that lack certain essential characteristics of a controlling financial interest or lacks sufficient funds to finance its own activities without financial support provided by other entities. We consider several significant factors in determining if our investments are VIEs and if we are the primary beneficiary including whether we have: (i) the power to direct activities of the VIE; (ii) the ability to remove the decision maker of the VIE; (iii) the ability to participate in making decisions that are significant to the VIE; and (iv) the obligation to absorb losses and the right to receive benefits that could potentially be significant to the VIE. We have determined that the investments in our other investment portfolio are VIEs, but that we are not the primary beneficiary and therefore, consolidation is not required. The following table summarizes our other investment portfolio by strategy: Other Investments June 30, 2016 December 31, 2015 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 28,439 34,117 62,556 35,088 30,204 65,292 Private credit 23,336 23,243 46,579 13,246 15,129 28,375 Real assets 14,132 30,273 44,405 19,500 25,820 45,320 Total alternative investments 65,907 87,633 153,540 67,834 71,153 138,987 Other securities 10,144 6,850 16,994 10,008 3,200 13,208 Total other investments $ 76,051 94,483 170,534 77,842 74,353 152,195 1 The maximum exposure to loss includes both the carry value of these investments and the related unfunded commitments. In addition, tax credits that have been previously recognized from our investment in Other securities are subject to the risk of recapture, which we do not consider significant. We do not have a future obligation to fund losses or debts on behalf of the investments above; however, we are contractually committed to make additional investments up to the remaining commitment outlined above. We have not provided any non-contractual financial support at any time during 2016 or 2015. In addition to the strategy descriptions included in Note 5. “Investments” in Item 8. “Financial Statements and Supplementary Data.” of our 2015 Annual Report , our private credit strategy now includes middle market lending, which is a strategy that provides privately negotiated loans to U.S. middle market companies. Typically, these are floating rate, senior secured loans diversified across industries. Loans can be made to private equity sponsor-backed companies or non-sponsored companies to finance leveraged buyouts, recapitalizations, and acquisitions. The following table sets forth gross summarized financial information for our other investments portfolio, including the portion not owned by us. The majority of these investments are carried under the equity method of accounting. The last line of the table below reflects our share of the aggregate loss, 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 and six-month periods ended March 31 is as follows: Income Statement Information Quarter ended March 31, Six months ended March 31, ($ in millions) 2016 2015 2016 2015 Net investment (loss) income $ (4.6 ) 8.5 $ 37.0 95.6 Realized gains 193.2 279.4 981.1 592.5 Net change in unrealized depreciation (253.9 ) (223.4 ) (1,236.5 ) (866.9 ) Net (loss) gain $ (65.3 ) 64.5 $ (218.4 ) (178.8 ) Selective’s insurance subsidiaries’ other investments loss $ (0.6 ) 1.4 $ (1.7 ) (2.1 ) (f) We have pledged certain AFS fixed income securities as collateral related to our: (i) relationships with the Federal Home Loan Bank of Indianapolis ("FHLBI") and the Federal Home Loan Bank of New York ("FHLBNY"); and (ii) 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 at June 30, 2016 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 June 30, 2016 : ($ in millions) FHLBI Collateral FHLBNY Collateral Reinsurance Collateral State and Regulatory Deposits Total U.S. government and government agencies $ 7.5 — — 23.5 31.0 Obligations of states and political subdivisions — — 5.0 — 5.0 Corporate securities — — 4.8 — 4.8 CMBS 1.1 — — — 1.1 RMBS 55.0 29.9 1.6 — 86.5 Total pledged as collateral $ 63.6 29.9 11.4 23.5 128.4 (g) The Company did not have exposure to any credit concentration risk of a single issuer greater than 10% of the Company's stockholders' equity, other than certain U.S. government agencies, as of June 30, 2016 or December 31, 2015 . (h) The components of pre-tax net investment income earned for the periods indicated were as follows: Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Fixed income securities $ 31,753 30,659 $ 63,397 61,626 Equity securities 2,204 2,384 4,434 4,176 Short-term investments 142 23 301 48 Other investments (611 ) 1,422 (1,677 ) (2,118 ) Investment expenses (2,306 ) (2,258 ) (4,504 ) (4,585 ) Net investment income earned $ 31,182 32,230 $ 61,951 59,147 (i) The following tables summarize OTTI by asset type for the periods indicated: Second Quarter 2016 Gross Included in Other Comprehensive Income ("OCI") Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 104 — 104 RMBS 98 10 88 Total AFS fixed income securities 202 10 192 AFS equity securities: Common stock 357 — 357 Total AFS equity securities 357 — 357 Total OTTI losses $ 559 10 549 Second Quarter 2015 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 183 — 183 Total AFS fixed income securities 183 — 183 AFS equity securities: Common stock 4,088 — 4,088 Preferred stock 180 — 180 Total AFS equity securities 4,268 — 4,268 Total OTTI losses $ 4,451 — 4,451 Six Months 2016 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 1,077 — 1,077 RMBS 98 10 88 Total AFS fixed income securities 1,175 10 1,165 AFS equity securities: Common stock 2,974 — 2,974 Preferred stock 3 — 3 Total AFS equity securities 2,977 — 2,977 Total OTTI losses $ 4,152 10 4,142 Six Months 2015 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 1,192 — 1,192 RMBS 1 — 1 Total AFS fixed income securities 1,193 — 1,193 AFS equity securities: Common stock 5,172 — 5,172 Preferred stock 180 — 180 Total AFS equity securities 5,352 — 5,352 Total OTTI losses $ 6,545 — 6,545 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 2015 Annual Report . (j) The components of net realized gains, excluding OTTI charges, for the periods indicated were as follows: Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 HTM fixed income securities Gains $ 3 2 3 2 Losses — — (1 ) (1 ) AFS fixed income securities Gains 365 487 985 1,989 Losses (5 ) (18 ) (41 ) (130 ) AFS equity securities Gains 2,171 830 2,501 22,148 Losses (220 ) (270 ) (240 ) (1,346 ) Other investments Losses — — (4 ) (654 ) Total net realized gains (excluding OTTI charges) $ 2,314 1,031 3,203 22,008 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 $88.7 million and $19.5 million in Second Quarter 2016 and Second Quarter 2015 , respectively, and $105.9 million and $157.9 million in Six Months 2016 and Six Months 2015 , respectively. The $22.0 million in net realized gains for Six Months 2015 were primarily 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.

Indebtedness

Indebtedness	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Indebtedness	NOTE 5. Indebtedness During Six Months 2016, Selective Insurance Company of America ("SICA") borrowed the following short-term funds from the FHLBNY: • $25 million on February 26, 2016 at an interest rate of 0.59% , which was repaid on March 18, 2016; • $15 million on April 7, 2016 at an interest rate of 0.52% , which was repaid on April 28, 2016; and • $15 million on April 28, 2016 at an interest rate of 0.53% , which was repaid on May 19, 2016. Additionally, on July 21, 2016, SICA borrowed $25 million for general corporate purposes from FHLBNY at an interest rate of 1.61% . The principal amount is due in 2021. For additional information on our indebtedness, see Note 10. "Indebtedness" in Item 8. "Financial Statements and Supplementary Data." of our 2015 Annual Report .

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 and December 31, 2015 : June 30, 2016 December 31, 2015 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Assets Fixed income securities: HTM $ 160,297 167,061 201,354 209,544 AFS 4,671,786 4,671,786 4,408,203 4,408,203 Equity securities, AFS 152,938 152,938 207,051 207,051 Short-term investments 205,451 205,451 194,819 194,819 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 15,000 15,001 15,000 14,977 1.25% borrowings from FHLBI 45,000 45,113 45,000 45,083 Total short-term debt $ 60,000 60,114 60,000 60,060 Long-term debt: 7.25% Senior Notes $ 49,900 61,003 49,898 56,929 6.70% Senior Notes 99,422 118,792 99,415 110,363 5.875% Senior Notes 185,000 194,176 185,000 192,474 Subtotal long-term debt 334,322 373,971 334,313 359,766 Unamortized debt issuance costs (5,889 ) (6,121 ) Total long-term debt $ 328,433 328,192 For a discussion of the fair value and hierarchy 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 2015 Annual Report . The following tables provide quantitative disclosures of our financial assets that were measured at fair value at June 30, 2016 and December 31, 2015 : June 30, 2016 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) 1 Significant Other Observable Inputs (Level 2) 1 Significant Unobservable Inputs (Level 3) Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 96,170 38,628 57,542 — Foreign government 9,059 — 9,059 — Obligations of states and political subdivisions 1,462,152 — 1,462,152 — Corporate securities 2,038,108 — 2,038,108 — ABS 258,711 — 258,711 — CMBS 256,036 — 256,036 — RMBS 551,550 — 551,550 — Total AFS fixed income securities 4,671,786 38,628 4,633,158 — AFS equity securities: Common stock 139,419 136,093 — 3,326 Preferred stock 13,519 13,519 — — Total AFS equity securities 152,938 149,612 — 3,326 Total AFS securities 4,824,724 188,240 4,633,158 3,326 Short-term investments 205,451 205,451 — — Total assets measured at fair value $ 5,030,175 393,691 4,633,158 3,326 December 31, 2015 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) 1 Significant Other Observable Inputs (Level 2) 1 Significant Unobservable Inputs (Level 3) Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 104,115 42,702 61,413 — Foreign government 15,181 — 15,181 — Obligations of states and political subdivisions 1,359,142 — 1,359,142 — Corporate securities 1,900,182 — 1,900,182 — ABS 244,154 — 244,154 — CMBS 243,592 — 243,592 — RMBS 541,837 — 541,837 — Total AFS fixed income securities 4,408,203 42,702 4,365,501 — AFS equity securities: Common stock 194,789 191,517 — 3,272 Preferred stock 12,262 12,262 — — Total AFS equity securities 207,051 203,779 — 3,272 Total AFS securities 4,615,254 246,481 4,365,501 3,272 Short-term investments 194,819 194,819 — — Total assets measured at fair value $ 4,810,073 441,300 4,365,501 3,272 1 There were no transfers of securities between Level 1 and Level 2. The following table provides a summary of the changes in the fair value of securities measured using Level 3 inputs and related quantitative information for Six Months 2016: June 30, 2016 Common Stock ($ in thousands) Fair value, December 31, 2015 $ 3,272 Total net (losses) gains for the period included in: OCI — Net income — Purchases 1,854 Sales (1,800 ) Issuances — Settlements — Transfers into Level 3 — Transfers out of Level 3 — Fair value, June 30, 2016 $ 3,326 The following tables provide quantitative information regarding our financial assets and liabilities that were disclosed at fair value at June 30, 2016 and December 31, 2015 : June 30, 2016 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets HTM: Obligations of states and political subdivisions $ 136,273 — 136,273 — Corporate securities 26,106 — 18,541 7,565 ABS 126 — 126 — CMBS 4,556 — 4,556 — Total HTM fixed income securities $ 167,061 — 159,496 7,565 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 15,001 — 15,001 — 1.25% borrowings from FHLBI 45,113 — 45,113 — Total short-term debt $ 60,114 — 60,114 — Long-term debt: 7.25% Senior Notes $ 61,003 — 61,003 — 6.70% Senior Notes 118,792 — 118,792 — 5.875% Senior Notes 194,176 194,176 — — Total long-term debt $ 373,971 194,176 179,795 — December 31, 2015 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets HTM: Obligations of states and political subdivisions $ 181,880 — 181,880 — Corporate securities 22,015 — 18,679 3,336 ABS 1,028 — 1,028 — CMBS 4,621 — 4,621 — Total HTM fixed income securities $ 209,544 — 206,208 3,336 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 14,977 — 14,977 — 1.25% borrowings from FHLBI 45,083 — 45,083 — Total short-term debt $ 60,060 — 60,060 — Long-term debt: 7.25% Senior Notes $ 56,929 — 56,929 — 6.70% Senior Notes 110,363 — 110,363 — 5.875% Senior Notes 192,474 192,474 — — Total long-term debt $ 359,766 192,474 167,292 —

Reinsurance

Reinsurance	6 Months Ended
	Jun. 30, 2016
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 2015 Annual Report . Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Premiums written: Direct $ 665,862 621,408 $ 1,312,140 1,220,191 Assumed 7,788 4,960 14,108 11,041 Ceded (95,510 ) (94,235 ) (182,749 ) (181,011 ) Net $ 578,140 532,133 $ 1,143,499 1,050,221 Premiums earned: Direct $ 612,406 576,107 $ 1,219,067 1,138,149 Assumed 7,171 5,093 13,441 11,001 Ceded (87,645 ) (90,891 ) (178,118 ) (182,718 ) Net $ 531,932 490,309 $ 1,054,390 966,432 Loss and loss expense incurred: Direct $ 362,064 316,648 $ 723,703 628,894 Assumed 6,140 4,228 12,495 8,890 Ceded (69,725 ) (29,315 ) (140,575 ) (61,224 ) Net $ 298,479 291,561 $ 595,623 576,560 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 June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Ceded premiums written $ (63,906 ) (62,479 ) $ (117,154 ) (116,321 ) Ceded premiums earned (56,667 ) (58,781 ) (113,481 ) (117,779 ) Ceded loss and loss expense incurred (24,261 ) (14,684 ) (64,979 ) (20,933 )

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information 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 insurance operations, as well as our earnings and amounts generated through our capital management strategies, which may include the issuance of debt and equity securities. 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. 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 June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Standard Commercial Lines: Net premiums earned: Commercial automobile $ 98,896 88,658 194,315 175,013 Workers compensation 75,251 70,954 151,251 139,431 General liability 129,283 119,207 257,368 234,178 Commercial property 73,591 66,549 143,769 131,112 Businessowners’ policies 24,651 23,178 48,555 45,877 Bonds 5,665 5,106 11,129 10,106 Other 3,940 3,553 7,779 7,021 Miscellaneous income 3,567 2,563 4,257 4,232 Total Standard Commercial Lines revenue 414,844 379,768 818,423 746,970 Standard Personal Lines: Net premiums earned: Personal automobile 35,881 36,740 71,661 73,750 Homeowners 33,411 33,731 66,311 67,452 Other 1,532 1,600 3,057 3,348 Miscellaneous income 301 291 561 591 Total Standard Personal Lines revenue 71,125 72,362 141,590 145,141 E&S Lines: Net premiums earned: General liability 35,452 28,793 70,974 55,519 Commercial property 11,716 10,464 23,160 20,119 Commercial automobile 2,663 1,776 5,061 3,506 Miscellaneous income — — 1 — Total E&S Lines revenue 49,831 41,033 99,196 79,144 Investments: Net investment income 31,182 32,230 61,951 59,147 Net realized investment gains (losses) 1,765 (3,420 ) (939 ) 15,463 Total Investments revenue 32,947 28,810 61,012 74,610 Total revenues $ 568,747 521,973 1,120,221 1,045,865 Income Before Federal Income Tax Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Standard Commercial Lines: Underwriting gain $ 40,173 35,241 71,105 65,277 GAAP combined ratio 90.2 % 90.7 91.3 91.2 Statutory combined ratio 88.6 90.1 89.1 89.9 Standard Personal Lines: Underwriting gain (loss) $ 6,125 (4,655 ) 14,730 (7,121 ) GAAP combined ratio 91.4 % 106.5 89.6 104.9 Statutory combined ratio 89.9 105.4 90.1 105.2 E&S Insurance Operations: Underwriting loss $ (2,521 ) (1,462 ) (1,103 ) (3,011 ) GAAP combined ratio 105.1 % 103.6 101.1 103.8 Statutory combined ratio 102.7 102.7 100.6 102.5 Investments: Net investment income $ 31,182 32,230 61,951 59,147 Net realized investment gains (losses) 1,765 (3,420 ) (939 ) 15,463 Total investment income, before federal income tax 32,947 28,810 61,012 74,610 Tax on investment income 8,275 6,254 14,538 18,572 Total investment income, after federal income tax $ 24,672 22,556 46,474 56,038 Reconciliation of Segment Results to Income Before Federal Income Tax Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Underwriting gain (loss), before federal income tax Standard Commercial Lines $ 40,173 35,241 71,105 65,277 Standard Personal Lines 6,125 (4,655 ) 14,730 (7,121 ) E&S Lines (2,521 ) (1,462 ) (1,103 ) (3,011 ) Investment income, before federal income tax 32,947 28,810 61,012 74,610 Total all segments 76,724 57,934 145,744 129,755 Interest expense (5,620 ) (5,612 ) (11,226 ) (11,216 ) General corporate and other expenses (8,793 ) (5,557 ) (20,332 ) (15,484 ) Income before federal income tax $ 62,311 46,765 114,186 103,055

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Retirement Plans	Retirement Plans SICA's primary pension plan is the Retirement Income Plan for Selective Insurance Company of America (the “Pension Plan”). SICA also sponsors the Supplemental Excess Retirement Plan (the “Excess Plan”) and a life insurance benefit plan. All plans are closed to new entrants and benefits ceased accruing under the Pension Plan and the Excess Plan after March 31, 2016. For more information concerning SICA's retirement plans, refer to Note 14. “Retirement Plans” in Item 8. “Financial Statements and Supplementary Data.” of our 2015 Annual Report . The following tables provide information regarding the Pension Plan: Pension Plan Pension Plan ($ in thousands) 2016 2015 2016 2015 Net Periodic Benefit Cost: Service cost $ — 1,912 1,606 3,825 Interest cost 3,101 3,407 6,203 6,816 Expected return on plan assets (3,988 ) (3,990 ) (7,976 ) (7,981 ) Amortization of unrecognized net actuarial loss 1,481 1,644 2,961 3,287 Total net periodic cost $ 594 2,973 2,794 5,947 Pension Plan 2016 2015 Weighted-Average Expense Assumptions: Discount rate 4.69 % 4.29 Effective interest rate for calculation of service cost 4.52 — Effective interest rate for calculation of interest cost 4.02 — Expected return on plan assets 6.37 6.27 Rate of compensation increase 4.00 4.00 Effective January 1, 2016, the approach used to calculate the service and interest components of net periodic benefit cost for the Pension Plan was changed to provide a more precise measurement of these costs. Historically, we calculated the service and interest components utilizing a single weighted-average discount rate derived from the yield curve used to measure the benefit obligation at the beginning of the period. On January 1, 2016, we elected to utilize an approach that discounts the individual expected cash flows using the applicable spot rates derived from the yield curve over the projected cash flow period. We accounted for this change prospectively as a change in accounting estimate. The decrease in service cost reflected in the table above is attributable to the discontinuation of benefit accruals for existing participants as of March 31, 2016. We presently anticipate contributing approximately $56 million to the Pension Plan in 2016 , $26.4 million of which has been funded as of June 30, 2016 .

Comprehensive Income

Comprehensive Income	6 Months Ended
	Jun. 30, 2016
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 Second Quarter and Six Months 2016 and 2015 were as follows: Second Quarter 2016 ($ in thousands) Gross Tax Net Net income $ 62,311 18,710 43,601 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during period 55,675 19,487 36,188 Non-credit portion of OTTI recognized in OCI (10 ) (4 ) (6 ) Amounts reclassified into net income: HTM securities (19 ) (7 ) (12 ) Realized gains on AFS securities (1,762 ) (617 ) (1,145 ) Total unrealized gains on investment securities 53,884 18,859 35,025 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 1,517 532 985 Total defined benefit pension and post-retirement plans 1,517 532 985 Other comprehensive income 55,401 19,391 36,010 Comprehensive income $ 117,712 38,101 79,611 Second Quarter 2015 ($ in thousands) Gross Tax Net Net income $ 46,765 12,997 33,768 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during period (60,244 ) (21,084 ) (39,160 ) Amounts reclassified into net income: HTM securities (185 ) (65 ) (120 ) Realized losses on AFS securities 3,422 1,197 2,225 Total unrealized losses on investment securities (57,007 ) (19,952 ) (37,055 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 1,709 598 1,111 Total defined benefit pension and post-retirement plans 1,709 598 1,111 Other comprehensive loss (55,298 ) (19,354 ) (35,944 ) Comprehensive loss $ (8,533 ) (6,357 ) (2,176 ) Six Months 2016 ($ in thousands) Gross Tax Net Net income $ 114,186 33,553 80,633 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during period 121,412 42,495 78,917 Non-credit portion of OTTI recognized in OCI (10 ) (4 ) (6 ) Amounts reclassified into net income: HTM securities (91 ) (32 ) (59 ) Realized losses on AFS securities 937 328 609 Total unrealized gains on investment securities 122,248 42,787 79,461 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 3,033 1,062 1,971 Total defined benefit pension and post-retirement plans 3,033 1,062 1,971 Other comprehensive income 125,281 43,849 81,432 Comprehensive income $ 239,467 77,402 162,065 Six Months 2015 ($ in thousands) Gross Tax Net Net income $ 103,055 29,579 73,476 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during period (36,267 ) (12,693 ) (23,574 ) Amounts reclassified into net income: HTM securities (446 ) (156 ) (290 ) Non-credit OTTI 357 125 232 Realized gains on AFS securities (16,473 ) (5,766 ) (10,707 ) Total unrealized losses on investment securities (52,829 ) (18,490 ) (34,339 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 3,418 1,196 2,222 Total defined benefit pension and post-retirement plans 3,418 1,196 2,222 Other comprehensive loss (49,411 ) (17,294 ) (32,117 ) Comprehensive income $ 53,644 12,285 41,359 The balances of, and changes in, each component of AOCI (net of taxes) as of June 30, 2016 were as follows: June 30, 2016 Net Unrealized Gain on Investment Securities Defined Benefit Pension and Post-Retirement Plans Total AOCI ($ in thousands) OTTI Related HTM Related All Other Investments Subtotal Balance, December 31, 2015 $ (282 ) 194 45,083 44,995 (54,420 ) (9,425 ) OCI before reclassifications (6 ) — 78,917 78,911 — 78,911 Amounts reclassified from AOCI — (59 ) 609 550 1,971 2,521 Net current period OCI (6 ) (59 ) 79,526 79,461 1,971 81,432 Balance, June 30, 2016 $ (288 ) 135 124,609 124,456 (52,449 ) 72,007 The reclassifications out of AOCI were as follows: Quarter ended June 30, Six Months ended Affected Line Item in the Unaudited Consolidated Statement of Income ($ in thousands) 2016 2015 2016 2015 OTTI related Non-credit OTTI on disposed securities $ — — — 357 Net realized gains (losses) — — — 357 Income before federal income tax — — — (125 ) Total federal income tax expense — — — 232 Net income HTM related Unrealized losses on HTM disposals 60 87 88 137 Net realized gains (losses) Amortization of net unrealized gains on HTM securities (79 ) (272 ) (179 ) (583 ) Net investment income earned (19 ) (185 ) (91 ) (446 ) Income before federal income tax 7 65 32 156 Total federal income tax expense (12 ) (120 ) (59 ) (290 ) Net income Realized losses (gains) on AFS and OTTI Realized losses (gains) on AFS disposals and OTTI (1,762 ) 3,422 937 (16,473 ) Net realized gains (losses) (1,762 ) 3,422 937 (16,473 ) Income before federal income tax 617 (1,197 ) (328 ) 5,766 Total federal income tax expense (1,145 ) 2,225 609 (10,707 ) Net income Defined benefit pension and post-retirement life plans Net actuarial loss 329 372 658 743 Loss and loss expense incurred 1,188 1,337 2,375 2,675 Policy acquisition costs Total defined benefit pension and post-retirement life 1,517 1,709 3,033 3,418 Income before federal income tax (532 ) (598 ) (1,062 ) (1,196 ) Total federal income tax expense 985 1,111 1,971 2,222 Net income Total reclassifications for the period $ (172 ) 3,216 2,521 (8,543 ) Net income

Litigation

Litigation	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , we do not believe the Company was involved in any legal action that could have a material adverse effect on our consolidated financial condition, results of operations, or cash flows.

Statements of Cash Flow (Tables

Statements of Cash Flow (Tables)	6 Months Ended
	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Six Months ended June 30, ($ in thousands) 2016 2015 Cash paid during the period for: Interest $ 10,986 10,947 Federal income tax 29,000 8,500 Non-cash items: Exchange of fixed income securities, AFS 17,702 17,120 Corporate actions related to equity securities, AFS 1 3,032 884 Assets acquired under capital lease arrangements 2,999 3,478 Non-cash purchase of property and equipment 577 — 1 Examples of such corporate actions include non-cash acquisitions and stock splits.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments [Line Items]
Schedule of Held-to-maturity Securities	June 30, 2016 ($ in thousands) Amortized Cost Net Unrealized Gains (Losses) Carrying Value Unrecognized Holding Gains Unrecognized Holding Losses Fair Value Obligations of states and political subdivisions $ 131,480 533 132,013 4,260 — 136,273 Corporate securities 23,995 (175 ) 23,820 2,286 — 26,106 Asset-backed securities (“ABS”) 126 — 126 — — 126 Commercial mortgage-backed securities (“CMBS”) 4,489 (151 ) 4,338 218 — 4,556 Total HTM fixed income securities $ 160,090 207 160,297 6,764 — 167,061 December 31, 2015 ($ in thousands) Amortized Cost Net Unrealized Gains (Losses) Carrying Value Unrecognized Holding Gains Unrecognized Holding Losses Fair Value Obligations of states and political subdivisions $ 175,269 848 176,117 5,763 — 181,880 Corporate securities 20,228 (185 ) 20,043 1,972 — 22,015 ABS 1,030 (120 ) 910 118 — 1,028 CMBS 4,527 (243 ) 4,284 337 — 4,621 Total HTM fixed income securities $ 201,054 300 201,354 8,190 — 209,544
Schedule of Available-for-sale Securities	June 30, 2016 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 91,933 4,237 — 96,170 Foreign government 8,635 424 — 9,059 Obligations of states and political subdivisions 1,379,548 82,604 — 1,462,152 Corporate securities 1,977,838 62,233 (1,963 ) 2,038,108 ABS 257,182 1,656 (127 ) 258,711 CMBS 249,603 6,484 (51 ) 256,036 Residential mortgage-backed securities (“RMBS”) 541,841 10,027 (318 ) 551,550 Total AFS fixed income securities 4,506,580 167,665 (2,459 ) 4,671,786 AFS equity securities: Common stock 114,099 26,343 (1,023 ) 139,419 Preferred stock 12,782 737 — 13,519 Total AFS equity securities 126,881 27,080 (1,023 ) 152,938 Total AFS securities $ 4,633,461 194,745 (3,482 ) 4,824,724 December 31, 2015 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 99,485 4,721 (91 ) 104,115 Foreign government 14,885 298 (2 ) 15,181 Obligations of states and political subdivisions 1,314,779 44,523 (160 ) 1,359,142 Corporate securities 1,892,296 23,407 (15,521 ) 1,900,182 ABS 244,541 531 (918 ) 244,154 CMBS 245,252 750 (2,410 ) 243,592 RMBS 541,276 4,274 (3,713 ) 541,837 Total AFS fixed income securities 4,352,514 78,504 (22,815 ) 4,408,203 AFS equity securities: Common stock 181,991 14,796 (1,998 ) 194,789 Preferred stock 11,825 477 (40 ) 12,262 Total AFS equity securities 193,816 15,273 (2,038 ) 207,051 Total AFS securities $ 4,546,330 93,777 (24,853 ) 4,615,254
Schedule of Fair Value and Gross Pre-Tax Net Unrealized/Unrecognized Loss of Securities by Length of Time	June 30, 2016 Less than 12 months 12 months or longer ($ in thousands) Fair Value Unrealized Losses 1 Fair Value Unrealized Losses 1 AFS fixed income securities: Corporate securities $ 96,244 (822 ) 33,616 (1,141 ) ABS 46,992 (117 ) 4,665 (10 ) CMBS 6,348 (4 ) 10,451 (47 ) RMBS 6,835 (19 ) 50,134 (299 ) Total AFS fixed income securities 156,419 (962 ) 98,866 (1,497 ) AFS equity securities: Common stock 16,428 (1,023 ) — — Total AFS equity securities 16,428 (1,023 ) — — Total AFS $ 172,847 (1,985 ) 98,866 (1,497 ) December 31, 2015 Less than 12 months 12 months or longer ($ in thousands) Fair Value Unrealized Losses 1 Fair Value Unrealized Losses 1 AFS fixed income securities: U.S. government and government agencies $ 16,006 (87 ) 396 (4 ) Foreign government 1,067 (2 ) — — Obligations of states and political subdivisions 28,617 (160 ) — — Corporate securities 761,479 (12,671 ) 50,382 (2,850 ) ABS 197,477 (807 ) 12,022 (111 ) CMBS 146,944 (2,196 ) 15,385 (214 ) RMBS 264,914 (1,992 ) 63,395 (1,721 ) Total AFS fixed income securities 1,416,504 (17,915 ) 141,580 (4,900 ) AFS equity securities: Common stock 31,148 (1,998 ) — — Preferred stock 1,531 (40 ) — — Total AFS equity securities 32,679 (2,038 ) — — Total AFS $ 1,449,183 (19,953 ) 141,580 (4,900 ) 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.
Schedule of The Number Of Securities In An Unrealized Unrecognized Loss Position	($ in thousands) June 30, 2016 December 31, 2015 Number of Issues % of Market/Book Unrealized/ Unrecognized Loss Number of Issues % of Market/Book Unrealized/ Unrecognized Loss 156 80% - 99% $ 3,482 606 80% - 99% $ 22,971 — 60% - 79% — 3 60% - 79% 1,888 — 40% - 59% — — 40% - 59% — — 20% - 39% — — 20% - 39% — — 0% - 19% — — 0% - 19% — $ 3,482 $ 24,859
Schedule of Other Investment Portfolio By Strategy And Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy	Other Investments June 30, 2016 December 31, 2015 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 28,439 34,117 62,556 35,088 30,204 65,292 Private credit 23,336 23,243 46,579 13,246 15,129 28,375 Real assets 14,132 30,273 44,405 19,500 25,820 45,320 Total alternative investments 65,907 87,633 153,540 67,834 71,153 138,987 Other securities 10,144 6,850 16,994 10,008 3,200 13,208 Total other investments $ 76,051 94,483 170,534 77,842 74,353 152,195 1 The maximum exposure to loss includes both the carry value of these investments and the related unfunded commitments. In addition, tax credits that have been previously recognized from our investment in Other securities are subject to the risk of recapture, which we do not consider significant.
Schedule of Aggregated Summarized Income Statement Financial Information For Partnerships In Our Alternative Investment Portfolio	Income Statement Information Quarter ended March 31, Six months ended March 31, ($ in millions) 2016 2015 2016 2015 Net investment (loss) income $ (4.6 ) 8.5 $ 37.0 95.6 Realized gains 193.2 279.4 981.1 592.5 Net change in unrealized depreciation (253.9 ) (223.4 ) (1,236.5 ) (866.9 ) Net (loss) gain $ (65.3 ) 64.5 $ (218.4 ) (178.8 ) Selective’s insurance subsidiaries’ other investments loss $ (0.6 ) 1.4 $ (1.7 ) (2.1 )
Schedule of Securities Pledged As Collateral	($ in millions) FHLBI Collateral FHLBNY Collateral Reinsurance Collateral State and Regulatory Deposits Total U.S. government and government agencies $ 7.5 — — 23.5 31.0 Obligations of states and political subdivisions — — 5.0 — 5.0 Corporate securities — — 4.8 — 4.8 CMBS 1.1 — — — 1.1 RMBS 55.0 29.9 1.6 — 86.5 Total pledged as collateral $ 63.6 29.9 11.4 23.5 128.4
Schedule of Net Investment Income Earned	Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Fixed income securities $ 31,753 30,659 $ 63,397 61,626 Equity securities 2,204 2,384 4,434 4,176 Short-term investments 142 23 301 48 Other investments (611 ) 1,422 (1,677 ) (2,118 ) Investment expenses (2,306 ) (2,258 ) (4,504 ) (4,585 ) Net investment income earned $ 31,182 32,230 $ 61,951 59,147
Schedule of OTTI By Asset Type	Second Quarter 2016 Gross Included in Other Comprehensive Income ("OCI") Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 104 — 104 RMBS 98 10 88 Total AFS fixed income securities 202 10 192 AFS equity securities: Common stock 357 — 357 Total AFS equity securities 357 — 357 Total OTTI losses $ 559 10 549 Second Quarter 2015 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 183 — 183 Total AFS fixed income securities 183 — 183 AFS equity securities: Common stock 4,088 — 4,088 Preferred stock 180 — 180 Total AFS equity securities 4,268 — 4,268 Total OTTI losses $ 4,451 — 4,451 Six Months 2016 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 1,077 — 1,077 RMBS 98 10 88 Total AFS fixed income securities 1,175 10 1,165 AFS equity securities: Common stock 2,974 — 2,974 Preferred stock 3 — 3 Total AFS equity securities 2,977 — 2,977 Total OTTI losses $ 4,152 10 4,142 Six Months 2015 Gross Included in OCI Recognized in ($ in thousands) AFS fixed income securities: Corporate securities $ 1,192 — 1,192 RMBS 1 — 1 Total AFS fixed income securities 1,193 — 1,193 AFS equity securities: Common stock 5,172 — 5,172 Preferred stock 180 — 180 Total AFS equity securities 5,352 — 5,352 Total OTTI losses $ 6,545 — 6,545
Schedule of Components of Net Realized Gains Excluding OTTI Charges	Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 HTM fixed income securities Gains $ 3 2 3 2 Losses — — (1 ) (1 ) AFS fixed income securities Gains 365 487 985 1,989 Losses (5 ) (18 ) (41 ) (130 ) AFS equity securities Gains 2,171 830 2,501 22,148 Losses (220 ) (270 ) (240 ) (1,346 ) Other investments Losses — — (4 ) (654 ) Total net realized gains (excluding OTTI charges) $ 2,314 1,031 3,203 22,008
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 $ 84,415 85,514 Due after one year through five years 65,616 69,914 Due after five years through 10 years 10,266 11,633 Total HTM fixed income securities $ 160,297 167,061
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 $ 482,867 Due after one year through five years 2,425,517 Due after five years through 10 years 1,647,615 Due after 10 years 115,787 Total AFS fixed income securities $ 4,671,786

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Schedule of The Carrying Amounts and Estimated Fair Values of Financial Instruments	June 30, 2016 December 31, 2015 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Assets Fixed income securities: HTM $ 160,297 167,061 201,354 209,544 AFS 4,671,786 4,671,786 4,408,203 4,408,203 Equity securities, AFS 152,938 152,938 207,051 207,051 Short-term investments 205,451 205,451 194,819 194,819 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 15,000 15,001 15,000 14,977 1.25% borrowings from FHLBI 45,000 45,113 45,000 45,083 Total short-term debt $ 60,000 60,114 60,000 60,060 Long-term debt: 7.25% Senior Notes $ 49,900 61,003 49,898 56,929 6.70% Senior Notes 99,422 118,792 99,415 110,363 5.875% Senior Notes 185,000 194,176 185,000 192,474 Subtotal long-term debt 334,322 373,971 334,313 359,766 Unamortized debt issuance costs (5,889 ) (6,121 ) Total long-term debt $ 328,433 328,192
Schedule of Quantitative Disclosures of Our Financial Assets That Were Measured At Fair Value	June 30, 2016 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) 1 Significant Other Observable Inputs (Level 2) 1 Significant Unobservable Inputs (Level 3) Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 96,170 38,628 57,542 — Foreign government 9,059 — 9,059 — Obligations of states and political subdivisions 1,462,152 — 1,462,152 — Corporate securities 2,038,108 — 2,038,108 — ABS 258,711 — 258,711 — CMBS 256,036 — 256,036 — RMBS 551,550 — 551,550 — Total AFS fixed income securities 4,671,786 38,628 4,633,158 — AFS equity securities: Common stock 139,419 136,093 — 3,326 Preferred stock 13,519 13,519 — — Total AFS equity securities 152,938 149,612 — 3,326 Total AFS securities 4,824,724 188,240 4,633,158 3,326 Short-term investments 205,451 205,451 — — Total assets measured at fair value $ 5,030,175 393,691 4,633,158 3,326 December 31, 2015 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) 1 Significant Other Observable Inputs (Level 2) 1 Significant Unobservable Inputs (Level 3) Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 104,115 42,702 61,413 — Foreign government 15,181 — 15,181 — Obligations of states and political subdivisions 1,359,142 — 1,359,142 — Corporate securities 1,900,182 — 1,900,182 — ABS 244,154 — 244,154 — CMBS 243,592 — 243,592 — RMBS 541,837 — 541,837 — Total AFS fixed income securities 4,408,203 42,702 4,365,501 — AFS equity securities: Common stock 194,789 191,517 — 3,272 Preferred stock 12,262 12,262 — — Total AFS equity securities 207,051 203,779 — 3,272 Total AFS securities 4,615,254 246,481 4,365,501 3,272 Short-term investments 194,819 194,819 — — Total assets measured at fair value $ 4,810,073 441,300 4,365,501 3,272 1 There were no transfers of securities between Level 1 and Level 2.
Schedule of Summary of the Changes in Fair Value of Securities Using Level 3 Inputs	June 30, 2016 Common Stock ($ in thousands) Fair value, December 31, 2015 $ 3,272 Total net (losses) gains for the period included in: OCI — Net income — Purchases 1,854 Sales (1,800 ) Issuances — Settlements — Transfers into Level 3 — Transfers out of Level 3 — Fair value, June 30, 2016 $ 3,326
Schedule of Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value	June 30, 2016 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets HTM: Obligations of states and political subdivisions $ 136,273 — 136,273 — Corporate securities 26,106 — 18,541 7,565 ABS 126 — 126 — CMBS 4,556 — 4,556 — Total HTM fixed income securities $ 167,061 — 159,496 7,565 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 15,001 — 15,001 — 1.25% borrowings from FHLBI 45,113 — 45,113 — Total short-term debt $ 60,114 — 60,114 — Long-term debt: 7.25% Senior Notes $ 61,003 — 61,003 — 6.70% Senior Notes 118,792 — 118,792 — 5.875% Senior Notes 194,176 194,176 — — Total long-term debt $ 373,971 194,176 179,795 — December 31, 2015 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Active Markets for Identical Assets/ Liabilities (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets HTM: Obligations of states and political subdivisions $ 181,880 — 181,880 — Corporate securities 22,015 — 18,679 3,336 ABS 1,028 — 1,028 — CMBS 4,621 — 4,621 — Total HTM fixed income securities $ 209,544 — 206,208 3,336 Financial Liabilities Short-term debt: 0.63% borrowings from FHLBI $ 14,977 — 14,977 — 1.25% borrowings from FHLBI 45,083 — 45,083 — Total short-term debt $ 60,060 — 60,060 — Long-term debt: 7.25% Senior Notes $ 56,929 — 56,929 — 6.70% Senior Notes 110,363 — 110,363 — 5.875% Senior Notes 192,474 192,474 — — Total long-term debt $ 359,766 192,474 167,292 —

Reinsurance (Tables)

Reinsurance (Tables)	6 Months Ended
	Jun. 30, 2016
Reinsurance Disclosures [Abstract]
Schedule of List Of Direct, Assumed, And Ceded Reinsurance Amounts	Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Premiums written: Direct $ 665,862 621,408 $ 1,312,140 1,220,191 Assumed 7,788 4,960 14,108 11,041 Ceded (95,510 ) (94,235 ) (182,749 ) (181,011 ) Net $ 578,140 532,133 $ 1,143,499 1,050,221 Premiums earned: Direct $ 612,406 576,107 $ 1,219,067 1,138,149 Assumed 7,171 5,093 13,441 11,001 Ceded (87,645 ) (90,891 ) (178,118 ) (182,718 ) Net $ 531,932 490,309 $ 1,054,390 966,432 Loss and loss expense incurred: Direct $ 362,064 316,648 $ 723,703 628,894 Assumed 6,140 4,228 12,495 8,890 Ceded (69,725 ) (29,315 ) (140,575 ) (61,224 ) Net $ 298,479 291,561 $ 595,623 576,560
Schedule of Ceded Premiums and Losses Related to Flood Operations	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 June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Ceded premiums written $ (63,906 ) (62,479 ) $ (117,154 ) (116,321 ) Ceded premiums earned (56,667 ) (58,781 ) (113,481 ) (117,779 ) Ceded loss and loss expense incurred (24,261 ) (14,684 ) (64,979 ) (20,933 )

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Schedule of Revenue By Segment	Revenue by Segment Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Standard Commercial Lines: Net premiums earned: Commercial automobile $ 98,896 88,658 194,315 175,013 Workers compensation 75,251 70,954 151,251 139,431 General liability 129,283 119,207 257,368 234,178 Commercial property 73,591 66,549 143,769 131,112 Businessowners’ policies 24,651 23,178 48,555 45,877 Bonds 5,665 5,106 11,129 10,106 Other 3,940 3,553 7,779 7,021 Miscellaneous income 3,567 2,563 4,257 4,232 Total Standard Commercial Lines revenue 414,844 379,768 818,423 746,970 Standard Personal Lines: Net premiums earned: Personal automobile 35,881 36,740 71,661 73,750 Homeowners 33,411 33,731 66,311 67,452 Other 1,532 1,600 3,057 3,348 Miscellaneous income 301 291 561 591 Total Standard Personal Lines revenue 71,125 72,362 141,590 145,141 E&S Lines: Net premiums earned: General liability 35,452 28,793 70,974 55,519 Commercial property 11,716 10,464 23,160 20,119 Commercial automobile 2,663 1,776 5,061 3,506 Miscellaneous income — — 1 — Total E&S Lines revenue 49,831 41,033 99,196 79,144 Investments: Net investment income 31,182 32,230 61,951 59,147 Net realized investment gains (losses) 1,765 (3,420 ) (939 ) 15,463 Total Investments revenue 32,947 28,810 61,012 74,610 Total revenues $ 568,747 521,973 1,120,221 1,045,865 Income Before Federal Income Tax Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Standard Commercial Lines: Underwriting gain $ 40,173 35,241 71,105 65,277 GAAP combined ratio 90.2 % 90.7 91.3 91.2 Statutory combined ratio 88.6 90.1 89.1 89.9 Standard Personal Lines: Underwriting gain (loss) $ 6,125 (4,655 ) 14,730 (7,121 ) GAAP combined ratio 91.4 % 106.5 89.6 104.9 Statutory combined ratio 89.9 105.4 90.1 105.2 E&S Insurance Operations: Underwriting loss $ (2,521 ) (1,462 ) (1,103 ) (3,011 ) GAAP combined ratio 105.1 % 103.6 101.1 103.8 Statutory combined ratio 102.7 102.7 100.6 102.5 Investments: Net investment income $ 31,182 32,230 61,951 59,147 Net realized investment gains (losses) 1,765 (3,420 ) (939 ) 15,463 Total investment income, before federal income tax 32,947 28,810 61,012 74,610 Tax on investment income 8,275 6,254 14,538 18,572 Total investment income, after federal income tax $ 24,672 22,556 46,474 56,038
Schedule of Income Before Federal Income Tax	Income Before Federal Income Tax Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Standard Commercial Lines: Underwriting gain $ 40,173 35,241 71,105 65,277 GAAP combined ratio 90.2 % 90.7 91.3 91.2 Statutory combined ratio 88.6 90.1 89.1 89.9 Standard Personal Lines: Underwriting gain (loss) $ 6,125 (4,655 ) 14,730 (7,121 ) GAAP combined ratio 91.4 % 106.5 89.6 104.9 Statutory combined ratio 89.9 105.4 90.1 105.2 E&S Insurance Operations: Underwriting loss $ (2,521 ) (1,462 ) (1,103 ) (3,011 ) GAAP combined ratio 105.1 % 103.6 101.1 103.8 Statutory combined ratio 102.7 102.7 100.6 102.5 Investments: Net investment income $ 31,182 32,230 61,951 59,147 Net realized investment gains (losses) 1,765 (3,420 ) (939 ) 15,463 Total investment income, before federal income tax 32,947 28,810 61,012 74,610 Tax on investment income 8,275 6,254 14,538 18,572 Total investment income, after federal income tax $ 24,672 22,556 46,474 56,038
Schedule of Reconciliation of Segment Results to Income Before Federal Income Tax	Reconciliation of Segment Results to Income Before Federal Income Tax Quarter ended June 30, Six Months ended June 30, ($ in thousands) 2016 2015 2016 2015 Underwriting gain (loss), before federal income tax Standard Commercial Lines $ 40,173 35,241 71,105 65,277 Standard Personal Lines 6,125 (4,655 ) 14,730 (7,121 ) E&S Lines (2,521 ) (1,462 ) (1,103 ) (3,011 ) Investment income, before federal income tax 32,947 28,810 61,012 74,610 Total all segments 76,724 57,934 145,744 129,755 Interest expense (5,620 ) (5,612 ) (11,226 ) (11,216 ) General corporate and other expenses (8,793 ) (5,557 ) (20,332 ) (15,484 ) Income before federal income tax $ 62,311 46,765 114,186 103,055

Retirement Plans (Table)

Retirement Plans (Table)	6 Months Ended
	Jun. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of Components of Net Periodic Benefit Cost	Pension Plan Pension Plan ($ in thousands) 2016 2015 2016 2015 Net Periodic Benefit Cost: Service cost $ — 1,912 1,606 3,825 Interest cost 3,101 3,407 6,203 6,816 Expected return on plan assets (3,988 ) (3,990 ) (7,976 ) (7,981 ) Amortization of unrecognized net actuarial loss 1,481 1,644 2,961 3,287 Total net periodic cost $ 594 2,973 2,794 5,947 Pension Plan 2016 2015 Weighted-Average Expense Assumptions: Discount rate 4.69 % 4.29 Effective interest rate for calculation of service cost 4.52 — Effective interest rate for calculation of interest cost 4.02 — Expected return on plan assets 6.37 6.27 Rate of compensation increase 4.00 4.00
Schedule of Weighted-Average Expense Assumptions	Pension Plan 2016 2015 Weighted-Average Expense Assumptions: Discount rate 4.69 % 4.29 Effective interest rate for calculation of service cost 4.52 — Effective interest rate for calculation of interest cost 4.02 — Expected return on plan assets 6.37 6.27 Rate of compensation increase 4.00 4.00

Comprehensive Income (Tables)

Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2016
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Components of Comprehensive Income-Gross and Net of Tax	Second Quarter 2016 ($ in thousands) Gross Tax Net Net income $ 62,311 18,710 43,601 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during period 55,675 19,487 36,188 Non-credit portion of OTTI recognized in OCI (10 ) (4 ) (6 ) Amounts reclassified into net income: HTM securities (19 ) (7 ) (12 ) Realized gains on AFS securities (1,762 ) (617 ) (1,145 ) Total unrealized gains on investment securities 53,884 18,859 35,025 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 1,517 532 985 Total defined benefit pension and post-retirement plans 1,517 532 985 Other comprehensive income 55,401 19,391 36,010 Comprehensive income $ 117,712 38,101 79,611 Second Quarter 2015 ($ in thousands) Gross Tax Net Net income $ 46,765 12,997 33,768 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during period (60,244 ) (21,084 ) (39,160 ) Amounts reclassified into net income: HTM securities (185 ) (65 ) (120 ) Realized losses on AFS securities 3,422 1,197 2,225 Total unrealized losses on investment securities (57,007 ) (19,952 ) (37,055 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 1,709 598 1,111 Total defined benefit pension and post-retirement plans 1,709 598 1,111 Other comprehensive loss (55,298 ) (19,354 ) (35,944 ) Comprehensive loss $ (8,533 ) (6,357 ) (2,176 ) Six Months 2016 ($ in thousands) Gross Tax Net Net income $ 114,186 33,553 80,633 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during period 121,412 42,495 78,917 Non-credit portion of OTTI recognized in OCI (10 ) (4 ) (6 ) Amounts reclassified into net income: HTM securities (91 ) (32 ) (59 ) Realized losses on AFS securities 937 328 609 Total unrealized gains on investment securities 122,248 42,787 79,461 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 3,033 1,062 1,971 Total defined benefit pension and post-retirement plans 3,033 1,062 1,971 Other comprehensive income 125,281 43,849 81,432 Comprehensive income $ 239,467 77,402 162,065 Six Months 2015 ($ in thousands) Gross Tax Net Net income $ 103,055 29,579 73,476 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during period (36,267 ) (12,693 ) (23,574 ) Amounts reclassified into net income: HTM securities (446 ) (156 ) (290 ) Non-credit OTTI 357 125 232 Realized gains on AFS securities (16,473 ) (5,766 ) (10,707 ) Total unrealized losses on investment securities (52,829 ) (18,490 ) (34,339 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 3,418 1,196 2,222 Total defined benefit pension and post-retirement plans 3,418 1,196 2,222 Other comprehensive loss (49,411 ) (17,294 ) (32,117 ) Comprehensive income $ 53,644 12,285 41,359
Schedule of Components of Accumulated Other Comprehensive Income	June 30, 2016 Net Unrealized Gain on Investment Securities Defined Benefit Pension and Post-Retirement Plans Total AOCI ($ in thousands) OTTI Related HTM Related All Other Investments Subtotal Balance, December 31, 2015 $ (282 ) 194 45,083 44,995 (54,420 ) (9,425 ) OCI before reclassifications (6 ) — 78,917 78,911 — 78,911 Amounts reclassified from AOCI — (59 ) 609 550 1,971 2,521 Net current period OCI (6 ) (59 ) 79,526 79,461 1,971 81,432 Balance, June 30, 2016 $ (288 ) 135 124,609 124,456 (52,449 ) 72,007
Schedule of Reclassifications Out Of Accumulated Other Comprehensive Income	Quarter ended June 30, Six Months ended Affected Line Item in the Unaudited Consolidated Statement of Income ($ in thousands) 2016 2015 2016 2015 OTTI related Non-credit OTTI on disposed securities $ — — — 357 Net realized gains (losses) — — — 357 Income before federal income tax — — — (125 ) Total federal income tax expense — — — 232 Net income HTM related Unrealized losses on HTM disposals 60 87 88 137 Net realized gains (losses) Amortization of net unrealized gains on HTM securities (79 ) (272 ) (179 ) (583 ) Net investment income earned (19 ) (185 ) (91 ) (446 ) Income before federal income tax 7 65 32 156 Total federal income tax expense (12 ) (120 ) (59 ) (290 ) Net income Realized losses (gains) on AFS and OTTI Realized losses (gains) on AFS disposals and OTTI (1,762 ) 3,422 937 (16,473 ) Net realized gains (losses) (1,762 ) 3,422 937 (16,473 ) Income before federal income tax 617 (1,197 ) (328 ) 5,766 Total federal income tax expense (1,145 ) 2,225 609 (10,707 ) Net income Defined benefit pension and post-retirement life plans Net actuarial loss 329 372 658 743 Loss and loss expense incurred 1,188 1,337 2,375 2,675 Policy acquisition costs Total defined benefit pension and post-retirement life 1,517 1,709 3,033 3,418 Income before federal income tax (532 ) (598 ) (1,062 ) (1,196 ) Total federal income tax expense 985 1,111 1,971 2,222 Net income Total reclassifications for the period $ (172 ) 3,216 2,521 (8,543 ) Net income

Statements of Cash Flow (Cash F

Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015
Interest		$ 10,986	$ 10,947
Federal income tax		29,000	8,500
Corporate actions related to equity securities, AFS	[1]	3,032	884
Assets acquired under capital lease arrangements		2,999	3,478
Non-cash purchase of property and equipment		577	0
AFS Fixed Maturity Securities [Member]
Exchange of fixed income securities, AFS		17,702	17,120
National Flood Insurance Program [Member]
Restricted cash		$ 8,900	$ 5,200
[1]	1Examples of such corporate actions include non-cash acquisitions and stock splits.

Investments (Held-To-Maturity S

Investments (Held-To-Maturity Securities Disclosure) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 160,090	$ 201,054
Net Unrealized Gains (Losses)	207	300
Carrying Value	160,297	201,354
Unrecognized Holding Gains	6,764	8,190
Unrecognized Holding Losses	0	0
Held-to-maturity Securities, Fair Value	$ 167,061	209,544
Held-to-maturity Securities Average Duration	1 year 9 months
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 131,480	175,269
Net Unrealized Gains (Losses)	533	848
Carrying Value	132,013	176,117
Unrecognized Holding Gains	4,260	5,763
Unrecognized Holding Losses	0	0
Held-to-maturity Securities, Fair Value	136,273	181,880
Corporate Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	23,995	20,228
Net Unrealized Gains (Losses)	(175)	(185)
Carrying Value	23,820	20,043
Unrecognized Holding Gains	2,286	1,972
Unrecognized Holding Losses	0	0
Held-to-maturity Securities, Fair Value	26,106	22,015
Asset-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	126	1,030
Net Unrealized Gains (Losses)	0	(120)
Carrying Value	126	910
Unrecognized Holding Gains	0	118
Unrecognized Holding Losses	0	0
Held-to-maturity Securities, Fair Value	126	1,028
Commercial Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	4,489	4,527
Net Unrealized Gains (Losses)	(151)	(243)
Carrying Value	4,338	4,284
Unrecognized Holding Gains	218	337
Unrecognized Holding Losses	0	0
Held-to-maturity Securities, Fair Value	$ 4,556	$ 4,621

Investments (Available-For-Sale

Investments (Available-For-Sale Securities Disclosure) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	$ 4,633,461	$ 4,546,330
Unrealized Gains	194,745	93,777
Unrealized Losses	(3,482)	(24,853)
Total AFS securities	4,824,724	4,615,254
AFS Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	4,506,580	4,352,514
Unrealized Gains	167,665	78,504
Unrealized Losses	(2,459)	(22,815)
Total AFS securities	4,671,786	4,408,203
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	91,933	99,485
Unrealized Gains	4,237	4,721
Unrealized Losses	0	(91)
Total AFS securities	96,170	104,115
AFS Fixed Income Securities [Member] | Foreign Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	8,635	14,885
Unrealized Gains	424	298
Unrealized Losses	0	(2)
Total AFS securities	9,059	15,181
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	1,379,548	1,314,779
Unrealized Gains	82,604	44,523
Unrealized Losses	0	(160)
Total AFS securities	1,462,152	1,359,142
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	1,977,838	1,892,296
Unrealized Gains	62,233	23,407
Unrealized Losses	(1,963)	(15,521)
Total AFS securities	2,038,108	1,900,182
AFS Fixed Income Securities [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	257,182	244,541
Unrealized Gains	1,656	531
Unrealized Losses	(127)	(918)
Total AFS securities	258,711	244,154
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	249,603	245,252
Unrealized Gains	6,484	750
Unrealized Losses	(51)	(2,410)
Total AFS securities	256,036	243,592
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	541,841	541,276
Unrealized Gains	10,027	4,274
Unrealized Losses	(318)	(3,713)
Total AFS securities	551,550	541,837
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	126,881	193,816
Unrealized Gains	27,080	15,273
Unrealized Losses	(1,023)	(2,038)
Total AFS securities	152,938	207,051
Equity Securities [Member] | Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	114,099	181,991
Unrealized Gains	26,343	14,796
Unrealized Losses	(1,023)	(1,998)
Total AFS securities	139,419	194,789
Equity Securities [Member] | Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost/Amortized Cost	12,782	11,825
Unrealized Gains	737	477
Unrealized Losses	0	(40)
Total AFS securities	$ 13,519	$ 12,262

Investments (Fair Value and Gro

Investments (Fair Value and Gross Pre-Tax Net Unrealized Unrecognized Loss of Securities By Length of Time) (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
AFS Fair Value, Less than 12 months		$ 172,847	$ 1,449,183
AFS Unrealized Losses, Less than 12 months	[1]	(1,985)	(19,953)
AFS Fair Value, 12 months or longer		98,866	141,580
AFS Unrealized Losses, 12 months or longer	[1]	(1,497)	(4,900)
AFS Fixed Income Securities [Member]
AFS Fair Value, Less than 12 months		156,419	1,416,504
AFS Unrealized Losses, Less than 12 months	[1]	(962)	(17,915)
AFS Fair Value, 12 months or longer		98,866	141,580
AFS Unrealized Losses, 12 months or longer	[1]	(1,497)	(4,900)
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member]
AFS Fair Value, Less than 12 months			16,006
AFS Unrealized Losses, Less than 12 months	[1]		(87)
AFS Fair Value, 12 months or longer			396
AFS Unrealized Losses, 12 months or longer	[1]		(4)
AFS Fixed Income Securities [Member] | Foreign Government [Member]
AFS Fair Value, Less than 12 months			1,067
AFS Unrealized Losses, Less than 12 months	[1]		(2)
AFS Fair Value, 12 months or longer			0
AFS Unrealized Losses, 12 months or longer	[1]		0
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
AFS Fair Value, Less than 12 months			28,617
AFS Unrealized Losses, Less than 12 months	[1]		(160)
AFS Fair Value, 12 months or longer			0
AFS Unrealized Losses, 12 months or longer	[1]		0
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
AFS Fair Value, Less than 12 months		96,244	761,479
AFS Unrealized Losses, Less than 12 months	[1]	(822)	(12,671)
AFS Fair Value, 12 months or longer		33,616	50,382
AFS Unrealized Losses, 12 months or longer	[1]	(1,141)	(2,850)
AFS Fixed Income Securities [Member] | Asset-Backed Securities [Member]
AFS Fair Value, Less than 12 months		46,992	197,477
AFS Unrealized Losses, Less than 12 months	[1]	(117)	(807)
AFS Fair Value, 12 months or longer		4,665	12,022
AFS Unrealized Losses, 12 months or longer	[1]	(10)	(111)
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 months		6,348	146,944
AFS Unrealized Losses, Less than 12 months	[1]	(4)	(2,196)
AFS Fair Value, 12 months or longer		10,451	15,385
AFS Unrealized Losses, 12 months or longer	[1]	(47)	(214)
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 months		6,835	264,914
AFS Unrealized Losses, Less than 12 months	[1]	(19)	(1,992)
AFS Fair Value, 12 months or longer		50,134	63,395
AFS Unrealized Losses, 12 months or longer	[1]	(299)	(1,721)
Equity Securities [Member]
AFS Fair Value, Less than 12 months		16,428	32,679
AFS Unrealized Losses, Less than 12 months	[1]	(1,023)	(2,038)
AFS Fair Value, 12 months or longer		0	0
AFS Unrealized Losses, 12 months or longer	[1]	0	0
Common Stock [Member] | Equity Securities [Member]
AFS Fair Value, Less than 12 months		16,428	31,148
AFS Unrealized Losses, Less than 12 months	[1]	(1,023)	(1,998)
AFS Fair Value, 12 months or longer		0	0
AFS Unrealized Losses, 12 months or longer	[1]	$ 0	0
Preferred Stock [Member] | Equity Securities [Member]
AFS Fair Value, Less than 12 months			1,531
AFS Unrealized Losses, Less than 12 months	[1]		(40)
AFS Fair Value, 12 months or longer			0
AFS Unrealized Losses, 12 months or longer	[1]		$ 0
[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.

Investments (Number of Securiti

Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) $ in Thousands	Jun. 30, 2016USD ($)Securities	Dec. 31, 2015USD ($)Securities
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Unrealized Unrecognized Loss	$ 3,482	$ 24,859
Eighty Percent to Ninety-Nine Percent [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position | Securities	156	606
Unrealized Unrecognized Loss	$ 3,482	$ 22,971
Sixty Percent to Seventy-Nine Percent [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position | Securities	0	3
Unrealized Unrecognized Loss	$ 0	$ 1,888
Forty Percent to Fifty-Nine Percent [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position | Securities	0	0
Unrealized Unrecognized Loss	$ 0	$ 0
Twenty Percent to Thirty-Nine Percent [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position | Securities	0	0
Unrealized Unrecognized Loss	$ 0	$ 0
Zero Percent to Nineteen Percent [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
Number Of Securities In An Unrealized/Unrecognized Loss Position | Securities	0	0
Unrealized Unrecognized Loss	$ 0	$ 0

Investments (HTM Fixed Income S

Investments (HTM Fixed Income Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Due in one year or less carrying value	$ 84,415
Due after one year through five years carrying value	65,616
Due after five years through 10 years carrying value	10,266
Carrying Value	160,297	$ 201,354
Due in one year or less fair value	85,514
Due after one year through five years fair value	69,914
Due after five years through 10 years fair value	11,633
HTM, Fair Value	$ 167,061	$ 209,544

Investments (AFS Fixed Income s

Investments (AFS Fixed Income securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less fair value	$ 482,867
Due after one year through five years fair value	2,425,517
Due after five years through 10 years fair value	1,647,615
Due after 10 years fair value	115,787
Total AFS fixed income securities	$ 4,671,786	$ 4,408,203

Investments (Other Investment P

Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Carrying Value	$ 76,051	$ 77,842
Alternative Investments [Member]
Carrying Value	65,907	67,834
Remaining Commitment	87,633	71,153
Maximum Exposure to Loss	153,540	138,987
Other Investments [Member]
Carrying Value	76,051	77,842
Remaining Commitment	94,483	74,353
Maximum Exposure to Loss	170,534	152,195
Private Equity [Member] | Alternative Investments [Member]
Carrying Value	28,439	35,088
Remaining Commitment	34,117	30,204
Maximum Exposure to Loss	62,556	65,292
Private Credit [Member] | Alternative Investments [Member]
Carrying Value	23,336	13,246
Remaining Commitment	23,243	15,129
Maximum Exposure to Loss	46,579	28,375
Real Assets [Member] | Alternative Investments [Member]
Carrying Value	14,132	19,500
Remaining Commitment	30,273	25,820
Maximum Exposure to Loss	44,405	45,320
Other Securities [Member]
Carrying Value	10,144	10,008
Remaining Commitment	6,850	3,200
Maximum Exposure to Loss	$ 16,994	$ 13,208

Investments (Aggregated Income

Investments (Aggregated Income Statement Summarized Financial Information for Partnerhips in our Alternative Investment Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 31,182		$ 32,230		$ 61,951		$ 59,147
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ (600)		$ 1,400		$ (1,700)		$ (2,100)
Investments accounted for under the equity method [Member]
Schedule of Equity Method Investments [Line Items]
Net Investment Income		$ (4,600)		$ 8,500		$ 37,000		$ 95,600
Realized gains (losses)		193,200		279,400		981,100		592,500
Net change in unrealized (depreciation) appreciation		(253,900)		(223,400)		(1,236,500)		(866,900)
Net income		$ (65,300)		$ 64,500		$ (218,400)		$ (178,800)

Investments (Investments Pledge

Investments (Investments Pledged as Collateral) (Details) $ in Millions	Jun. 30, 2016USD ($)
Investments Pledged As Collateral [Line Items]
Securities Pledged As Collateral For Reinsurance Obligations	$ 11.4
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	23.5
Securities Pledged As Collateral	128.4
U.S. Government and Government Agencies [Member]
Investments Pledged As Collateral [Line Items]
Securities Pledged As Collateral For Reinsurance Obligations	0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	23.5
Securities Pledged As Collateral	31
Obligations of States and Political Subdivisions [Member]
Investments Pledged As Collateral [Line Items]
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]
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
Commercial Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Securities Pledged As Collateral For Reinsurance Obligations	0
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	1.1
Residential Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Securities Pledged As Collateral For Reinsurance Obligations	1.6
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	86.5
Federal Home Loan Bank of Indianapolis [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	63.6
Federal Home Loan Bank of Indianapolis [Member] | U.S. Government and Government Agencies [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	7.5
Federal Home Loan Bank of Indianapolis [Member] | Obligations of States and Political Subdivisions [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of Indianapolis [Member] | Corporate Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of Indianapolis [Member] | Commercial Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	1.1
Federal Home Loan Bank of Indianapolis [Member] | Residential Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	55
Federal Home Loan Bank of New York [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	29.9
Federal Home Loan Bank of New York [Member] | U.S. Government and Government Agencies [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of New York [Member] | Obligations of States and Political Subdivisions [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of New York [Member] | Corporate Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of New York [Member] | Commercial Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Federal Home Loan Bank of New York [Member] | Residential Mortgage Backed Securities [Member]
Investments Pledged As Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	$ 29.9

Investments (Credit Concentrati

Investments (Credit Concentration Risk) (Details)	Jun. 30, 2016	Dec. 31, 2015
Investments [Abstract]
Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government agencies	10.00%	10.00%

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Investment Income [Line Items]
Net investment income earned	$ 31,182	$ 32,230	$ 61,951	$ 59,147
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	31,753	30,659	63,397	61,626
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	2,204	2,384	4,434	4,176
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	142	23	301	48
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	(611)	1,422	(1,677)	(2,118)
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	$ (2,306)	$ (2,258)	$ (4,504)	$ (4,585)

Investments (OTTI by Asset Type

Investments (OTTI by Asset Type) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
OTTI Losses Gross	$ 559	$ 4,451	$ 4,152	$ 6,545
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	(10)	0	(10)	0
OTTI Losses Recognized in Earnings	549	4,451	4,142	6,545
AFS Fixed Income Securities [Member]
OTTI Losses Gross	202	183	1,175	1,193
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	(10)	0	(10)	0
OTTI Losses Recognized in Earnings	192	183	1,165	1,193
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
OTTI Losses Gross	104	183	1,077	1,192
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0	0	0
OTTI Losses Recognized in Earnings	104	183	1,077	1,192
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
OTTI Losses Gross	98		98	1
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	(10)		(10)	0
OTTI Losses Recognized in Earnings	88		88	1
Total AFS Securities [Member] | Equity Securities [Member]
OTTI Losses Gross	357	4,268	2,977	5,352
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0	0	0
OTTI Losses Recognized in Earnings	357	4,268	2,977	5,352
Common Stock [Member] | Total AFS Securities [Member] | Equity Securities [Member]
OTTI Losses Gross	357	4,088	2,974	5,172
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income	0	0	0	0
OTTI Losses Recognized in Earnings	$ 357	4,088	2,974	5,172
Preferred Stock [Member] | Total AFS Securities [Member] | Equity Securities [Member]
OTTI Losses Gross		180	3	180
Other-than-temporary impairments on fixed income securities recognized in other comprehensive income		0	0	0
OTTI Losses Recognized in Earnings		$ 180	$ 3	$ 180

Investments (Components Of Net

Investments (Components Of Net Realized Gains, Excluding OTTI Charges) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
HTM securities realized gain	$ 3	$ 2	$ 3	$ 2
HTM fixed income securities losses	0	0	(1)	(1)
Other investments losses	0	0	(4)	(654)
Total net realized gains (excluding OTTI charges)	2,314	1,031	3,203	22,008
Proceeds from sale of available for sale securities	88,700	19,500	105,900	157,900
Fixed Income Securities [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
AFS securities gains	365	487	985	1,989
AFS securities losses	(5)	(18)	(41)	(130)
Equity Securities [Member]
Schedule of Available-for-sale and held-to-maturity Securities [Line Items]
AFS securities gains	2,171	830	2,501	22,148
AFS securities losses	$ (220)	$ (270)	$ (240)	$ (1,346)

Indebtedness (Details)

Indebtedness (Details) $ in Millions	Jun. 30, 2016USD ($)
Zero Point Fifty Nine Percent Borrowing From Federal Home Loan Bank Due March 18, 2016 [Member]
Short-term Debt [Line Items]
Outstanding Borrowing With The Federal Home Loan Bank Of New York	$ 25
Unpaid principal amount interest rate	0.59%
Zero Point Fifty Two Percent Borrowing From Federal Home Loan Bank Due April 28, 2016 [Member]
Short-term Debt [Line Items]
Outstanding Borrowing With The Federal Home Loan Bank Of New York	$ 15
Unpaid principal amount interest rate	0.52%
Zero Point Fifty Three Percent Borrowing From Federal Home Loan Bank Due May 19, 2016 [Member]
Short-term Debt [Line Items]
Outstanding Borrowing With The Federal Home Loan Bank Of New York	$ 15
Unpaid principal amount interest rate	0.53%
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Short-term Debt [Line Items]
Outstanding Borrowing With The Federal Home Loan Bank Of New York	$ 25
Unpaid principal amount interest rate	1.61%

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Value and Estimated Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Carrying Amount [Member]
Held-to-maturity securities	$ 160,297	$ 201,354
Available-for-sale securities	4,671,786	4,408,203
Equity securities, AFS	152,938	207,051
Short-term investments	205,451	194,819
Short-term debt	60,000	60,000
Long-term debt	328,433	328,192
Carrying Amount [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Long-term debt	49,900	49,898
Carrying Amount [Member] | Six Point Seventy Percent Senior Notes [Member]
Long-term debt	99,422	99,415
Carrying Amount [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Long-term debt	185,000	185,000
Carrying Amount [Member] | Long Term Debt Excluding Issuance Costs [Member]
Long-term debt	334,322	334,313
Carrying Amount [Member] | Unamortized Debt Issuance Costs [Member]
Unamortized debt issuance costs	(5,889)	(6,121)
Carrying Amount [Member] | Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Short-term debt	15,000	15,000
Carrying Amount [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Short-term debt	45,000	45,000
Fair Value [Member]
Held-to-maturity securities	167,061	209,544
Available-for-sale securities	4,671,786	4,408,203
Equity securities, AFS	152,938	207,051
Short-term investments	205,451	194,819
Short-term debt	60,114	60,060
Long-term debt	373,971	359,766
Fair Value [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Long-term debt	61,003	56,929
Fair Value [Member] | Six Point Seventy Percent Senior Notes [Member]
Long-term debt	118,792	110,363
Fair Value [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Long-term debt	194,176	192,474
Fair Value [Member] | Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Short-term debt	15,001	14,977
Fair Value [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Short-term debt	$ 45,113	$ 45,083

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Disclosures of Fair Value Assets) (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Available-for-sale Securities, Debt Securities		$ 4,671,786	$ 4,408,203
Equity securities, AFS		152,938	207,051
Total AFS securities		4,824,724	4,615,254
Short-term investments		205,451	194,819
Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		4,671,786	4,408,203
Equity securities, AFS		152,938	207,051
Total AFS securities		4,824,724	4,615,254
Short-term investments		205,451	194,819
Total assets measured at fair value		5,030,175	4,810,073
U.S. Government and Government Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		96,170	104,115
Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		9,059	15,181
Obligations of States and Political Subdivisions [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		1,462,152	1,359,142
Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		2,038,108	1,900,182
Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		258,711	244,154
Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		256,036	243,592
Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		551,550	541,837
Common Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS		139,419	194,789
Preferred Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS		13,519	12,262
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	38,628	42,702
Equity securities, AFS	[1]	149,612	203,779
Total AFS securities	[1]	188,240	246,481
Short-term investments	[1]	205,451	194,819
Total assets measured at fair value	[1]	393,691	441,300
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	[1]	38,628	42,702
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	[1]	0	0
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	[1]	0	0
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	[1]	0	0
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	[1]	0	0
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	[1]	0	0
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	[1]	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Common Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS	[1]	136,093	191,517
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Preferred Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS	[1]	13,519	12,262
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	4,633,158	4,365,501
Equity securities, AFS	[1]	0	0
Total AFS securities	[1]	4,633,158	4,365,501
Short-term investments	[1]	0	0
Total assets measured at fair value	[1]	4,633,158	4,365,501
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	[1]	57,542	61,413
Significant Other Observable Inputs (Level 2) [Member] | Foreign Government [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	9,059	15,181
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]	1,462,152	1,359,142
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	2,038,108	1,900,182
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	258,711	244,154
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	256,036	243,592
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities	[1]	551,550	541,837
Significant Other Observable Inputs (Level 2) [Member] | Common Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS	[1]	0	0
Significant Other Observable Inputs (Level 2) [Member] | Preferred Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS	[1]	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities, Debt Securities		0	0
Equity securities, AFS		3,326	3,272
Total AFS securities		3,326	3,272
Short-term investments		0	0
Total assets measured at fair value		3,326	3,272
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
Significant Unobservable Inputs (Level 3) [Member] | Common Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS		3,326	3,272
Significant Unobservable Inputs (Level 3) [Member] | Preferred Stock [Member] | Fair Value, Measurements, Recurring [Member]
Equity securities, AFS		$ 0	$ 0
[1]	1 There were no transfers of securities between Level 1 and Level 2.

Fair Value Measurements (Change

Fair Value Measurements (Changes in Fair Value of Securities Using Level 3 Inputs) (Details) - Common Stock [Member] - AFS Fixed Maturity Securities [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, December 31, 2015	$ 3,272
Total net (losses) gains for the period included in other comprehensive income	0
Total net (losses) gains for the period included in net income	0
Purchases	1,854
Sales	(1,800)
Issuances	0
Settlements	0
Transfers into Level 3	0
Transfers out of Level 3	0
Fair Value, June 30, 2016	$ 3,326

Fair Value Measurements (Quan45

Fair Value Measurements (Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	$ 167,061	$ 209,544
Short-term debt	60,000	60,000
Long-term debt	328,433	328,192
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	61,003	56,929
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	118,792	110,363
Five Point Eight Hundred Seventy Five Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	194,176	192,474
Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	373,971	359,766
Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	15,001	14,977
One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	45,113	45,083
Short-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	60,114	60,060
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	136,273	181,880
Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	26,106	22,015
Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	126	1,028
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	4,556	4,621
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, Fair Value	0	0
Short-term debt	0	0
Long-term debt	194,176	192,474
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	194,176	192,474
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	159,496	206,208
Short-term debt	60,114	60,060
Long-term debt	179,795	167,292
Significant Other Observable Inputs (Level 2) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	61,003	56,929
Significant Other Observable Inputs (Level 2) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	118,792	110,363
Significant Other Observable Inputs (Level 2) [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Significant Other Observable Inputs (Level 2) [Member] | Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	15,001	14,977
Significant Other Observable Inputs (Level 2) [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	45,113	45,083
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	136,273	181,880
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	18,541	18,679
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	126	1,028
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	4,556	4,621
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	7,565	3,336
Short-term debt	0	0
Long-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | Five Point Eight Hundred Seventy Five Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | Zero Point Sixty Three Percent Borrowing From Federal Home Loan Bank Due July 22, 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | One Point Twenty Five Percent Borrowing From Federal Home Loan Bank [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term debt	0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	7,565	3,336
Significant Unobservable Inputs (Level 3) [Member] | Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	$ 0	$ 0

Reinsurance (List of Direct, As

Reinsurance (List of Direct, Assumed, and Ceded Reinsurance Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Premiums written:
Direct	$ 665,862	$ 621,408	$ 1,312,140	$ 1,220,191
Assumed	7,788	4,960	14,108	11,041
Ceded	(95,510)	(94,235)	(182,749)	(181,011)
Net	578,140	532,133	1,143,499	1,050,221
Premiums earned:
Direct	612,406	576,107	1,219,067	1,138,149
Assumed	7,171	5,093	13,441	11,001
Ceded	(87,645)	(90,891)	(178,118)	(182,718)
Net	531,932	490,309	1,054,390	966,432
Loss and loss expense incurred:
Direct	362,064	316,648	723,703	628,894
Assumed	6,140	4,228	12,495	8,890
Ceded	(69,725)	(29,315)	(140,575)	(61,224)
Net	298,479	291,561	595,623	576,560
National Flood Insurance Program [Member]
Premiums written:
Ceded	(63,906)	(62,479)	(117,154)	(116,321)
Premiums earned:
Ceded	(56,667)	(58,781)	(113,481)	(117,779)
Loss and loss expense incurred:
Ceded	$ (24,261)	$ (14,684)	$ (64,979)	$ (20,933)

Reinsurance (Ceded Premiums and

Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Ceded premiums written	$ (95,510)	$ (94,235)	$ (182,749)	$ (181,011)
Ceded premiums earned	(87,645)	(90,891)	(178,118)	(182,718)
Ceded loss and loss expense incurred	(69,725)	(29,315)	(140,575)	(61,224)
National Flood Insurance Program [Member]
Ceded premiums written	(63,906)	(62,479)	(117,154)	(116,321)
Ceded premiums earned	(56,667)	(58,781)	(113,481)	(117,779)
Ceded loss and loss expense incurred	$ (24,261)	$ (14,684)	$ (64,979)	$ (20,933)
Percentage of NFIP claims ceded by federal government			100.00%

Segment Information Narrative (

Segment Information Narrative (Details)	6 Months Ended
	Jun. 30, 2016
Number of Operating Segments	4

Segment Information (Revenue by

Segment Information (Revenue by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Total net premiums earned	$ 531,932	$ 490,309	$ 1,054,390	$ 966,432
Net investment income	31,182	32,230	61,951	59,147
Net realized investment gains (losses)	1,765	(3,420)	(939)	15,463
Total investment revenues	32,947	28,810	61,012	74,610
Other income	3,868	2,854	4,819	4,823
Total revenues	568,747	521,973	1,120,221	1,045,865
Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	414,844	379,768	818,423	746,970
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	98,896	88,658	194,315	175,013
Standard Commercial Lines [Member] | Workers Compensation [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	75,251	70,954	151,251	139,431
Standard Commercial Lines [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	129,283	119,207	257,368	234,178
Standard Commercial Lines [Member] | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	73,591	66,549	143,769	131,112
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	24,651	23,178	48,555	45,877
Standard Commercial Lines [Member] | Bonds Segment [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	5,665	5,106	11,129	10,106
Standard Commercial Lines [Member] | Other Commercial [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	3,940	3,553	7,779	7,021
Standard Commercial Lines [Member] | Miscellaneous Income [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	3,567	2,563	4,257	4,232
Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	71,125	72,362	141,590	145,141
Standard Personal Lines [Member] | Miscellaneous Income [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	301	291	561	591
Standard Personal Lines [Member] | Personal Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	35,881	36,740	71,661	73,750
Standard Personal Lines [Member] | Homeowners [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	33,411	33,731	66,311	67,452
Standard Personal Lines [Member] | Other Personal [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	1,532	1,600	3,057	3,348
Excess And Surplus Operations [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	49,831	41,033	99,196	79,144
Excess And Surplus Operations [Member] | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	2,663	1,776	5,061	3,506
Excess And Surplus Operations [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	35,452	28,793	70,974	55,519
Excess And Surplus Operations [Member] | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	11,716	10,464	23,160	20,119
Excess And Surplus Operations [Member] | Miscellaneous Income [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	$ 0	$ 0	$ 1	$ 0

Segment Information (Income Bef

Segment Information (Income Before Federal Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Net investment income	$ 31,182	$ 32,230	$ 61,951	$ 59,147
Net realized investment gains (losses)	1,765	(3,420)	(939)	15,463
Total investment income, before federal income tax	32,947	28,810	61,012	74,610
Tax on investment income	8,275	6,254	14,538	18,572
Total investment income, after federal income tax	24,672	22,556	46,474	56,038
Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ 40,173	$ 35,241	$ 71,105	$ 65,277
GAAP combined ratio	90.20%	90.70%	91.30%	91.20%
Statutory combined ratio	88.60%	90.10%	89.10%	89.90%
Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ 6,125	$ (4,655)	$ 14,730	$ (7,121)
GAAP combined ratio	91.40%	106.50%	89.60%	104.90%
Statutory combined ratio	89.90%	105.40%	90.10%	105.20%
Excess And Surplus Operations [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ (2,521)	$ (1,462)	$ (1,103)	$ (3,011)
GAAP combined ratio	105.10%	103.60%	101.10%	103.80%
Statutory combined ratio	102.70%	102.70%	100.60%	102.50%

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Results to Income Before Federal Income Tax (Details)) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Investment income, before federal income tax	$ 32,947	$ 28,810	$ 61,012	$ 74,610
Interest expense	(5,620)	(5,612)	(11,226)	(11,216)
General corporate and other expenses	(8,793)	(5,557)	(20,332)	(15,484)
Income before federal income tax	62,311	46,765	114,186	103,055
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	40,173	35,241	71,105	65,277
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	6,125	(4,655)	14,730	(7,121)
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	(2,521)	(1,462)	(1,103)	(3,011)
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total all segments	$ 76,724	$ 57,934	$ 145,744	$ 129,755

Retirement Plans (Components of

Retirement Plans (Components of Net Periodic Benefit Cost) (Details) - Pension Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0	$ 1,912	$ 1,606	$ 3,825
Interest cost	3,101	3,407	6,203	6,816
Expected return on plan assets	(3,988)	(3,990)	(7,976)	(7,981)
Amortization of unrecognized net actuarial loss	1,481	1,644	2,961	3,287
Total net periodic cost	$ 594	$ 2,973	$ 2,794	$ 5,947

Retirement Plans (Weighted-Aver

Retirement Plans (Weighted-Average Expense Assumptions) (Details) - Pension Plan [Member] - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.69%	4.29%
Effective interest rate for calculation of service cost	4.52%	0.00%
Effective interest rate for calculation of interest cost	4.02%	0.00%
Expected return on plan assets	6.37%	6.27%
Rate of compensation increase	4.00%	4.00%
Contributions by employer	$ 26.4
Scenario, Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated contribution from the employer			$ 56

Comprehensive Income (Component

Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net income, Gross	$ 62,311	$ 46,765	$ 114,186	$ 103,055
Unrealized holding gains (losses) during the period, Gross	55,675	(60,244)	121,412	(36,267)
Non-credit portion of OTTI recognized in OCI, Gross	(10)		(10)
Amounts reclassified into net income: HTM securities, Gross	(19)	(185)	(91)	(446)
Amounts reclassified into net income: Non-credit OTTI, Gross				357
Realized (gains) losses on AFS securities, Gross	(1,762)	3,422	937	(16,473)
Total unrealized gains (losses) on investment securities, Gross	53,884	(57,007)	122,248	(52,829)
Amount reclassified into net income: Net actuarial loss, Gross	1,517	1,709	3,033	3,418
Total defined pension and other post-retirement benefit plans, Gross	1,517	1,709	3,033	3,418
Other comprehensive income (loss), Gross	55,401	(55,298)	125,281	(49,411)
Comprehensive income (loss) before tax	117,712	(8,533)	239,467	53,644
Net income, Tax	18,710	12,997	33,553	29,579
Unrealized holding gains (losses) during the period, Tax	19,487	(21,084)	42,495	(12,693)
Non-credit portion of OTTI recognized in OCI, Tax	(4)		(4)
Amounts reclassified into net income: HTM securities, Tax	(7)	(65)	(32)	(156)
Amounts reclassified into net income: Non-credit OTTI, Tax				125
Realized (gains) losses on AFS securities, Tax	(617)	1,197	328	(5,766)
Total unrealized gains (losses) on investment securities, Tax	18,859	(19,952)	42,787	(18,490)
Amount reclassified into net income: Net actuarial loss, Tax	532	598	1,062	1,196
Total defined pension and other post-retirement benefit plans, Tax	532	598	1,062	1,196
Other comprehensive income (loss), Tax	19,391	(19,354)	43,849	(17,294)
Comprehensive income (loss), Tax	38,101	(6,357)	77,402	12,285
Net income	43,601	33,768	80,633	73,476
Unrealized holding gains (losses) arising during period	36,188	(39,160)	78,917	(23,574)
Non-credit portion of OTTI recognized in OCI	(6)		(6)
Amounts reclassified into net income: HTM Securities	(12)	(120)	(59)	(290)
Amounts reclassified into net income: Non-credit OTTI	0	0	0	232
Realized (gains) losses on available-for-sale securities	(1,145)	2,225	609	(10,707)
Total unrealized gains (losses) on investment securities	35,025	(37,055)	79,461	(34,339)
Amount reclassified into net income: Net actuarial loss	985	1,111	1,971	2,222
Total defined benefit pension and post-retirement plans	985	1,111	1,971	2,222
Other comprehensive income (loss)	36,010	(35,944)	81,432	(32,117)
Comprehensive income (loss)	$ 79,611	$ (2,176)	$ 162,065	$ 41,359

Comprehensive Income (Compone55

Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			$ (9,425)
Amounts reclassified into net income: Non-credit OTTI	$ 0	$ 0	0	$ 232
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans			0
Amount reclassified into net income: Net actuarial loss	985	1,111	1,971	2,222
Amounts reclassified from AOCI, HTM related	(12)	(120)	(59)	(290)
Amounts reclassified from AOCI, All Other	(1,145)	2,225	609	(10,707)
Other comprehensive income	36,010	(35,944)	81,432	(32,117)
Other Comprehensive Income, Defined Benefit Pension and Post Retirement Plans, Adjustment, Net of Tax	985	$ 1,111	1,971	2,222
Ending Balance, June 30, 2016	72,007		72,007
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			45,083
OCI before reclassifications			78,917
Other comprehensive income			79,526
Ending Balance, June 30, 2016	124,609		124,609
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			44,995
OCI before reclassifications			78,911
Amounts reclassified from AOCI			550
Other comprehensive income			79,461
Ending Balance, June 30, 2016	124,456		124,456
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			(282)
OCI before reclassifications			(6)
Other comprehensive income			(6)
Ending Balance, June 30, 2016	(288)		(288)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			194
OCI before reclassifications			0
Other comprehensive income			(59)
Ending Balance, June 30, 2016	135		135
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			(54,420)
Amount reclassified into net income: Net actuarial loss			1,971
Ending Balance, June 30, 2016	(52,449)		(52,449)
Accumulated other comprehensive income (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2015			(9,425)
OCI before reclassifications			78,911
Amounts reclassified from AOCI			2,521
Other comprehensive income			81,432	$ (32,117)
Ending Balance, June 30, 2016	$ 72,007		$ 72,007

Comprehensive Income (Reclassif

Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net realized gains (losses)	$ 1,765	$ (3,420)	$ (939)	$ 15,463
Net investment income	31,182	32,230	61,951	59,147
Loss and loss expense incurred	298,479	291,561	595,623	576,560
Policy acquisition costs	190,731	169,770	373,958	334,493
Income before federal income tax	62,311	46,765	114,186	103,055
Total federal income tax expense	(18,710)	(12,997)	(33,553)	(29,579)
Net income (loss)	43,601	33,768	80,633	73,476
Reclassification out of AOCI
Net income (loss)	(172)	3,216	2,521	(8,543)
Reclassification out of AOCI | Non-credit OTTI on Disposed Securities [Member]
Net realized gains (losses)	0	0	0	357
Income before federal income tax	0	0	0	357
Total federal income tax expense	0	0	0	(125)
Net income (loss)	0	0	0	232
Reclassification out of AOCI | Held-to-maturity Securities [Member]
Net realized gains (losses)	60	87	88	137
Net investment income	(79)	(272)	(179)	(583)
Income before federal income tax	(19)	(185)	(91)	(446)
Total federal income tax expense	7	65	32	156
Net income (loss)	(12)	(120)	(59)	(290)
Reclassification out of AOCI | Available-for-sale Securities [Member]
Net realized gains (losses)	(1,762)	3,422	937	(16,473)
Income before federal income tax	(1,762)	3,422	937	(16,473)
Total federal income tax expense	617	(1,197)	(328)	5,766
Net income (loss)	(1,145)	2,225	609	(10,707)
Pension Plan [Member] | Reclassification out of AOCI
Loss and loss expense incurred	329	372	658	743
Policy acquisition costs	1,188	1,337	2,375	2,675
Income before federal income tax	1,517	1,709	3,033	3,418
Total federal income tax expense	(532)	(598)	(1,062)	(1,196)
Net income (loss)	$ 985	$ 1,111	$ 1,971	$ 2,222