Selective Insurance (SIGI) 10-Q 6 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 24, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-33067
Entity Registrant Name	SELECTIVE INSURANCE GROUP, INC
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-2168890
Entity Address, Address Line One	40 Wantage Avenue
Entity Address, City or Town	Branchville
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07890
City Area Code	973
Local Phone Number	948-3000
Title of 12(b) Security	Common Stock, par value $2 per share
Trading Symbol	SIGI
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock , Shares Outstanding		59,707,580
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Entity Central Index Key	0000230557
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
ASSETS
Fixed income securities, held-to-maturity – at carrying value (fair value: $21,921 - 2020; $21,975 - 2019)	$ 20,408	$ 20,800
Less: allowance for credit losses	(28)	0
Fixed income securities, held-to-maturity, net of allowance for credit losses	20,380	20,800
Fixed income securities, available-for-sale – at fair value (allowance for credit losses: $15,787 - 2020; amortized cost: $5,877,779 – 2020; $5,879,986 – 2019)	5,945,360	6,095,620
Commercial mortgage loans - at carrying value (fair value: $13,856 – 2020)	14,096	0
Less: allowance for credit losses	(240)	0
Commercial mortgage loans, net of allowance for credit losses	13,856	0
Equity securities – at fair value (cost: $116,249 – 2020; $72,061 – 2019)	99,989	72,937
Short-term investments (at cost which approximates fair value)	517,558	282,490
Other investments	244,934	216,807
Total investments (Note 4 and 6)	6,842,077	6,688,654
Cash	9,429	300
Restricted cash	5,177	7,675
Interest and dividends due or accrued	43,893	44,846
Premiums receivable	815,271	830,301
Less: allowance for credit losses (Note 7)	(18,000)	(6,400)
Premiums receivable, net of allowance for credit losses	797,271	823,901
Reinsurance recoverable	565,036	577,635
Less: allowance for credit losses (Note 8)	1,502	4,400	[1]
Reinsurance recoverable, net of allowance for credit losses	563,534	573,235
Prepaid reinsurance premiums	162,491	166,705
Deferred federal income tax (Note 14)	43,099	6,776
Property and equipment – at cost, net of accumulated depreciation and amortization of: $231,651 – 2020; $227,566 – 2019	80,061	77,409
Deferred policy acquisition costs	269,581	271,186
Goodwill	7,849	7,849
Other assets	150,588	128,614
Total assets	8,975,050	8,797,150
Liabilities And Stockholders' Equity
Reserve for loss and loss expense (Note 9)	4,103,635	4,067,163
Unearned premiums	1,514,577	1,523,167
Short-term debt (Note 5)	302,000	0
Long-term Debt (Note 5)	550,577	550,597
Current federal income tax	12,352	2,987
Accrued salaries and benefits	74,031	126,753
Other liabilities	321,422	331,547
Total liabilities	6,878,594	6,602,214
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: 103,832,370 – 2020; 103,484,159 – 2019	207,665	206,968
Additional paid-in capital	427,328	418,521
Retained earnings	2,083,340	2,080,529
Accumulated other comprehensive income (loss) (Note 12)	(22,117)	81,750
Treasury stock – at cost (shares: 44,124,825 – 2020; 44,023,006 – 2019)	(599,760)	(592,832)
Total stockholders' equity	2,096,456	2,194,936
Commitments and contingencies
Total liabilities and stockholders' equity	$ 8,975,050	$ 8,797,150
[1]	See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fixed income securities, held-to-maturity, fair value	$ 21,921	$ 21,975
Fixed income securities, available-for-sale, amortized cost	5,877,779	5,879,986
Fixed income securities, available-for-sale, allowance for credit losses	15,787	0
Commercial mortgage loans, fair value	13,856	0
Equity securities, cost	116,249	72,061
Property and equipment - at cost, accumulated depreciation and amortization	$ 231,651	$ 227,566
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	103,832,370	103,484,159
Treasury stock - at cost, shares	44,124,825	44,023,006

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues:
Net premiums earned	$ 651,703	$ 632,573
Net investment income earned	55,967	50,618
Net realized and unrealized (losses) gains:
Net realized investment gains on disposals	4,100	3,444
Unrealized (losses) gains on equity securities	(17,137)	10,111
Other-than-temporary impairments	(31,629)	(104)
Total net realized and unrealized (losses) gains	(44,666)	13,451
Other income	1,825	2,320
Total revenues	664,829	698,962
Expenses:
Loss and loss expense incurred	400,324	386,579
Amortization of deferred policy acquisition costs	136,501	129,674
Other insurance expenses	95,346	85,079
Interest expense	7,601	11,526
Corporate expenses	9,060	12,410
Total expenses	648,832	625,268
Income before federal income tax	15,997	73,694
Federal income tax expense:
Current	9,886	12,581
Deferred	(9,125)	(235)
Total federal income tax expense	761	12,346
Net income	$ 15,236	$ 61,348
Earnings per share:
Basic net income	$ 0.26	$ 1.04
Diluted net income	$ 0.25	$ 1.02

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net income	$ 15,236	$ 61,348
Unrealized holding (losses) gains arising during period	(74,245)	81,313
Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income	(51,658)	0
Amounts reclassified into net income: Held-to-maturity securities	20	(7)
Amounts reclassified into net income: Net realized losses (gains) on disposals and intent-to-sell OTTI on AFS securities	8,948	(851)
Amounts reclssified into net income: Credit loss expense recognized in OTTI	12,472	0
Total unrealized (losses) gains on investment securities	(104,463)	80,455
Amount reclassified into net income: Net actuarial loss	596	525
Total defined benefit pension and post-retirement plans	596	525
Other comprehensive (loss) income	(103,867)	80,980
Comprehensive (loss) income	$ (88,631)	$ 142,328

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]
Cumulative effect of new accounting principle in period of adoption | Accounting Standards Update 2016-02 [Member]				$ 342
Cumulative effect of new accounting principle in period of adoption | Accounting Standards Update 2016-13 [Member]				0
Balance at beginning of year, as adjusted				1,858,756
Beginning of year at Dec. 31, 2018		$ 205,697	$ 390,315	1,858,414	$ (77,956)	$ (584,668)
Dividend reinvestment plan		11	365
Stock purchase and compensation plans		743	8,201
Net income	$ 61,348			61,348
Dividends to stockholders				(11,985)
Other comprehensive (loss) income	80,980				80,980
Acquisition of treasury stock						(6,585)
End of period at Mar. 31, 2019	$ 1,925,222	206,451	398,881	1,908,119	3,024	(591,253)
Dividends declared per share to stockholders	$ 0.20
Common stock, shares outstanding, beginning of period at Dec. 31, 2018	58,948,554
Dividend reinvestment plan, shares	5,694
Stock purchase and compensation plan, shares	371,628
Acquisition of treasury stock, shares	(102,971)
Common stock, shares outstanding, end of period at Mar. 31, 2019	59,222,905
Cumulative effect of new accounting principle in period of adoption	$ 1,435
Cumulative effect of new accounting principle in period of adoption | Accounting Standards Update 2016-02 [Member]				0
Cumulative effect of new accounting principle in period of adoption | Accounting Standards Update 2016-13 [Member]				1,435
Balance at beginning of year, as adjusted				2,081,964
Beginning of year at Dec. 31, 2019	2,194,936	206,968	418,521	2,080,529	81,750	(592,832)
Dividend reinvestment plan		14	408
Stock purchase and compensation plans		683	8,399
Net income	15,236			15,236
Dividends to stockholders				(13,860)
Other comprehensive (loss) income	(103,867)				(103,867)
Acquisition of treasury stock						(6,928)
End of period at Mar. 31, 2020	$ 2,096,456	$ 207,665	$ 427,328	$ 2,083,340	$ (22,117)	$ (599,760)
Dividends declared per share to stockholders	$ 0.23
Common stock, shares outstanding, beginning of period at Dec. 31, 2019	59,461,153
Dividend reinvestment plan, shares	6,975
Stock purchase and compensation plan, shares	341,236
Acquisition of treasury stock, shares	(101,819)
Common stock, shares outstanding, end of period at Mar. 31, 2020	59,707,545

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	Mar. 31, 2020	Mar. 31, 2019
Preferred stock, par value per share	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Series A Preferred Stock [Member]
Preferred stock, par value per share	$ 0	$ 0
Preferred stock, shares authorized	300,000	300,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities
Net income	$ 15,236	$ 61,348
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	15,415	16,278
Stock-based compensation expense	7,038	6,677
Undistributed gains of equity method investments	(5,602)	(971)
Proceeds from equity investments, in excess of current year earnings	614	1,771
Net realized and unrealized (gains) losses	44,666	(13,451)
Loss on disposal of fixed assets	14	0
Changes in assets and liabilities:
Increase in reserve for loss and loss expense, net of reinsurance recoverable	49,077	68,607
(Decrease) increase in unearned premiums, net of prepaid reinsurance	(4,376)	40,374
Decrease in net federal income taxes	276	12,044
Decrease (increase) in premiums receivable	25,572	(44,396)
Decrease (increase) in deferred policy acquisition costs	1,605	(8,142)
Decrease (increase) in interest and dividends due or accrued	880	(491)
Decrease in accrued salaries and benefits	(52,722)	(38,529)
Decrease (increase) in other assets	4,583	(8,711)
Decrease in other liabilities	(62,959)	(45,769)
Net Cash Provided by Operating Activities	39,317	46,639
Investing Activities
Purchase of fixed income securities, available-for-sale	(319,539)	(474,962)
Purchase of commercial mortgage loans	(14,096)	0
Purchase of equity securities	(45,511)	(6,702)
Purchase of other investments	(27,433)	(12,178)
Purchase of short-term investments	(2,086,599)	(2,416,285)
Sale of fixed income securities, available-for-sale	101,671	218,411
Sale of short-term investments	1,851,532	2,449,725
Redemption and maturities of fixed income securities, held-to-maturity	405	579
Redemption and maturities of fixed income securities, available-for-sale	227,686	86,572
Sale of equity securities	1,320	3,721
Sale of other investments	0	4,995
Distributions from other investments	3,152	11,350
Purchase of property and equipment	(8,416)	(7,955)
Net Cash (Used in) Investing Activities	(315,828)	(142,729)
Financing Activities
Dividends to stockholders	(13,313)	(11,462)
Acquisition of treasury stock	(6,928)	(6,585)
Net proceeds from stock purchase and compensation plans	1,525	1,760
Proceeds from borrowings	387,000	341,256
Repayments of borrowings	(85,000)	(235,000)
Repayments of finance lease obligations	(142)	(284)
Net Cash Provided by (Used in) Financing Activities	283,142	89,685
Cash and restricted cash, beginning of year	7,975	16,919
Cash and restricted cash, end of period	14,606	10,514
Net increase (decrease) in cash and restricted cash	$ 6,631	$ (6,405)

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2020
Basis of Presentation And Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation and Accounting Policies (a) Basis of Presentation The words "Company,” “we,” “us,” or “our” refer to Selective Insurance Group, Inc. (the "Parent"), and its subsidiaries except as expressly indicated or the context requires otherwise. We have prepared our interim unaudited consolidated financial statements (“Financial Statements”) 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. In preparing the Financial Statements in conformity with GAAP, we are required to make estimates and assumptions that affect the reported financial statement balances and 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. Our Financial Statements reflect all adjustments that, in our opinion, are normal, recurring, and necessary for a fair presentation of our results of operations and financial condition. Our Financial Statements cover the first quarters ended March 31, 2020 (“ First Quarter 2020 ”) and March 31, 2019 (“ First Quarter 2019 ”). These 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, 2019 (“ 2019 Annual Report”) filed with the SEC. (b) Accounting Policies There have been no material changes from the accounting policies disclosed in Note 2. "Summary of Significant Accounting Policies" in Item 8. “Financial Statements and Supplementary Data.” of our 2019 Annual Report other than those associated with our First Quarter 2020 adoption of ASU 2016-13, Financial Instruments - Credit Losses ("CECL") and our recent investment allocation to commercial mortgage loans ("CMLs"). The pertinent additions and changes to our accounting policies are centered around the following items: (i) Investments, (ii) Allowance for Uncollectible Premiums Receivable, and (iii) Allowance for Uncollectible Reinsurance Recoverable. Investments Fixed Income Securities We have updated our policy associated with our review of fixed income securities for other-than-temporary impairments ("OTTI"), and we follow a two-step process: (i) We review our fixed income securities in an unrealized loss position to determine: (i) if we have the intent to sell the security; or (ii) if it is more likely than not we will be required to sell the security before its anticipated recovery. If we determine that we have the intent or likely requirement to sell the security, we write down its amortized cost to its fair value. In writing down amortized cost, any amount previously recorded as an allowance for credit losses is reversed and any incremental impairment is recorded directly to earnings as OTTI. (ii) If we do not have either the intent or likely requirement to sell the security, our evaluation for expected credit losses primarily focuses on performing a discounted cash flow (“DCF”) analysis on each of our fixed income securities to determine if an allowance for credit loss is required. We incorporate the results of the DCF analysis on individual security holdings into our calculation of the allowance for credit losses as follows: • For our held-to-maturity ("HTM") portfolio, the allowance for credit losses is calculated as the shortfall between amortized cost at the reporting date and the present value of future cash flows calculated in the DCF analysis. • For our available-for-sale ("AFS") portfolio and fixed income securities included in our short-term investment portfolio, the allowance for credit losses is calculated in the same manner as for the HTM portfolio; but the allowance amount is limited to the difference between the security’s amortized cost and fair value, or the fair value floor. This treatment is appropriate as we have the ability to recover the amortized cost of an AFS security either through: (i) collection of the contractual cash flows; or (ii) sale of the security. Fair value declines on our AFS securities not recorded through OTTI are recognized in accumulated other comprehensive income, after tax. Our DCF analyses calculate the present value of future cash flows using various models that are specific to the major security types within our portfolio. These models use security-specific information as well as forecasted macroeconomic data to determine possible expected credit loss scenarios based on projected changes in the economy. The forecasted economic data incorporated into the models is based on the Federal Reserve Board’s annual supervisory stress test review on certain large banks and financial institutions. Additionally, we have the ability to incorporate internally-developed forecast information into the models as we deem appropriate. Model scenarios include a baseline assumption with projections for moderate economic expansion, an adverse assumption with projections for a weakening economy, and a severely adverse assumption with projections for a global recession. In developing our best estimate of the allowance for credit losses, we consider our outlook as to the probability of each of these scenarios occurring over the estimated contractual cash flows of our investment portfolio. For additional information about the various assumptions we make, including the discount rates used in our DCF analyses, see Note 2. "Summary of Significant Accounting Policies" in Item 8. “Financial Statements and Supplementary Data.” of our 2019 Annual Report. The allowance for credit losses are recorded as a contra-asset reflected in the carrying value of the investment on the Consolidated Balance Sheet, and are charged to earnings as credit loss expense, which is a component of "Other-than-temporary impairments" within "Net realized and unrealized (losses) gains" on our Consolidated Statements of Income. The income statement treatment is consistent with how we accounted for credit losses prior to the adoption of CECL. However, subsequent changes in the expected cash flows associated with a future period's updated DCF analysis are recorded as an increase to (or reversal of) credit loss expense with the offset recorded to the allowance. We charge write-offs against the allowance when either: (i) we determine the recovery of amortized cost to be uncollectible based on our evaluation of the financial condition of the issuer; (ii) we have the intent, or requirement, to sell a security for which an allowance for credit losses was previously established; and (iii) we have sold a security that for which an allowance for credit losses was previously established. Accrued interest on fixed income securities and CMLs is recorded as a component of “Interest and dividends due or accrued” on our Consolidated Balance Sheet. If accrued interest is due but not paid within 90 days, we reverse the delinquent amount against investment income, which is a component of “Net investment income earned” on our Consolidated Statements of Income. We do not record a valuation allowance on our accrued interest balance as we reverse delinquent amounts on a timely basis. We consider a debt security to be past due at the time any principal or interest payments become 90 days delinquent. Commercial Mortgage Loans Beginning in 2020, our investment portfolio contains an allocation to CMLs. As of March 31, 2020, CMLs accounted for less than 1% of our invested assets. CMLs are loans secured by commercial property, such as an office building, multi-family apartment complex, industrial warehouse, or shopping center. We may acquire investments in CMLs through direct originations under a loan syndication arrangement or purchase CMLs in the marketplace. We record our investment in CMLs on the settlement date of the loan. Our CMLs are classified as held-for-investment and reported at amortized cost, net of the applicable allowance for credit losses, on our Consolidated Balance Sheet. We evaluate our CMLs for expected credit loss under the same methodology described above for fixed income securities using a DCF model. The discount rate used in this DCF model is either the effective interest rate implicit in the CML at the date of acquisition for fixed rate investments, or the effective interest rate in effect as of the reporting date for non-fixed-rate CMLs. The allowance for credit losses on our CML investments is calculated as the shortfall between amortized cost at the reporting date and the present value of future cash flows calculated in the DCF analysis. The treatment of earnings and the related classification of the expected credit losses on the Consolidated Statements of Income and the Consolidated Balance Sheet are consistent with our fixed income securities as described above. Allowance for Uncollectible Premiums Receivable We estimate an allowance for expected credit losses on our outstanding premiums receivable balance at each reporting date. In determining this allowance, we use a method that considers the aging of the receivable, based on the effective year of the related policy, along with our historical receivable loss experience. We also contemplate expected macroeconomic conditions over the expected collection period of these receivables that, because the majority of the balances are collected within a year or two of policy issuance, are short-term in nature. Expected credit losses on premiums receivable are charged to earnings as credit loss expense, which is a component of "Other insurance expenses" on our Consolidated Statements of Income with an offsetting allowance being recorded as a contra-asset reflected in the carry value of the receivable. Subsequent changes in the allowance are recorded as an increase to (or reversal of) credit loss expense. We charge write-offs against the allowance when we determine the account to be uncollectible after considering information obtained from our collection efforts. Allowance for Uncollectible Reinsurance Recoverable The "Reinsurance recoverable" balance on our Consolidated Balance Sheets represents our estimate of amounts that will be recovered from reinsurers under our various treaties. Generally, amounts recoverable from reinsurers are recognized as assets at the same time and in a manner consistent with the paid and unpaid losses associated with the reinsured policies. We would consider a recoverable balance from a reinsurer to be past due if payment is not received by the first day following the invoice due date. We require collateral to secure reinsurance recoverable balances primarily from our reinsurance carriers that are not authorized, otherwise approved, or certified to do business in one or more of our ten insurance subsidiaries' domiciliary states. Our ten insurance subsidiaries are collectively referred to as the "Insurance Subsidiaries." This collateral is typically in the form of a letter of credit or cash. We estimate an allowance for expected credit losses on our outstanding reinsurance recoverable balance at each reporting date. Credit risk is mitigated to the extent we have obtained collateral as described above. We, therefore, reduce the recoverable balance by the amount of the collateral as part of our allowance calculation. We then pool the uncollateralized balances by similar risk characteristics, including the financial strength rating of the reinsurer, and use a probability-of-default methodology in calculating the allowance. Historical default rates are sourced from AM Best and are coupled with severity assumptions in developing a baseline scenario. We then stress this scenario by incorporating forecasts of industry catastrophe losses and economic factors sourced through third-party data providers. In developing our best estimate of the allowance for credit losses, we consider our outlook as to the probability of each of these scenarios occurring.
Percent of commercial mortgage loans of our invested assets	1.00%

Accounting Pronouncements

Accounting Pronouncements	3 Months Ended
	Mar. 31, 2020
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting Pronouncements	Adoption of Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, Financial Instruments - Credit Losses , and subsequent additional implementation guidance (collectively referred to as “ASU 2016-13”) that changes the way entities recognize impairment of financial assets. The new guidance requires immediate recognition of estimated credit losses expected to occur over the remaining life of many financial assets through the establishment of a valuation allowance. The valuation allowance is a measurement of expected losses 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. Additionally, ASU 2016-03 requires the presentation of the impacted financial assets on the consolidated balance sheet net of the valuation allowance. We adopted this guidance on January 1, 2020, and applied a modified retrospective approach for the adoption and recorded a net cumulative-effect adjustment to increase the opening balance of 2020 retained earnings by $1.4 million , after tax. Also, as prescribed in ASU 2016-13, we did not adjust the amortized cost basis of any securities for which we had previously recorded OTTI. The cumulative-effect increase to retained earnings represents the net adjustment required to establish valuation allowances on our held-to-maturity ("HTM") debt securities and to re-estimate valuation allowances on our premiums receivables and reinsurance recoverables under ASU 2016-13. See Note 1. Basis of Presentation and Accounting Policies of this Form 10-Q for accounting policy updates related to ASU 2016-13. Additionally, see Note 4. "Investments," Note 7. "Allowance for Uncollectible Premiums Receivable," and Note 8. "Reinsurance" of this Form 10-Q for additional information regarding credit losses related to the respective financial assets. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement: Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13 modifies the disclosure requirements for fair value measurements by removing certain disclosures, and modifying and adding disclosure requirements. The additional disclosure requirements include (i) the change in unrealized gains and losses for the period included in other comprehensive income (“OCI”) for recurring Level 3 fair value measurements held at the end of the reporting period, and (ii) the range and weighted average of significant observable inputs used to develop Level 3 fair value measurements. We adopted the provisions related to removed disclosures in the fourth quarter of 2019 and adopted the remaining disclosure requirements in the first quarter of 2020 as permitted under ASU 2018-13. As this literature requires disclosure only, ASU 2018-13 has no impact on our financial condition or results of operations. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software: Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a cloud computing hosting service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. We adopted this guidance prospectively on January 1, 2020, and it did not have a material impact on our financial condition or results of operations. Pronouncements to be effective in the future In December 2019, the FASB issued ASU 2019-12, Income Taxes - Simplifying the Accounting for Income Taxes (“ASU 2019-12”). Among other items, the amendments in ASU 2019-12 simplify the accounting treatment of tax law changes and year-to-date losses in interim periods. An entity generally recognizes the effects of a change in tax law in the period of enactment; however, there is an exception for tax laws with delayed effective dates. Under current guidance, an entity may not adjust its annual effective tax rate for a tax law change until the period in which the law is effective. This exception was removed by ASU 2019-12. This guidance provides that all effects of a tax law change are recognized in the period of enactment, including adjustment of the estimated annual effective tax rate. For year-to-date losses in interim periods, an entity is required to estimate its annual effective tax rate for the full fiscal year at the end of each interim period and use that rate to calculate its income taxes on a year-to-date basis. Current guidance provides an exception that, when an interim period loss exceeds the anticipated loss for the year, the income tax benefit is limited to the amount that would be recognized if the year-to-date loss were the anticipated loss for the full year. ASU 2019-12 removes this exception and provides that, in this situation, an entity would compute its income tax benefit at each interim period based on its estimated annual effective tax rate. ASU 2019-12 is effective for fiscal years beginning after December 15, 2020, including interim periods within those annual periods. Early adoption is permitted. We are currently evaluating the impact of this guidance on our financial condition and results of operations. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting

Statements of Cash Flows

Statements of Cash Flows	3 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Information [Abstract]
Statements of Cash Flows	Statements of Cash Flows Supplemental cash flow information was as follows: Quarter Ended March 31, ($ in thousands) 2020 2019 Cash paid during the period for: Interest $ 8,854 4,477 Federal income tax — — Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 2,130 1,983 Operating cash flows from financing leases 6 — Financing cash flows from finance leases 142 284 Non-cash items: Corporate actions related to fixed income securities, AFS 1 8,040 18,447 Tax-free exchange of fixed income securities, HTM 2,596 — Assets acquired under finance lease arrangements 29 — Assets acquired under operating lease arrangements 3,828 6,136 Non-cash purchase of property and equipment 5 162 1 Examples of such corporate actions include exchanges, non-cash acquisitions, and stock splits. The following table provides a reconciliation of cash and restricted cash reported within the Consolidated Balance Sheets that equate to the amount reported in the Consolidated Statements of Cash Flows: ($ in thousands) March 31, 2020 December 31, 2019 Cash $ 9,429 300 Restricted cash 5,177 7,675 Total cash and restricted cash shown in the Statements of Cash Flows $ 14,606 7,975 Amounts included in restricted cash represent cash received from the National Flood Insurance Program ("NFIP"), which is restricted to pay flood claims under the Write Your Own program.

Investments

Investments	3 Months Ended
	Mar. 31, 2020
Investments [Abstract]
Investments	Investments (a) Our HTM fixed income securities as of March 31, 2020, represented less than 1% of our total invested assets, largely unchanged from December 31, 2019. The carry value and net unrealized/unrecognized gains were $20.4 million and $1.6 million , respectively, at March 31, 2020, and $20.8 million and $1.2 million , respectively, at December 31, 2019. Unrecognized holding gains and losses of HTM securities are not reflected in the Financial Statements, as they represent fair value fluctuations from the date a security is designated as HTM through the date of the balance sheet. (b) Information regarding our AFS securities as of March 31, 2020 and December 31, 2019 was as follows: March 31, 2020 ($ in thousands) Cost/ Amortized Cost Allowance for Credit Losses Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 134,569 — 7,668 — 142,237 Foreign government 12,987 (21 ) 172 (252 ) 12,886 Obligations of states and political subdivisions 1,146,160 (29 ) 52,516 (1,434 ) 1,197,213 Corporate securities 1,911,377 (13,412 ) 44,397 (32,858 ) 1,909,504 Collateralized loan obligations ("CLO") and other asset-backed securities ("ABS") 789,240 (1,565 ) 2,084 (67,498 ) 722,261 Commercial mortgage-backed securities ("CMBS") 516,702 (38 ) 26,511 (12,142 ) 531,033 Residential mortgage-backed securities ("RMBS") 1,366,744 (722 ) 66,931 (2,727 ) 1,430,226 Total AFS fixed income securities $ 5,877,779 (15,787 ) 200,279 (116,911 ) 5,945,360 December 31, 2019 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 112,680 3,506 — 116,186 Foreign government 18,011 533 (2 ) 18,542 Obligations of states and political subdivisions 1,168,185 62,175 (270 ) 1,230,090 Corporate securities 1,866,881 81,906 (1,310 ) 1,947,477 CLO and other ABS 790,517 7,929 (5,434 ) 793,012 CMBS 514,709 23,902 (267 ) 538,344 RMBS 1,409,003 43,421 (455 ) 1,451,969 Total AFS fixed income securities $ 5,879,986 223,372 (7,738 ) 6,095,620 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. The following table provides a rollforward of the allowance for credit losses on our AFS fixed income securities for 2020 : March 31, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase or (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government — 21 — — — 21 Obligations of states and political subdivisions — 29 — — — 29 Corporate securities — 13,412 — — — 13,412 CLO and other ABS — 1,565 — — — 1,565 CMBS — 38 — — — 38 RMBS — 722 — — — 722 Total AFS fixed income securities $ — 15,787 — — — 15,787 During 2020, we did not experience any write-offs or recoveries of our AFS fixed income securities, nor did we purchase any assets with credit deterioration, therefore these items are not included in the table above. As disclosed in Note 1. "Basis of Presentation and Accounting Policies," we do not evaluate accrued interest on our AFS securities for credit impairment as we write-off these balance in a timely manner. As of March 31, 2020 , accrued interest on AFS securities amounted to $42.8 million and we did not record any write-offs of accrued interest during First Quarter 2020 . (c) Quantitative information about unrealized losses on our AFS portfolio is provided below. March 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized AFS fixed income securities: Foreign government 4,376 (252 ) — — 4,376 (252 ) Obligations of states and political subdivisions 70,830 (1,434 ) — — 70,830 (1,434 ) Corporate securities 553,419 (31,677 ) 8,185 (1,181 ) 561,604 (32,858 ) CLO and other ABS 445,676 (49,404 ) 136,413 (18,094 ) 582,089 (67,498 ) CMBS 144,010 (11,119 ) 11,373 (1,023 ) 155,383 (12,142 ) RMBS 71,741 (2,561 ) 1,974 (166 ) 73,715 (2,727 ) Total AFS fixed income securities $ 1,290,052 (96,447 ) 157,945 (20,464 ) 1,447,997 (116,911 ) December 31, 2019 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized AFS fixed income securities: Foreign government 1,416 (2 ) — — 1,416 (2 ) Obligations of states and political subdivisions 35,838 (270 ) — — 35,838 (270 ) Corporate securities 84,832 (480 ) 20,182 (830 ) 105,014 (1,310 ) CLO and other ABS 205,191 (1,938 ) 204,385 (3,496 ) 409,576 (5,434 ) CMBS 62,893 (264 ) 828 (3 ) 63,721 (267 ) RMBS 126,089 (425 ) 5,375 (30 ) 131,464 (455 ) Total AFS fixed income securities $ 516,259 (3,379 ) 230,770 (4,359 ) 747,029 (7,738 ) We do not currently intend to sell any of the securities in the tables above, nor is it likely we will be required to sell any of these securities. Considering these factors and our review of these securities under our methodology for analyzing OTTI, we have concluded that they are temporarily impaired as we believe: (i) they will mature at par value; (ii) they have not incurred a credit impairment; and (iii) future values of these securities will fluctuate with changes in interest rates. 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. The COVID-19-related governmental orders have caused uncertainty and extreme volatility in the financial markets. Consequently, our gross unrealized losses on our AFS fixed income securities portfolio increased to $116.9 million from $7.7 million at December 31, 2019. The increase in total unrealized losses was driven by widening credit spreads as a result of the uncertainty in the marketplace, and partially offset by a significant decline in benchmark risk-free rates. (d) Fixed income securities at March 31, 2020 , are shown below by contractual maturity. Mortgage-backed securities are included in the maturity tables using the estimated average life of each security. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations, with or without call or prepayment penalties. AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 295,885 929 965 Due after one year through five years 3,471,503 13,943 15,115 Due after five years through 10 years 1,925,970 5,508 5,841 Due after 10 years 252,002 — — Total fixed income securities $ 5,945,360 20,380 21,921 (e) The following table summarizes our other investment portfolio by strategy: Other Investments March 31, 2020 December 31, 2019 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 131,936 102,801 234,737 118,352 93,138 211,490 Private credit 46,515 101,587 148,102 42,532 105,340 147,872 Real assets 23,385 23,406 46,791 23,256 20,741 43,997 Total alternative investments 201,836 227,794 429,630 184,140 219,219 403,359 Other securities 43,098 — 43,098 32,667 — 32,667 Total other investments $ 244,934 227,794 472,728 216,807 219,219 436,026 1 The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant. We are contractually committed to make additional investments up to the remaining commitments outlined above; however, we do not have a future obligation to fund losses or debts on behalf of these investments. We have not provided any non-contractual financial support at any time during 2020 or 2019 . The following table shows gross summarized financial information for our other investments portfolio, including the portion we do not own. 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 income or 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-month period ended December 31 is included in our First Quarter results. This information is as follows: Income Statement Information Quarter Ended March 31, ($ in millions) 2020 2019 Net investment (loss) income $ 12.7 (150.0 ) Realized (losses) gains 164.8 143.3 Net change in unrealized appreciation (depreciation) 1,204.0 554.3 Net income $ 1,381.5 547.6 Insurance Subsidiaries’ alternative investments income $ 6.3 0.6 As noted above, the $6.3 million of income associated with our alternative investment portfolio is largely recorded on a one-quarter lag, so the carry value of $201.8 million at March 31, 2020, does not reflect the significant COVID-19-related financial market volatility. Refer to Note 16. "Subsequent Events" below for additional information regarding our estimate of the results of our alternative investments portfolio to be recorded in the second quarter of 2020. (f) Certain Insurance Subsidiaries have pledged certain AFS fixed income securities as collateral as members of the Federal Home Loan Bank of Indianapolis ("FHLBI") and the Federal Home Loan Bank of New York ("FHLBNY"). In addition, we had certain securities deposited with various state and regulatory agencies at March 31, 2020 , to comply with insurance laws. We retain all rights regarding all securities pledged as collateral. The following table summarizes the market value of these securities at March 31, 2020 : ($ in millions) FHLBI Collateral FHLBNY Collateral State and Regulatory Deposits Total U.S. government and government agencies $ — — 23.4 23.4 Obligations of states and political subdivisions — — 4.0 4.0 Corporate securities — — 0.3 0.3 CMBS 7.1 28.1 — 35.2 RMBS 139.7 225.7 — 365.4 Total pledged as collateral $ 146.8 253.8 27.7 428.3 (g) We did not have exposure to any credit concentration risk of a single issuer greater than 10% of our stockholders' equity, other than certain U.S. government-backed investments, as of March 31, 2020 , or December 31, 2019 . (h) The components of pre-tax net investment income earned were as follows: Quarter Ended March 31, ($ in thousands) 2020 2019 Fixed income securities $ 50,253 49,033 CMLs 62 — Equity securities 1,552 1,640 Short-term investments 1,166 2,044 Other investments 6,342 660 Investment expenses (3,408 ) (2,759 ) Net investment income earned $ 55,967 50,618 (i) The following table summarizes OTTI by asset type for the periods indicated: Quarter Ended March 31, 2020 2019 ($ in thousands) Credit Loss Expense Other Impairment Charges Recognized in Earnings Recognized in Earnings AFS fixed income securities: U.S. government and government agencies — 14 14 — Foreign government 21 — 21 — Obligations of states and political subdivisions 29 62 91 65 Corporate securities 13,412 11,603 25,015 — CLO and other ABS 1,565 2,000 3,565 — CMBS 38 1,852 1,890 — RMBS 722 71 793 — Total AFS fixed income securities 15,787 15,602 31,389 65 CMLs 240 — 240 — Other Investments — — — 39 Total OTTI 16,027 15,602 31,629 104 The $31.6 million of OTTI during First Quarter 2020 was a $31.5 million increase from First Quarter 2019. Included in the $31.6 million of First Quarter 2020 OTTI are $15.6 million of other impairment charges, which represent securities that are in an unrealized loss position that we intend to sell. This provided our investment managers significant flexibility to trade and optimize our investment portfolio in the COVID-19-related financial market volatility. (j) Net realized and unrealized gains and losses (excluding OTTI charges) for First Quarter 2020 and 2019 included the following: Quarter Ended March 31, ($ in thousands) 2020 2019 Net realized gains (losses) on the disposals of securities: Fixed income securities $ 4,276 1,143 Equity securities (3 ) 2,280 Short-term investments (168 ) 14 Other investments (5 ) 7 Net realized gains (losses) on the disposal of securities 4,100 3,444 OTTI charges (31,629 ) (104 ) Net realized gains (losses) (27,529 ) 3,340 Unrealized (losses) gains recognized in income on equity securities (17,137 ) 10,111 Total net realized and unrealized investment (losses) gains $ (44,666 ) 13,451 The $58.1 million increase in net realized and unrealized investment losses was primarily driven by the increase in OTTI discussed above, coupled with a $27.2 million increase in unrealized losses on our equity securities in First Quarter 2020, related to the COVID-19-related financial market disruption. Unrealized (losses) recognized in income on equity securities, as reflected in the table above, include the following: Quarter Ended March 31, ($ in thousands) 2020 2019 Unrealized (losses) gains recognized in income on equity securities: On securities remaining in our portfolio at March 31, 2020 $ (17,140 ) 12,055 On securities sold in each respective period 3 (1,944 ) Total unrealized (losses) gains recognized in income on equity securities $ (17,137 ) 10,111 The components of net realized gains on disposals of securities for the periods indicated were as follows: Quarter Ended March 31, ($ in thousands) 2020 2019 HTM fixed income securities Gains $ 1 — Losses — — AFS fixed income securities Gains 5,653 1,844 Losses (1,378 ) (701 ) Equity securities Gains — 2,280 Losses (3 ) — Short-term investments Gains 22 14 Losses (190 ) — Other investments Gains — 7 Losses (5 ) — Total net realized gains on disposals of securities $ 4,100 3,444 Realized gains and losses on the sale of investments are determined on the basis of the cost of the specific investments sold.

Indebtedness

Indebtedness	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Indebtedness	Indebtedness The table below provides a summary of our outstanding debt at March 31, 2020 , and December 31, 2019 : Outstanding Debt Issuance Date Maturity Date Interest Rate Original Amount 2020 Carry Value ($ in thousands) Unamortized Issuance Costs Debt Discount March 31, 2020 December 31, 2019 Description Short-term Issuance: FHLBNY 3/12/2020 9/14/2020 0.78 % 100,000 — — 100,000 — FHLBNY 3/18/2020 9/18/2020 0.68 % 85,000 — — 85,000 — FHLBI 3/19/2020 12/14/2020 0.58 % 67,000 — — 67,000 — Line of Credit 3/24/2020 9/24/2020 2.244 % 50,000 — — 50,000 — Total short-term debt — — 302,000 — Other Outstanding: FHLBI 12/16/2016 12/16/2026 3.03 % 60,000 — — 60,000 60,000 FHLBNY 8/15/2016 8/16/2021 1.56 % 25,000 — — 25,000 25,000 FHLBNY 7/21/2016 7/21/2021 1.61 % 25,000 — — 25,000 25,000 Senior Notes 11/3/2005 11/1/2035 6.70 % 100,000 346 515 99,139 99,125 Senior Notes 11/16/2004 11/15/2034 7.25 % 50,000 180 89 49,731 49,725 Senior Notes 3/1/2019 3/1/2049 5.375 % 300,000 3,092 5,823 291,085 291,010 Finance lease obligations 622 737 Total long-term debt 3,618 6,427 550,577 550,597 Total debt 3,618 6,427 852,577 550,597 Our long-term debt balance did not materially change from December 31, 2019 . However, we increased our short-term debt by $302 million during the First Quarter 2020 as a contingency in light of the COVID-19-related volatility and uncertainty in the financial markets. The proceeds from these short-term borrowings were invested in high-quality money market funds, and for the most part, were to increase liquidity and operating flexibility in the next few quarters. Our short-term borrowings in First Quarter 2020 consisted of the following: • On February 18, 2020, Selective Insurance Company of America (“SICA”) borrowed short-term funds of $85 million from the FHLBNY at an interest rate of 1.81% . This borrowing was refinanced upon its maturity on March 18, 2020, at a lower interest rate of 0.68% . This borrowing matures on September 18, 2020. • On March 12, 2020, SICA borrowed $100 million from the FHLBNY at an interest rate of 0.78% . This borrowing matures on September 14, 2020. • On March 19, 2020 Selective Insurance Company of South Carolina ("SISC") and Selective Insurance Company of the Southeast ("SISE") borrowed $39 million and $28 million , respectively, from the FHLBI at an interest rate of 0.58% . These borrowings mature on December 14, 2020. • On March 24, 2020, Selective Insurance Group ("SIGI") borrowed $50 million on its line of credit issued by the Bank of Montreal at an interest rate of 2.244% . The borrowings can be repaid at anytime, without a prepayment penalty, through the December 20, 2022 maturity of the line of credit. The interest rate is based on a spread over 180 LIBOR and will reset on September 24, 2020 if the borrowings under the line of credit remain outstanding at that time. As of March 31, 2020, we were compliant with our required financial debt covenants under the line of credit. For additional information on our indebtedness and debt covenants, see Note 10. "Indebtedness" in Item 8. "Financial Statements and Supplementary Data." of our 2019 Annual Report.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We primarily measure the financial assets in our investment portfolio at fair value as disclosed on the Consolidated Balance Sheets. The following table presents the carrying amounts and estimated fair values of our financial liabilities as of March 31, 2020 and December 31, 2019 : March 31, 2020 December 31, 2019 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Liabilities Short-term debt: 0.78% Borrowings from FHLBNY $ 100,000 100,096 — — 0.68% Borrowings from FHLBNY 85,000 85,039 — — 0.58% Borrowings from FHLBI 67,000 67,006 — — 2.244% Line of Credit 1 50,000 — — — Total short-term debt 302,000 252,141 — — Long-term debt: 7.25% Senior Notes 49,911 61,134 49,910 66,365 6.70% Senior Notes 99,485 118,561 99,480 123,104 5.375% Senior Notes 294,177 316,400 294,157 357,025 1.61% borrowings from FHLBNY 25,000 25,261 25,000 24,901 1.56% borrowings from FHLBNY 25,000 25,260 25,000 24,875 3.03% borrowings from FHLBI 60,000 65,404 60,000 63,002 Subtotal long-term debt 553,573 612,020 553,547 659,272 Unamortized debt issuance costs (3,618 ) (3,687 ) Finance lease obligations 622 737 Total long-term debt $ 550,577 550,597 1 Total short-term debt includes our $50 million line of credit borrowing. As there is no scheduled or definitive repayment plan for this borrowing as of March 31, 2020, the fair value cannot be calculated and the borrowing is not classified in the fair value hierarchy table below. For more information about these new short-term borrowings, refer to Note 5. "Indebtedness" above. For a discussion of the fair value hierarchy and techniques used to value our financial assets and liabilities, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2019 Annual Report. The following tables provide quantitative disclosures of our financial assets that were measured and recorded at fair value at March 31, 2020 , and December 31, 2019 : March 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in 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 $ 142,237 44,093 98,144 — Foreign government 12,886 — 12,886 — Obligations of states and political subdivisions 1,197,213 — 1,194,323 2,890 Corporate securities 1,909,504 — 1,885,319 24,185 CLO and other ABS 722,261 — 685,889 36,372 RMBS 1,430,226 — 1,430,226 — CMBS 531,033 — 531,033 — Total AFS fixed income securities 5,945,360 44,093 5,837,820 63,447 Equity securities: Common stock 1 98,410 59,175 — — Preferred stock 1,579 1,579 — — Total equity securities 99,989 60,754 — — Short-term investments 517,558 504,243 13,315 — Total assets measured at fair value $ 6,562,907 609,090 5,851,135 63,447 December 31, 2019 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 $ 116,186 41,083 75,103 — Foreign government 18,542 — 18,542 — Obligations of states and political subdivisions 1,230,090 — 1,230,090 — Corporate securities 1,947,477 — 1,930,426 17,051 CLO and other ABS 793,012 3,635 772,343 17,034 RMBS 1,451,969 — 1,451,969 — CMBS 538,344 — 538,344 — Total AFS fixed income securities 6,095,620 44,718 6,016,817 34,085 Equity securities: Common stock 1 69,900 32,145 — — Preferred stock 3,037 3,037 — — Total equity securities 72,937 35,182 — — Short-term investments 282,490 265,306 17,184 — Total assets measured at fair value $ 6,451,047 345,206 6,034,001 34,085 1 Investments amounting to $39.2 million at March 31, 2020 , and $37.8 million at December 31, 2019 , were measured at fair value using net asset value per share (or its practical expedient) and are not classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period disclosed above. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value. The following table provides a summary of Level 3 changes in First Quarter 2020 and First Quarter 2019 : March 31, 2020 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2019 — 17,051 17,034 34,085 Total net (losses) gains for the period included in: OCI — 1 (1,756 ) (1,755 ) Net realized and unrealized (losses) gains — (61 ) (214 ) (275 ) Purchases — 3,002 4,831 7,833 Sales — — — — Issuances — — — — Settlements — — — — Transfers into Level 3 2,890 4,192 20,107 27,189 Transfers out of Level 3 — — (3,630 ) (3,630 ) Fair value, March 31, 2020 2,890 24,185 36,372 63,447 Change in unrealized (losses) gains for the period included in earnings for assets held at period end — (61 ) (214 ) (275 ) Change in unrealized gains (losses) for the period included in other comprehensive income for assets held at period end — 1 (1,756 ) (1,755 ) March 31, 2019 ($ in thousands) Corporate Securities CLO and Other ABS Total Fair value, December 31, 2018 — 7,409 7,409 Total net (losses) gains for the period included in: OCI — (225 ) (225 ) Net realized and unrealized (losses) gains — — — Purchases — 12,434 12,434 Sales — — — Issuances — — — Settlements — — — Transfers into Level 3 16,419 11,674 28,093 Transfers out of Level 3 — — — Fair value, March 31, 2019 16,419 31,292 47,711 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — — — The following tables provide quantitative information regarding our financial assets and liabilities that were disclosed at fair value at March 31, 2020 , and December 31, 2019 : March 31, 2020 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 $ 4,871 — 4,871 — Corporate securities 17,050 — 17,050 — Total HTM fixed income securities $ 21,921 — 21,921 — CMLs 13,856 — — 13,856 Financial Liabilities Short-term debt: 0.78% Borrowings from FHLBNY 100,096 — 100,096 — 0.68% Borrowings from FHLBNY 85,039 — 85,039 — 0.58% Borrowings from FHLBI 67,006 — 67,006 — Total short-term debt 252,141 — 252,141 — Long-term debt: 7.25% Senior Notes $ 61,134 — 61,134 — 6.70% Senior Notes 118,561 — 118,561 — 5.375% Senior Notes 316,400 — 316,400 — 1.61% borrowings from FHLBNY 25,261 — 25,261 — 1.56% borrowings from FHLBNY 25,260 — 25,260 — 3.03% borrowings from FHLBI 65,404 — 65,404 — Total long-term debt $ 612,020 — 612,020 — December 31, 2019 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 $ 4,921 — 4,921 — Corporate securities 17,054 — 17,054 — Total HTM fixed income securities $ 21,975 — 21,975 — Financial Liabilities Long-term debt: 7.25% Senior Notes $ 66,365 — 66,365 — 6.70% Senior Notes 123,104 — 123,104 — 5.375% Senior Notes 357,025 — 357,025 — 1.61% borrowings from FHLBNY 24,901 — 24,901 — 1.56% borrowings from FHLBNY 24,875 — 24,875 — 3.03% borrowings from FHLBI 63,002 — 63,002 — Total long-term debt $ 659,272 — 659,272 —

Allowance for Uncollectible Pre

Allowance for Uncollectible Premiums Receivable (Notes)	3 Months Ended
	Mar. 31, 2020
Premiums Receivable [Abstract]
Allowance for Uncollectible Premiums Receivable Note [Text Block]	Premiums Receivable The following table provides a rollforward of the allowance for credit losses on our premiums receivable balance during First Quarter 2020 : ($ in thousands) March 31, 2020 Balance, December 31, 2019 $ 6,400 Cumulative effect adjustment 1 1,058 Balance, January 1, 2020 $ 7,458 Current period provision for expected credit losses 11,195 Write-offs charged against the allowance (653 ) Recoveries — Allowance for credit losses, end of period $ 18,000 1 See Note 2. "Adoption of Accounting Pronouncements" above for additional information regarding our adoption of ASU 2016-13. Based on an evaluation of the recoverability of our premiums receivable, in light of the billing accommodations we announced during First Quarter 2020 and the impact of recent state regulations that provided for the deferral of payments without cancellation for a period up to 90 day in certain states, which will increase earned but uncollected premiums, we recognized an additional allowance for credit losses of $10.5 million , net of write-offs. The billing accommodations include individualized payment flexibility and suspending the effect of policy cancellations, late payment notices, and late or reinstatement fees.

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2020
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance We evaluate and monitor the financial condition of our reinsurers under voluntary reinsurance arrangements to minimize our exposure to significant losses from reinsurer insolvencies. The following table provides (i) a disaggregation of our reinsurance recoverable balance by financial strength rating, and (ii) an aging analysis of our past due reinsurance recoverable balances as of March 31, 2020: March 31, 2020 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers 1 A++ $ 20,835 $ — $ 20,835 A+ 428,354 3,229 431,583 A 25,915 — 25,915 A- 508 — 508 B++ 316 94 410 B+ 21 — 21 Total rated reinsurers $ 475,949 $ 3,323 $ 479,272 Non-rated reinsurers Federal and state pools 80,245 60 80,305 Other than federal and state pools 5,459 — 5,459 Total non-rated reinsurers $ 85,704 $ 60 $ 85,764 Total reinsurance recoverable, gross $ 561,653 $ 3,383 $ 565,036 Less: allowance for credit losses 2 (1,502 ) — (1,502 ) Total reinsurance recoverable, net $ 560,151 $ 3,383 $ 563,534 1 Credit ratings as of March 31, 2020 . 2 Represents our current expectation of credit losses on total current and past due reinsurance recoverables, and is not identifiable by reinsurer. We evaluate our estimate of expected credit losses through the methodology outlined in Note 1. “Basis of Presentation and Accounting Policies.” The following table provides a rollforward of the allowance for credit losses on our reinsurance recoverable balance at March 31, 2020: ($ in thousands) March 31, 2020 Balance, December 31, 2019 $ 4,400 Cumulative effect adjustment 1 (2,903 ) Balance, January 1, 2020 $ 1,497 Current period provision for expected credit losses 5 Write-offs charged against the allowance — Recoveries — Allowance for credit losses, end of period $ 1,502 1 See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13. 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 2019 Annual Report. Quarter Ended March 31, ($ in thousands) 2020 2019 Premiums written: Direct $ 746,431 766,394 Assumed 6,043 6,555 Ceded (105,147 ) (100,002 ) Net $ 647,327 672,947 Premiums earned: Direct $ 754,892 728,037 Assumed 6,173 6,562 Ceded (109,362 ) (102,026 ) Net $ 651,703 632,573 Loss and loss expenses incurred: Direct $ 425,795 424,657 Assumed 4,898 5,265 Ceded (30,369 ) (43,343 ) Net $ 400,324 386,579 Direct premiums written decreased in First Quarter 2020 compared to First Quarter 2019 as a result of a $75 million increase in our return audit and mid-term endorsement premium accrual during First Quarter 2020, which reflects lower exposure that determines the premium that we charge due to the economic impacts of the COVID-19 pandemic and the anticipated decline in sales and payroll exposures on the general liability and workers compensation lines of business. Ceded premiums and losses related to our participation in the NFIP, under which 100% of our flood premiums, losses, and loss expenses are ceded to the NFIP, are as follows: Ceded to NFIP Quarter Ended March 31, ($ in thousands) 2020 2019 Ceded premiums written $ (62,087 ) (60,013 ) Ceded premiums earned (66,861 ) (62,263 ) Ceded loss and loss expenses incurred (5,096 ) (13,686 )

Reserve for Loss and Loss Expen

Reserve for Loss and Loss Expense	3 Months Ended
	Mar. 31, 2020
Insurance Loss Reserves [Abstract]
Reserve for Loss and Loss Expense	Reserve for Loss and Loss Expense The table below provides a roll forward of reserve for loss and loss expense balances: Quarter Ended March 31, ($ in thousands) 2020 2019 Gross reserve for loss and loss expense, at beginning of year $ 4,067,163 3,893,868 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 547,066 537,388 Net reserve for loss and loss expense, at beginning of year 3,520,097 3,356,480 Incurred loss and loss expense for claims occurring in the: Current year 407,276 397,253 Prior years (6,952 ) (10,674 ) Total incurred loss and loss expense 400,324 386,579 Paid loss and loss expense for claims occurring in the: Current year 70,610 73,964 Prior years 281,736 246,168 Total paid loss and loss expense 352,346 320,132 Net reserve for loss and loss expense, at end of period 3,568,075 3,422,927 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period 535,560 543,582 Gross reserve for loss and loss expense at end of period $ 4,103,635 3,966,509 1 Includes an adjustment of $2.9 million related to our adoption of ASU 2016-13. Refer to Note 2. "Adoption of Accounting Pronouncements" for additional information. Our current year incurred losses of $407.3 million include an estimate of $10.0 million for COVID-19-related losses related to a small portion of our policies that include a $25,000 sub-limited coverage for specified extra expenses to clean or disinfect a property when ordered by a Board of Health. In most instances, COVID-19 does not cause a direct physical loss to property, and when combined with other policy wording requirements, we do not expect material business interruption losses from COVID-19. We also attach a regulatory approved virus exclusion to all standard commercial lines property and businessowners policies. Prior year reserve development in First Quarter 2020 was $7.0 million and included $10.0 million of favorable casualty reserve development in our workers compensation lines of business that was partially offset by $3.0 million of unfavorable property reserve development. Prior year reserve development in First Quarter 2019 was $10.7 million , driven by favorable casualty reserve development of $8.0 million in our workers compensation line of business and $2.0 million in our general liability line of business.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information We evaluate the results of our four reportable segments as follows: • Our Standard Commercial Lines, Standard Personal Lines, and E&S Lines are evaluated on before and after-tax underwriting results (net premiums earned, incurred loss and loss expense, policyholder dividends, policy acquisition costs, and other underwriting expenses), return on equity ("ROE") contribution, and combined ratios. • Our Investments segment is primarily evaluated on after-tax net investment income and its ROE contribution. After-tax net realized and unrealized gains and losses, which are not included in non-GAAP operating income, are also included in our Investment segment results. In computing the results of each segment, we do not make adjustments for interest expense or corporate expenses. We do not maintain separate investment portfolios for the segments and do not allocate assets to each segment. The following summaries present revenues (net investment income and net realized and unrealized gains on investments for the Investments segment) and pre-tax income for the individual segments: Revenue by Segment Quarter Ended March 31, ($ in thousands) 2020 2019 Standard Commercial Lines: Net premiums earned: Commercial automobile $ 149,690 131,186 Workers compensation 66,706 78,715 General liability 164,580 161,525 Commercial property 93,869 86,067 Businessowners’ policies 27,036 26,081 Bonds 9,639 8,904 Other 5,060 4,706 Miscellaneous income 1,391 2,044 Total Standard Commercial Lines revenue 517,971 499,228 Standard Personal Lines: Net premiums earned: Personal automobile 42,487 43,163 Homeowners 31,490 32,130 Other 2,151 2,014 Miscellaneous income 434 276 Total Standard Personal Lines revenue 76,562 77,583 E&S Lines: Net premiums earned: Casualty lines 44,072 44,528 Property lines 14,923 13,554 Miscellaneous income — — Total E&S Lines revenue 58,995 58,082 Investments: Net investment income 55,967 50,618 Net realized and unrealized investment (losses) gains (44,666 ) 13,451 Total Investments revenue 11,301 64,069 Total revenues $ 664,829 698,962 Income Before and After Federal Income Tax Quarter Ended March 31, ($ in thousands) 2020 2019 Standard Commercial Lines: Underwriting gain, before federal income tax $ 17,126 25,815 Underwriting gain, after federal income tax 13,529 20,394 Combined ratio 96.7 % 94.8 ROE contribution 2.4 4.4 Standard Personal Lines: Underwriting gain, before federal income tax $ 387 3,167 Underwriting gain, after federal income tax 306 2,502 Combined ratio 99.5 % 95.9 ROE contribution 0.1 0.5 E&S Lines: Underwriting gain, before federal income tax $ 3,844 4,579 Underwriting gain, after federal income tax 3,037 3,617 Combined ratio 93.5 % 92.1 ROE contribution 0.6 0.8 Investments: Net investment income $ 55,967 50,618 Net realized and unrealized investment (losses) gains (44,666 ) 13,451 Total investment segment income, before federal income tax 11,301 64,069 Tax on investment segment income 1,104 12,120 Total investment segment income, after federal income tax $ 10,197 51,949 ROE contribution of after-tax net investment income 8.5 8.9 Reconciliation of Segment Results to Income Before Federal Income Tax Quarter Ended March 31, ($ in thousands) 2020 2019 Underwriting gain Standard Commercial Lines $ 17,126 25,815 Standard Personal Lines 387 3,167 E&S Lines 3,844 4,579 Investment income 11,301 64,069 Total all segments 32,658 97,630 Interest expense (7,601 ) (11,526 ) Corporate expenses (9,060 ) (12,410 ) Income, before federal income tax $ 15,997 73,694

Retirement Plans

Retirement Plans	3 Months Ended
	Mar. 31, 2020
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans The primary pension plan for our employees 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 2019 Annual Report. The following tables provide information about the Pension Plan: Pension Plan Quarter Ended March 31, ($ in thousands) 2020 2019 Net Periodic Pension Cost (Benefit): Interest cost $ 2,828 3,377 Expected return on plan assets (5,477 ) (5,279 ) Amortization of unrecognized net actuarial loss 704 644 Total net periodic pension cost (benefit) 1 $ (1,945 ) (1,258 ) 1 The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income. Pension Plan Quarter Ended March 31, 2020 2019 Weighted-Average Expense Assumptions: Discount rate 3.33 % 4.46 % Effective interest rate for calculation of interest cost 2.95 4.12 Expected return on plan assets 5.80 6.50

Comprehensive Income

Comprehensive Income	3 Months Ended
	Mar. 31, 2020
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income	Comprehensive Income The components of comprehensive income, both gross and net of tax, for First Quarter 2020 and 2019 were as follows: First Quarter 2020 ($ in thousands) Gross Tax Net Net income $ 15,997 761 15,236 Components of other comprehensive loss: Unrealized losses on investment securities : Unrealized holding losses during the period (93,981 ) (19,736 ) (74,245 ) Non-credit portion of OTTI recognized in OCI (65,390 ) (13,732 ) (51,658 ) Amounts reclassified into net income: HTM securities 25 5 20 Realized losses on disposals and intent-to-sell OTTI on AFS securities 11,327 2,379 8,948 Credit loss expense recognized in OTTI 15,787 3,315 12,472 Total unrealized losses on investment securities (132,232 ) (27,769 ) (104,463 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 754 158 596 Total defined benefit pension and post-retirement plans 754 158 596 Other comprehensive loss (131,478 ) (27,611 ) (103,867 ) Comprehensive loss $ (115,481 ) (26,850 ) (88,631 ) First Quarter 2019 ($ in thousands) Gross Tax Net Net income $ 73,694 12,346 61,348 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 102,926 21,613 81,313 Amounts reclassified into net income: HTM securities (9 ) (2 ) (7 ) Realized gains on disposals and OTTI of AFS securities (1,077 ) (226 ) (851 ) Total unrealized gains on investment securities 101,840 21,385 80,455 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 664 139 525 Total defined benefit pension and post-retirement plans 664 139 525 Other comprehensive income 102,504 21,524 80,980 Comprehensive income $ 176,198 33,870 142,328 The balances and changes in each component of AOCI (net of taxes) as of March 31, 2020 , were as follows: March 31, 2020 Defined Benefit Pension and Post-Retirement Plans Net Unrealized Gains (Losses) on Investment Securities Total AOCI ($ in thousands) OTTI Related 1 HTM Related All Other Investments Subtotal Balance, December 31, 2019 $ (71 ) 25 170,439 170,393 (88,643 ) 81,750 OCI before reclassifications (51,658 ) — (74,245 ) (125,903 ) — (125,903 ) Amounts reclassified from AOCI 12,472 20 8,948 21,440 596 22,036 Net current period OCI (39,186 ) 20 (65,297 ) (104,463 ) 596 (103,867 ) Balance, March 31, 2020 $ (39,257 ) 45 105,142 65,930 (88,047 ) (22,117 ) 1 Represents unrealized gains and losses on AFS securities with credit-related OTTI recognized in earnings. The reclassifications out of AOCI were as follows: Quarter Ended March 31, Affected Line Item in the Unaudited Consolidated Statements of Income ($ in thousands) 2020 2019 HTM related Unrealized losses on HTM disposals $ 1 — Net realized and unrealized (losses) gains Amortization of net unrealized losses (gains) on HTM securities 24 (9 ) Net investment income earned 25 (9 ) Income before federal income tax (5 ) 2 Total federal income tax expense 20 (7 ) Net income Net realized losses (gains) on disposals and intent-to-sell OTTI Net realized losses (gains) on disposals and intent-to-sell OTTI 11,327 (1,077 ) Net realized and unrealized (losses) gains 11,327 (1,077 ) Income before federal income tax (2,379 ) 226 Total federal income tax expense 8,948 (851 ) Net income OTTI related Credit loss expense recognized in OTTI 15,787 — Net realized and unrealized (losses) gains 15,787 — Income before federal income tax (3,315 ) — Total federal income tax expense 12,472 — Net income Defined benefit pension and post-retirement life plans Net actuarial loss 162 145 Loss and loss expense incurred 592 519 Other insurance expenses Total defined benefit pension and post-retirement life 754 664 Income before federal income tax (158 ) (139 ) Total federal income tax expense 596 525 Net income Total reclassifications for the period $ 22,036 (333 ) Net income

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	Leases We have various operating leases for office space, equipment, and fleet vehicles. We also have various finance leases for computer hardware. These lease agreements expire at various dates through 2030 and are generally expected to be renewed or replaced by similar leases. The components of lease expense for First Quarter 2020 and 2019 were as follows: Quarter Ended March 31, ($ in thousands) 2020 2019 Operating lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 2,259 2,152 Finance lease cost: Amortization of assets, included in Other insurance expenses on the Consolidated Statements of Income 142 284 Interest on lease liabilities, included in Interest expense on the Consolidated Statements of Income 6 — Total finance lease cost 148 284 Variable lease cost, included in Other insurance expenses on the Consolidated Statements of Income 176 788 Short-term lease cost, included in Other insurance expenses on the Consolidated Statements of Income 476 739 The following table provides supplemental information regarding our operating and finance leases. March 31, 2020 December 31, 2019 Weighted-average remaining lease term Operating leases 6 years 6 years Finance leases 2 2 Weighted-average discount rate Operating leases 3.2 % 3.4 % Finance leases 2.2 2.1 Operating and finance lease asset and liability balances are included within the following line items on the Consolidated Balance Sheets: ($ in thousands) March 31, 2020 December 31, 2019 Operating leases Other assets $ 28,270 $ 26,535 Other liabilities 29,364 27,506 Finance leases Property and equipment - at cost, net of accumulated depreciation and amortization 615 731 Long-term debt 622 737 The maturities of our lease liabilities at March 31, 2020 , and December 31, 2019 , were as follows: March 31, 2020 ($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2020 (excluding the three months ended March 31, 2020) $ 332 6,291 6,623 2021 248 6,372 6,620 2022 54 4,798 4,852 2023 — 3,434 3,434 2024 — 2,920 2,920 Thereafter — 8,638 8,638 Total lease payments 634 32,453 33,087 Less: imputed interest 12 3,089 3,101 Total lease liabilities $ 622 29,364 29,986 December 31, 2019 ($ in thousands) Finance Leases Operating Leases Total 2020 $ 451 8,244 8,695 2021 248 6,168 6,416 2022 54 4,590 4,644 2023 — 3,329 3,329 2024 — 2,920 2,920 Thereafter — 8,638 8,638 Total lease payments 753 33,889 34,642 Less: imputed interest 16 2,995 3,011 Less: leases that have not yet commenced — 3,388 3,388 Total lease liabilities $ 737 27,506 28,243 Refer to Note. 3 "Statements of Cash Flows" of this Form 10-Q for supplemental cash and non-cash transactions included in the measurement of operating and finance lease liabilities.

Litigation

Litigation	3 Months Ended
	Mar. 31, 2020
Loss Contingency, Information about Litigation Matters [Abstract]
Litigation	Litigation As of March 31, 2020 , we do not believe we are involved in any legal action that could have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. In the ordinary course of conducting business, we are parties in various legal actions. Most are claims litigation involving our Insurance Subsidiaries as either: (i) liability insurers defending or providing indemnity for third-party claims brought against our customers; (ii) insurers defending first-party coverage claims brought against them; or (iii) liability insurers seeking declaratory judgment on our insurance coverage obligations. We account for such activity through the establishment of unpaid loss and loss expense reserves. In ordinary course claims litigation, we expect that any potential ultimate liability, 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. All of our commercial property and businessowners policies require direct physical loss of or damage to property by a covered cause of loss. Whether COVID-19-related contamination, the existence of the COVID-19 pandemic, and the resulting COVID-19-related government shutdown orders cause physical loss of or damage to property is already the subject of much public debate and first-party coverage litigation against some insurers. We cannot predict the outcome of that litigation, which may interpret language similar or identical to what is in our insurance policies. It also is our practice to attach to all standard commercial property and businessowners policies an exclusion that states that all loss or property damage caused by or resulting from any virus, bacterium, or other microorganism that induces or is capable of inducing physical distress, illness, or disease is not a covered cause of loss. That exclusion also may be the subject of first-party coverage litigation against some insurers. We cannot predict the outcome of that litigation, which may interpret language similar or identical to what is in our insurance policies.

Federal Income Taxes Federal In

Federal Income Taxes Federal Income Taxes (Notes)	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Federal Income Taxes A reconciliation of federal income tax on income at the corporate rate to the effective tax rate is as follows: Quarter Ended March 31, ($ in thousands) 2020 2019 Tax at statutory rate (21% in 2020 and 2019) $ 3,359 15,476 Tax-advantaged interest (1,214 ) (1,253 ) Dividends received deduction (55 ) (83 ) Executive compensation 351 473 Stock-based compensation (1,881 ) (2,635 ) Other 201 368 Federal income tax expense $ 761 12,346 During First Quarter 2020, we recorded federal income taxes based on our actual effective tax rate during the quarter instead of an estimate of our full-year effective tax rate. This approach gives consideration to the anticipated volatility in certain components of our net income. Estimating these components is challenging given the uncertainty around the future impact of the COVID-19-related governmental directives and their impact on the financial markets and potential volatility. Our effective tax rate during First Quarter 2020 was 4.8% , down from 16.8% a year ago. This decrease was driven by net realized and unrealized losses of $44.7 million, pre-tax, which significantly offset the other components of pre-tax net income and reduced the effective tax rate. After considering all positive and negative evidence about our federal net operating and capital loss carryback capacity, expected levels of pre-tax financial statement income, and federal taxable income, we believe it is more likely than not the existing deductible temporary differences will reverse during periods in which we generate net federal taxable income or have adequate federal carryback capacity. As a result, we had no valuation allowance recognized for federal tax assets at March 31, 2020 ( $43.1 million net deferred tax asset) or December 31, 2019 ( $6.8 million

Subsequent Events (Notes)

Subsequent Events (Notes)	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events Governmental (international, federal, state, and local) directives to contain or delay the spread of the COVID-19 pandemic have resulted in directives requiring social distancing, operational alteration or temporary closure of most non-essential businesses to public access, and “sheltering-in-place” of everyone other than essential service workers. These actions have disrupted regular commerce, supply chains, and travel. Most of these governmental directives were issued in First Quarter 2020, and to date, these directives have significantly limited the operations of those businesses that are considered non-essential, and their employees, along with the general public who are "sheltering-in-place." As a result, we are expecting that claims frequency for our personal and commercial automobile lines of business will decline because of the reduced miles being driven consistent with the governmental directives. As the number of vehicles we insure has not significantly declined and we expect that frequencies will return to normal after the governmental directives expire or are lifted, we do not believe that changes in our filed rating plans are appropriate. Unlike our workers compensation and general liability lines of business policies, in which we anticipate a decline in sales and payroll exposures, our commercial and personal automobile policies do not provide for an audit that would reduce annual premium. Because of the unprecedented nature of the COVID-19-related governmental directives and the associated expected short-term favorable claims frequency impact, we felt it was appropriate to seek regulatory approval during April to provide a premium-based credit to our personal and commercial automobile customers. The premium-based credit would provide for an amount to be returned to customers with in-force policies equivalent to 15% of their April and May premiums. This approval process has been completed and this premium-based credit will be recorded as other insurance expense in the second quarter of 2020 of approximately $20 million . We believe the impact to our other insurance expenses will be largely offset by a reduction in our loss and loss expenses as a result of expected reduced insured automobile accident claims frequency in those respective months. The COVID-19-related governmental directives also have induced significant uncertainty and volatility in the financial markets and decreased equity market valuations. To date, this has been reflected in the market values of our invested assets and the corresponding OTTI charges discussed in Note 4. "Investments." However, as our other investment portfolio largely consists of alternative investments that are recorded on a one quarter lag, the impact of the First Quarter 2020 financial market volatility on those alternative investments will not be reflected in our Financial Statements until second quarter of 2020. While it is extremely difficult to accurately estimate the potential losses associated with this portion of our investment portfolio, we performed a sensitivity analysis that indicates a potential pre-tax loss of between $15 million and $20 million . However, while these are our current estimates, our second quarter net investment income will reflect the actual decrease reported by these alternative investments as of March 31, 2020. We cannot predict the extent and duration of the current COVID-19-related governmental directives, which also may change based on future COVID-19 infection rates, nor can we predict COVID-19-related impacts on the economy or financial markets or changes in legislation. A change in any of these factors, however, could impact our estimates and assumptions in future periods. Changes in these assumptions and estimates in future periods may be material to the results of our operations and could materially reduce our net income, cash flow, and stockholders' equity. We also expect to incur estimated pre-tax net losses of approximately $35 million due to several severe storms in April, which impacted parts of the mid-west and east coast regions of the United States with damaging wind and tornadoes.

Statements of Cash Flows (Table

Statements of Cash Flows (Tables)	3 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Quarter Ended March 31, ($ in thousands) 2020 2019 Cash paid during the period for: Interest $ 8,854 4,477 Federal income tax — — Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 2,130 1,983 Operating cash flows from financing leases 6 — Financing cash flows from finance leases 142 284 Non-cash items: Corporate actions related to fixed income securities, AFS 1 8,040 18,447 Tax-free exchange of fixed income securities, HTM 2,596 — Assets acquired under finance lease arrangements 29 — Assets acquired under operating lease arrangements 3,828 6,136 Non-cash purchase of property and equipment 5 162 1 Examples of such corporate actions include exchanges, non-cash acquisitions, and stock splits.
Schedule of Cash and Restricted Cash	($ in thousands) March 31, 2020 December 31, 2019 Cash $ 9,429 300 Restricted cash 5,177 7,675 Total cash and restricted cash shown in the Statements of Cash Flows $ 14,606 7,975

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Schedule of Available-for-sale Securities	March 31, 2020 ($ in thousands) Cost/ Amortized Cost Allowance for Credit Losses Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 134,569 — 7,668 — 142,237 Foreign government 12,987 (21 ) 172 (252 ) 12,886 Obligations of states and political subdivisions 1,146,160 (29 ) 52,516 (1,434 ) 1,197,213 Corporate securities 1,911,377 (13,412 ) 44,397 (32,858 ) 1,909,504 Collateralized loan obligations ("CLO") and other asset-backed securities ("ABS") 789,240 (1,565 ) 2,084 (67,498 ) 722,261 Commercial mortgage-backed securities ("CMBS") 516,702 (38 ) 26,511 (12,142 ) 531,033 Residential mortgage-backed securities ("RMBS") 1,366,744 (722 ) 66,931 (2,727 ) 1,430,226 Total AFS fixed income securities $ 5,877,779 (15,787 ) 200,279 (116,911 ) 5,945,360 December 31, 2019 ($ in thousands) Cost/ Amortized Cost Unrealized Gains Unrealized Losses Fair Value AFS fixed income securities: U.S. government and government agencies $ 112,680 3,506 — 116,186 Foreign government 18,011 533 (2 ) 18,542 Obligations of states and political subdivisions 1,168,185 62,175 (270 ) 1,230,090 Corporate securities 1,866,881 81,906 (1,310 ) 1,947,477 CLO and other ABS 790,517 7,929 (5,434 ) 793,012 CMBS 514,709 23,902 (267 ) 538,344 RMBS 1,409,003 43,421 (455 ) 1,451,969 Total AFS fixed income securities $ 5,879,986 223,372 (7,738 ) 6,095,620
Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]	March 31, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase or (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government — 21 — — — 21 Obligations of states and political subdivisions — 29 — — — 29 Corporate securities — 13,412 — — — 13,412 CLO and other ABS — 1,565 — — — 1,565 CMBS — 38 — — — 38 RMBS — 722 — — — 722 Total AFS fixed income securities $ — 15,787 — — — 15,787
Schedule of Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities by Length of Time, AFS	March 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized AFS fixed income securities: Foreign government 4,376 (252 ) — — 4,376 (252 ) Obligations of states and political subdivisions 70,830 (1,434 ) — — 70,830 (1,434 ) Corporate securities 553,419 (31,677 ) 8,185 (1,181 ) 561,604 (32,858 ) CLO and other ABS 445,676 (49,404 ) 136,413 (18,094 ) 582,089 (67,498 ) CMBS 144,010 (11,119 ) 11,373 (1,023 ) 155,383 (12,142 ) RMBS 71,741 (2,561 ) 1,974 (166 ) 73,715 (2,727 ) Total AFS fixed income securities $ 1,290,052 (96,447 ) 157,945 (20,464 ) 1,447,997 (116,911 ) December 31, 2019 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized AFS fixed income securities: Foreign government 1,416 (2 ) — — 1,416 (2 ) Obligations of states and political subdivisions 35,838 (270 ) — — 35,838 (270 ) Corporate securities 84,832 (480 ) 20,182 (830 ) 105,014 (1,310 ) CLO and other ABS 205,191 (1,938 ) 204,385 (3,496 ) 409,576 (5,434 ) CMBS 62,893 (264 ) 828 (3 ) 63,721 (267 ) RMBS 126,089 (425 ) 5,375 (30 ) 131,464 (455 ) Total AFS fixed income securities $ 516,259 (3,379 ) 230,770 (4,359 ) 747,029 (7,738 )
Schedule of Fixed Maturity Securities By Contractual Maturities	AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 295,885 929 965 Due after one year through five years 3,471,503 13,943 15,115 Due after five years through 10 years 1,925,970 5,508 5,841 Due after 10 years 252,002 — — Total fixed income securities $ 5,945,360 20,380 21,921
Schedule of Other Investment Portfolio By Strategy And Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy	Other Investments March 31, 2020 December 31, 2019 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 131,936 102,801 234,737 118,352 93,138 211,490 Private credit 46,515 101,587 148,102 42,532 105,340 147,872 Real assets 23,385 23,406 46,791 23,256 20,741 43,997 Total alternative investments 201,836 227,794 429,630 184,140 219,219 403,359 Other securities 43,098 — 43,098 32,667 — 32,667 Total other investments $ 244,934 227,794 472,728 216,807 219,219 436,026 1 The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized 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, ($ in millions) 2020 2019 Net investment (loss) income $ 12.7 (150.0 ) Realized (losses) gains 164.8 143.3 Net change in unrealized appreciation (depreciation) 1,204.0 554.3 Net income $ 1,381.5 547.6 Insurance Subsidiaries’ alternative investments income $ 6.3 0.6
Schedule of Securities Pledged As Collateral	($ in millions) FHLBI Collateral FHLBNY Collateral State and Regulatory Deposits Total U.S. government and government agencies $ — — 23.4 23.4 Obligations of states and political subdivisions — — 4.0 4.0 Corporate securities — — 0.3 0.3 CMBS 7.1 28.1 — 35.2 RMBS 139.7 225.7 — 365.4 Total pledged as collateral $ 146.8 253.8 27.7 428.3
Schedule of Pre-Tax Net Investment Income Earned	Quarter Ended March 31, ($ in thousands) 2020 2019 Fixed income securities $ 50,253 49,033 CMLs 62 — Equity securities 1,552 1,640 Short-term investments 1,166 2,044 Other investments 6,342 660 Investment expenses (3,408 ) (2,759 ) Net investment income earned $ 55,967 50,618
Schedule Of O T T I By Asset Type [Table Text Block]	Quarter Ended March 31, 2020 2019 ($ in thousands) Credit Loss Expense Other Impairment Charges Recognized in Earnings Recognized in Earnings AFS fixed income securities: U.S. government and government agencies — 14 14 — Foreign government 21 — 21 — Obligations of states and political subdivisions 29 62 91 65 Corporate securities 13,412 11,603 25,015 — CLO and other ABS 1,565 2,000 3,565 — CMBS 38 1,852 1,890 — RMBS 722 71 793 — Total AFS fixed income securities 15,787 15,602 31,389 65 CMLs 240 — 240 — Other Investments — — — 39 Total OTTI 16,027 15,602 31,629 104
Schedule of Components of Net Realized and Unrealized Gains and Losses Excluding OTTI Charges	Quarter Ended March 31, ($ in thousands) 2020 2019 Net realized gains (losses) on the disposals of securities: Fixed income securities $ 4,276 1,143 Equity securities (3 ) 2,280 Short-term investments (168 ) 14 Other investments (5 ) 7 Net realized gains (losses) on the disposal of securities 4,100 3,444 OTTI charges (31,629 ) (104 ) Net realized gains (losses) (27,529 ) 3,340 Unrealized (losses) gains recognized in income on equity securities (17,137 ) 10,111 Total net realized and unrealized investment (losses) gains $ (44,666 ) 13,451
Schedule of Realized Gains and Losses on Disposals of Securities	Quarter Ended March 31, ($ in thousands) 2020 2019 HTM fixed income securities Gains $ 1 — Losses — — AFS fixed income securities Gains 5,653 1,844 Losses (1,378 ) (701 ) Equity securities Gains — 2,280 Losses (3 ) — Short-term investments Gains 22 14 Losses (190 ) — Other investments Gains — 7 Losses (5 ) — Total net realized gains on disposals of securities $ 4,100 3,444
Equity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Schedule of Components of Net Realized and Unrealized Gains and Losses Excluding OTTI Charges	Quarter Ended March 31, ($ in thousands) 2020 2019 Unrealized (losses) gains recognized in income on equity securities: On securities remaining in our portfolio at March 31, 2020 $ (17,140 ) 12,055 On securities sold in each respective period 3 (1,944 ) Total unrealized (losses) gains recognized in income on equity securities $ (17,137 ) 10,111

Indebtedness (Tables)

Indebtedness (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Outstanding Debt	Outstanding Debt Issuance Date Maturity Date Interest Rate Original Amount 2020 Carry Value ($ in thousands) Unamortized Issuance Costs Debt Discount March 31, 2020 December 31, 2019 Description Short-term Issuance: FHLBNY 3/12/2020 9/14/2020 0.78 % 100,000 — — 100,000 — FHLBNY 3/18/2020 9/18/2020 0.68 % 85,000 — — 85,000 — FHLBI 3/19/2020 12/14/2020 0.58 % 67,000 — — 67,000 — Line of Credit 3/24/2020 9/24/2020 2.244 % 50,000 — — 50,000 — Total short-term debt — — 302,000 — Other Outstanding: FHLBI 12/16/2016 12/16/2026 3.03 % 60,000 — — 60,000 60,000 FHLBNY 8/15/2016 8/16/2021 1.56 % 25,000 — — 25,000 25,000 FHLBNY 7/21/2016 7/21/2021 1.61 % 25,000 — — 25,000 25,000 Senior Notes 11/3/2005 11/1/2035 6.70 % 100,000 346 515 99,139 99,125 Senior Notes 11/16/2004 11/15/2034 7.25 % 50,000 180 89 49,731 49,725 Senior Notes 3/1/2019 3/1/2049 5.375 % 300,000 3,092 5,823 291,085 291,010 Finance lease obligations 622 737 Total long-term debt 3,618 6,427 550,577 550,597 Total debt 3,618 6,427 852,577 550,597

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Schedule of Carrying Values and Estimated Fair Values of Financial Liabilities	March 31, 2020 December 31, 2019 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Liabilities Short-term debt: 0.78% Borrowings from FHLBNY $ 100,000 100,096 — — 0.68% Borrowings from FHLBNY 85,000 85,039 — — 0.58% Borrowings from FHLBI 67,000 67,006 — — 2.244% Line of Credit 1 50,000 — — — Total short-term debt 302,000 252,141 — — Long-term debt: 7.25% Senior Notes 49,911 61,134 49,910 66,365 6.70% Senior Notes 99,485 118,561 99,480 123,104 5.375% Senior Notes 294,177 316,400 294,157 357,025 1.61% borrowings from FHLBNY 25,000 25,261 25,000 24,901 1.56% borrowings from FHLBNY 25,000 25,260 25,000 24,875 3.03% borrowings from FHLBI 60,000 65,404 60,000 63,002 Subtotal long-term debt 553,573 612,020 553,547 659,272 Unamortized debt issuance costs (3,618 ) (3,687 ) Finance lease obligations 622 737 Total long-term debt $ 550,577 550,597
Schedule of Quantitative Disclosures of Our Financial Assets That Were Measured At Fair Value	March 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in 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 $ 142,237 44,093 98,144 — Foreign government 12,886 — 12,886 — Obligations of states and political subdivisions 1,197,213 — 1,194,323 2,890 Corporate securities 1,909,504 — 1,885,319 24,185 CLO and other ABS 722,261 — 685,889 36,372 RMBS 1,430,226 — 1,430,226 — CMBS 531,033 — 531,033 — Total AFS fixed income securities 5,945,360 44,093 5,837,820 63,447 Equity securities: Common stock 1 98,410 59,175 — — Preferred stock 1,579 1,579 — — Total equity securities 99,989 60,754 — — Short-term investments 517,558 504,243 13,315 — Total assets measured at fair value $ 6,562,907 609,090 5,851,135 63,447 December 31, 2019 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 $ 116,186 41,083 75,103 — Foreign government 18,542 — 18,542 — Obligations of states and political subdivisions 1,230,090 — 1,230,090 — Corporate securities 1,947,477 — 1,930,426 17,051 CLO and other ABS 793,012 3,635 772,343 17,034 RMBS 1,451,969 — 1,451,969 — CMBS 538,344 — 538,344 — Total AFS fixed income securities 6,095,620 44,718 6,016,817 34,085 Equity securities: Common stock 1 69,900 32,145 — — Preferred stock 3,037 3,037 — — Total equity securities 72,937 35,182 — — Short-term investments 282,490 265,306 17,184 — Total assets measured at fair value $ 6,451,047 345,206 6,034,001 34,085 1 Investments amounting to $39.2 million at March 31, 2020 , and $37.8 million at December 31, 2019
Schedule of Changes in Fair Value of Securities Using Level 3 Inputs	March 31, 2020 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2019 — 17,051 17,034 34,085 Total net (losses) gains for the period included in: OCI — 1 (1,756 ) (1,755 ) Net realized and unrealized (losses) gains — (61 ) (214 ) (275 ) Purchases — 3,002 4,831 7,833 Sales — — — — Issuances — — — — Settlements — — — — Transfers into Level 3 2,890 4,192 20,107 27,189 Transfers out of Level 3 — — (3,630 ) (3,630 ) Fair value, March 31, 2020 2,890 24,185 36,372 63,447 Change in unrealized (losses) gains for the period included in earnings for assets held at period end — (61 ) (214 ) (275 ) Change in unrealized gains (losses) for the period included in other comprehensive income for assets held at period end — 1 (1,756 ) (1,755 ) March 31, 2019 ($ in thousands) Corporate Securities CLO and Other ABS Total Fair value, December 31, 2018 — 7,409 7,409 Total net (losses) gains for the period included in: OCI — (225 ) (225 ) Net realized and unrealized (losses) gains — — — Purchases — 12,434 12,434 Sales — — — Issuances — — — Settlements — — — Transfers into Level 3 16,419 11,674 28,093 Transfers out of Level 3 — — — Fair value, March 31, 2019 16,419 31,292 47,711 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — — —
Schedule of Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value	March 31, 2020 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 $ 4,871 — 4,871 — Corporate securities 17,050 — 17,050 — Total HTM fixed income securities $ 21,921 — 21,921 — CMLs 13,856 — — 13,856 Financial Liabilities Short-term debt: 0.78% Borrowings from FHLBNY 100,096 — 100,096 — 0.68% Borrowings from FHLBNY 85,039 — 85,039 — 0.58% Borrowings from FHLBI 67,006 — 67,006 — Total short-term debt 252,141 — 252,141 — Long-term debt: 7.25% Senior Notes $ 61,134 — 61,134 — 6.70% Senior Notes 118,561 — 118,561 — 5.375% Senior Notes 316,400 — 316,400 — 1.61% borrowings from FHLBNY 25,261 — 25,261 — 1.56% borrowings from FHLBNY 25,260 — 25,260 — 3.03% borrowings from FHLBI 65,404 — 65,404 — Total long-term debt $ 612,020 — 612,020 — December 31, 2019 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 $ 4,921 — 4,921 — Corporate securities 17,054 — 17,054 — Total HTM fixed income securities $ 21,975 — 21,975 — Financial Liabilities Long-term debt: 7.25% Senior Notes $ 66,365 — 66,365 — 6.70% Senior Notes 123,104 — 123,104 — 5.375% Senior Notes 357,025 — 357,025 — 1.61% borrowings from FHLBNY 24,901 — 24,901 — 1.56% borrowings from FHLBNY 24,875 — 24,875 — 3.03% borrowings from FHLBI 63,002 — 63,002 — Total long-term debt $ 659,272 — 659,272 —

Allowance for Uncollectible P_2

Allowance for Uncollectible Premiums Receivable (Tables)	3 Months Ended
	Mar. 31, 2020
Premiums Receivable [Abstract]
Premium Receivable, Allowance for Credit Loss [Table Text Block]	($ in thousands) March 31, 2020 Balance, December 31, 2019 $ 6,400 Cumulative effect adjustment 1 1,058 Balance, January 1, 2020 $ 7,458 Current period provision for expected credit losses 11,195 Write-offs charged against the allowance (653 ) Recoveries — Allowance for credit losses, end of period $ 18,000

Reinsurance (Tables)

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2020
Reinsurance Disclosures [Abstract]
Reinsurance Recoverable, Credit Quality Indicator [Table Text Block]	March 31, 2020 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers 1 A++ $ 20,835 $ — $ 20,835 A+ 428,354 3,229 431,583 A 25,915 — 25,915 A- 508 — 508 B++ 316 94 410 B+ 21 — 21 Total rated reinsurers $ 475,949 $ 3,323 $ 479,272 Non-rated reinsurers Federal and state pools 80,245 60 80,305 Other than federal and state pools 5,459 — 5,459 Total non-rated reinsurers $ 85,704 $ 60 $ 85,764 Total reinsurance recoverable, gross $ 561,653 $ 3,383 $ 565,036 Less: allowance for credit losses 2 (1,502 ) — (1,502 ) Total reinsurance recoverable, net $ 560,151 $ 3,383 $ 563,534 1 Credit ratings as of March 31, 2020 .
Reinsurance Recoverable, Allowance for Credit Loss [Table Text Block]	($ in thousands) March 31, 2020 Balance, December 31, 2019 $ 4,400 Cumulative effect adjustment 1 (2,903 ) Balance, January 1, 2020 $ 1,497 Current period provision for expected credit losses 5 Write-offs charged against the allowance — Recoveries — Allowance for credit losses, end of period $ 1,502 1 See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.
Schedule of List Of Direct, Assumed, And Ceded Reinsurance Amounts	Quarter Ended March 31, ($ in thousands) 2020 2019 Premiums written: Direct $ 746,431 766,394 Assumed 6,043 6,555 Ceded (105,147 ) (100,002 ) Net $ 647,327 672,947 Premiums earned: Direct $ 754,892 728,037 Assumed 6,173 6,562 Ceded (109,362 ) (102,026 ) Net $ 651,703 632,573 Loss and loss expenses incurred: Direct $ 425,795 424,657 Assumed 4,898 5,265 Ceded (30,369 ) (43,343 ) Net $ 400,324 386,579
Schedule of Ceded Premiums and Losses Related to Flood Operations	Ceded to NFIP Quarter Ended March 31, ($ in thousands) 2020 2019 Ceded premiums written $ (62,087 ) (60,013 ) Ceded premiums earned (66,861 ) (62,263 ) Ceded loss and loss expenses incurred (5,096 ) (13,686 )

Reserve for Loss and Loss Exp_2

Reserve for Loss and Loss Expense (Tables)	3 Months Ended
	Mar. 31, 2020
Insurance Loss Reserves [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	Quarter Ended March 31, ($ in thousands) 2020 2019 Gross reserve for loss and loss expense, at beginning of year $ 4,067,163 3,893,868 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 547,066 537,388 Net reserve for loss and loss expense, at beginning of year 3,520,097 3,356,480 Incurred loss and loss expense for claims occurring in the: Current year 407,276 397,253 Prior years (6,952 ) (10,674 ) Total incurred loss and loss expense 400,324 386,579 Paid loss and loss expense for claims occurring in the: Current year 70,610 73,964 Prior years 281,736 246,168 Total paid loss and loss expense 352,346 320,132 Net reserve for loss and loss expense, at end of period 3,568,075 3,422,927 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period 535,560 543,582 Gross reserve for loss and loss expense at end of period $ 4,103,635 3,966,509 1 Includes an adjustment of $2.9 million related to our adoption of ASU 2016-13. Refer to Note 2. "Adoption of Accounting Pronouncements" for additional information.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Revenue By Segment	Revenue by Segment Quarter Ended March 31, ($ in thousands) 2020 2019 Standard Commercial Lines: Net premiums earned: Commercial automobile $ 149,690 131,186 Workers compensation 66,706 78,715 General liability 164,580 161,525 Commercial property 93,869 86,067 Businessowners’ policies 27,036 26,081 Bonds 9,639 8,904 Other 5,060 4,706 Miscellaneous income 1,391 2,044 Total Standard Commercial Lines revenue 517,971 499,228 Standard Personal Lines: Net premiums earned: Personal automobile 42,487 43,163 Homeowners 31,490 32,130 Other 2,151 2,014 Miscellaneous income 434 276 Total Standard Personal Lines revenue 76,562 77,583 E&S Lines: Net premiums earned: Casualty lines 44,072 44,528 Property lines 14,923 13,554 Miscellaneous income — — Total E&S Lines revenue 58,995 58,082 Investments: Net investment income 55,967 50,618 Net realized and unrealized investment (losses) gains (44,666 ) 13,451 Total Investments revenue 11,301 64,069 Total revenues $ 664,829 698,962
Schedule of Income Before and After Federal Income Tax	Income Before and After Federal Income Tax Quarter Ended March 31, ($ in thousands) 2020 2019 Standard Commercial Lines: Underwriting gain, before federal income tax $ 17,126 25,815 Underwriting gain, after federal income tax 13,529 20,394 Combined ratio 96.7 % 94.8 ROE contribution 2.4 4.4 Standard Personal Lines: Underwriting gain, before federal income tax $ 387 3,167 Underwriting gain, after federal income tax 306 2,502 Combined ratio 99.5 % 95.9 ROE contribution 0.1 0.5 E&S Lines: Underwriting gain, before federal income tax $ 3,844 4,579 Underwriting gain, after federal income tax 3,037 3,617 Combined ratio 93.5 % 92.1 ROE contribution 0.6 0.8 Investments: Net investment income $ 55,967 50,618 Net realized and unrealized investment (losses) gains (44,666 ) 13,451 Total investment segment income, before federal income tax 11,301 64,069 Tax on investment segment income 1,104 12,120 Total investment segment income, after federal income tax $ 10,197 51,949 ROE contribution of after-tax net investment income 8.5 8.9
Schedule of Reconciliation of Segment Results to Income Before Federal Income Tax	Reconciliation of Segment Results to Income Before Federal Income Tax Quarter Ended March 31, ($ in thousands) 2020 2019 Underwriting gain Standard Commercial Lines $ 17,126 25,815 Standard Personal Lines 387 3,167 E&S Lines 3,844 4,579 Investment income 11,301 64,069 Total all segments 32,658 97,630 Interest expense (7,601 ) (11,526 ) Corporate expenses (9,060 ) (12,410 ) Income, before federal income tax $ 15,997 73,694

Retirement Plans (Table)

Retirement Plans (Table)	3 Months Ended
	Mar. 31, 2020
Retirement Benefits [Abstract]
Schedule of Components of Net Periodic Benefit Cost	Pension Plan Quarter Ended March 31, ($ in thousands) 2020 2019 Net Periodic Pension Cost (Benefit): Interest cost $ 2,828 3,377 Expected return on plan assets (5,477 ) (5,279 ) Amortization of unrecognized net actuarial loss 704 644 Total net periodic pension cost (benefit) 1 $ (1,945 ) (1,258 ) 1 The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income.
Schedule of Weighted-Average Expense Assumptions	Pension Plan Quarter Ended March 31, 2020 2019 Weighted-Average Expense Assumptions: Discount rate 3.33 % 4.46 % Effective interest rate for calculation of interest cost 2.95 4.12 Expected return on plan assets 5.80 6.50

Comprehensive Income (Tables)

Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2020
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Components of Comprehensive Income-Gross and Net of Tax	First Quarter 2020 ($ in thousands) Gross Tax Net Net income $ 15,997 761 15,236 Components of other comprehensive loss: Unrealized losses on investment securities : Unrealized holding losses during the period (93,981 ) (19,736 ) (74,245 ) Non-credit portion of OTTI recognized in OCI (65,390 ) (13,732 ) (51,658 ) Amounts reclassified into net income: HTM securities 25 5 20 Realized losses on disposals and intent-to-sell OTTI on AFS securities 11,327 2,379 8,948 Credit loss expense recognized in OTTI 15,787 3,315 12,472 Total unrealized losses on investment securities (132,232 ) (27,769 ) (104,463 ) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 754 158 596 Total defined benefit pension and post-retirement plans 754 158 596 Other comprehensive loss (131,478 ) (27,611 ) (103,867 ) Comprehensive loss $ (115,481 ) (26,850 ) (88,631 ) First Quarter 2019 ($ in thousands) Gross Tax Net Net income $ 73,694 12,346 61,348 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 102,926 21,613 81,313 Amounts reclassified into net income: HTM securities (9 ) (2 ) (7 ) Realized gains on disposals and OTTI of AFS securities (1,077 ) (226 ) (851 ) Total unrealized gains on investment securities 101,840 21,385 80,455 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 664 139 525 Total defined benefit pension and post-retirement plans 664 139 525 Other comprehensive income 102,504 21,524 80,980 Comprehensive income $ 176,198 33,870 142,328
Schedule of Components of Accumulated Other Comprehensive Income Net of Tax	March 31, 2020 Defined Benefit Pension and Post-Retirement Plans Net Unrealized Gains (Losses) on Investment Securities Total AOCI ($ in thousands) OTTI Related 1 HTM Related All Other Investments Subtotal Balance, December 31, 2019 $ (71 ) 25 170,439 170,393 (88,643 ) 81,750 OCI before reclassifications (51,658 ) — (74,245 ) (125,903 ) — (125,903 ) Amounts reclassified from AOCI 12,472 20 8,948 21,440 596 22,036 Net current period OCI (39,186 ) 20 (65,297 ) (104,463 ) 596 (103,867 ) Balance, March 31, 2020 $ (39,257 ) 45 105,142 65,930 (88,047 ) (22,117 )
Schedule of Reclassifications Out Of Accumulated Other Comprehensive Income	Quarter Ended March 31, Affected Line Item in the Unaudited Consolidated Statements of Income ($ in thousands) 2020 2019 HTM related Unrealized losses on HTM disposals $ 1 — Net realized and unrealized (losses) gains Amortization of net unrealized losses (gains) on HTM securities 24 (9 ) Net investment income earned 25 (9 ) Income before federal income tax (5 ) 2 Total federal income tax expense 20 (7 ) Net income Net realized losses (gains) on disposals and intent-to-sell OTTI Net realized losses (gains) on disposals and intent-to-sell OTTI 11,327 (1,077 ) Net realized and unrealized (losses) gains 11,327 (1,077 ) Income before federal income tax (2,379 ) 226 Total federal income tax expense 8,948 (851 ) Net income OTTI related Credit loss expense recognized in OTTI 15,787 — Net realized and unrealized (losses) gains 15,787 — Income before federal income tax (3,315 ) — Total federal income tax expense 12,472 — Net income Defined benefit pension and post-retirement life plans Net actuarial loss 162 145 Loss and loss expense incurred 592 519 Other insurance expenses Total defined benefit pension and post-retirement life 754 664 Income before federal income tax (158 ) (139 ) Total federal income tax expense 596 525 Net income Total reclassifications for the period $ 22,036 (333 ) Net income

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Components of Lease Expense	Quarter Ended March 31, ($ in thousands) 2020 2019 Operating lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 2,259 2,152 Finance lease cost: Amortization of assets, included in Other insurance expenses on the Consolidated Statements of Income 142 284 Interest on lease liabilities, included in Interest expense on the Consolidated Statements of Income 6 — Total finance lease cost 148 284 Variable lease cost, included in Other insurance expenses on the Consolidated Statements of Income 176 788 Short-term lease cost, included in Other insurance expenses on the Consolidated Statements of Income 476 739
Supplemental Lease Information	March 31, 2020 December 31, 2019 Weighted-average remaining lease term Operating leases 6 years 6 years Finance leases 2 2 Weighted-average discount rate Operating leases 3.2 % 3.4 % Finance leases 2.2 2.1
Lease Assets and Liabilities	($ in thousands) March 31, 2020 December 31, 2019 Operating leases Other assets $ 28,270 $ 26,535 Other liabilities 29,364 27,506 Finance leases Property and equipment - at cost, net of accumulated depreciation and amortization 615 731 Long-term debt 622 737
Maturities of Lease Liabilities	March 31, 2020 ($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2020 (excluding the three months ended March 31, 2020) $ 332 6,291 6,623 2021 248 6,372 6,620 2022 54 4,798 4,852 2023 — 3,434 3,434 2024 — 2,920 2,920 Thereafter — 8,638 8,638 Total lease payments 634 32,453 33,087 Less: imputed interest 12 3,089 3,101 Total lease liabilities $ 622 29,364 29,986
Schedule of Future Minimum Rental Commitments For Non-Cancelable Leases	December 31, 2019 ($ in thousands) Finance Leases Operating Leases Total 2020 $ 451 8,244 8,695 2021 248 6,168 6,416 2022 54 4,590 4,644 2023 — 3,329 3,329 2024 — 2,920 2,920 Thereafter — 8,638 8,638 Total lease payments 753 33,889 34,642 Less: imputed interest 16 2,995 3,011 Less: leases that have not yet commenced — 3,388 3,388 Total lease liabilities $ 737 27,506 28,243

Federal Income Taxes (Tables)

Federal Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2020
Federal Income Taxes [Abstract]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Quarter Ended March 31, ($ in thousands) 2020 2019 Tax at statutory rate (21% in 2020 and 2019) $ 3,359 15,476 Tax-advantaged interest (1,214 ) (1,253 ) Dividends received deduction (55 ) (83 ) Executive compensation 351 473 Stock-based compensation (1,881 ) (2,635 ) Other 201 368 Federal income tax expense $ 761 12,346

Basis of Presentation Commercia

Basis of Presentation Commercial mortgage loans (Details)	3 Months Ended
	Mar. 31, 2020
Commercial mortgage loans [Abstract]
Percent of commercial mortgage loans of our invested assets	1.00%

Accounting Pronouncements Adopt

Accounting Pronouncements Adoption of Accounting Pronouncements (Details) $ in Thousands	Dec. 31, 2019USD ($)
Adoption of Accounting Pronouncements [Abstract]
Cumulative effect of new accounting principle in period of adoption	$ 1,435

Statements of Cash Flows (Cash

Statements of Cash Flows (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Interest		$ 8,854	$ 4,477
Federal income tax		0	0
Operating cash flows from operating leases		2,130	1,983
Operating cash flows from financing leases		6	0
Financing cash flows from finance leases		142	284
Assets acquired under finance lease arrangements		29	0
Assets acquired under operating lease arrangements		3,828	6,136
Non-cash purchase of property and equipment		5	162
AFS Fixed Income Securities [Member]
Corporate actions related to securities	[1]	8,040	18,447
Held-to-maturity Securities [Member]
Corporate actions related to securities		$ 2,596	$ 0
[1]	Examples of such corporate actions include exchanges, non-cash acquisitions, and stock splits.

Statements of Cash Flows (Sched

Statements of Cash Flows (Schedule of Cash and Restricted Cash) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Schedule of Cash and Restricted Cash [Line Items]
Cash	$ 9,429	$ 300
Restricted cash	5,177	7,675
Total cash and restricted cash shown in the Statements of Cash Flows	$ 14,606	$ 7,975	$ 10,514	$ 16,919

Investments (Held-To-Maturity S

Investments (Held-To-Maturity Securities Disclosure) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
HTM Securities Percent of Invested Assets	1.00%
HTM, Carrying Value	$ 20,380	$ 20,800
Net unrealized unrecognized gain or loss on HTMs	$ 1,600	$ 1,200

Investments (Available-For-Sale

Investments (Available-For-Sale Securities Disclosure) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	$ 5,877,779	$ 5,879,986
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(15,787)
Interest and dividends due or accrued	43,893	44,846
Current provision for securities without prior allowance	(15,787)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Reductions for securities identified as intent (or requirement) to sell during the period	0
Unrealized Gains	200,279	223,372
Unrealized Losses	(116,911)	(7,738)
Debt Securities, Available-for-sale	5,945,360	6,095,620
AFS Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Interest and dividends due or accrued	42,800
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	134,569	112,680
Allowance for credit losses, ending balance at March 31, 2020	0
Current provision for securities without prior allowance	0
Unrealized Gains	7,668	3,506
Unrealized Losses	0	0
Debt Securities, Available-for-sale	142,237	116,186
AFS Fixed Income Securities [Member] | Foreign Government [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	12,987	18,011
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(21)
Current provision for securities without prior allowance	(21)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	172	533
Unrealized Losses	(252)	(2)
Debt Securities, Available-for-sale	12,886	18,542
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	1,146,160	1,168,185
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(29)
Current provision for securities without prior allowance	(29)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	52,516	62,175
Unrealized Losses	(1,434)	(270)
Debt Securities, Available-for-sale	1,197,213	1,230,090
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	1,911,377	1,866,881
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(13,412)
Current provision for securities without prior allowance	(13,412)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	44,397	81,906
Unrealized Losses	(32,858)	(1,310)
Debt Securities, Available-for-sale	1,909,504	1,947,477
AFS Fixed Income Securities [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	789,240	790,517
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(1,565)
Current provision for securities without prior allowance	(1,565)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	2,084	7,929
Unrealized Losses	(67,498)	(5,434)
Debt Securities, Available-for-sale	722,261	793,012
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	516,702	514,709
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(38)
Current provision for securities without prior allowance	(38)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	26,511	23,902
Unrealized Losses	(12,142)	(267)
Debt Securities, Available-for-sale	531,033	538,344
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Cost/Amortized Cost	1,366,744	1,409,003
Allowance for credit losses, beginning balance at January 1, 2020	0
Allowance for credit losses, ending balance at March 31, 2020	(722)
Current provision for securities without prior allowance	(722)
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0
Reductions for securities sold	0
Unrealized Gains	66,931	43,421
Unrealized Losses	(2,727)	(455)
Debt Securities, Available-for-sale	$ 1,430,226	$ 1,451,969

Investments (Fair Value and Gro

Investments (Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities By Length of Time) (Details) - AFS Fixed Income Securities [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
AFS Fair Value, Less than 12 Months	$ 1,290,052	$ 516,259
AFS Unrealized Losses, Less than 12 months	(96,447)	(3,379)
AFS Fair Value, 12 months or longer	157,945	230,770
AFS Unrealized Losses, 12 months or longer	(20,464)	(4,359)
AFS Fair Value	1,447,997	747,029
AFS Unrealized Losses	(116,911)	(7,738)
Foreign Government [Member]
AFS Fair Value, Less than 12 Months	4,376	1,416
AFS Unrealized Losses, Less than 12 months	(252)	(2)
AFS Fair Value, 12 months or longer	0	0
AFS Unrealized Losses, 12 months or longer	0	0
AFS Fair Value	4,376	1,416
AFS Unrealized Losses	(252)	(2)
Obligations of States and Political Subdivisions [Member]
AFS Fair Value, Less than 12 Months	70,830	35,838
AFS Unrealized Losses, Less than 12 months	(1,434)	(270)
AFS Fair Value, 12 months or longer	0	0
AFS Unrealized Losses, 12 months or longer	0	0
AFS Fair Value	70,830	35,838
AFS Unrealized Losses	(1,434)	(270)
Corporate Securities [Member]
AFS Fair Value, Less than 12 Months	553,419	84,832
AFS Unrealized Losses, Less than 12 months	(31,677)	(480)
AFS Fair Value, 12 months or longer	8,185	20,182
AFS Unrealized Losses, 12 months or longer	(1,181)	(830)
AFS Fair Value	561,604	105,014
AFS Unrealized Losses	(32,858)	(1,310)
Collateralized Loan Obligations and Other Asset Backed Securities [Member]
AFS Fair Value, Less than 12 Months	445,676	205,191
AFS Unrealized Losses, Less than 12 months	(49,404)	(1,938)
AFS Fair Value, 12 months or longer	136,413	204,385
AFS Unrealized Losses, 12 months or longer	(18,094)	(3,496)
AFS Fair Value	582,089	409,576
AFS Unrealized Losses	(67,498)	(5,434)
Commercial Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 Months	144,010	62,893
AFS Unrealized Losses, Less than 12 months	(11,119)	(264)
AFS Fair Value, 12 months or longer	11,373	828
AFS Unrealized Losses, 12 months or longer	(1,023)	(3)
AFS Fair Value	155,383	63,721
AFS Unrealized Losses	(12,142)	(267)
Residential Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 Months	71,741	126,089
AFS Unrealized Losses, Less than 12 months	(2,561)	(425)
AFS Fair Value, 12 months or longer	1,974	5,375
AFS Unrealized Losses, 12 months or longer	(166)	(30)
AFS Fair Value	73,715	131,464
AFS Unrealized Losses	$ (2,727)	$ (455)

Investments (Fixed Income Secur

Investments (Fixed Income Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Fixed Income Securities [Line Items]
Due in one year or less fair value, AFS	$ 295,885
Due after one year through five years fair value, AFS	3,471,503
Due after five years through 10 years fair value, AFS	1,925,970
Due after 10 years fair value, AFS	252,002
AFS, Fair Value	5,945,360	$ 6,095,620
Due in one year or less carrying value, HTM	929
Due after one year through five years carrying value, HTM	13,943
Due after five years through 10 years carrying value, HTM	5,508
Due after 10 years carrying value, HTM	0
HTM, Carrying Value	20,380	20,800
Due in one year or less fair value, HTM	965
Due after one year through five years fair value, HTM	15,115
Due after five years through 10 years fair value, HTM	5,841
Due after 10 years fair value, HTM	0
HTM, Fair Value	$ 21,921	$ 21,975

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		Mar. 31, 2020	Dec. 31, 2019
Carrying Value		$ 244,934	$ 216,807
Other Securities [Member]
Carrying Value		43,098	32,667
Remaining Commitment		0	0
Maximum Exposure to Loss	[1]	43,098	32,667
Alternative Investments [Member]
Carrying Value		201,836	184,140
Remaining Commitment		227,794	219,219
Maximum Exposure to Loss	[1]	429,630	403,359
Alternative Investments [Member] | Private Equity Funds [Member]
Carrying Value		131,936	118,352
Remaining Commitment		102,801	93,138
Maximum Exposure to Loss	[1]	234,737	211,490
Alternative Investments [Member] | Real Assets [Member]
Carrying Value		23,385	23,256
Remaining Commitment		23,406	20,741
Maximum Exposure to Loss	[1]	46,791	43,997
Alternative Investments [Member] | Private Credit Funds [Member]
Carrying Value		46,515	42,532
Remaining Commitment		101,587	105,340
Maximum Exposure to Loss	[1]	148,102	147,872
Other Investments [Member]
Carrying Value		244,934	216,807
Remaining Commitment		227,794	219,219
Maximum Exposure to Loss	[1]	$ 472,728	$ 436,026
[1]	The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant.

Investments (Aggregated Income

Investments (Aggregated Income Statement Summarized Financial Information for Partnerhips in our Alternative Investment Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 55,967	$ 50,618
Carrying Value	244,934		$ 216,807
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned	6,300	600
Carrying Value	201,800
Investments accounted for under the equity method [Member]
Schedule of Equity Method Investments [Line Items]
Net investment (loss) income	12,700	(150,000)
Realized (losses) gains	164,800	143,300
Net change in unrealized appreciation (depreciation)	1,204,000	554,300
Net income	$ 1,381,500	$ 547,600

Investments (Investments Pledge

Investments (Investments Pledged as Collateral) (Details) $ in Millions	Mar. 31, 2020USD ($)
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	$ 27.7
Securities Pledged As Collateral	428.3
Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	146.8
Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	253.8
U.S. Government and Government Agencies [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	23.4
Securities Pledged As Collateral	23.4
U.S. Government and Government Agencies [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
U.S. Government and Government Agencies [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Obligations of States and Political Subdivisions [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	4
Securities Pledged As Collateral	4
Obligations of States and Political Subdivisions [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Obligations of States and Political Subdivisions [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Corporate Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0.3
Securities Pledged As Collateral	0.3
Corporate Securities [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Corporate Securities [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	0
Commercial Mortgage Backed Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	35.2
Commercial Mortgage Backed Securities [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	7.1
Commercial Mortgage Backed Securities [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	28.1
Residential Mortgage Backed Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Carrying Value Bonds On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	365.4
Residential Mortgage Backed Securities [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	139.7
Residential Mortgage Backed Securities [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Fixed Income Securities Pledged For FHLB Collateral	$ 225.7

Investments (Credit Concentrati

Investments (Credit Concentration Risk) (Details)	Mar. 31, 2020	Dec. 31, 2019
Investments [Abstract]
Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government-backed investments	10.00%	10.00%

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Investment Income [Line Items]
Net investment income earned	$ 55,967	$ 50,618
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	50,253	49,033
Commercial Mortgage Loans [Member]
Net Investment Income [Line Items]
Net investment income earned	62	0
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	1,552	1,640
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	1,166	2,044
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	6,342	660
Investment Expenses [Member]
Net Investment Income [Line Items]
Net investment income earned	$ (3,408)	$ (2,759)

Investments (OTTI) (Details)

Investments (OTTI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	$ 15,787
Credit loss expense, Not Previously Recorded	16,027
Other Impairment Charges	15,602
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	31,629	$ 104
Change in OTTI Balance	31,525
Commercial Mortgage Loans [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other Impairment Charges	0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	240	0
Commercial mortgage loan, Credit Loss, Not Previously Recorded	240
Other Investments [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other Impairment Charges	0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	39
Other investments, Credit Loss, Not Previously Recorded	0
AFS Fixed Income Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	31,389	65
AFS Fixed Income Securities [Member] | US Treasury and Government [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	0
Other Impairment Charges	14
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	14	0
AFS Fixed Income Securities [Member] | Foreign Government [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	21
Other Impairment Charges	0
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	21	0
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	29
Other Impairment Charges	62
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	91	65
AFS Fixed Income Securities [Member] | Corporate Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	13,412
Other Impairment Charges	11,603
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	25,015	0
AFS Fixed Income Securities [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	1,565
Other Impairment Charges	2,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	3,565	0
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	38
Other Impairment Charges	1,852
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	1,890	0
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Available-for-sale, Credit Loss, Not Previously Recorded	722
Other Impairment Charges	71
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	793	$ 0
Securities intended to sell [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	$ 15,602

Investments (Components Of Net

Investments (Components Of Net Realized and Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	$ 4,100	$ 3,444
OTTI Charges	31,629	104
Net realized (losses) gains	(27,529)	3,340
Unrealized Gains Losses on Equity Securities	(27,200)
Net realized and unrealized investment (losses) gains	(44,666)	13,451
Total unrealized (losses) gains recognized in income on equity securities	(17,137)	10,111
Increase in net realized and unrealized investment losses	(58,100)
Fixed Income Securities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	4,276	1,143
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(3)	2,280
Short-Term Investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(168)	14
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on disposals of securities, fixed income securities (excluding OTTI charges)	(5)	7
OTTI Charges	$ 0	$ 39

Investments (Realized and Unrea

Investments (Realized and Unrealized Gains (Losses) on Equity Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Gain (Loss) on Securities [Line Items]
Unrealized (losses) gains recognized in income on equity securities on securities remaining in our portfolio at March 31, 2020	$ (17,140)	$ 12,055
Unrealized (losses) gains recognized in income on equity securities on securities sold in each respective period	3	(1,944)
Total unrealized (losses) gains recognized in income on equity securities	$ (17,137)	$ 10,111

Investments (Net Realized Gains

Investments (Net Realized Gains (Losses) on Disposals) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items]
HTM fixed income securities Gains	$ 1	$ 0
HTM fixed income securities Losses	0	0
Equity securities Gains	0	2,280
Equity securities Losses	(3)	0
Short-term investments Gains	22	14
Short-term investments Losses	(190)	0
Other investments Gains	0	7
Other investments Losses	(5)	0
Net realized investment gains on disposals	4,100	3,444
Fixed Maturities [Member]
Schedule of Realized Gains (Losses) on Disposals Excluding OTTI [Line Items]
AFS securities Gains	5,653	1,844
AFS securities Losses	$ (1,378)	$ (701)

Indebtedness (Schedule of Outst

Indebtedness (Schedule of Outstanding Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2020		Dec. 31, 2019
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 3,618
Unamortized debt discount	6,427
Short-term Debt	302,000		$ 0
Long-term Debt	550,577		550,597
Finance lease liabilities	622		737
Total debt	$ 852,577		550,597
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Debt Instrument [Line Items]
Interest Rate	3.03%
Original Amount	$ 60,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	$ 60,000		60,000
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Debt Instrument [Line Items]
Interest Rate	1.56%
Original Amount	$ 25,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	$ 25,000		25,000
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Debt Instrument [Line Items]
Interest Rate	1.61%
Original Amount	$ 25,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	$ 25,000		25,000
Six Point Seventy Percent Senior Notes [Member]
Debt Instrument [Line Items]
Interest Rate	6.70%
Original Amount	$ 100,000
Unamortized debt issuance costs	346
Unamortized debt discount	515
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	$ 99,139		99,125
Seven Point Twenty Five Percent Senior Notes [Member]
Debt Instrument [Line Items]
Interest Rate	7.25%
Original Amount	$ 50,000
Unamortized debt issuance costs	180
Unamortized debt discount	89
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	$ 49,731		49,725
Five Point Three Hundred Seventy Five Senior Notes [Member]
Debt Instrument [Line Items]
Interest Rate	5.375%
Original Amount	$ 300,000
Unamortized debt issuance costs	3,092
Unamortized debt discount	5,823
Long Term Debt Excluding Debt Discount And Debt Issuance Costs	291,085		291,010
Long-term Debt
Debt Instrument [Line Items]
Unamortized debt issuance costs	3,618
Unamortized debt discount	6,427
Long-term Debt	$ 550,577		550,597
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member]
Debt Instrument [Line Items]
Interest Rate	0.78%
Original Amount	$ 100,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Short-term Debt	$ 100,000		0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member]
Debt Instrument [Line Items]
Interest Rate	0.68%
Original Amount	$ 85,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Short-term Debt	$ 85,000		0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Debt Instrument [Line Items]
Interest Rate	0.58%
Original Amount	$ 67,000
Unamortized debt issuance costs	0
Unamortized debt discount	0
Short-term Debt	$ 67,000		0
Two Point Two Hundred and Fourty Four Percent Borrowing from Bank of Montreal Due September 24, 2020 [Member]
Debt Instrument [Line Items]
Interest Rate	2.244%
Unamortized debt issuance costs	$ 0
Unamortized debt discount	0
Line of Credit	50,000
Short-term Debt	50,000	[1]	0
Short-term Debt
Debt Instrument [Line Items]
Unamortized debt issuance costs	0
Unamortized debt discount	0
Short-term Debt	$ 302,000		$ 0
[1]	Total short-term debt includes our $50 million line of credit borrowing. As there is no scheduled or definitive repayment plan for this borrowing as of March 31, 2020, the fair value cannot be calculated and the borrowing is not classified in the fair value hierarchy table below.

Indebtedness (Short Term Debt A

Indebtedness (Short Term Debt Activity) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Short-term Debt	$ 302,000	$ 0
Short-term Debt [Member]
Short-term Debt [Line Items]
Short-term Debt	302,000	0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member]
Short-term Debt [Line Items]
Short-term Debt	85,000	0
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member]
Short-term Debt [Line Items]
Short-term Debt	100,000	0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Short-term Debt [Line Items]
Short-term Debt	67,000	$ 0
Selective Insurance Group [Member]
Short-term Debt [Line Items]
Line of Credit	$ 50,000
Line of Credit Interest Rate	2.244%
Selective Insurance Company of South Carolina [Member] | Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances	$ 28,000
Federal Home Loan Bank, Advances, Interest Rate	0.58%
Selective Insurance Company of the Southeast [Member] | Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances	$ 39,000
Federal Home Loan Bank, Advances, Interest Rate	0.58%
Selective Insurance Company of America [Member] | Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances	$ 85,000
Federal Home Loan Bank, Advances, Interest Rate	0.68%
Selective Insurance Company of America [Member] | Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank Advances	$ 100,000
Federal Home Loan Bank, Advances, Interest Rate	0.78%
Selective Insurance Company of America [Member] | One Point Eighty One Percent Borrowing from FHLBNY Due March 18, 2020 [Member]
Short-term Debt [Line Items]
Federal Home Loan Bank, Advances, Interest Rate	1.81%

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Values and Estimated Fair Values of Financial Liabilities) (Details) - USD ($) $ in Thousands		Mar. 31, 2020		Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		$ 302,000		$ 0
Short-term Debt, Fair Value		252,141		0
Finance lease liabilities		622		737
Long-term debt		550,577		550,597
Long-term debt, fair value		612,020		659,272
Unamortized debt issuance costs		(3,618)
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		61,134		66,365
Unamortized debt issuance costs		(180)
Seven Point Twenty Five Percent Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		49,911		49,910
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		118,561		123,104
Unamortized debt issuance costs		(346)
Six Point Seventy Percent Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		99,485		99,480
Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		316,400		357,025
Unamortized debt issuance costs		(3,092)
Five Point Three Hundred Seventy Five Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		294,177		294,157
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		25,261		24,901
Unamortized debt issuance costs		0
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		25,000		25,000
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		25,260		24,875
Unamortized debt issuance costs		0
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		25,000		25,000
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		65,404		63,002
Unamortized debt issuance costs		0
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		60,000		60,000
Long Term Debt Excluding Issuance Costs and Finance Lease Obligations [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt		553,573		553,547
Unamortized Debt Issuance Costs [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized debt issuance costs		(3,618)		(3,687)
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		100,000		0
Short-term Debt, Fair Value		100,096		0
Unamortized debt issuance costs		0
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		100,000
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		85,000		0
Short-term Debt, Fair Value		85,039		0
Unamortized debt issuance costs		0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		85,000
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		67,000		0
Short-term Debt, Fair Value		67,006		0
Unamortized debt issuance costs		0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		67,000
Two Point Two Hundred and Fourty Four Percent Borrowing from Bank of Montreal Due September 24, 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		50,000	[1]	0
Short-term Debt, Fair Value		0		0
Unamortized debt issuance costs		0
Two Point Two Hundred and Fourty Four Percent Borrowing from Bank of Montreal Due September 24, 2020 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt	[1]	50,000
Short-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		302,000		$ 0
Unamortized debt issuance costs		0
Short-term Debt [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt		$ 302,000
[1]	Total short-term debt includes our $50 million line of credit borrowing. As there is no scheduled or definitive repayment plan for this borrowing as of March 31, 2020, the fair value cannot be calculated and the borrowing is not classified in the fair value hierarchy table below.

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Disclosures of Fair Value Assets) (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
AFS Fixed Income Securities		$ 5,945,360	$ 6,095,620
Equity Securities		99,989	72,937
Short-term investments		517,558	282,490
Net Asset Value		39,200	37,800
Fair Value, Recurring [Member]
AFS Fixed Income Securities		5,945,360	6,095,620
Equity Securities		99,989	72,937
Short-term investments		517,558	282,490
Total assets measured at fair value		6,562,907	6,451,047
U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		142,237	116,186
Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		12,886	18,542
Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,197,213	1,230,090
Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,909,504	1,947,477
Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		722,261	793,012
Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,430,226	1,451,969
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		531,033	538,344
Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	98,410	69,900
Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		1,579	3,037
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		44,093	44,718
Equity Securities		60,754	35,182
Short-term investments		504,243	265,306
Total assets measured at fair value		609,090	345,206
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		44,093	41,083
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	3,635
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	59,175	32,145
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		1,579	3,037
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		5,837,820	6,016,817
Equity Securities		0	0
Short-term investments		13,315	17,184
Total assets measured at fair value		5,851,135	6,034,001
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		98,144	75,103
Significant Other Observable Inputs (Level 2) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		12,886	18,542
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,194,323	1,230,090
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,885,319	1,930,426
Significant Other Observable Inputs (Level 2) [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		685,889	772,343
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,430,226	1,451,969
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		531,033	538,344
Significant Other Observable Inputs (Level 2) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	0	0
Significant Other Observable Inputs (Level 2) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		63,447	34,085
Equity Securities		0	0
Short-term investments		0	0
Total assets measured at fair value		63,447	34,085
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		2,890	0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		24,185	17,051
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		36,372	17,034
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	0	0
Significant Unobservable Inputs (Level 3) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		$ 0	$ 0
[1]	Investments amounting to $39.2 million at March 31, 2020 , and $37.8 million at December 31, 2019 , were measured at fair value using net asset value per share (or its practical expedient) and are not classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period disclosed above. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value.

Fair Value Measurements (Change

Fair Value Measurements (Change in Fair Value of Securities Using Level 3 Inputs) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31,	$ 0
Total net (losses) gains for the period included in OCI	0
Total net (losses) gains for the period included in net income	0
Purchases	0
Sales	0
Issuances	0
Settlements	0
Transfers into Level 3	2,890
Transfers out of Level 3	0
Fair value, March 31	2,890
Period change unrealized gains (losses) in earnings	0
Period change unrealized gains (losses) in OCI	0
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31,	17,051	$ 0
Total net (losses) gains for the period included in OCI	1	0
Total net (losses) gains for the period included in net income	(61)	0
Purchases	3,002	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	4,192	16,419
Transfers out of Level 3	0	0
Fair value, March 31	24,185	16,419
Period change unrealized gains (losses) in earnings	(61)	0
Period change unrealized gains (losses) in OCI	1
Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31,	17,034	7,409
Total net (losses) gains for the period included in OCI	(1,756)	(225)
Total net (losses) gains for the period included in net income	(214)	0
Purchases	4,831	12,434
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	20,107	11,674
Transfers out of Level 3	(3,630)	0
Fair value, March 31	36,372	31,292
Period change unrealized gains (losses) in earnings	(214)	0
Period change unrealized gains (losses) in OCI	(1,756)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31,	34,085	7,409
Total net (losses) gains for the period included in OCI	(1,755)	(225)
Total net (losses) gains for the period included in net income	(275)	0
Purchases	7,833	12,434
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	27,189	28,093
Transfers out of Level 3	(3,630)	0
Fair value, March 31	63,447	47,711
Period change unrealized gains (losses) in earnings	(275)	$ 0
Period change unrealized gains (losses) in OCI	$ (1,755)

Fair Value Measurements (Quan_2

Fair Value Measurements (Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	$ 252,141	$ 0
Held-to-maturity securities, fair value	21,921	21,975
Long-term debt, fair value	612,020	659,272
Commercial mortgage loan, fair value	13,856
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	61,134	66,365
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	118,561	123,104
Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	316,400	357,025
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	25,261	24,901
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	25,260	24,875
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	65,404	63,002
Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	612,020	659,272
Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	4,871	4,921
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	17,050	17,054
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Held-to-maturity securities, fair value	0	0
Long-term debt, fair value	0	0
Commercial mortgage loan, fair value	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [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, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	252,141
Held-to-maturity securities, fair value	21,921	21,975
Long-term debt, fair value	612,020	659,272
Commercial mortgage loan, fair value	0
Significant Other Observable Inputs (Level 2) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	61,134	66,365
Significant Other Observable Inputs (Level 2) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	118,561	123,104
Significant Other Observable Inputs (Level 2) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	316,400	357,025
Significant Other Observable Inputs (Level 2) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	25,261	24,901
Significant Other Observable Inputs (Level 2) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	25,260	24,875
Significant Other Observable Inputs (Level 2) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	65,404	63,002
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	4,871	4,921
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	17,050	17,054
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Held-to-maturity securities, fair value	0	0
Long-term debt, fair value	0	0
Commercial mortgage loan, fair value	13,856
Significant Unobservable Inputs (Level 3) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, fair value	0	0
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	100,096	0
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	100,096
Zero Point Seventy Eight Percent Borrowing from FHLBNY Due September 14, 2020. [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	85,039	0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	85,039
Zero Point Sixty Eight Percent Borrowing from FHLBNY Due September 18, 2020. [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	67,006	$ 0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	0
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	67,006
Zero Point Fifty Eight Percent Borrowing from FHLBI Due December 14, 2020. [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt, Fair Value	$ 0

Allowance for Uncollectible P_3

Allowance for Uncollectible Premiums Receivable (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss		$ 18,000	$ 6,400
Cumulative effect of new accounting principle in period of adoption			1,435
Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Cumulative effect of new accounting principle in period of adoption			1,435	$ 0
Premiums Receivable [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss		18,000	7,458
Current period provision for expected credit losses		11,195
Write-offs charged against the allowance		(653)
Recoveries		0
Allowance for credit losses, net of write-offs		$ 10,500
Premiums Receivable [Member] | Accounting Standards Update 2016-13 [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss	[1]		6,400
Premiums Receivable [Member] | Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Cumulative effect of new accounting principle in period of adoption	[1]		$ 1,058
[1]	See Note 2. "Adoption of Accounting Pronouncements" above for additional information regarding our adoption of ASU 2016-13.

Reinsurance Reinsurance Recover

Reinsurance Reinsurance Recoverable Credit Ratings (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverable, Credit Quality Indicator, Date Updated	Mar. 31, 2020
Reinsurance recoverable	$ 565,036	$ 577,635
Reinsurance Recoverable, Allowance for Credit Loss	(1,502)	(4,400)	[1]
Reinsurance recoverable, net of allowance for credit losses	563,534	$ 573,235
AM Best, A++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	20,835
Reinsurance Recoverable, Current	20,835
Reinsurance Recoverable, Past Due	0
AM Best, A+ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	431,583
Reinsurance Recoverable, Current	428,354
Reinsurance Recoverable, Past Due	3,229
AM Best, A Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	25,915
Reinsurance Recoverable, Current	25,915
Reinsurance Recoverable, Past Due	0
AM Best, A- Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	508
Reinsurance Recoverable, Current	508
Reinsurance Recoverable, Past Due	0
AM Best, B++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	410
Reinsurance Recoverable, Current	316
Reinsurance Recoverable, Past Due	94
AM Best, B+ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	21
Reinsurance Recoverable, Current	21
Reinsurance Recoverable, Past Due	0
AM Best Rated Reinsurer [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	479,272
Reinsurance Recoverable, Current	475,949
Reinsurance Recoverable, Past Due	3,323
Total federal and state pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	80,305
Reinsurance Recoverable, Current	80,245
Reinsurance Recoverable, Past Due	60
Other Federal And State Pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	5,459
Reinsurance Recoverable, Current	5,459
Reinsurance Recoverable, Past Due	0
Total Non Rated Reinsurer [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	85,764
Reinsurance Recoverable, Current	85,704
Reinsurance Recoverable, Past Due	60
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverable, Current	561,653
Reinsurance Recoverable, Past Due	3,383
Reinsurance recoverable not past due [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverable, Allowance for Credit Loss	(1,502)
Reinsurance recoverable past due [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverable, Allowance for Credit Loss	0
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverable, Current	560,151
Reinsurance Recoverable, Past Due	$ 3,383
[1]	See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.

Reinsurance Reinsurance Allowan

Reinsurance Reinsurance Allowance for Credit Losses (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	[1]	$ 4,400
Cumulative effect of new accounting principle in period of adoption			$ 1,435
Current period provision for expected credit losses		5
Write-offs charged against the allowance		0
Recoveries		0
Allowance for credit losses, end of period		1,502
Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Cumulative effect of new accounting principle in period of adoption			1,435	$ 0
Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member] | Reinsurance Recoverable [Domain]
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	[1]	$ 1,497
Cumulative effect of new accounting principle in period of adoption	[1]		$ (2,903)
[1]	See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.

Reinsurance (List of Direct, As

Reinsurance (List of Direct, Assumed, and Ceded Reinsurance Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Premiums written:
Direct	$ 746,431	$ 766,394
Assumed	6,043	6,555
Ceded	(105,147)	(100,002)
Net	647,327	672,947
Premiums earned:
Direct	754,892	728,037
Assumed	6,173	6,562
Ceded	(109,362)	(102,026)
Net	651,703	632,573
Loss and loss expenses incurred:
Direct	425,795	424,657
Assumed	4,898	5,265
Ceded	(30,369)	(43,343)
Net	400,324	$ 386,579
COVID-19 [Member]
Effects of Reinsurance [Line Items]
Premium audit accrual decrease	$ 75,000

Reinsurance (Ceded Premiums and

Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Ceded premiums written	$ (105,147)	$ (100,002)
Ceded premiums earned	(109,362)	(102,026)
Ceded loss and loss expenses incurred	$ (30,369)	(43,343)
National Flood Insurance Program [Member]
Percentage of NFIP claims ceded by federal government	100.00%
Ceded premiums written	$ (62,087)	(60,013)
Ceded premiums earned	(66,861)	(62,263)
Ceded loss and loss expenses incurred	$ (5,096)	$ (13,686)

Reserve for Loss and Loss Exp_3

Reserve for Loss and Loss Expense (Rollforward of Reserve for Loss and Loss Expense) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020		Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Cumulative effect of new accounting principle in period of adoption					$ 1,435
Gross reserve for loss and loss expense, at beginning of year		$ 4,067,163		$ 3,893,868
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year		547,066	[1]	537,388
Net reserve for loss and loss expense, at beginning of year		3,520,097		3,356,480
Incurred loss and loss expense for claims occurring in the current year		407,276		397,253
Total incurred loss and loss expense		400,324		386,579
Paid loss and loss expense for claims occurring in the current year		70,610		73,964
Paid loss and loss expense for claims occurring in the prior years		281,736		246,168
Total paid loss and loss expense		352,346		320,132
Net reserve for loss and loss expense, at end of period		3,568,075		3,422,927
Add: reinsurance recoverable on unpaid loss and loss expense, at end of period		535,560		543,582
Gross reserve for loss and loss expense, at end of period		4,103,635		3,966,509
Loss Reserve for COVID-19		10,000
Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development		(6,952)		(10,674)
Workers' Compensation Insurance [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development		(10,000)
Property Insurance [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development		$ 3,000
Workers Compensation [Member] | Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development				(8,000)
General Liability [Member] | Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development				$ (2,000)
Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Cumulative effect of new accounting principle in period of adoption					1,435	$ 0
Reinsurance Recoverable [Domain] | Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Cumulative effect of new accounting principle in period of adoption	[2]				$ (2,903)
[1]	Includes an adjustment of $2.9 million related to our adoption of ASU 2016-13. Refer to Note 2. "Adoption of Accounting Pronouncements" for additional information.
[2]	See Note 2. "Adoption of Accounting Pronouncements" for additional information regarding our adoption of ASU 2016-13.

Segment Information Narrative (

Segment Information Narrative (Details)	3 Months Ended
	Mar. 31, 2020
Number of Operating Segments	4

Segment Information (Revenue by

Segment Information (Revenue by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total net premiums earned	$ 651,703	$ 632,573
Miscellaneous income	1,825	2,320
Net investment income	55,967	50,618
Net realized and unrealized investment (losses) gains	(44,666)	13,451
Total Investments revenue	11,301	64,069
Total revenues	664,829	698,962
Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Miscellaneous income	1,391	2,044
Total revenues	517,971	499,228
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	149,690	131,186
Standard Commercial Lines [Member] | Workers Compensation [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	66,706	78,715
Standard Commercial Lines [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	164,580	161,525
Standard Commercial Lines [Member] | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	93,869	86,067
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	27,036	26,081
Standard Commercial Lines [Member] | Bonds Segment [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	9,639	8,904
Standard Commercial Lines [Member] | Other Commercial [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	5,060	4,706
Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Miscellaneous income	434	276
Total revenues	76,562	77,583
Standard Personal Lines [Member] | Personal Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	42,487	43,163
Standard Personal Lines [Member] | Homeowners [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	31,490	32,130
Standard Personal Lines [Member] | Other Personal [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	2,151	2,014
Excess And Surplus Operations [Member]
Segment Reporting Information [Line Items]
Miscellaneous income	0	0
Total revenues	58,995	58,082
Excess And Surplus Operations [Member] | Casualty Insurance Product Line [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	44,072	44,528
Excess And Surplus Operations [Member] | Property Insurance [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	$ 14,923	$ 13,554

Segment Information (Income Bef

Segment Information (Income Before and After Federal Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Total investment segment income, after federal income tax	$ 10,197	$ 51,949
Net investment income	55,967	50,618
Net realized and unrealized investment (losses) gains	(44,666)	13,451
Total investment segment income, before federal income tax	11,301	64,069
Tax on investment income	1,104	12,120
Standard Commercial Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	17,126	25,815
Underwriting gain (loss), after federal income tax	$ 13,529	$ 20,394
Combined ratio	96.70%	94.80%
ROE Contribution	2.40%	4.40%
Standard Personal Lines [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ 387	$ 3,167
Underwriting gain (loss), after federal income tax	$ 306	$ 2,502
Combined ratio	99.50%	95.90%
ROE Contribution	0.10%	0.50%
Excess And Surplus Operations [Member]
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ 3,844	$ 4,579
Underwriting gain (loss), after federal income tax	$ 3,037	$ 3,617
Combined ratio	93.50%	92.10%
ROE Contribution	0.60%	0.80%
Investments [Member]
Segment Reporting Information [Line Items]
ROE Contribution	8.50%	8.90%

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Results to Income Before Federal Income Tax (Details)) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Investment income	$ 11,301	$ 64,069
Interest expense	(7,601)	(11,526)
Corporate expenses	(9,060)	(12,410)
Income before federal income tax	15,997	73,694
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	17,126	25,815
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	387	3,167
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	3,844	4,579
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total income, before federal income tax all segments	$ 32,658	$ 97,630

Retirement Plans (Components of

Retirement Plans (Components of Net Periodic Benefit Cost) (Details) - Pension Plan [Member] - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost		$ 2,828	$ 3,377
Expected return on plan assets		(5,477)	(5,279)
Amortization of unrecognized net actuarial loss		704	644
Total net periodic cost (benefit)	[1]	$ (1,945)	$ (1,258)
[1]	The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income.

Retirement Plans (Weighted-Aver

Retirement Plans (Weighted-Average Expense Assumptions) (Details) - Pension Plan [Member]	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.33%	4.46%
Effective interest rate for calculation of interest cost	2.95%	4.12%
Expected return on plan assets	5.80%	6.50%

Comprehensive Income (Component

Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net income, Gross	$ 15,997	$ 73,694
Unrealized holding (losses) gains during the period, Gross	(93,981)	102,926
Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income; Gross	(65,390)
Amounts reclassified into net income: HTM securities, Gross	25	(9)
Realized losses (gains) on disposals and intent-to-sell OTTI on AFS securities, Gross	11,327	(1,077)
Credit loss expense recognized in OTTI, Gross	15,787
Total unrealized (losses) gains on investment securities, Gross	(132,232)	101,840
Amount reclassified into net income: Net actuarial loss, Gross	754	664
Total defined pension and other post-retirement benefit plans, Gross	754	664
Other comprehensive (loss) income, Gross	(131,478)	102,504
Comprehensive (loss) income before tax	(115,481)	176,198
Net income, Tax	761	12,346
Unrealized holding (losses) gains during the period, Tax	(19,736)	21,613
Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income; Tax	(13,732)
Amounts reclassified into net income: HTM securities, Tax	5	(2)
Realized losses (gains) on disposals and intent-to-sell OTTI on AFS securities, Tax	2,379	(226)
Credit loss expense recognized in OTTI, Tax	3,315
Total unrealized (losses) gains on investment securities, Tax	(27,769)	21,385
Amount reclassified into net income: Net actuarial loss, Tax	158	139
Total defined pension and other post-retirement benefit plans, Tax	158	139
Other comprehensive (loss) income, Tax	(27,611)	21,524
Comprehensive (loss) income, Tax	(26,850)	33,870
Net income	15,236	61,348
Unrealized holding gains (losses) arising during period	(74,245)	81,313
Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income	(51,658)	0
Amounts reclassified into net income: HTM Securities	20	(7)
Credit loss expense recognized in OTTI, Net	12,472	0
Total unrealized (losses) gains on investment securities	(104,463)	80,455
Amount reclassified into net income: Net actuarial loss	596	525
Total defined benefit pension and post-retirement plans	596	525
Other comprehensive (loss) income	(103,867)	80,980
Comprehensive (loss) income	$ (88,631)	$ 142,328

Comprehensive Income (Compone_2

Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	$ 81,750
Amounts reclassified from AOCI, HTM related	20	$ (7)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans	0
Amount reclassified into net income: Net actuarial loss	596	525
Other comprehensive (loss) income	(103,867)	80,980
Other comprehensive income, defined pension and post retirement plans	596	525
Ending Balance, March 31, 2020	(22,117)
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	170,439
OCI before reclassifications	(74,245)
Amounts reclassified from AOCI, All Other	8,948
Other comprehensive (loss) income	(65,297)
Ending Balance, March 31, 2020	105,142
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	170,393
OCI before reclassifications	(125,903)
Amounts reclassified from AOCI	21,440
Other comprehensive (loss) income	(104,463)
Ending Balance, March 31, 2020	65,930
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	(71)
OCI before reclassifications	(51,658)
Amounts reclassified from AOCI, Non-credit OTTI	12,472
Other comprehensive (loss) income	(39,186)
Ending Balance, March 31, 2020	(39,257)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	25
OCI before reclassifications	0
Amounts reclassified from AOCI, HTM related	20
Other comprehensive (loss) income	20
Ending Balance, March 31, 2020	45
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	(88,643)
Amount reclassified into net income: Net actuarial loss	596
Ending Balance, March 31, 2020	(88,047)
Accumulated other comprehensive income (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2019	81,750
OCI before reclassifications	(125,903)
Amounts reclassified from AOCI	22,036
Other comprehensive (loss) income	(103,867)	$ 80,980
Ending Balance, March 31, 2020	$ (22,117)

Comprehensive Income (Reclassif

Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net realized and unrealized investment (losses) gains	$ (44,666)	$ 13,451
Net investment income	55,967	50,618
Loss and loss expense incurred	400,324	386,579
Other insurance expenses	95,346	85,079
Income before federal income tax	15,997	73,694
Total federal income tax expense	(761)	(12,346)
Net income	15,236	61,348
Reclassification out of AOCI
Net income	22,036	(333)
Pension Plan [Member] | Reclassification out of AOCI
Loss and loss expense incurred	162	145
Other insurance expenses	592	519
Income before federal income tax	754	664
Total federal income tax expense	(158)	(139)
Net income	596	525
Held-to-maturity Securities [Member] | Reclassification out of AOCI
Net realized and unrealized investment (losses) gains	1	0
Net investment income	24	(9)
Income before federal income tax	25	(9)
Total federal income tax expense	(5)	2
Net income	20	(7)
Available for sale securities, excluding credit losses [Member] | Reclassification out of AOCI
Net realized and unrealized investment (losses) gains	11,327	(1,077)
Income before federal income tax	11,327	(1,077)
Total federal income tax expense	(2,379)	226
Net income	8,948	(851)
Available for sale securities, including credit losses | Reclassification out of AOCI
Net realized and unrealized investment (losses) gains	15,787	0
Income before federal income tax	15,787	0
Total federal income tax expense	(3,315)	0
Net income	$ 12,472	$ 0

Leases (Components of Lease Exp

Leases (Components of Lease Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lease Expense [Line Items]
Operating lease cost	$ 2,259	$ 2,152
Finance lease cost: Amortization of assets	142	284
Finance lease cost: Interest on lease liabilities	6	0
Total finance lease cost	148	284
Variable lease cost	176	788
Short-term lease cost	$ 476	$ 739

Leases (Supplemental Lease Info

Leases (Supplemental Lease Information) (Details)	Mar. 31, 2020	Dec. 31, 2019
Supplemental Lease Information [Line Items]
Weighted average remaining lease term, operating leases	6 years	6 years
Weighted average remaining lease term, finance leases	2 years	2 years
Weighted average discount rate, operating leases	3.20%	3.40%
Weighted average discount rate, finance leases	2.20%	2.10%

Leases (Lease Assets and Liabil

Leases (Lease Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lease Assets and Liabilities [Line Items]
Operating leases, Other assets	$ 28,270	$ 26,535
Operating leases, Other liabilities	29,364	27,506
Finance leases, Property and equipment - at cost, net of accumulated depreciation and amortization	615	731
Finance leases, Long-term debt	$ 622	$ 737

Leases (Maturities of Lease Lia

Leases (Maturities of Lease Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lease Liabilities Payments Due [Line Items]
Finance Lease Liability, due remainder of fiscal year	$ 332
Finance lease liability, due 2021	248	$ 451
Finance lease liability, due 2022	54	248
Finance lease liability, due 2023	0	54
Finance lease liability, due 2024	0	0
Finance lease liability, due after 2024	0	0
Finance lease liability, total payments	634	753
Finance lease imputed interest	12	16
Finance Lease Liability Not Yet Commenced		0
Finance lease liabilities	622	737
Operating lease liability, due remainder of fiscal year	6,291
Operating lease liability, due 2021	6,372	8,244
Operating lease liability, due 2022	4,798	6,168
Operating lease liability, due 2023	3,434	4,590
Operating lease liability, due 2024	2,920	3,329
Operating lease liability, due after 2024	8,638	2,920
Operating lease liability, total payments	32,453	33,889
Operating Lease Liability Not Yet Commenced		3,388
Operating lease imputed interest	3,089	2,995
Operating lease liability	29,364	27,506
Total lease liability, due remainder of fiscal year	6,623
Total lease liability, due 2021	6,620	8,695
Total lease liability, due 2022	4,852	6,416
Total lease liability, due 2023	3,434	4,644
Total lease liability, due 2024	2,920	3,329
Total lease liability, due after 2024	8,638	8,638
Total lease liability, total payments	33,087	34,642
Total imputed interest	3,101	3,011
Total lease liability not yet commenced		3,388
Total lease liability	$ 29,986	$ 28,243

Leases (Schedule of Future Mini

Leases (Schedule of Future Minimum Rental Payments Prior Year) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Finance lease liability, due 2020	$ 248	$ 451
Finance lease liability, due 2021	54	248
Finance lease liability, due 2022	0	54
Finance lease liability, due 2023	0	0
Finance lease liability, due 2024	0	0
Finance lease liability, due after 2024		0
Finance lease liability, total payments	634	753
Finance lease imputed interest	12	16
Finance Lease Liability Not Yet Commenced		0
Finance lease liabilities	622	737
Operating lease liability, due 2020	6,372	8,244
Operating lease liability, due 2021	4,798	6,168
Operating lease liability, due 2022	3,434	4,590
Operating lease liability, due 2023	2,920	3,329
Operating lease liability, due 2024	8,638	2,920
Operating lease liability, due after 2024		8,638
Operating lease liability, total payments	32,453	33,889
Operating lease imputed interest	3,089	2,995
Operating Lease Liability Not Yet Commenced		3,388
Operating lease liability	29,364	27,506
Total lease liability, due 2020	6,620	8,695
Total lease liability, due 2021	4,852	6,416
Total lease liability, due 2022	3,434	4,644
Total lease liability, due 2023	2,920	3,329
Total lease liability, due 2024		2,920
Total lease liability, due after 2024	8,638	8,638
Total lease liability, total payments	33,087	34,642
Total imputed interest	3,101	3,011
Total lease liability not yet commenced		3,388
Total lease liability	$ 29,986	$ 28,243

Federal Income Taxes Federal _2

Federal Income Taxes Federal Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Tax at statutory rate (21% in 2020 and 2019)	$ 3,359	$ 15,476
Tax-advantaged interest	(1,214)	(1,253)
Dividends received deduction	(55)	(83)
Executive compensation	351	473
Stock-based compensation	(1,881)	(2,635)
Other	201	368
Federal income tax expense	$ 761	$ 12,346
Effective Income Tax Rate Reconciliation, Percent	4.80%	16.80%
Net realized and unrealized investment (losses) gains	$ (44,666)	$ 13,451
Deferred Income Tax Assets, Net	$ 43,099		$ 6,776

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended
	May 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2019
Subsequent Event [Line Items]
Other insurance expenses			$ 95,346	$ 85,079
Net investment income			(55,967)	(50,618)
Subsequent Event [Member]
Subsequent Event [Line Items]
Policyholder's Premium Credit	15.00%
Other insurance expenses		$ 20,000
Alternative Investments [Member]
Subsequent Event [Line Items]
Net investment income			$ (6,300)	$ (600)
Minimum [Member] | Alternative Investments [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net investment income		(15,000)
Maximum [Member] | Alternative Investments [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net investment income		(20,000)
Property Insurance [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims		$ 35,000