ProAssurance (PRA) 10-Q 6 May 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	May 01, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	0-16533
Entity Registrant Name	ProAssurance Corporation
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	63-1261433
Entity Address, Address Line One	100 Brookwood Place,
Entity Address, City or Town	Birmingham,
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	35209
City Area Code	(205)
Local Phone Number	877-4400
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	PRA
Security Exchange Name	NYSE
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 (in shares)		51,012,066
Entity Central Index Key	0001127703
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments
Fixed maturities, available-for-sale, at fair value (amortized cost, $3,813,857 and $3,758,720, respectively; allowance for expected credit losses, $1,137 as of March 31, 2024 and $555 as of December 31, 2023)	$ 3,544,137	$ 3,493,597
Fixed maturities, trading, at fair value (cost, $49,409 and $48,449, respectively)	50,106	48,324
Equity investments, at fair value (cost, $150,099 and $164,262, respectively)	137,914	151,295
Short-term investments	184,001	235,785
Business owned life insurance	78,657	78,205
Investment in unconsolidated subsidiaries	278,931	276,756
Other investments (at fair value, $55,732 and $62,604, respectively, otherwise at cost or amortized cost)	59,796	65,819
Total Investments	4,333,542	4,349,781
Cash and cash equivalents	65,400	65,898
Premiums receivable, net (allowance for expected credit losses, $8,072 as of March 31, 2024 and $7,809 as of December 31, 2023)	262,270	235,569
Receivable from reinsurers on paid losses and loss adjustment expenses	9,387	21,122
Receivable from reinsurers on unpaid losses and loss adjustment expenses	447,157	445,573
Prepaid reinsurance premiums	35,808	31,149
Deferred policy acquisition costs	63,619	60,336
Deferred tax asset, net	184,897	186,164
Real estate, net	29,523	29,757
Operating lease ROU assets	17,530	16,275
Intangible assets, net	58,676	60,308
Goodwill	5,500	5,500
Other assets	136,727	124,493
Total Assets	5,650,036	5,631,925
Policy liabilities and accruals
Reserve for losses and loss adjustment expenses	3,382,512	3,401,281
Unearned premiums	476,941	433,715
Reinsurance premiums payable	29,435	24,019
Total Policy Liabilities and Accruals	3,888,888	3,859,015
Operating lease liabilities	18,517	17,179
Other liabilities	201,792	216,618
Debt less unamortized debt issuance costs	427,774	427,133
Total Liabilities	4,536,971	4,519,945
Shareholders' Equity
Common shares (par value $0.01 per share, 100,000,000 shares authorized, 63,616,659 and 63,576,932 shares issued, respectively)	636	636
Additional paid-in capital	402,485	403,554
Accumulated other comprehensive income (loss) (net of deferred tax expense (benefit) of ($55,743) and ($55,738), respectively)	(206,961)	(204,489)
Retained earnings	1,386,607	1,381,981
Treasury shares, at cost (12,606,968 shares as of each respective period end)	(469,702)	(469,702)
Total Shareholders' Equity	1,113,065	1,111,980
Total Liabilities and Shareholders' Equity	$ 5,650,036	$ 5,631,925

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 3,813,857	$ 3,758,720
Allowance for expected credit losses	1,137	555
Trading securities, cost	49,409	48,449
Equity investments at fair value, cost	150,099	164,262
Other investments, portion carried at fair value	55,732	62,604
Premium receivable, allowance for credit loss	$ 8,072	$ 7,809
Common shares, par value (in usd per share)	$ 0.01	$ 0.01
Common shares, shares authorized (in shares)	100,000,000	100,000,000
Common shares, shares issued (in shares)	63,616,659	63,576,932
Deferred tax expense (benefit) on accumulated other comprehensive income (loss)	$ (55,743)	$ (55,738)
Treasury shares (in shares)	12,606,968

Condensed Consolidated Statemen

Condensed Consolidated Statements of Changes in Capital (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Increase (Decrease) in Stockholders' Equity:
Beginning balance	$ 1,111,980	$ 1,104,018
Common shares issued for compensation	(1,045)	10
Share-based compensation	945	1,146
Net effect of restricted and performance shares issued	(969)	(638)
Dividends to shareholders		(2,701)
Other comprehensive income (loss)	(2,472)	42,629
Net income (loss)	4,626	(6,174)
Ending balance	1,113,065	1,138,290
Common Stock
Increase (Decrease) in Stockholders' Equity:
Beginning balance	636	634
Common shares issued for compensation	(1)
Net effect of restricted and performance shares issued	1	1
Ending balance	636	635
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity:
Beginning balance	403,554	397,919
Common shares issued for compensation	(1,044)	10
Share-based compensation	945	1,146
Net effect of restricted and performance shares issued	(970)	(639)
Ending balance	402,485	398,436
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity:
Beginning balance	(204,489)	(298,607)
Other comprehensive income (loss)	(2,472)	42,629
Ending balance	(206,961)	(255,978)
Retained Earnings
Increase (Decrease) in Stockholders' Equity:
Beginning balance	1,381,981	1,423,286
Dividends to shareholders		(2,701)
Net income (loss)	4,626	(6,174)
Ending balance	1,386,607	1,414,411
Treasury Stock
Increase (Decrease) in Stockholders' Equity:
Beginning balance	(469,702)	(419,214)
Ending balance	$ (469,702)	$ (419,214)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Net premiums earned	$ 244,150,000	$ 239,787,000
Net investment income	33,897,000	30,310,000
Equity in earnings (loss) of unconsolidated subsidiaries	2,963,000	(1,121,000)
Net investment gains (losses):
Impairment losses	(1,510,000)	(2,933,000)
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	576,000	0
Net impairment losses recognized in earnings	(934,000)	(2,933,000)
Other net investment gains (losses)	666,000	5,845,000
Total net investment gains (losses)	(268,000)	2,912,000
Other income	3,955,000	787,000
Total revenues	284,697,000	272,675,000
Expenses
Net losses and loss adjustment expenses	194,694,000	205,296,000
Underwriting, policy acquisition and operating expenses:
Operating expense	44,311,000	35,084,000
DPAC amortization	33,694,000	32,704,000
SPC U.S. federal income tax expense (benefit)	416,000	532,000
SPC dividend expense (income)	607,000	1,942,000
Interest expense	5,657,000	5,463,000
Total expenses	279,379,000	281,021,000
Income (loss) before income taxes	5,318,000	(8,346,000)
Provision for income taxes:
Current expense (benefit)	(561,000)	458,000
Deferred expense (benefit)	1,253,000	(2,630,000)
Total income tax expense (benefit)	692,000	(2,172,000)
Net income (loss)	4,626,000	(6,174,000)
Other comprehensive income (loss), after tax, net of reclassification adjustments	(2,472,000)	42,629,000
Comprehensive income (loss)	$ 2,154,000	$ 36,455,000
Earnings (loss) per share:
Basic (in usd per share)	$ 0.09	$ (0.11)
Diluted (in usd per share)	$ 0.09	$ (0.11)
Weighted average number of common shares outstanding:
Basic (in shares)	51,013	53,987
Diluted (in shares)	51,149	54,117
Cash dividends declared per common share (in usd per share)	$ 0	$ 0.05

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Activities
Net income (loss)	$ 4,626	$ (6,174)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation and amortization, net of accretion	5,332	7,677
(Increase) decrease in cash surrender value of BOLI	(452)	(656)
Net investment (gains) losses	268	(2,912)
Share-based compensation	945	1,146
Deferred income tax expense (benefit)	1,253	(2,630)
Policy acquisition costs, net of amortization (net deferral)	(3,283)	(5,830)
Equity in (earnings) loss of unconsolidated subsidiaries	(2,963)	1,121
Distributed earnings from unconsolidated subsidiaries	1,778	3,176
Other, net	(962)	(35)
Change in:
Premiums receivable	(26,701)	(20,537)
Reinsurance related assets and liabilities	10,908	(22,547)
Other assets	(2,183)	163
Reserve for losses and loss adjustment expenses	(18,769)	(1,868)
Unearned premiums	43,226	50,746
Other liabilities	(24,672)	(30,683)
Net cash provided (used) by operating activities	(11,649)	(29,843)
Purchases of:
Fixed maturities, available-for-sale	(230,549)	(68,755)
Equity investments	(80)	(170)
Other investments	(17,381)	(11,749)
Investment in unconsolidated subsidiaries	(7,871)	(9,381)
Proceeds from sales or maturities of:
Fixed maturities, available-for-sale	167,762	119,447
Equity investments	14,016	868
Other investments	24,068	18,338
Net sales or (purchases) of fixed maturities, trading	(1,553)	(1,395)
Return of invested capital from unconsolidated subsidiaries	6,882	12,756
Net sales or maturities (purchases) of short-term investments	54,710	(5,432)
Unsettled security transactions, net change	3,077	3,407
Purchases of capital assets	(961)	(930)
Other	0	2,659
Net cash provided (used) by investing activities	12,120	59,663
Financing Activities
Dividends to shareholders	0	(2,688)
Capital contribution received from (return of capital to) external segregated portfolio cell participants	0	(18)
Other	(969)	(639)
Net cash provided (used) by financing activities	(969)	(3,345)
Increase (decrease) in cash and cash equivalents	(498)	26,475
Cash and cash equivalents at beginning of period	65,898	29,959
Cash and cash equivalents at end of period	65,400	56,434
Significant Non-Cash Transactions
Dividends declared and not yet paid	0	2,701
Operating lease liabilities arising from obtaining ROU assets	1,988	0
Increase (decrease) in fair value of contingent consideration issued in NORCAL acquisition	$ 0	$ (2,000)

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of ProAssurance Corporation, its wholly owned subsidiaries and VIEs in which ProAssurance is the primary beneficiary (ProAssurance, PRA or the Company). See Note 10 for more information on ProAssurance's VIE interests. The financial statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation, consisting of normal recurring adjustments, have been included. ProAssurance’s results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes contained in ProAssurance’s December 31, 2023 report on Form 10-K. Beginning in the third quarter of 2023, ProAssurance operates in four reportable segments as follows: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance and Corporate. For more information on the Company's segment reporting, including the nature of products and services provided and financial information by segment, refer to Note 12. Reclassifications As a result of the third quarter 2023 segment reorganization, prior period segment information in Note 12 has been recast to conform to the Company's current segment reporting. Accounting Policies The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and disclosures related to these amounts at the date of the financial statements. The Company evaluates these estimates and assumptions on an ongoing basis based on current and historical developments, market conditions, industry trends and other information that the Company believes to be reasonable under the circumstances. The Company can make no assurance that actual results will conform to its estimates and assumptions; reported results of operations may be materially affected by changes in these estimates and assumptions. The significant accounting policies followed by ProAssurance in making estimates that materially affect financial reporting are summarized in Note 1 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K. Accounting Changes Adopted The Company did not adopt any new accounting standards during the three months ended March 31, 2024. Accounting Changes Not Yet Adopted Disclosure Improvements (ASU 2023-06) In October 2023, the FASB amended guidance to clarify or improve disclosure and presentation requirements of a variety of topics, which will allow users to more easily compare entities subject to the SEC's existing disclosures with those entities that were not previously subject to the requirements and align the requirements in the Codification with the SEC's regulations. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X becomes effective, with early adoption prohibited. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures. Improvements to Reportable Segment Disclosures (ASU 2023-07) Effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, and requiring retrospective application to all prior periods presented in the financial statements, the FASB amended disclosure requirements for segment reporting by modifying and adding disclosure requirements, primarily related to significant segment expenses which are regularly provided to the Company’s CODM. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures. Improvements to Income Tax Disclosures (ASU 2023-09) Effective for fiscal years beginning after December 31, 2024, the FASB amended disclosure requirements to provide greater transparency on income tax disclosures, including the disaggregation of existing disclosures related to the tax rate reconciliation and income taxes paid. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three level hierarchy has been established for valuing assets and liabilities based on how transparent (observable) the inputs are that are used to determine fair value, with the inputs considered most observable categorized as Level 1 and those that are the least observable categorized as Level 3. Hierarchy levels are defined as follows: Level 1: quoted (unadjusted) market prices in active markets for identical assets and liabilities. For ProAssurance, Level 1 inputs are generally quotes for securities actively traded in exchange or over-the-counter markets. Level 2: market data obtained from sources independent of the reporting entity (observable inputs). For ProAssurance, Level 2 inputs generally include quoted prices in markets that are not active, quoted prices for similar assets or liabilities, and results from pricing models that use observable inputs such as interest rates and yield curves that are generally available at commonly quoted intervals. Level 3: the reporting entity’s own assumptions about market participant assumptions based on the best information available in the circumstances (non-observable inputs). For ProAssurance, Level 3 inputs are used in situations where little or no Level 1 or 2 inputs are available or are inappropriate given the particular circumstances. Level 3 inputs include results from pricing models for which some or all of the inputs are not observable, discounted cash flow methodologies, single non-binding broker quotes and adjustments to externally quoted prices that are based on management judgment or estimation. Fair values of assets measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023 are shown in the following tables. Where applicable, the tables also indicate the fair value hierarchy of the valuation techniques utilized to determine those fair values. For some assets, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. When this is the case, the asset is categorized based on the level of the most significant input to the fair value measurement. Assessments of the significance of a particular input to the fair value measurement require judgment and consideration of factors specific to the assets being valued. For more information on the valuation methodologies used regarding securities in the Level 2 and Level 3 categories, see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K. March 31, 2024 Fair Value Measurements Using Total (In thousands) Level 1 Level 2 Level 3 Fair Value Assets: Fixed maturities, available-for-sale U.S. Treasury obligations $ — $ 240,889 $ — $ 240,889 U.S. Government-sponsored enterprise obligations — 18,927 — 18,927 State and municipal bonds — 474,265 — 474,265 Corporate debt, multiple observable inputs — 1,647,844 — 1,647,844 Corporate debt, limited observable inputs — — 66,208 66,208 Residential mortgage-backed securities — 450,052 — 450,052 Agency commercial mortgage-backed securities — 7,950 — 7,950 Other commercial mortgage-backed securities — 229,029 — 229,029 Other asset-backed securities — 406,832 2,141 408,973 Fixed maturities, trading — 50,106 — 50,106 Equity investments Financial 9,750 2,270 288 12,308 Utilities/Energy 1,258 — — 1,258 Industrial — — 4,946 4,946 Bond funds 101,571 — — 101,571 All other 17,831 — — 17,831 Short-term investments 102,675 81,326 — 184,001 Other investments — 54,990 742 55,732 Other assets — 7,674 — 7,674 Total assets categorized within the fair value hierarchy $ 233,085 $ 3,672,154 $ 74,325 3,979,564 Assets carried at NAV, which approximates fair value and which are not categorized within the fair value hierarchy, reported as a part of: Investment in unconsolidated subsidiaries 246,143 Total assets at fair value $ 4,225,707 Liabilities: Other liabilities $ 9,050 $ — $ 6,500 $ 15,550 Total liabilities categorized within the fair value hierarchy $ 9,050 $ — $ 6,500 $ 15,550 December 31, 2023 Fair Value Measurements Using Total (In thousands) Level 1 Level 2 Level 3 Fair Value Assets: Fixed maturities, available-for-sale U.S. Treasury obligations $ — $ 243,525 $ — $ 243,525 U.S. Government-sponsored enterprise obligations — 18,724 — 18,724 State and municipal bonds — 454,381 — 454,381 Corporate debt, multiple observable inputs — 1,668,197 — 1,668,197 Corporate debt, limited observable inputs — — 82,377 82,377 Residential mortgage-backed securities — 429,883 254 430,137 Agency commercial mortgage-backed securities — 8,387 — 8,387 Other commercial mortgage-backed securities — 188,464 1,010 189,474 Other asset-backed securities — 395,245 3,150 398,395 Fixed maturities, trading — 48,324 — 48,324 Equity investments Financial 9,464 2,287 291 12,042 Utilities/Energy 1,256 — — 1,256 Industrial — — 4,946 4,946 Bond funds 114,901 — — 114,901 All other 18,150 — — 18,150 Short-term investments 163,499 72,286 — 235,785 Other investments — 57,478 5,126 62,604 Other assets — 3,876 — 3,876 Total assets categorized within the fair value hierarchy $ 307,270 $ 3,591,057 $ 97,154 3,995,481 Assets carried at NAV, which approximates fair value and which are not categorized within the fair value hierarchy, reported as a part of: Investment in unconsolidated subsidiaries 245,455 Total assets at fair value $ 4,240,936 Liabilities: Other liabilities $ 4,030 $ — $ 6,500 $ 10,530 Total liabilities categorized within the fair value hierarchy $ 4,030 $ — $ 6,500 $ 10,530 Level 3 Valuations See Note 2 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K for a summary description of the valuation methodologies used regarding securities in the Level 3 category, by security type. Quantitative Information Regarding Level 3 Valuations Below is quantitative information regarding securities in the Level 3 category, by security type: Fair Value at ($ in thousands) March 31, 2024 December 31, 2023 Valuation Technique Unobservable Input Range Assets: Corporate debt, limited observable inputs $66,208 $82,377 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities $2,141 $4,414 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Equity investments $5,234 $5,237 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Other investments $742 $5,126 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Liabilities: Other liabilities $6,500 $6,500 Stochastic Model/Discounted Cash Flows Weighted Average Cost of Capital 0% - 10% (8%) The significant unobservable inputs used in the fair value measurement of the above listed securities were the valuations of comparable securities with similar issuers, credit quality and maturity. Changes in the availability of comparable securities could result in changes in the fair value measurements. Fair Value Measurements - Level 3 Assets & Liabilities The following tables present summary information regarding changes in the fair value of assets and liabilities measured using Level 3 inputs. March 31, 2024 Level 3 Fair Value Measurements Assets Liabilities (In thousands) Corporate Debt Asset-backed Securities Equity Investments Other Investments Total Assets Other Liabilities Total Liabilities Balance, December 31, 2023 $ 82,377 $ 4,414 $ 5,237 $ 5,126 $ 97,154 $ (6,500) $ (6,500) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment gains (losses) — — (3) 88 85 — — Included in other comprehensive income (loss) (171) (28) — — (199) — — Purchases 2,201 1,200 — — 3,401 — — Sales (702) — — — (702) — — Transfers in — — — — — — — Transfers out (17,497) (3,445) — (4,472) (25,414) — — Balance, March 31, 2024 $ 66,208 $ 2,141 $ 5,234 $ 742 $ 74,325 $ (6,500) $ (6,500) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ (3) $ 88 $ 85 $ — $ — March 31, 2023 Level 3 Fair Value Measurements Assets Liabilities (In thousands) Corporate Debt Asset-backed Securities Equity Investments Other Investments Total Assets Other Liabilities Total Liabilities Balance, December 31, 2022 $ 63,973 $ 2,954 $ 2,803 $ 1,783 $ 71,513 $ (15,000) $ (15,000) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment gains (losses) 16 — (3) — 13 1,000 1,000 Operating expense — — — — — 1,000 1,000 Included in other comprehensive income (loss) 209 39 — — 248 — — Purchases 6,322 1,863 — — 8,185 — — Sales (432) — — — (432) — — Transfers in 11,220 1,779 — — 12,999 — — Transfers out (5,151) (1,581) — (1,283) (8,015) — — Balance, March 31, 2023 $ 76,157 $ 5,054 $ 2,800 $ 500 $ 84,511 $ (13,000) $ (13,000) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ (3) $ — $ (3) $ — $ — Transfers Transfers shown in the preceding Level 3 tables were as of the end of the period in which the transfer occurred. All transfers were to or from Level 2. All transfers in and out of Level 3 during the three months ended March 31, 2024 and 2023 related to securities held for which the level of market activity for identical or nearly identical securities varies from period to period. The securities were valued using multiple observable inputs when those inputs were available; otherwise the securities were valued using limited observable inputs. Fair Values Not Categorized At March 31, 2024 and December 31, 2023, certain LPs/LLCs and investment funds measure fund assets at fair value on a recurring basis and provide a NAV for ProAssurance's interest. The carrying value of these interests is based on the NAV provided and was considered to approximate the fair value of the interests. For investment in unconsolidated subsidiaries, ProAssurance recognizes any changes in the NAV of its interests in equity in earnings (loss) of unconsolidated subsidiaries during the period of change. In accordance with GAAP, the fair value of these investments was not classified within the fair value hierarchy. The amount of ProAssurance's unfunded contractual commitments related to these investments as of March 31, 2024 and fair values of these investments as of March 31, 2024 and December 31, 2023 were as follows: Unfunded Fair Value (In thousands) March 31, March 31, December 31, Investment in unconsolidated subsidiaries: Private debt funds (1) $4,565 $ 16,768 $ 19,886 Long/short equity funds (2) None 4,243 4,497 Non-public equity funds (3) $38,970 115,421 111,251 Credit funds (4) $31,552 56,595 55,740 Strategy focused funds (5) $50,427 53,116 54,081 Total investments carried at NAV $ 246,143 $ 245,455 Below is additional information regarding each of the investments listed in the table above as of March 31, 2024. (1) This investment is comprised of interests in two unrelated LP funds that are structured to provide interest distributions primarily through diversified portfolios of private debt instruments. One LP allows redemption by special consent, while the other does not permit redemption. Income and capital are to be periodically distributed at the discretion of the LPs over an anticipated time frame that spans from three (2) This investment is comprised of one LP fund, which holds long and short publicly traded securities that will passively generate income. Redemptions are permitted with 30 days written notice if outside of a lock-up period. (3) This investment is comprised of interests in multiple unrelated LP funds, each structured to provide capital appreciation through diversified investments in private equity, which can include investments in buyout, venture capital, debt including senior, second lien and mezzanine, distressed debt, collateralized loan obligations and other private equity-oriented LPs. Two of the LPs allow redemption by terms set forth in the LP agreements; the others do not permit redemption. Income and capital are to be periodically distributed at the discretion of the LP over time frames that are anticipated to span up to ten years. (4) This investment is comprised of multiple unrelated LP funds. Two funds seek to obtain superior risk-adjusted absolute returns through a diversified portfolio of debt securities, including bonds, loans and other asset-backed instruments. The remaining funds focus on private middle market company mezzanine and senior secured loans, opportunities across the credit spectrum, mortgage backed-loans, as well as various types of loan-backed investments. One fund allows redemptions at any quarter-end with prior notice requirements of 180 days, while two other funds allow for redemptions with consent of the General Partner. The remaining funds do not allow redemptions. For the funds that do not allow redemptions, income and capital are to be periodically distributed at the discretion of the LP over time frames throughout the remaining life of the funds. (5) This investment is comprised of multiple unrelated LPs/LLCs funds. One fund is an LLC focused on investing in North American consumer products companies, comprised of equity and equity-related securities, as well as debt instruments. A second fund is focused on aircraft investments, along with components and assets related to aircrafts. A third fund is an LLC focused on acquiring ownership stakes in insurance agencies. For all three funds, redemptions are not permitted. The remaining funds are real estate focused LPs, two of which allow for redemption with prior notice. ProAssurance may not sell, transfer or assign its interest in any of the above LPs/LLCs without special consent from the LPs/LLCs. Nonrecurring Fair Value Measurement ProAssurance did not have any assets or liabilities that were measured at fair value on a nonrecurring basis at March 31, 2024 or December 31, 2023. Financial Instruments - Methodologies Other Than Fair Value The following table provides the estimated fair value of the Company's financial instruments that, in accordance with GAAP for the type of investment, are measured using a methodology other than fair value. Fair values provided primarily fall within the Level 3 fair value category. March 31, 2024 December 31, 2023 (In thousands) Carrying Fair Carrying Fair Financial assets: BOLI $ 78,657 $ 78,657 $ 78,205 $ 78,205 Other investments $ 4,064 $ 4,064 $ 3,215 $ 3,215 Other assets $ 34,824 $ 34,824 $ 33,231 $ 33,221 Financial liabilities: Revolving Credit Agreement* $ 125,000 $ 125,000 $ 125,000 $ 125,000 Term Loan* $ 125,000 $ 125,000 $ 125,000 $ 125,000 Contribution Certificates $ 179,865 $ 147,328 $ 179,387 $ 149,782 Other liabilities $ 33,548 $ 33,548 $ 32,043 $ 32,043 * Carrying value excludes unamortized debt issuance costs. The fair value of the BOLI was equal to the cash surrender value associated with the policies on the valuation date. Other investments listed in the table above include FHLB common stock carried at cost and an annuity investment carried at amortized cost. Three of ProAssurance's insurance subsidiaries are members of an FHLB. The estimated fair value of the FHLB common stock was based on the amount the subsidiaries would receive if their memberships were canceled, as the memberships cannot be sold. The fair value of the annuity represents the present value of the expected future cash flows discounted using a rate available in active markets for similarly structured instruments. Other assets and other liabilities primarily consisted of related investment assets and liabilities associated with funded deferred compensation agreements. The fair value of the funded deferred compensation assets was based upon quoted market prices, which is categorized as a Level 1 valuation, and had a fair value of $33.8 million and $32.3 million at March 31, 2024 and December 31, 2023, respectively. Other assets also included an unsecured note receivable. The fair value of the note receivable was based on the present value of expected cash flows from the note receivable, discounted at market rates on the valuation date for receivables with similar credit standings and similar payment structures. Other liabilities primarily consisted of liabilities associated with funded deferred compensation agreements. The reported balance is determined based on the amount of elective deferrals and employer contributions adjusted for periodic changes in the fair value of the participant balances based on the performance of the funds selected by the participants and had a fair value of $33.5 million and $32.0 million at March 31, 2024 and December 31, 2023, respectively. The fair value of the debt, excluding the Contribution Certificates, was estimated based on the present value of expected future cash outflows, discounted at rates available on the valuation date for similar debt issued by entities with a similar credit standing to ProAssurance. The fair value of the Contribution Certificates was estimated based on a binomial option pricing model. The Contribution Certificates were a portion of the purchase consideration for the NORCAL acquisition and were issued to certain NORCAL policyholders in the conversion, and those instruments are an obligation of NORCAL Insurance Company, the successor of NORCAL Mutual Insurance Company (see Note 6 for further discussion of the terms of the Contribution Certificates).

Investments

Investments	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Available-for-sale fixed maturities at March 31, 2024 and December 31, 2023 included the following: March 31, 2024 (In thousands) Amortized Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Fixed maturities, available-for-sale U.S. Treasury obligations $ 258,462 $ — $ 24 $ 17,597 $ 240,889 U.S. Government-sponsored enterprise obligations 19,957 — — 1,030 18,927 State and municipal bonds 502,549 — 1,736 30,020 474,265 Corporate debt 1,849,162 740 2,421 136,791 1,714,052 Residential mortgage-backed securities 507,312 207 2,020 59,073 450,052 Agency commercial mortgage-backed securities 8,964 — — 1,014 7,950 Other commercial mortgage-backed securities 248,756 — 221 19,948 229,029 Other asset-backed securities 418,695 190 921 10,453 408,973 $ 3,813,857 $ 1,137 $ 7,343 $ 275,926 $ 3,544,137 December 31, 2023 (In thousands) Amortized Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Fixed maturities, available-for-sale U.S. Treasury obligations $ 259,834 $ — $ 165 $ 16,474 $ 243,525 U.S. Government-sponsored enterprise obligations 19,752 — 2 1,030 18,724 State and municipal bonds 482,367 — 1,885 29,871 454,381 Corporate debt 1,883,308 — 4,025 136,759 1,750,574 Residential mortgage-backed securities 481,267 211 2,876 53,795 430,137 Agency commercial mortgage-backed securities 9,369 — 5 987 8,387 Other commercial mortgage-backed securities 210,469 151 60 20,904 189,474 Other asset-backed securities 412,354 193 1,104 14,870 398,395 $ 3,758,720 $ 555 $ 10,122 $ 274,690 $ 3,493,597 The recorded cost basis and estimated fair value of available-for-sale fixed maturities at March 31, 2024, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (In thousands) Amortized Due in one Due after Due after Due after Total Fair Fixed maturities, available-for-sale U.S. Treasury obligations $ 258,462 $ 36,249 $ 169,651 $ 32,387 $ 2,602 $ 240,889 U.S. Government-sponsored enterprise obligations 19,957 4,790 11,653 505 1,979 18,927 State and municipal bonds 502,549 30,409 157,707 161,274 124,875 474,265 Corporate debt 1,849,162 179,206 886,529 569,033 79,284 1,714,052 Residential mortgage-backed securities 507,312 450,052 Agency commercial mortgage-backed securities 8,964 7,950 Other commercial mortgage-backed securities 248,756 229,029 Other asset-backed securities 418,695 408,973 $ 3,813,857 $ 3,544,137 Excluding obligations of the U.S. Government, U.S. Government-sponsored enterprises and a U.S. Government obligations money market fund, no investment in any entity or its affiliates exceeded 10% of shareholders’ equity at March 31, 2024. Cash and securities with a carrying value of $53.5 million at March 31, 2024 were on deposit with various state insurance departments to meet regulatory requirements. ProAssurance also held securities with a carrying value of $70.6 million at March 31, 2024 that are pledged as collateral security for advances under the Company's borrowing relationships with FHLBs. As a member of Lloyd's, ProAssurance is required to maintain capital at Lloyd's, referred to as FAL, to support the Company's previous participation in underwriting years that remain open at Syndicate 1729. At March 31, 2024, the fair value of ProAssurance's FAL investments was $20.2 million and were comprised of investment securities, primarily short-term investments, and cash and cash equivalents on deposit with Lloyd's in order to satisfy these FAL requirements. Investments Held in a Loss Position The following tables provide summarized information with respect to investments held in an unrealized loss position at March 31, 2024 and December 31, 2023, including the length of time the investment had been held in a continuous unrealized loss position. March 31, 2024 Total Less than 12 months 12 months or longer Fair Unrealized Fair Unrealized Fair Unrealized (In thousands) Value Loss Value Loss Value Loss Fixed maturities, available-for-sale U.S. Treasury obligations $ 226,103 $ 17,597 $ 40,747 $ 1,412 $ 185,356 $ 16,185 U.S. Government-sponsored enterprise obligations 18,928 1,030 10,631 486 8,297 544 State and municipal bonds 389,539 30,020 98,395 5,941 291,144 24,079 Corporate debt 1,498,062 136,791 459,157 38,451 1,038,905 98,340 Residential mortgage-backed securities 335,297 59,073 130,058 16,800 205,239 42,273 Agency commercial mortgage-backed securities 7,950 1,014 2,652 344 5,298 670 Other commercial mortgage-backed securities 214,030 19,948 90,586 8,120 123,444 11,828 Other asset-backed securities 252,384 10,453 125,871 3,746 126,513 6,707 $ 2,942,293 $ 275,926 $ 958,097 $ 75,300 $ 1,984,196 $ 200,626 December 31, 2023 Total Less than 12 months 12 months or longer Fair Unrealized Fair Unrealized Fair Unrealized (In thousands) Value Loss Value Loss Value Loss Fixed maturities, available-for-sale U.S. Treasury obligations $ 213,634 $ 16,474 $ 32,925 $ 1,364 $ 180,709 $ 15,110 U.S. Government-sponsored enterprise obligations 18,428 1,030 4,128 242 14,300 788 State and municipal bonds 378,313 29,871 48,960 2,287 329,353 27,584 Corporate debt 1,524,940 136,759 84,221 5,054 1,440,719 131,705 Residential mortgage-backed securities 313,082 53,795 74,463 10,271 238,619 43,524 Agency commercial mortgage-backed securities 7,955 987 212 1 7,743 986 Other commercial mortgage-backed securities 184,416 20,904 18,092 1,140 166,324 19,764 Other asset-backed securities 293,447 14,870 30,115 867 263,332 14,003 $ 2,934,215 $ 274,690 $ 293,116 $ 21,226 $ 2,641,099 $ 253,464 As of March 31, 2024, excluding U.S. Government or U.S. Government-sponsored enterprise obligations, there were 2,545 debt securities (64.8% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 1,328 issuers. The greatest and second greatest unrealized loss positions among those securities were approximately $5.3 million and $3.3 million, respectively. The securities were evaluated for impairment as of March 31, 2024. As of December 31, 2023, excluding U.S. Government or U.S. Government-sponsored enterprise obligations, there were 2,531 debt securities (65.6% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 1,319 issuers. The greatest and second greatest unrealized loss positions among those securities were approximately $5.0 million and $3.2 million, respectively. The securities were evaluated for impairment as of December 31, 2023. Each quarter, ProAssurance performs a detailed analysis for the purpose of assessing whether any of the securities it holds in an unrealized loss position has suffered an impairment due to credit or non-credit factors. A detailed discussion of the factors considered in the assessment is included in Note 1 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2023 report on Form 10-K. Fixed maturity securities held in an unrealized loss position at March 31, 2024, excluding asset-backed securities, have paid all scheduled contractual payments and are expected to continue. Expected future cash flows of asset-backed securities, excluding those issued by GNMA, FNMA and FHLMC, held in an unrealized loss position were estimated as part of the March 31, 2024 impairment evaluation using the most recently available six-month historical performance data for the collateral (loans) underlying the security or, if historical data was not available, sector based assumptions, and equaled or exceeded the current amortized cost basis of the security. The following tables present a roll forward of the allowance for expected credit losses on available-for-sale fixed maturities for the three months ended March 31, 2024 and 2023. Three Months Ended March 31, 2024 (In thousands) Corporate Debt Residential mortgage-backed securities Other commercial mortgage-backed securities Other asset-backed securities Total Balance, at December 31, 2023 $ — $ 211 $ 151 $ 193 $ 555 Additional credit losses related to securities for which: No allowance for credit losses has been previously recognized 740 — — — 740 Reductions related to: Securities sold during the period — (4) (151) (3) (158) Balance, at March 31, 2024 $ 740 $ 207 $ — $ 190 $ 1,137 Three Months Ended March 31, 2023 (In thousands) Residential mortgage-backed securities Other asset-backed securities Total Balance, at December 31, 2022 $ 229 $ 198 $ 427 Reductions related to: Securities sold during the period (2) (1) (3) Balance, at March 31, 2023 $ 227 $ 197 $ 424 Other information regarding sales and purchases of fixed maturity available-for-sale securities is as follows: Three Months Ended March 31 (In millions) 2024 2023 Proceeds from sales (exclusive of maturities and paydowns) $ 17.1 $ 3.8 Purchases $ 230.5 $ 68.8 Net Investment Income Net investment income (loss) by investment category was as follows: Three Months Ended (In thousands) 2024 2023 Fixed maturities $ 31,451 $ 27,327 Equities 892 807 Short-term investments, including Other 3,411 3,350 BOLI 452 657 Investment fees and expenses (2,309) (1,831) Net investment income $ 33,897 $ 30,310 Investment in Unconsolidated Subsidiaries ProAssurance's investment in unconsolidated subsidiaries were as follows: March 31, 2024 Carrying Value (In thousands) Percentage March 31, December 31, Qualified affordable housing project tax credit partnerships See below $ 562 $ 666 All other investments, primarily investment fund LPs/LLCs See below 278,369 276,090 $ 278,931 $ 276,756 Qualified affordable housing project tax credit partnership interests held by ProAssurance generate investment returns by providing tax benefits to fund investors in the form of tax credits and project operating losses. The carrying value of these investments reflects ProAssurance's total commitments (both funded and unfunded) to the partnerships, less any amortization. At March 31, 2024 and December 31, 2023, ProAssurance did not have an ownership percentage greater than 20% in any tax credit partnership interests. Since ProAssurance has the ability to exert influence over the partnerships but does not control them, all are accounted for using the equity method. See further discussion of the entities in which ProAssurance holds passive interests in Note 10. ProAssurance holds interests in investment fund LPs/LLCs and other equity method investments and LPs/LLCs which are not considered to be investment funds. ProAssurance's ownership percentage relative to four of the LPs/LLCs is greater than 25% at March 31, 2024 and December 31, 2023 which is likely to be reduced as the funds mature and other investors participate in the funds; these investments had a carrying value of $24.0 million at March 31, 2024 and $23.0 million at December 31, 2023. ProAssurance's ownership percentage relative to the remaining investments and LPs/LLCs is less than 25%; these interests had a carrying value of $254.4 million at March 31, 2024 and $253.1 million at December 31, 2023. ProAssurance does not have the ability to exert control over any of these funds. Equity in Earnings (Loss) of Unconsolidated Subsidiaries Equity in earnings (loss) of unconsolidated subsidiaries included losses from qualified affordable housing project tax credit partnerships and a historic tax credit partnership. Investment results recorded reflect ProAssurance's allocable portion of partnership operating results. Tax credits reduce income tax expense in the period they are utilized. The results recorded and tax credits recognized related to ProAssurance's tax credit partnership investments were as follows: Three Months Ended (In thousands) 2024 2023 Qualified affordable housing project tax credit partnerships Losses recorded $ 103 $ 354 Tax credits recognized $ 8 $ 43 ProAssurance accounts for its tax credit partnership investments under the equity method of accounting and records its allocable portion of the operating losses of the underlying properties based on estimates provided by the partnerships. For the Company's qualified affordable housing project tax credit partnerships, it adjusts its estimates of their allocable portion of operating losses periodically as actual operating results of the underlying properties become available. The primary benefits of tax credits and tax-deductible operating losses from the historic tax credit partnerships are earned in a short period with potential for additional cash flows extending over several years. For the three months ended March 31, 2024 and 2023, the Company generated a nominal amount of tax credits from its tax credit partnership investments, which were deferred and are expected to be utilized in future periods. As of March 31, 2024, the Company had approximately $52.7 million of available tax credit carryforwards generated from its investments in tax credit partnerships which they expect to utilize in future periods. Tax credits provided by the underlying projects of the Company's historic tax credit partnership are typically available in the tax year in which the project is put into active service, whereas the tax credits provided by qualified affordable housing project tax credit partnerships are provided over approximately a ten-year period. Net Investment Gains (Losses) Realized investment gains and losses are recognized on the first-in, first-out basis. The following table provides detailed information regarding net investment gains (losses): Three Months Ended (In thousands) 2024 2023 Total impairment losses: Corporate debt $ (1,316) $ (2,936) Asset-backed securities (194) 3 Portion of impairment losses recognized in other comprehensive income before taxes: Corporate debt 576 — Net impairment losses recognized in earnings (934) (2,933) Gross realized gains, available-for-sale fixed maturities 366 79 Gross realized (losses), available-for-sale fixed maturities (1,099) (457) Net realized gains (losses), trading fixed maturities 15 (108) Net realized gains (losses), equity investments (256) 84 Net realized gains (losses), other investments 1,776 229 Change in unrealized holding gains (losses), trading fixed maturities 214 97 Change in unrealized holding gains (losses), equity investments 774 3,746 Change in unrealized holding gains (losses), convertible securities, carried at fair value (1,119) 1,132 Other (1) (5) 1,043 Net investment gains (losses) $ (268) $ 2,912 (1) Includes a gain of $1.0 million recognized during the 2023 three-month period related to the change in the fair value of contingent consideration issued in connection with the NORCAL acquisition. See further discussion on the contingent consideration in Note 2 and Note 6 and discussion on the Company's accounting policy in Note 1 in its December 31, 2023 report on Form 10-K. For the three months ended March 31, 2024, ProAssurance recognized $0.9 million of credit-related impairment losses in earnings related to a corporate bond in the consumer sector as well as an asset-backed security. The Company recognized non-credit impairment losses in OCI of $0.6 million related to a corporate bond during the three months ended March 31, 2024. For the three months ended March 31, 2023, ProAssurance recognized credit-related impairment losses in earnings of $2.9 million related to two corporate bonds in the financial sector. The Company did not recognize any non-credit impairment losses in OCI during the three months ended March 31, 2023. The following table presents a roll forward of cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the impairment was recorded in OCI. Three Months Ended (In thousands) 2024 2023 Balance beginning of period $ 57 $ 57 Additional credit losses recognized during the period, related to securities for which: No impairment has been previously recognized 740 — Balance March 31 $ 797 $ 57

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For interim periods, ProAssurance generally utilizes the estimated annual effective tax rate method under which the Company determines its provision (benefit) for income taxes based on the current estimate of its annual effective tax rate. For the three months ended March 31, 2024 and March 31, 2023, we utilized the estimated annual effective tax rate method. Under this method, items which are unusual, infrequent, or that cannot be reliably estimated are considered in the effective tax rate in the period in which the item is included in income, and are referred to as discrete items. For the three months ended March 31, 2024 and 2023, the provision for income taxes is different from that which would be obtained by applying the statutory federal income tax rate to income (loss) before income taxes primarily due to the estimated tax rate differential between the Company's actual effective tax rate and its projected annual effective tax rate as calculated under the estimated annual effective tax rate method and, to a lesser extent, the effects of tax-favored income. In addition, the provision for income taxes for the three months ended March 31, 2023 was impacted by the $2.0 million decrease in the contingent consideration liability related to the NORCAL acquisition, all of which was non-taxable. See further discussion on the Company's contingent consideration in Note 2 and Note 6. ProAssurance had a liability for U.S. federal and U.K. income taxes carried as a part of other liabilities of $3.0 million as of March 31, 2024 and $4.0 million as of December 31, 2023. At March 31, 2024 and December 31, 2023, the liability for unrecognized tax benefits, which is included in the total liability for U.S. federal and U.K. income taxes, was $5.4 million and $5.3 million, respectively, which included an accrued liability for interest of approximately $0.6 million and $0.5 million, respectively.

Reserve for Losses and Loss Adj

Reserve for Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
Reserve for Losses and Loss Adjustment Expenses	Reserve for Losses and Loss Adjustment Expenses The reserve for losses is established based on estimates of individual claims and actuarially determined estimates of future losses based on ProAssurance’s past loss experience, available industry data and projections as to future claims frequency, severity, inflationary trends and settlement patterns. Estimating the reserve, particularly the reserve appropriate for liability exposures, is a complex process. For a high proportion of the risks insured or reinsured by ProAssurance, claims may be resolved over an extended period of time, often five years or more, and may be subject to litigation. Estimating losses requires ProAssurance to make and revise judgments and assessments regarding multiple uncertainties over an extended period of time. As a result, the reserve estimate may vary considerably from the eventual outcome. The assumptions used in establishing ProAssurance’s reserve are regularly reviewed and updated by management as new data becomes available. Changes to estimates of previously established reserves are included in earnings in the period in which the estimate is changed. For additional information regarding ProAssurance's reserve for losses, see Note 1 and Note 7 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2023 report on Form 10-K. Activity in the reserve for losses and loss adjustment expenses is summarized as follows: (In thousands) Three Months Ended March 31, 2024 Three Months Ended March 31, 2023 Year Ended December 31, 2023 Balance, beginning of year $ 3,401,281 $ 3,471,147 $ 3,471,147 Less reinsurance recoverables on unpaid losses and loss adjustment expenses 445,573 431,889 431,889 Net balance, beginning of year 2,955,708 3,039,258 3,039,258 Net losses: Current year 195,110 198,240 794,848 (Favorable) unfavorable development of reserves established in prior years, net (1) (416) 7,056 5,646 Total 194,694 205,296 800,494 Paid related to: Current year (12,867) (11,052) (101,996) Prior years (202,180) (211,916) (782,048) Total paid (215,047) (222,968) (884,044) Net balance, end of period 2,935,355 3,021,586 2,955,708 Plus reinsurance recoverables on unpaid losses and loss adjustment expenses 447,157 447,693 445,573 Balance, end of period $ 3,382,512 $ 3,469,279 $ 3,401,281 (1) Net prior year reserve development recognized for the three months ended March 31, 2024 and 2023 as well as the year ended December 31, 2023 included $1.7 million, $2.5 million and $8.3 million, respectively, of amortization of the purchase accounting fair value adjustment on NORCAL's assumed net reserve and amortization of the negative VOBA associated with NORCAL's DDR reserve which is recorded as a reduction to prior accident year net losses and loss adjustment expenses. Estimating liability reserves is complex and requires the use of many assumptions. As time passes and ultimate losses for prior years are either known or become subject to a more precise estimation, ProAssurance increases or decreases the reserve estimates established in prior periods. The consolidated net favorable prior year reserve development recognized for the three months ended March 31, 2024 primarily reflected: • Net favorable development recognized in the Specialty P&C segment of $1.7 million related to the amortization of the purchase accounting fair value adjustment on NORCAL's assumed net reserve and amortization of the negative VOBA associated with NORCAL's DDR reserve which is recorded as a reduction to prior accident year net losses and loss adjustment expenses. • Consolidated net favorable loss development recognized in the three months ended March 31, 2024 was partially offset by net unfavorable reserve development of $0.9 million recognized in the Segregated Portfolio Cell Reinsurance segment and unfavorable reserve development of $0.4 million attributable to the Company's Lloyd’s Syndicates operations in the Specialty P&C segment. The unfavorable development in the Segregated Portfolio Cell Reinsurance segment includes net favorable development in the workers' compensation business of $0.5 million that was more than offset by net unfavorable development of $1.4 million in the medical professional liability business related to higher than expected claim frequency in on program in which the Company does not participate in the underwriting results. For additional information regarding ProAssurance's prior year reserve development recognized for the three months ended March 31, 2023 and the year ended December 31, 2023, see Note 5 of the Notes to Condensed Consolidated Financial Statements included in ProAssurance's March 31, 2023 report on Form 10-Q and Note 7 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2023 report on Form 10-K, respectively.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies ProAssurance is involved in various legal actions related to insurance policies and claims handling including, but not limited to, claims asserted by policyholders. These types of legal actions arise in the Company's ordinary course of business and, in accordance with GAAP for insurance entities, are considered as a part of the Company's loss reserving process, which is described in detail under the heading "Losses and Loss Adjustment Expenses" in the Accounting Policies section in Note 1 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2023 report on Form 10-K. ProAssurance also has other direct actions against the Company unrelated to its claims activity which are evaluated and accounted for as a part of other liabilities. For these corporate legal actions, the Company evaluates each case separately and establishes what it believes is an appropriate reserve based on GAAP guidance related to contingent liabilities. As of March 31, 2024, there were no material reserves established for corporate legal actions. As a member of Lloyd's, ProAssurance has obligations to Syndicate 1729 including FAL requirements. ProAssurance provides FAL to support its previous participation in underwriting years that remain open at Syndicate 1729, which is comprised of investment securities, primarily short-term investments, and cash and cash equivalents deposited with Lloyd's with a total fair value of approximately $20.2 million at March 31, 2024 (see Note 3). ProAssurance has entered into financial instrument transactions that may present off-balance sheet credit risk or market risk. These transactions include a short-term loan commitment and commitments to provide funding to non-public investment entities. Under the short-term loan commitment, ProAssurance has agreed to advance funds on a 30 day basis to a counterparty provided there is no violation of any condition established in the contract. As of March 31, 2024, ProAssurance had total funding commitments related to non-public investment entities as well as the short-term loan commitment of approximately $161.9 million which included the amount at risk if the full short-term loan is extended and the counterparties default. However, the credit risk associated with the short-term loan commitment is minimal as the counterparties to the contract are highly rated commercial institutions and to-date have been performing in accordance with their contractual obligations. As such, ProAssurance’s expected credit losses associated with this short-term loan commitment were nominal in amount as of March 31, 2024. ProAssurance entered into a services agreement with a company to provide data analytics services for certain product lines within the Company's MPL book of business. Under the services agreement, the Company has committed to an annual fee of approximately $3.5 million for three years. In addition, the services agreement contains an annual one-year auto-extension feature, in November, unless either party elects to non-renew the services agreement by providing notice at least six-months prior to the end of the contract. In April 2024, ProAssurance provided such notice of termination of the services agreement. As a result, the services agreement will expire on November 30, 2024. ProAssurance incurred operating expenses associated with this services agreement of $0.8 million and $0.9 million for the three months ended March 31, 2024 and 2023, respectively. As of March 31, 2024, the remaining commitment under this agreement was estimated to be approximately $2.2 million. The purchase consideration in the NORCAL acquisition included contingent consideration. NORCAL policyholders who elected to receive NORCAL stock and tender it to ProAssurance are eligible for a share of contingent consideration in an amount of up to approximately $84 million. As defined in the purchase agreement, the contingent consideration is dependent upon the after-tax development of NORCAL's ultimate net losses for accident years ended on or before December 31, 2020 determined as of December 31, 2023 by a mutually agreed upon independent actuarial consultant. This independent actuarial consultant has until June 30, 2024 to complete their estimate. As of May 1, 2024, the independent actuarial consultant had not completed their estimate. As of March 31, 2024 and December 31, 2023, the contingent consideration liability was $6.5 million carried at fair value utilizing a stochastic model. This estimate of fair value does not guarantee nor suggest that contingent consideration will ultimately be paid, and any amounts ultimately paid by the Company may be greater than or less than the $6.5 million current fair value estimate. As of March 31, 2024 and December 31, 2023, the Company's analysis of NORCAL's reserves related to accident years 2020 and prior suggests that no contingent consideration will be due; however, the actual amount due to be paid, if any, will be determined based on analysis to be performed by an independent actuary, as previously discussed. This remaining uncertainty is a significant component in the determination of the fair value of the liability as of March 31, 2024 and December 31, 2023. See further discussion around the contingent consideration in Note 2.

Debt

Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt ProAssurance’s outstanding debt consisted of the following: ($ in thousands) March 31, December 31, Contribution Certificates due 2031, interest at 3.0% (effective interest rate at 4.35%) paid annually in April $ 179,865 $ 179,387 Revolving Credit Agreement, outstanding borrowings are not permitted to exceed $300 million aggregately, including a $50 million accordion feature; Revolving Credit Agreement expires in 2028. The effective interest rate was 7.53% as of March 31, 2024 125,000 125,000 Term Loan, principal repayments in quarterly installments beginning June 30, 2024; Term Loan expires in 2028. The effective interest rate was 7.65% as of March 31, 2024 125,000 125,000 Total principal 429,865 429,387 Less unamortized debt issuance costs 2,091 2,254 Debt less unamortized debt issuance costs $ 427,774 $ 427,133 Covenant Compliance There are no financial covenants associated with the Contribution Certificates due 2031. The Revolving Credit Agreement contains customary representations, covenants and events constituting default, and remedies for default, as previously discussed. As of March 31, 2024, ProAssurance is in compliance with all covenants of the Revolving Credit Agreement. Additional Information For additional information regarding ProAssurance's debt, see Note 10 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2023 report on Form 10-K.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives ProAssurance is exposed to certain risks relating to its ongoing business and investment activities. ProAssurance utilizes derivative instruments as part of its risk management strategy to reduce the market risk related to fluctuations in future interest rates associated with a portion of its variable-rate debt. See Note 1 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2023 report on Form 10-K for the Company's accounting policy regarding derivative instruments. To manage the Company's exposure to variability in cash flows of forecasted interest payments attributable to variability in the selected base rates on borrowings under both the Revolving Credit Agreement and Term Loan, ProAssurance entered into two forward-starting interest rate swap agreements ("Interest Rate Swaps") on May 2, 2023, each with an effective date of December 29, 2023 and a maturity date of March 31, 2028. As ProAssurance's Interest Rate Swaps are designated and qualify as highly effective cash flow hedges, changes in the fair value of the Interest Rate Swaps are recorded in AOCI, net of tax, and are reclassified into earnings when the hedged cash flows impact earnings. The Interest Rate Swap hedging the variability in cash flows associated with interest payments on the Revolving Credit Agreement will have a constant $125 million notional amount throughout the term of the swap, while the Interest Rate Swap hedging the variability in cash flows associated with interest payments on the Term Loan will have an amortizing $125 million notional amount, which is designed to match the outstanding principal on the Term Loan throughout the term of the swap. Borrowings under the Revolving Credit Agreement and Term Loan will accrue interest at a selected base rate, adjusted by a margin. The Interest Rate Swaps effectively fix the base rate on borrowings under the Revolving Credit Agreement and Term Loan to 3.187% and 3.207%, respectively. The margin component of the interest rate, which can vary from 0% to 2.375%, will remain variable and is based on ProAssurance’s debt to capitalization ratio. As of March 31, 2024, the margin component of the interest rate on the outstanding borrowings under the Revolving Credit Agreement and Term Loan was 2.23% and 2.35%, respectively, based on ProAssurance's debt to capitalization ratio as of December 31, 2023 resulting in a total interest rate of 5.42% and 5.56%, respectively, including the effect of the Interest Rate Swaps on the base rate. Additional information regarding the Company's Revolving Credit Agreement and Term Loan is provided in Note 10 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2023 report on Form 10-K. ProAssurance received cash collateral from the counterparty to secure the net present value of future cash flows associated with the Interest Rate Swaps which is reflected as a component of other liabilities on the Condensed Consolidated Balance Sheet. Those cash collateral balances were $9.1 million and $4.0 million at March 31, 2024 and December 31, 2023, respectively. The following table provides a summary of the volume and fair value position of the Interest Rate Swaps as well as the reporting location in the Condensed Consolidated Balance Sheet as of March 31, 2024 and December 31, 2023. ($ in thousands) March 31, 2024 December 31, 2023 Derivatives Designated and Qualifying as Cash Flow Hedging Instruments Location in the Condensed Consolidated Balance Sheets Number of Instruments Aggregate Notional Amount (1) Estimated Fair Value (2) Number of Instruments Aggregate Notional Amount (1) Estimated Fair Value (2) Interest Rate Swaps Other Assets 2 $250,000 $7,674 2 $250,000 $3,876 (1) Volume is represented by the derivative instruments' notional amount. (2) Additional information regarding the fair value of the Company's Interest Rate Swaps is provided in Note 2. For the three months ended March 31, 2024, ProAssurance reclassified a gain on the Interest Rate Swaps from AOCI, net of tax, into earnings as shown in the table below: Qualifying Cash Flow Hedges - Gains (Losses) Reclassified from AOCI, net of tax, to Earnings (In thousands) Three Months Ended March 31 Derivatives Designated as Hedging Instruments Location in the Condensed Consolidated Statements of Income and Comprehensive Income 2024 2023 Interest Rate Swaps Interest Expense $ 1,073 $ — At March 31, 2024, management estimates that it will reclassify approximately $4.3 million of pre-tax net gains on the Interest Rate Swaps from AOCI to earnings over the next twelve months, which will be recorded to interest expense. See additional information on gains or losses related to the Interest Rate Swaps reported as a component of AOCI in Note 9. As a result of the Interest Rate Swaps, ProAssurance is exposed to risk that the counterparty will fail to meet its contractual obligations. To mitigate this counterparty credit risk, ProAssurance only enters into derivative contracts with carefully selected major financial institutions based upon their credit ratings and monitors their creditworthiness. As of March 31, 2024, the counterparty had an investment grade rating of A and has performed in accordance with their contractual obligations.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity At March 31, 2024 and December 31, 2023, ProAssurance had 100 million shares of authorized common stock and 50 million shares of authorized preferred stock. The Board has the authority to determine provisions for the issuance of preferred shares, including the number of shares to be issued, the designations, powers, preferences and rights, and the qualifications, limitations or restrictions of such shares. ProAssurance declared cash dividends of $0.05 per share during the first quarter of 2023 totaling $2.7 million. In light of the price range in which the Company's stock traded in the second quarter of 2023, the Board decided to suspend payment of a quarterly cash dividend. Instead, the Company used available capital to repurchase shares pursuant to the existing share repurchase authorization. Any decision to pay future cash dividends is subject to the Board’s final determination after a comprehensive review of financial performance, future expectations and other factors deemed relevant by the Board. See Note 12 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2023 report on Form 10-K for additional information. At March 31, 2024, Board authorizations for the repurchase of common shares or the retirement of outstanding debt of $55.9 million remained available for use. ProAssurance did not repurchase any common shares during the three months ended March 31, 2024 or 2023. Other Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Loss) The following tables provide a detailed breakout of the components of AOCI and the amounts reclassified from AOCI to net income (loss). The tax effects of all amounts in the tables below, except for an immaterial amount of unrealized gains and losses on available-for-sale securities held at the Company's U.K. subsidiary, were computed using the enacted U.S. federal corporate tax rate of 21%. OCI included a nominal deferred tax benefit and deferred tax expense of $10.8 million for the three months ended March 31, 2024 and 2023, respectively. The changes in the balance of each component of AOCI for the three months ended March 31, 2024 and 2023 were as follows: (In thousands) Unrealized Investment Gains (Losses) Cash Flow Hedging Gains (Losses) (1) Non-credit Impairments Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2023 $ (206,327) $ 3,026 $ (11) $ (1,177) $ (204,489) OCI, before reclassifications, net of tax (6,339) 4,074 (455) — (2,720) Amounts reclassified from AOCI, net of tax 1,321 (1,073) — — 248 Net OCI, current period (5,018) 3,001 (455) — (2,472) Balance, March 31, 2024 $ (211,345) $ 6,027 $ (466) $ (1,177) $ (206,961) (In thousands) Unrealized Investment Gains (Losses) Non-credit Impairments Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2022 $ (297,142) $ (11) $ (1,454) $ (298,607) OCI, before reclassifications, net of tax 40,007 — — 40,007 Amounts reclassified from AOCI, net of tax 2,622 — — 2,622 Net OCI, current period 42,629 — — 42,629 Balance, March 31, 2023 $ (254,513) $ (11) $ (1,454) $ (255,978) (1) ProAssurance entered into two forward-starting interest rate swap agreements ("Interest Rate Swaps") on May 2, 2023, which are designated and qualify as highly effective cash flow hedges. See Note 8 for additional information on the Interest Rate Swaps.

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2024
Variable Interest Entities [Abstract]
Variable Interest Entities	Variable Interest Entities ProAssurance holds passive interests in a number of entities that are considered to be VIEs under GAAP guidance. ProAssurance's VIE interests principally consist of interests in LPs/LLCs formed for the purpose of achieving diversified equity and debt returns. ProAssurance's VIE interests, carried as a part of investment in unconsolidated subsidiaries, totaled $252.9 million at March 31, 2024 and $250.4 million at December 31, 2023. ProAssurance does not have power over the activities that most significantly impact the economic performance of these VIEs and thus is not the primary beneficiary. Investments in entities where ProAssurance holds a greater than minor interest but does not hold a controlling interest are accounted for using the equity method. Therefore, ProAssurance has not consolidated these VIEs. ProAssurance’s involvement with each of these VIEs is limited to its direct ownership interest in the VIE. Except for the funding commitments disclosed in Note 6, ProAssurance has no arrangements with any of these VIEs to provide other financial support to or on behalf of the VIE. At March 31, 2024, ProAssurance’s maximum loss exposure relative to these investments was limited to the carrying value of ProAssurance’s investment in the VIE. ProAssurance is the primary beneficiary of PPM RRG. While there is no direct ownership of PPM RRG by ProAssurance, it manages the business operations of PPM RRG through its management services agreement and has effective control of the PPM RRG's Board of Directors through an irrevocable voting proxy. The management services agreement allows ProAssurance to provide management and oversight services to PPM RRG, which includes the ability to make business decisions impacting the operations of PPM RRG. PPM RRG has a $5 million surplus note to NORCAL which is its only source of capital. At March 31, 2024 and December 31, 2023, approximately $135 million and $142 million of ProAssurance's assets, respectively, and approximately $135 million and $142 million of its liabilities, respectively, included on the Condensed Consolidated Balance Sheet were related to PPM RRG.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Diluted weighted average shares is calculated as basic weighted average shares plus the effect, calculated using the treasury stock method, of assuming that restricted share units and performance share units have vested. The following table provides a reconciliation between the Company's basic weighted average number of common shares outstanding to its diluted weighted average number of common shares outstanding: (In thousands, except per share data) Three Months Ended 2024 2023 Weighted average number of common shares outstanding, basic 51,013 53,987 Dilutive effect of securities: Restricted Share Units 112 103 Performance Share Units 24 27 Weighted average number of common shares outstanding, diluted 51,149 54,117 Effect of dilutive shares on earnings (loss) per share $ — $ — The diluted weighted average number of common shares outstanding for the three months ended March 31, 2024 excluded approximately 251,000 of common share equivalents issuable under the Company's stock compensation plans as their effect would have been antidilutive. There were no antidilutive common share equivalents for the three months ended March 31, 2023. Dilutive common share equivalents are reflected in the earnings (loss) per share calculation while antidilutive common share equivalents are not reflected in the earnings (loss) per share calculation. For the three months ended March 31, 2023, all incremental common share equivalents were not included in the computation of diluted loss per share because to do so would have been antidilutive.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Information	Segment Information ProAssurance's segments are based on the Company's internal management reporting structure for which financial results are regularly evaluated by the Company's CODM to determine resource allocation and assess operating performance. The Company continually assesses its internal management reporting structure and information evaluated by its CODM to determine whether any changes have occurred that would impact its segment reporting structure. Segment Reorganization Effective September 2023, ProAssurance elected to discontinue its participation in the results of Syndicate 1729 beginning with the 2024 underwriting year. The results from the Company's participation in Syndicate 1729 from open underwriting years prior to 2024 will continue to earn out pro rata over the entire policy period of the underlying business. Due to the quarter lag, the Company's ceased participation in Syndicate 1729 will begin to be reflected in its results in the second quarter of 2024. During the third quarter of 2023, ProAssurance reorganized the financial results evaluated by its CODM; therefore, ProAssurance changed its operating and reportable segments to align with how the CODM currently oversees the business, allocates resources and evaluates operating performance. As a result, ProAssurance now reports the underwriting results from its participation in Lloyd’s Syndicates in the Specialty P&C segment and the investment results of assets solely allocated to its Lloyd's Syndicate operations and U.K. income taxes in the Corporate segment. All prior period segment information has been recast to conform to the current period presentation. The segment reorganization had no impact on previously reported consolidated financial results. The Company operates in four segments that are organized around the nature of the products and services provided: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance and Corporate. Additional information regarding ProAssurance's segments is included in Note 16 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K. A description of each of ProAssurance's four operating and reportable segments follows. • Specialty P&C primarily includes medical professional liability insurance and medical technology liability insurance. The Specialty P&C segment also includes the underwriting results from ProAssurance's participation in Lloyd's of London Syndicate 1729 and Syndicate 6131. • Workers' Compensation Insurance includes workers' compensation insurance products which are provided primarily to employers with 1,000 or fewer employees. • Segregated Portfolio Cell Reinsurance includes the results (underwriting profit or loss, plus investment results, net of U.S. federal income taxes) of SPCs at Inova Re and Eastern Re, the Company's Cayman Islands SPC operations. • Corporate includes ProAssurance's investment operations excluding those reported in the Company's Segregated Portfolio Cell Reinsurance segment. In addition, this segment includes corporate expenses, interest expense, U.S. and U.K. income taxes and non-premium revenues generated outside of the Company's insurance entities. The accounting policies of the segments are described in Note 1 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K. ProAssurance evaluates the performance of its Specialty P&C and Workers' Compensation Insurance segments based on before tax underwriting profit or loss. ProAssurance evaluates the performance of its Segregated Portfolio Cell Reinsurance segment based on operating profit or loss, which includes investment results of investment assets solely allocated to SPC operations, net of U.S. federal income taxes. Performance of the Corporate segment is evaluated based on the contribution made to consolidated after-tax results. ProAssurance accounts for inter-segment transactions as if the transactions were to third parties at current market prices. Assets are not allocated to segments because investments, other than the investments discussed above that are solely allocated to the Segregated Portfolio Cell Reinsurance segment, and other assets are not managed at the segment level. The tabular information that follows shows the financial results of the Company's reportable segments reconciled to results reflected in the Condensed Consolidated Statements of Income and Comprehensive Income. ProAssurance does not consider goodwill or intangible asset impairments, changes in the fair value of contingent consideration or transaction-related costs for completed business combinations, including any related tax impacts, in assessing the financial performance of its operating and reportable segments, and thus are included in the reconciliation of segment results to consolidated results. Financial results by segment were as follows: Three Months Ended March 31, 2024 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 188,888 $ 41,094 $ 14,168 $ — $ — $ 244,150 Net investment income — — 693 33,204 — 33,897 Equity in earnings (loss) of unconsolidated subsidiaries — — — 2,963 — 2,963 Net investment gains (losses) — — 1,471 (1,739) — (268) Other income (expense) (1) 1,353 477 (1) 3,061 (935) 3,955 Net losses and loss adjustment expenses (152,994) (31,636) (10,064) — — (194,694) Underwriting, policy acquisition and operating expenses (1) (51,049) (14,490) (4,713) (8,688) 935 (78,005) SPC U.S. federal income tax benefit (expense) (2) — — (416) — — (416) SPC dividend (expense) income — — (607) — — (607) Interest expense — — — (5,657) — (5,657) Income tax benefit (expense) — — — (692) — (692) Segment results $ (13,802) $ (4,555) $ 531 $ 22,452 $ — 4,626 Net income (loss) $ 4,626 Significant non-cash items: Depreciation and amortization, net of accretion $ 2,429 $ 1,164 $ (370) $ 2,109 $ — $ 5,332 Three Months Ended March 31, 2023 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 183,684 $ 40,803 $ 15,300 $ — $ — $ 239,787 Net investment income — — 420 29,890 — 30,310 Equity in earnings (loss) of unconsolidated subsidiaries — — — (1,121) — (1,121) Net investment gains (losses) — — 1,160 752 — 1,912 Other income (expense) (1) 990 581 1 327 (1,112) 787 Net losses and loss adjustment expenses (166,029) (30,844) (8,423) — — (205,296) Underwriting, policy acquisition and operating expenses (1) (42,681) (12,980) (5,035) (8,204) 1,112 (67,788) SPC U.S. federal income tax benefit (expense) (2) — — (532) — — (532) SPC dividend (expense) income — — (1,942) — — (1,942) Interest expense — — — (5,463) — (5,463) Income tax benefit (expense) — — — 2,172 — 2,172 Segment results $ (24,036) $ (2,440) $ 949 $ 18,353 $ — (7,174) Reconciliation of segments to consolidated results: Contingent Consideration (3) 1,000 Net income (loss) $ (6,174) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,640 $ 869 $ 64 $ 4,104 $ — $ 7,677 (1) Includes certain fees for services provided by the Workers' Compensation Insurance segment to the SPCs at Inova Re and Eastern Re which are recorded as expenses within the Segregated Portfolio Cell Reinsurance segment and as other income within the Workers' Compensation Insurance segment. These fees are primarily SPC rental fees and are eliminated between segments in consolidation. (2) Represents the provision for U.S. federal income taxes for SPCs at Inova Re, which have elected to be taxed as a U.S. corporation under Section 953(d) of the Internal Revenue Code. U.S. federal income taxes are included in the total SPC net results and are paid by the individual SPCs. (3) Represents the change in the fair value of contingent consideration issued in connection with the NORCAL acquisition included as a component of consolidated net investment gains (losses) on the Condensed Consolidated Statements of Income and Comprehensive Income. See further discussion on the contingent consideration in Note 2. The following table provides detailed information regarding ProAssurance's gross premiums earned by product as well as a reconciliation to net premiums earned. All gross premiums earned are from external customers except as noted. ProAssurance's insured risks are primarily within the U.S. Three Months Ended March 31 (In thousands) 2024 2023 Specialty P&C Segment Gross premiums earned: MPL $ 184,744 $ 181,800 Medical Technology Liability 10,938 10,546 Lloyd's Syndicates 4,934 5,046 Other 6,011 6,661 Ceded premiums earned (17,739) (20,369) Segment net premiums earned 188,888 183,684 Workers' Compensation Insurance Segment Gross premiums earned: Traditional business 44,376 43,540 Alternative market business 17,163 17,626 Ceded premiums earned (20,445) (20,363) Segment net premiums earned 41,094 40,803 Segregated Portfolio Cell Reinsurance Segment Gross premiums earned: Workers' compensation (1) 15,867 16,304 MPL (2) 543 1,299 Ceded premiums earned (2,242) (2,303) Segment net premiums earned 14,168 15,300 Consolidated net premiums earned $ 244,150 $ 239,787 (1) Premium for all periods is assumed from the Workers' Compensation Insurance segment. (2) Premium for all periods is assumed from the Specialty P&C segment.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net income (loss)	$ 4,626	$ (6,174)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of ProAssurance Corporation, its wholly owned subsidiaries and VIEs in which ProAssurance is the primary beneficiary (ProAssurance, PRA or the Company). See Note 10 for more information on ProAssurance's VIE interests. The financial statements have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation, consisting of normal recurring adjustments, have been included. ProAssurance’s results for the three months ended March 31, 2024 are not necessarily indicative of the results that may be expected for the year ending December 31, 2024. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes contained in ProAssurance’s December 31, 2023 report on Form 10-K. Beginning in the third quarter of 2023, ProAssurance operates in four reportable segments as follows: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance and Corporate. For more information on the Company's segment reporting, including the nature of products and services provided and financial information by segment, refer to Note 12.
Accounting Policies	Accounting Policies The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and disclosures related to these amounts at the date of the financial statements. The Company evaluates these estimates and assumptions on an ongoing basis based on current and historical developments, market conditions, industry trends and other information that the Company believes to be reasonable under the circumstances. The Company can make no assurance that actual results will conform to its estimates and assumptions; reported results of operations may be materially affected by changes in these estimates and assumptions. The significant accounting policies followed by ProAssurance in making estimates that materially affect financial reporting are summarized in Note 1 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K.
Accounting Changes Adopted and Accounting Changes Not Yet Adopted	Accounting Changes Adopted The Company did not adopt any new accounting standards during the three months ended March 31, 2024. Accounting Changes Not Yet Adopted Disclosure Improvements (ASU 2023-06) In October 2023, the FASB amended guidance to clarify or improve disclosure and presentation requirements of a variety of topics, which will allow users to more easily compare entities subject to the SEC's existing disclosures with those entities that were not previously subject to the requirements and align the requirements in the Codification with the SEC's regulations. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X becomes effective, with early adoption prohibited. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures. Improvements to Reportable Segment Disclosures (ASU 2023-07) Effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, and requiring retrospective application to all prior periods presented in the financial statements, the FASB amended disclosure requirements for segment reporting by modifying and adding disclosure requirements, primarily related to significant segment expenses which are regularly provided to the Company’s CODM. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures. Improvements to Income Tax Disclosures (ASU 2023-09) Effective for fiscal years beginning after December 31, 2024, the FASB amended disclosure requirements to provide greater transparency on income tax disclosures, including the disaggregation of existing disclosures related to the tax rate reconciliation and income taxes paid. ProAssurance is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets	Fair values of assets measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023 are shown in the following tables. Where applicable, the tables also indicate the fair value hierarchy of the valuation techniques utilized to determine those fair values. For some assets, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. When this is the case, the asset is categorized based on the level of the most significant input to the fair value measurement. Assessments of the significance of a particular input to the fair value measurement require judgment and consideration of factors specific to the assets being valued. For more information on the valuation methodologies used regarding securities in the Level 2 and Level 3 categories, see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2023 report on Form 10-K. March 31, 2024 Fair Value Measurements Using Total (In thousands) Level 1 Level 2 Level 3 Fair Value Assets: Fixed maturities, available-for-sale U.S. Treasury obligations $ — $ 240,889 $ — $ 240,889 U.S. Government-sponsored enterprise obligations — 18,927 — 18,927 State and municipal bonds — 474,265 — 474,265 Corporate debt, multiple observable inputs — 1,647,844 — 1,647,844 Corporate debt, limited observable inputs — — 66,208 66,208 Residential mortgage-backed securities — 450,052 — 450,052 Agency commercial mortgage-backed securities — 7,950 — 7,950 Other commercial mortgage-backed securities — 229,029 — 229,029 Other asset-backed securities — 406,832 2,141 408,973 Fixed maturities, trading — 50,106 — 50,106 Equity investments Financial 9,750 2,270 288 12,308 Utilities/Energy 1,258 — — 1,258 Industrial — — 4,946 4,946 Bond funds 101,571 — — 101,571 All other 17,831 — — 17,831 Short-term investments 102,675 81,326 — 184,001 Other investments — 54,990 742 55,732 Other assets — 7,674 — 7,674 Total assets categorized within the fair value hierarchy $ 233,085 $ 3,672,154 $ 74,325 3,979,564 Assets carried at NAV, which approximates fair value and which are not categorized within the fair value hierarchy, reported as a part of: Investment in unconsolidated subsidiaries 246,143 Total assets at fair value $ 4,225,707 Liabilities: Other liabilities $ 9,050 $ — $ 6,500 $ 15,550 Total liabilities categorized within the fair value hierarchy $ 9,050 $ — $ 6,500 $ 15,550 December 31, 2023 Fair Value Measurements Using Total (In thousands) Level 1 Level 2 Level 3 Fair Value Assets: Fixed maturities, available-for-sale U.S. Treasury obligations $ — $ 243,525 $ — $ 243,525 U.S. Government-sponsored enterprise obligations — 18,724 — 18,724 State and municipal bonds — 454,381 — 454,381 Corporate debt, multiple observable inputs — 1,668,197 — 1,668,197 Corporate debt, limited observable inputs — — 82,377 82,377 Residential mortgage-backed securities — 429,883 254 430,137 Agency commercial mortgage-backed securities — 8,387 — 8,387 Other commercial mortgage-backed securities — 188,464 1,010 189,474 Other asset-backed securities — 395,245 3,150 398,395 Fixed maturities, trading — 48,324 — 48,324 Equity investments Financial 9,464 2,287 291 12,042 Utilities/Energy 1,256 — — 1,256 Industrial — — 4,946 4,946 Bond funds 114,901 — — 114,901 All other 18,150 — — 18,150 Short-term investments 163,499 72,286 — 235,785 Other investments — 57,478 5,126 62,604 Other assets — 3,876 — 3,876 Total assets categorized within the fair value hierarchy $ 307,270 $ 3,591,057 $ 97,154 3,995,481 Assets carried at NAV, which approximates fair value and which are not categorized within the fair value hierarchy, reported as a part of: Investment in unconsolidated subsidiaries 245,455 Total assets at fair value $ 4,240,936 Liabilities: Other liabilities $ 4,030 $ — $ 6,500 $ 10,530 Total liabilities categorized within the fair value hierarchy $ 4,030 $ — $ 6,500 $ 10,530
Schedule of Quantitative Information Regarding Level 3 Valuations	Quantitative Information Regarding Level 3 Valuations Below is quantitative information regarding securities in the Level 3 category, by security type: Fair Value at ($ in thousands) March 31, 2024 December 31, 2023 Valuation Technique Unobservable Input Range Assets: Corporate debt, limited observable inputs $66,208 $82,377 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities $2,141 $4,414 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Equity investments $5,234 $5,237 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Other investments $742 $5,126 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Liabilities: Other liabilities $6,500 $6,500 Stochastic Model/Discounted Cash Flows Weighted Average Cost of Capital 0% - 10% (8%)
Schedule of Fair Value Measurements - Level 3 Assets & Liabilities	The following tables present summary information regarding changes in the fair value of assets and liabilities measured using Level 3 inputs. March 31, 2024 Level 3 Fair Value Measurements Assets Liabilities (In thousands) Corporate Debt Asset-backed Securities Equity Investments Other Investments Total Assets Other Liabilities Total Liabilities Balance, December 31, 2023 $ 82,377 $ 4,414 $ 5,237 $ 5,126 $ 97,154 $ (6,500) $ (6,500) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment gains (losses) — — (3) 88 85 — — Included in other comprehensive income (loss) (171) (28) — — (199) — — Purchases 2,201 1,200 — — 3,401 — — Sales (702) — — — (702) — — Transfers in — — — — — — — Transfers out (17,497) (3,445) — (4,472) (25,414) — — Balance, March 31, 2024 $ 66,208 $ 2,141 $ 5,234 $ 742 $ 74,325 $ (6,500) $ (6,500) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ (3) $ 88 $ 85 $ — $ — March 31, 2023 Level 3 Fair Value Measurements Assets Liabilities (In thousands) Corporate Debt Asset-backed Securities Equity Investments Other Investments Total Assets Other Liabilities Total Liabilities Balance, December 31, 2022 $ 63,973 $ 2,954 $ 2,803 $ 1,783 $ 71,513 $ (15,000) $ (15,000) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment gains (losses) 16 — (3) — 13 1,000 1,000 Operating expense — — — — — 1,000 1,000 Included in other comprehensive income (loss) 209 39 — — 248 — — Purchases 6,322 1,863 — — 8,185 — — Sales (432) — — — (432) — — Transfers in 11,220 1,779 — — 12,999 — — Transfers out (5,151) (1,581) — (1,283) (8,015) — — Balance, March 31, 2023 $ 76,157 $ 5,054 $ 2,800 $ 500 $ 84,511 $ (13,000) $ (13,000) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ (3) $ — $ (3) $ — $ —
Schedule of Investments in LLCs and Limited Partnerships	The amount of ProAssurance's unfunded contractual commitments related to these investments as of March 31, 2024 and fair values of these investments as of March 31, 2024 and December 31, 2023 were as follows: Unfunded Fair Value (In thousands) March 31, March 31, December 31, Investment in unconsolidated subsidiaries: Private debt funds (1) $4,565 $ 16,768 $ 19,886 Long/short equity funds (2) None 4,243 4,497 Non-public equity funds (3) $38,970 115,421 111,251 Credit funds (4) $31,552 56,595 55,740 Strategy focused funds (5) $50,427 53,116 54,081 Total investments carried at NAV $ 246,143 $ 245,455 Below is additional information regarding each of the investments listed in the table above as of March 31, 2024. (1) This investment is comprised of interests in two unrelated LP funds that are structured to provide interest distributions primarily through diversified portfolios of private debt instruments. One LP allows redemption by special consent, while the other does not permit redemption. Income and capital are to be periodically distributed at the discretion of the LPs over an anticipated time frame that spans from three (2) This investment is comprised of one LP fund, which holds long and short publicly traded securities that will passively generate income. Redemptions are permitted with 30 days written notice if outside of a lock-up period. (3) This investment is comprised of interests in multiple unrelated LP funds, each structured to provide capital appreciation through diversified investments in private equity, which can include investments in buyout, venture capital, debt including senior, second lien and mezzanine, distressed debt, collateralized loan obligations and other private equity-oriented LPs. Two of the LPs allow redemption by terms set forth in the LP agreements; the others do not permit redemption. Income and capital are to be periodically distributed at the discretion of the LP over time frames that are anticipated to span up to ten years. (4) This investment is comprised of multiple unrelated LP funds. Two funds seek to obtain superior risk-adjusted absolute returns through a diversified portfolio of debt securities, including bonds, loans and other asset-backed instruments. The remaining funds focus on private middle market company mezzanine and senior secured loans, opportunities across the credit spectrum, mortgage backed-loans, as well as various types of loan-backed investments. One fund allows redemptions at any quarter-end with prior notice requirements of 180 days, while two other funds allow for redemptions with consent of the General Partner. The remaining funds do not allow redemptions. For the funds that do not allow redemptions, income and capital are to be periodically distributed at the discretion of the LP over time frames throughout the remaining life of the funds. (5) This investment is comprised of multiple unrelated LPs/LLCs funds. One fund is an LLC focused on investing in North American consumer products companies, comprised of equity and equity-related securities, as well as debt instruments. A second fund is focused on aircraft investments, along with components and assets related to aircrafts. A third fund is an LLC focused on acquiring ownership stakes in insurance agencies. For all three funds, redemptions are not permitted. The remaining funds are real estate focused LPs, two of which allow for redemption with prior notice.
Schedule of Financial Instruments Not Measured at Fair Value	The following table provides the estimated fair value of the Company's financial instruments that, in accordance with GAAP for the type of investment, are measured using a methodology other than fair value. Fair values provided primarily fall within the Level 3 fair value category. March 31, 2024 December 31, 2023 (In thousands) Carrying Fair Carrying Fair Financial assets: BOLI $ 78,657 $ 78,657 $ 78,205 $ 78,205 Other investments $ 4,064 $ 4,064 $ 3,215 $ 3,215 Other assets $ 34,824 $ 34,824 $ 33,231 $ 33,221 Financial liabilities: Revolving Credit Agreement* $ 125,000 $ 125,000 $ 125,000 $ 125,000 Term Loan* $ 125,000 $ 125,000 $ 125,000 $ 125,000 Contribution Certificates $ 179,865 $ 147,328 $ 179,387 $ 149,782 Other liabilities $ 33,548 $ 33,548 $ 32,043 $ 32,043 * Carrying value excludes unamortized debt issuance costs.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-For-Sale Fixed Maturities	Available-for-sale fixed maturities at March 31, 2024 and December 31, 2023 included the following: March 31, 2024 (In thousands) Amortized Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Fixed maturities, available-for-sale U.S. Treasury obligations $ 258,462 $ — $ 24 $ 17,597 $ 240,889 U.S. Government-sponsored enterprise obligations 19,957 — — 1,030 18,927 State and municipal bonds 502,549 — 1,736 30,020 474,265 Corporate debt 1,849,162 740 2,421 136,791 1,714,052 Residential mortgage-backed securities 507,312 207 2,020 59,073 450,052 Agency commercial mortgage-backed securities 8,964 — — 1,014 7,950 Other commercial mortgage-backed securities 248,756 — 221 19,948 229,029 Other asset-backed securities 418,695 190 921 10,453 408,973 $ 3,813,857 $ 1,137 $ 7,343 $ 275,926 $ 3,544,137 December 31, 2023 (In thousands) Amortized Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Fixed maturities, available-for-sale U.S. Treasury obligations $ 259,834 $ — $ 165 $ 16,474 $ 243,525 U.S. Government-sponsored enterprise obligations 19,752 — 2 1,030 18,724 State and municipal bonds 482,367 — 1,885 29,871 454,381 Corporate debt 1,883,308 — 4,025 136,759 1,750,574 Residential mortgage-backed securities 481,267 211 2,876 53,795 430,137 Agency commercial mortgage-backed securities 9,369 — 5 987 8,387 Other commercial mortgage-backed securities 210,469 151 60 20,904 189,474 Other asset-backed securities 412,354 193 1,104 14,870 398,395 $ 3,758,720 $ 555 $ 10,122 $ 274,690 $ 3,493,597
Schedule of Available-For-Sale Securities by Contractual Maturity	The recorded cost basis and estimated fair value of available-for-sale fixed maturities at March 31, 2024, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (In thousands) Amortized Due in one Due after Due after Due after Total Fair Fixed maturities, available-for-sale U.S. Treasury obligations $ 258,462 $ 36,249 $ 169,651 $ 32,387 $ 2,602 $ 240,889 U.S. Government-sponsored enterprise obligations 19,957 4,790 11,653 505 1,979 18,927 State and municipal bonds 502,549 30,409 157,707 161,274 124,875 474,265 Corporate debt 1,849,162 179,206 886,529 569,033 79,284 1,714,052 Residential mortgage-backed securities 507,312 450,052 Agency commercial mortgage-backed securities 8,964 7,950 Other commercial mortgage-backed securities 248,756 229,029 Other asset-backed securities 418,695 408,973 $ 3,813,857 $ 3,544,137
Schedule of Investments Held in an Unrealized Loss Position	The following tables provide summarized information with respect to investments held in an unrealized loss position at March 31, 2024 and December 31, 2023, including the length of time the investment had been held in a continuous unrealized loss position. March 31, 2024 Total Less than 12 months 12 months or longer Fair Unrealized Fair Unrealized Fair Unrealized (In thousands) Value Loss Value Loss Value Loss Fixed maturities, available-for-sale U.S. Treasury obligations $ 226,103 $ 17,597 $ 40,747 $ 1,412 $ 185,356 $ 16,185 U.S. Government-sponsored enterprise obligations 18,928 1,030 10,631 486 8,297 544 State and municipal bonds 389,539 30,020 98,395 5,941 291,144 24,079 Corporate debt 1,498,062 136,791 459,157 38,451 1,038,905 98,340 Residential mortgage-backed securities 335,297 59,073 130,058 16,800 205,239 42,273 Agency commercial mortgage-backed securities 7,950 1,014 2,652 344 5,298 670 Other commercial mortgage-backed securities 214,030 19,948 90,586 8,120 123,444 11,828 Other asset-backed securities 252,384 10,453 125,871 3,746 126,513 6,707 $ 2,942,293 $ 275,926 $ 958,097 $ 75,300 $ 1,984,196 $ 200,626 December 31, 2023 Total Less than 12 months 12 months or longer Fair Unrealized Fair Unrealized Fair Unrealized (In thousands) Value Loss Value Loss Value Loss Fixed maturities, available-for-sale U.S. Treasury obligations $ 213,634 $ 16,474 $ 32,925 $ 1,364 $ 180,709 $ 15,110 U.S. Government-sponsored enterprise obligations 18,428 1,030 4,128 242 14,300 788 State and municipal bonds 378,313 29,871 48,960 2,287 329,353 27,584 Corporate debt 1,524,940 136,759 84,221 5,054 1,440,719 131,705 Residential mortgage-backed securities 313,082 53,795 74,463 10,271 238,619 43,524 Agency commercial mortgage-backed securities 7,955 987 212 1 7,743 986 Other commercial mortgage-backed securities 184,416 20,904 18,092 1,140 166,324 19,764 Other asset-backed securities 293,447 14,870 30,115 867 263,332 14,003 $ 2,934,215 $ 274,690 $ 293,116 $ 21,226 $ 2,641,099 $ 253,464
Schedule of a Roll Forward of Cumulative Credit Losses Recorded in Earnings Related to Impaired Debt Securities	The following tables present a roll forward of the allowance for expected credit losses on available-for-sale fixed maturities for the three months ended March 31, 2024 and 2023. Three Months Ended March 31, 2024 (In thousands) Corporate Debt Residential mortgage-backed securities Other commercial mortgage-backed securities Other asset-backed securities Total Balance, at December 31, 2023 $ — $ 211 $ 151 $ 193 $ 555 Additional credit losses related to securities for which: No allowance for credit losses has been previously recognized 740 — — — 740 Reductions related to: Securities sold during the period — (4) (151) (3) (158) Balance, at March 31, 2024 $ 740 $ 207 $ — $ 190 $ 1,137 Three Months Ended March 31, 2023 (In thousands) Residential mortgage-backed securities Other asset-backed securities Total Balance, at December 31, 2022 $ 229 $ 198 $ 427 Reductions related to: Securities sold during the period (2) (1) (3) Balance, at March 31, 2023 $ 227 $ 197 $ 424 The following table presents a roll forward of cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the impairment was recorded in OCI. Three Months Ended (In thousands) 2024 2023 Balance beginning of period $ 57 $ 57 Additional credit losses recognized during the period, related to securities for which: No impairment has been previously recognized 740 — Balance March 31 $ 797 $ 57
Schedule of Other Information Regarding Available-For-Sale Securities	Other information regarding sales and purchases of fixed maturity available-for-sale securities is as follows: Three Months Ended March 31 (In millions) 2024 2023 Proceeds from sales (exclusive of maturities and paydowns) $ 17.1 $ 3.8 Purchases $ 230.5 $ 68.8
Schedule of Net Investment Income	Net investment income (loss) by investment category was as follows: Three Months Ended (In thousands) 2024 2023 Fixed maturities $ 31,451 $ 27,327 Equities 892 807 Short-term investments, including Other 3,411 3,350 BOLI 452 657 Investment fees and expenses (2,309) (1,831) Net investment income $ 33,897 $ 30,310
Schedule of Investment in Unconsolidated Subsidiaries	ProAssurance's investment in unconsolidated subsidiaries were as follows: March 31, 2024 Carrying Value (In thousands) Percentage March 31, December 31, Qualified affordable housing project tax credit partnerships See below $ 562 $ 666 All other investments, primarily investment fund LPs/LLCs See below 278,369 276,090 $ 278,931 $ 276,756
Schedule of Equity Method Investments	The results recorded and tax credits recognized related to ProAssurance's tax credit partnership investments were as follows: Three Months Ended (In thousands) 2024 2023 Qualified affordable housing project tax credit partnerships Losses recorded $ 103 $ 354 Tax credits recognized $ 8 $ 43
Schedule of Net Realized Investment Gains (Losses)	Realized investment gains and losses are recognized on the first-in, first-out basis. The following table provides detailed information regarding net investment gains (losses): Three Months Ended (In thousands) 2024 2023 Total impairment losses: Corporate debt $ (1,316) $ (2,936) Asset-backed securities (194) 3 Portion of impairment losses recognized in other comprehensive income before taxes: Corporate debt 576 — Net impairment losses recognized in earnings (934) (2,933) Gross realized gains, available-for-sale fixed maturities 366 79 Gross realized (losses), available-for-sale fixed maturities (1,099) (457) Net realized gains (losses), trading fixed maturities 15 (108) Net realized gains (losses), equity investments (256) 84 Net realized gains (losses), other investments 1,776 229 Change in unrealized holding gains (losses), trading fixed maturities 214 97 Change in unrealized holding gains (losses), equity investments 774 3,746 Change in unrealized holding gains (losses), convertible securities, carried at fair value (1,119) 1,132 Other (1) (5) 1,043 Net investment gains (losses) $ (268) $ 2,912 (1) Includes a gain of $1.0 million recognized during the 2023 three-month period related to the change in the fair value of contingent consideration issued in connection with the NORCAL acquisition. See further discussion on the contingent consideration in Note 2 and Note 6 and discussion on the Company's accounting policy in Note 1 in its December 31, 2023 report on Form 10-K.

Reserve for Losses and Loss A_2

Reserve for Losses and Loss Adjustment Expenses (Tables)	3 Months Ended
	Mar. 31, 2024
Insurance [Abstract]
Schedule of Reserve for Losses and Loss Adjustment Expenses	Activity in the reserve for losses and loss adjustment expenses is summarized as follows: (In thousands) Three Months Ended March 31, 2024 Three Months Ended March 31, 2023 Year Ended December 31, 2023 Balance, beginning of year $ 3,401,281 $ 3,471,147 $ 3,471,147 Less reinsurance recoverables on unpaid losses and loss adjustment expenses 445,573 431,889 431,889 Net balance, beginning of year 2,955,708 3,039,258 3,039,258 Net losses: Current year 195,110 198,240 794,848 (Favorable) unfavorable development of reserves established in prior years, net (1) (416) 7,056 5,646 Total 194,694 205,296 800,494 Paid related to: Current year (12,867) (11,052) (101,996) Prior years (202,180) (211,916) (782,048) Total paid (215,047) (222,968) (884,044) Net balance, end of period 2,935,355 3,021,586 2,955,708 Plus reinsurance recoverables on unpaid losses and loss adjustment expenses 447,157 447,693 445,573 Balance, end of period $ 3,382,512 $ 3,469,279 $ 3,401,281 (1) Net prior year reserve development recognized for the three months ended March 31, 2024 and 2023 as well as the year ended December 31, 2023 included $1.7 million, $2.5 million and $8.3 million, respectively, of amortization of the purchase accounting fair value adjustment on NORCAL's assumed net reserve and amortization of the negative VOBA associated with NORCAL's DDR reserve which is recorded as a reduction to prior accident year net losses and loss adjustment expenses.

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Outstanding Debt	ProAssurance’s outstanding debt consisted of the following: ($ in thousands) March 31, December 31, Contribution Certificates due 2031, interest at 3.0% (effective interest rate at 4.35%) paid annually in April $ 179,865 $ 179,387 Revolving Credit Agreement, outstanding borrowings are not permitted to exceed $300 million aggregately, including a $50 million accordion feature; Revolving Credit Agreement expires in 2028. The effective interest rate was 7.53% as of March 31, 2024 125,000 125,000 Term Loan, principal repayments in quarterly installments beginning June 30, 2024; Term Loan expires in 2028. The effective interest rate was 7.65% as of March 31, 2024 125,000 125,000 Total principal 429,865 429,387 Less unamortized debt issuance costs 2,091 2,254 Debt less unamortized debt issuance costs $ 427,774 $ 427,133

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Swaps	The following table provides a summary of the volume and fair value position of the Interest Rate Swaps as well as the reporting location in the Condensed Consolidated Balance Sheet as of March 31, 2024 and December 31, 2023. ($ in thousands) March 31, 2024 December 31, 2023 Derivatives Designated and Qualifying as Cash Flow Hedging Instruments Location in the Condensed Consolidated Balance Sheets Number of Instruments Aggregate Notional Amount (1) Estimated Fair Value (2) Number of Instruments Aggregate Notional Amount (1) Estimated Fair Value (2) Interest Rate Swaps Other Assets 2 $250,000 $7,674 2 $250,000 $3,876 (1) Volume is represented by the derivative instruments' notional amount. (2) Additional information regarding the fair value of the Company's Interest Rate Swaps is provided in Note 2.
Schedule of Derivative Instruments, Gain (Loss)	For the three months ended March 31, 2024, ProAssurance reclassified a gain on the Interest Rate Swaps from AOCI, net of tax, into earnings as shown in the table below: Qualifying Cash Flow Hedges - Gains (Losses) Reclassified from AOCI, net of tax, to Earnings (In thousands) Three Months Ended March 31 Derivatives Designated as Hedging Instruments Location in the Condensed Consolidated Statements of Income and Comprehensive Income 2024 2023 Interest Rate Swaps Interest Expense $ 1,073 $ —

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Components of AOCI, Net of Tax	The changes in the balance of each component of AOCI for the three months ended March 31, 2024 and 2023 were as follows: (In thousands) Unrealized Investment Gains (Losses) Cash Flow Hedging Gains (Losses) (1) Non-credit Impairments Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2023 $ (206,327) $ 3,026 $ (11) $ (1,177) $ (204,489) OCI, before reclassifications, net of tax (6,339) 4,074 (455) — (2,720) Amounts reclassified from AOCI, net of tax 1,321 (1,073) — — 248 Net OCI, current period (5,018) 3,001 (455) — (2,472) Balance, March 31, 2024 $ (211,345) $ 6,027 $ (466) $ (1,177) $ (206,961) (In thousands) Unrealized Investment Gains (Losses) Non-credit Impairments Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2022 $ (297,142) $ (11) $ (1,454) $ (298,607) OCI, before reclassifications, net of tax 40,007 — — 40,007 Amounts reclassified from AOCI, net of tax 2,622 — — 2,622 Net OCI, current period 42,629 — — 42,629 Balance, March 31, 2023 $ (254,513) $ (11) $ (1,454) $ (255,978) (1) ProAssurance entered into two forward-starting interest rate swap agreements ("Interest Rate Swaps") on May 2, 2023, which are designated and qualify as highly effective cash flow hedges. See Note 8 for additional information on the Interest Rate Swaps.

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table provides a reconciliation between the Company's basic weighted average number of common shares outstanding to its diluted weighted average number of common shares outstanding: (In thousands, except per share data) Three Months Ended 2024 2023 Weighted average number of common shares outstanding, basic 51,013 53,987 Dilutive effect of securities: Restricted Share Units 112 103 Performance Share Units 24 27 Weighted average number of common shares outstanding, diluted 51,149 54,117 Effect of dilutive shares on earnings (loss) per share $ — $ —

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The tabular information that follows shows the financial results of the Company's reportable segments reconciled to results reflected in the Condensed Consolidated Statements of Income and Comprehensive Income. ProAssurance does not consider goodwill or intangible asset impairments, changes in the fair value of contingent consideration or transaction-related costs for completed business combinations, including any related tax impacts, in assessing the financial performance of its operating and reportable segments, and thus are included in the reconciliation of segment results to consolidated results. Financial results by segment were as follows: Three Months Ended March 31, 2024 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 188,888 $ 41,094 $ 14,168 $ — $ — $ 244,150 Net investment income — — 693 33,204 — 33,897 Equity in earnings (loss) of unconsolidated subsidiaries — — — 2,963 — 2,963 Net investment gains (losses) — — 1,471 (1,739) — (268) Other income (expense) (1) 1,353 477 (1) 3,061 (935) 3,955 Net losses and loss adjustment expenses (152,994) (31,636) (10,064) — — (194,694) Underwriting, policy acquisition and operating expenses (1) (51,049) (14,490) (4,713) (8,688) 935 (78,005) SPC U.S. federal income tax benefit (expense) (2) — — (416) — — (416) SPC dividend (expense) income — — (607) — — (607) Interest expense — — — (5,657) — (5,657) Income tax benefit (expense) — — — (692) — (692) Segment results $ (13,802) $ (4,555) $ 531 $ 22,452 $ — 4,626 Net income (loss) $ 4,626 Significant non-cash items: Depreciation and amortization, net of accretion $ 2,429 $ 1,164 $ (370) $ 2,109 $ — $ 5,332 Three Months Ended March 31, 2023 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 183,684 $ 40,803 $ 15,300 $ — $ — $ 239,787 Net investment income — — 420 29,890 — 30,310 Equity in earnings (loss) of unconsolidated subsidiaries — — — (1,121) — (1,121) Net investment gains (losses) — — 1,160 752 — 1,912 Other income (expense) (1) 990 581 1 327 (1,112) 787 Net losses and loss adjustment expenses (166,029) (30,844) (8,423) — — (205,296) Underwriting, policy acquisition and operating expenses (1) (42,681) (12,980) (5,035) (8,204) 1,112 (67,788) SPC U.S. federal income tax benefit (expense) (2) — — (532) — — (532) SPC dividend (expense) income — — (1,942) — — (1,942) Interest expense — — — (5,463) — (5,463) Income tax benefit (expense) — — — 2,172 — 2,172 Segment results $ (24,036) $ (2,440) $ 949 $ 18,353 $ — (7,174) Reconciliation of segments to consolidated results: Contingent Consideration (3) 1,000 Net income (loss) $ (6,174) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,640 $ 869 $ 64 $ 4,104 $ — $ 7,677 (1) Includes certain fees for services provided by the Workers' Compensation Insurance segment to the SPCs at Inova Re and Eastern Re which are recorded as expenses within the Segregated Portfolio Cell Reinsurance segment and as other income within the Workers' Compensation Insurance segment. These fees are primarily SPC rental fees and are eliminated between segments in consolidation. (2) Represents the provision for U.S. federal income taxes for SPCs at Inova Re, which have elected to be taxed as a U.S. corporation under Section 953(d) of the Internal Revenue Code. U.S. federal income taxes are included in the total SPC net results and are paid by the individual SPCs. (3) Represents the change in the fair value of contingent consideration issued in connection with the NORCAL acquisition included as a component of consolidated net investment gains (losses) on the Condensed Consolidated Statements of Income and Comprehensive Income. See further discussion on the contingent consideration in Note 2.
Schedule of Gross Premiums by Product	The following table provides detailed information regarding ProAssurance's gross premiums earned by product as well as a reconciliation to net premiums earned. All gross premiums earned are from external customers except as noted. ProAssurance's insured risks are primarily within the U.S. Three Months Ended March 31 (In thousands) 2024 2023 Specialty P&C Segment Gross premiums earned: MPL $ 184,744 $ 181,800 Medical Technology Liability 10,938 10,546 Lloyd's Syndicates 4,934 5,046 Other 6,011 6,661 Ceded premiums earned (17,739) (20,369) Segment net premiums earned 188,888 183,684 Workers' Compensation Insurance Segment Gross premiums earned: Traditional business 44,376 43,540 Alternative market business 17,163 17,626 Ceded premiums earned (20,445) (20,363) Segment net premiums earned 41,094 40,803 Segregated Portfolio Cell Reinsurance Segment Gross premiums earned: Workers' compensation (1) 15,867 16,304 MPL (2) 543 1,299 Ceded premiums earned (2,242) (2,303) Segment net premiums earned 14,168 15,300 Consolidated net premiums earned $ 244,150 $ 239,787 (1) Premium for all periods is assumed from the Workers' Compensation Insurance segment. (2) Premium for all periods is assumed from the Specialty P&C segment.

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2024 segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments	4

Fair Value Measurement (Assets

Fair Value Measurement (Assets and Liabilities Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets:
Fixed maturities, available-for-sale	$ 3,544,137	$ 3,493,597
Fixed maturities, trading	50,106	48,324
Equity investments	137,914	151,295
Level 3
Liabilities:
Other liabilities	6,500	6,500
U.S. Treasury obligations
Assets:
Fixed maturities, available-for-sale	240,889	243,525
U.S. Government-sponsored enterprise obligations
Assets:
Fixed maturities, available-for-sale	18,927	18,724
State and municipal bonds
Assets:
Fixed maturities, available-for-sale	474,265	454,381
Corporate debt, limited observable inputs | Level 3
Assets:
Fixed maturities, available-for-sale	66,208	82,377
Residential mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	450,052	430,137
Agency commercial mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	7,950	8,387
Other commercial mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	229,029	189,474
Other asset-backed securities
Assets:
Fixed maturities, available-for-sale	408,973	398,395
Recurring
Assets:
Total assets categorized within the fair value hierarchy	4,225,707	4,240,936
Recurring | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, trading	50,106	48,324
Other assets	7,674	3,876
Total assets categorized within the fair value hierarchy	3,979,564	3,995,481
Liabilities:
Other liabilities	15,550	10,530
Total liabilities categorized within the fair value hierarchy	15,550	10,530
Recurring | Level 1
Assets:
Fixed maturities, trading	0	0
Other assets	0	0
Total assets categorized within the fair value hierarchy	233,085	307,270
Liabilities:
Other liabilities	9,050	4,030
Total liabilities categorized within the fair value hierarchy	9,050	4,030
Recurring | Level 2
Assets:
Fixed maturities, trading	50,106	48,324
Other assets	7,674	3,876
Total assets categorized within the fair value hierarchy	3,672,154	3,591,057
Liabilities:
Other liabilities	0	0
Total liabilities categorized within the fair value hierarchy	0	0
Recurring | Level 3
Assets:
Fixed maturities, trading	0	0
Other assets	0	0
Total assets categorized within the fair value hierarchy	74,325	97,154
Liabilities:
Other liabilities	6,500	6,500
Total liabilities categorized within the fair value hierarchy	6,500	6,500
Recurring | U.S. Treasury obligations | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	240,889	243,525
Recurring | U.S. Treasury obligations | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | U.S. Treasury obligations | Level 2
Assets:
Fixed maturities, available-for-sale	240,889	243,525
Recurring | U.S. Treasury obligations | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | U.S. Government-sponsored enterprise obligations | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	18,927	18,724
Recurring | U.S. Government-sponsored enterprise obligations | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | U.S. Government-sponsored enterprise obligations | Level 2
Assets:
Fixed maturities, available-for-sale	18,927	18,724
Recurring | U.S. Government-sponsored enterprise obligations | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | State and municipal bonds | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	474,265	454,381
Recurring | State and municipal bonds | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | State and municipal bonds | Level 2
Assets:
Fixed maturities, available-for-sale	474,265	454,381
Recurring | State and municipal bonds | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Corporate debt, multiple observable inputs | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	1,647,844	1,668,197
Recurring | Corporate debt, multiple observable inputs | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Corporate debt, multiple observable inputs | Level 2
Assets:
Fixed maturities, available-for-sale	1,647,844	1,668,197
Recurring | Corporate debt, multiple observable inputs | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Corporate debt, limited observable inputs | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	66,208	82,377
Recurring | Corporate debt, limited observable inputs | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Corporate debt, limited observable inputs | Level 2
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Corporate debt, limited observable inputs | Level 3
Assets:
Fixed maturities, available-for-sale	66,208	82,377
Recurring | Residential mortgage-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	450,052	430,137
Recurring | Residential mortgage-backed securities | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Residential mortgage-backed securities | Level 2
Assets:
Fixed maturities, available-for-sale	450,052	429,883
Recurring | Residential mortgage-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	0	254
Recurring | Agency commercial mortgage-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	7,950	8,387
Recurring | Agency commercial mortgage-backed securities | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Agency commercial mortgage-backed securities | Level 2
Assets:
Fixed maturities, available-for-sale	7,950	8,387
Recurring | Agency commercial mortgage-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Other commercial mortgage-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	229,029	189,474
Recurring | Other commercial mortgage-backed securities | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Other commercial mortgage-backed securities | Level 2
Assets:
Fixed maturities, available-for-sale	229,029	188,464
Recurring | Other commercial mortgage-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	0	1,010
Recurring | Other asset-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	408,973	398,395
Recurring | Other asset-backed securities | Level 1
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Other asset-backed securities | Level 2
Assets:
Fixed maturities, available-for-sale	406,832	395,245
Recurring | Other asset-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	2,141	3,150
Recurring | Financial | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	12,308	12,042
Recurring | Financial | Level 1
Assets:
Equity investments	9,750	9,464
Recurring | Financial | Level 2
Assets:
Equity investments	2,270	2,287
Recurring | Financial | Level 3
Assets:
Equity investments	288	291
Recurring | Utilities/Energy | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	1,258	1,256
Recurring | Utilities/Energy | Level 1
Assets:
Equity investments	1,258	1,256
Recurring | Utilities/Energy | Level 2
Assets:
Equity investments	0	0
Recurring | Utilities/Energy | Level 3
Assets:
Equity investments	0	0
Recurring | Industrial | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	4,946	4,946
Recurring | Industrial | Level 1
Assets:
Equity investments	0	0
Recurring | Industrial | Level 2
Assets:
Equity investments	0	0
Recurring | Industrial | Level 3
Assets:
Equity investments	4,946	4,946
Recurring | Bond funds | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	101,571	114,901
Recurring | Bond funds | Level 1
Assets:
Equity investments	101,571	114,901
Recurring | Bond funds | Level 2
Assets:
Equity investments	0	0
Recurring | Bond funds | Level 3
Assets:
Equity investments	0	0
Recurring | All other | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	17,831	18,150
Recurring | All other | Level 1
Assets:
Equity investments	17,831	18,150
Recurring | All other | Level 2
Assets:
Equity investments	0	0
Recurring | All other | Level 3
Assets:
Equity investments	0	0
Recurring | Short-term investments | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Short-term and other investments	184,001	235,785
Recurring | Short-term investments | Level 1
Assets:
Short-term and other investments	102,675	163,499
Recurring | Short-term investments | Level 2
Assets:
Short-term and other investments	81,326	72,286
Recurring | Short-term investments | Level 3
Assets:
Short-term and other investments	0	0
Recurring | Other investments | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Short-term and other investments	55,732	62,604
Recurring | Other investments | Level 1
Assets:
Short-term and other investments	0	0
Recurring | Other investments | Level 2
Assets:
Short-term and other investments	54,990	57,478
Recurring | Other investments | Level 3
Assets:
Short-term and other investments	742	5,126
Recurring | Equity investments | Fair Value Measured at Net Asset Value Per Share | Investment in unconsolidated subsidiaries
Assets:
Total assets categorized within the fair value hierarchy	$ 246,143	$ 245,455

Fair Value Measurement (Quantit

Fair Value Measurement (Quantitative Information Regarding Level 3 Valuations) (Details) $ in Thousands	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Assets:
Estimated Fair Value	$ 3,544,137	$ 3,493,597
Other investments	246,143	245,455
Level 3
Assets:
Equity investments	5,234	5,237
Other investments	742	5,126
Liabilities:
Other liabilities	$ 6,500	6,500
Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Equity securities measured at fair value	0
Other investments, measurement input	0
Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Equity securities measured at fair value	0.10
Other investments, measurement input	0.10
Level 3 | Comparability Adjustment | Discounted Cash Flows | Weighted Average
Assets:
Equity securities measured at fair value	0.05
Other investments, measurement input	0.05
Level 3 | Weighted Average Cost of Capital | Stochastic Model/Discounted Cash Flows | Minimum
Liabilities:
Other liabilities, measurement input	0%
Level 3 | Weighted Average Cost of Capital | Stochastic Model/Discounted Cash Flows | Maximum
Liabilities:
Other liabilities, measurement input	10%
Level 3 | Weighted Average Cost of Capital | Stochastic Model/Discounted Cash Flows | Weighted Average
Liabilities:
Other liabilities, measurement input	8%
Corporate debt, limited observable inputs | Level 3
Assets:
Estimated Fair Value	$ 66,208	82,377
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Market Comparable Securities | Minimum
Assets:
Assets measured at fair value	0
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Market Comparable Securities | Maximum
Assets:
Assets measured at fair value	0.05
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Market Comparable Securities | Weighted Average
Assets:
Assets measured at fair value	0.025
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Assets measured at fair value	0
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Assets measured at fair value	0.05
Corporate debt, limited observable inputs | Level 3 | Comparability Adjustment | Discounted Cash Flows | Weighted Average
Assets:
Assets measured at fair value	0.025
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3
Assets:
Estimated Fair Value	$ 2,141	$ 4,414
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Minimum
Assets:
Assets measured at fair value	0
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Maximum
Assets:
Assets measured at fair value	0.05
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Weighted Average
Assets:
Assets measured at fair value	0.025
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Assets measured at fair value	0
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Assets measured at fair value	0.05
Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Weighted Average
Assets:
Assets measured at fair value	0.025

Fair Value Measurement (Level 3

Fair Value Measurement (Level 3 Assets and Liability) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 97,154	$ 71,513
Included in earnings, as a part of:
Included in earnings	$ 85	$ 13
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Operating expense		$ 0
Included in other comprehensive income (loss)	$ (199)	248
Purchases	3,401	8,185
Sales	(702)	(432)
Transfers in	0	12,999
Transfers out	(25,414)	(8,015)
Ending balance	74,325	84,511
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	$ 85	$ (3)
Fair Value Asset Recurring Basis Still Held Unrealized Gain Loss Statement Of Income Extensible List Not Disclosed Flag	Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (6,500)	$ (15,000)
Total gains (losses) realized and unrealized:
Net investment gains (losses)	0	1,000
Operating expense		1,000
Included in other comprehensive income (loss)	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	0	0
Ending balance	(6,500)
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	$ 0	$ 0
Net investment income (loss)
Included in earnings, as a part of:
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Net Investment Income
Net investment gains (losses)
Included in earnings, as a part of:
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain (Loss) on Investments
Corporate Debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 82,377	$ 63,973
Included in earnings, as a part of:
Included in earnings	0	16
Operating expense		0
Included in other comprehensive income (loss)	(171)	209
Purchases	2,201	6,322
Sales	(702)	(432)
Transfers in	0	11,220
Transfers out	(17,497)	(5,151)
Ending balance	66,208	76,157
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	0	0
Asset-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4,414	2,954
Included in earnings, as a part of:
Included in earnings	0	0
Operating expense		0
Included in other comprehensive income (loss)	(28)	39
Purchases	1,200	1,863
Sales	0	0
Transfers in	0	1,779
Transfers out	(3,445)	(1,581)
Ending balance	2,141	5,054
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	0	0
Equity Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5,237	2,803
Included in earnings, as a part of:
Included in earnings	(3)	(3)
Operating expense		0
Included in other comprehensive income (loss)	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	0	0
Ending balance	5,234	2,800
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	(3)	(3)
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5,126	1,783
Included in earnings, as a part of:
Included in earnings	88	0
Operating expense		0
Included in other comprehensive income (loss)	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	(4,472)	(1,283)
Ending balance	742	500
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	88	0
Other Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(6,500)	(15,000)
Total gains (losses) realized and unrealized:
Net investment gains (losses)	0	1,000
Operating expense		1,000
Included in other comprehensive income (loss)	0	0
Purchases	0	0
Sales	0	0
Transfers in	0	0
Transfers out	0	0
Ending balance	(6,500)	(13,000)
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	$ 0	$ 0

Fair Value Measurement (Investm

Fair Value Measurement (Investments in LLCs and Limited Partnerships) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) fund	Dec. 31, 2023 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 246,143	$ 245,455
Private debt funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners in investment | fund	2
Number of limited partners to allow redemption by special consent | fund	1
Private debt funds | Minimum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Liquidating investments remaining period	3 years
Private debt funds | Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Liquidating investments remaining period	8 years
Private debt funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Contractual Commitments	$ 4,565
Fair Value	$ 16,768	19,886
Long/short equity funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners in investment | fund	1
Payment period for redemption of LP valued at NAV	30 days
Long/short equity funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Contractual Commitments	$ 0
Fair Value	$ 4,243	4,497
Non-public equity funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners in investment | fund	2
Liquidating investments remaining period	10 years
Non-public equity funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Contractual Commitments	$ 38,970
Fair Value	$ 115,421	111,251
Credit funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners in investment | fund	2
Number of limited partners to allow redemption by special consent | fund	1
Investment redemption notice period	180 days
Number of limited partners to allow redemption by special consent of partner | fund	2
Credit funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Contractual Commitments	$ 31,552
Fair Value	$ 56,595	55,740
Strategy focused funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners not permitted for redemption | fund	3
Number of limited partners, redemption allowed with prior notice | fund	2
Strategy focused funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Contractual Commitments	$ 50,427
Fair Value	$ 53,116	$ 54,081

Fair Value Measurement (Narrati

Fair Value Measurement (Narrative) (Details)	Mar. 31, 2024 USD ($) subsidiary	Dec. 31, 2023 USD ($)
Credit Derivatives [Line Items]
Number of proassurance's insurance subsidiaries | subsidiary	3
Fair value of funded deferred compensation assets	$ 33,800,000	$ 32,300,000
Fair Value
Credit Derivatives [Line Items]
Deferred compensation liabilities	33,500,000	32,000,000
Fair Value, Nonrecurring
Credit Derivatives [Line Items]
Fair value, net asset (liability)	$ 0	$ 0

Fair Value Measurement (Financi

Fair Value Measurement (Financial Instruments Not Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Carrying Value
Financial assets:
Other assets	$ 34,824	$ 33,231
Financial liabilities:
Other liabilities	33,548	32,043
Carrying Value | Revolving Credit Facility
Financial liabilities:
Senior notes due 2023	125,000	125,000
Carrying Value | Term Loan
Financial liabilities:
Senior notes due 2023	125,000	125,000
Carrying Value | Contribution Certificates
Financial liabilities:
Contribution Certificates	179,865	179,387
Carrying Value | BOLI
Financial assets:
Short-term and other investments	78,657	78,205
Carrying Value | Other investments
Financial assets:
Short-term and other investments	4,064	3,215
Fair Value
Financial assets:
Other assets	34,824	33,221
Financial liabilities:
Other liabilities	33,548	32,043
Fair Value | Revolving Credit Facility
Financial liabilities:
Senior notes due 2023	125,000	125,000
Fair Value | Term Loan
Financial liabilities:
Senior notes due 2023	125,000	125,000
Fair Value | Contribution Certificates
Financial liabilities:
Contribution Certificates	147,328	149,782
Fair Value | BOLI
Financial assets:
Short-term and other investments	78,657	78,205
Fair Value | Other investments
Financial assets:
Short-term and other investments	$ 4,064	$ 3,215

Investments (Available-For-Sale

Investments (Available-For-Sale Fixed Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 3,813,857	$ 3,758,720
Allowance for Expected Credit Losses	1,137	555	$ 424	$ 427
Gross Unrealized Gains	7,343	10,122
Gross Unrealized Losses	275,926	274,690
Estimated Fair Value	3,544,137	3,493,597
U.S. Treasury obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	258,462	259,834
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	24	165
Gross Unrealized Losses	17,597	16,474
Estimated Fair Value	240,889	243,525
U.S. Government-sponsored enterprise obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	19,957	19,752
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	0	2
Gross Unrealized Losses	1,030	1,030
Estimated Fair Value	18,927	18,724
State and municipal bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	502,549	482,367
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	1,736	1,885
Gross Unrealized Losses	30,020	29,871
Estimated Fair Value	474,265	454,381
Corporate debt
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,849,162	1,883,308
Allowance for Expected Credit Losses	740	0
Gross Unrealized Gains	2,421	4,025
Gross Unrealized Losses	136,791	136,759
Estimated Fair Value	1,714,052	1,750,574
Residential mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	507,312	481,267
Allowance for Expected Credit Losses	207	211	$ 227	$ 229
Gross Unrealized Gains	2,020	2,876
Gross Unrealized Losses	59,073	53,795
Estimated Fair Value	450,052	430,137
Agency commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	8,964	9,369
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	0	5
Gross Unrealized Losses	1,014	987
Estimated Fair Value	7,950	8,387
Other commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	248,756	210,469
Allowance for Expected Credit Losses	0	151
Gross Unrealized Gains	221	60
Gross Unrealized Losses	19,948	20,904
Estimated Fair Value	229,029	189,474
Other asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	418,695	412,354
Allowance for Expected Credit Losses	190	193
Gross Unrealized Gains	921	1,104
Gross Unrealized Losses	10,453	14,870
Estimated Fair Value	$ 408,973	$ 398,395

Investments (Available-For-Sa_2

Investments (Available-For-Sale Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 3,813,857	$ 3,758,720
Total Fair Value	3,544,137	3,493,597
U.S. Treasury obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	258,462	259,834
Due in one year or less	36,249
Due after one year through five years	169,651
Due after five years through ten years	32,387
Due after ten years	2,602
Total Fair Value	240,889	243,525
U.S. Government-sponsored enterprise obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	19,957	19,752
Due in one year or less	4,790
Due after one year through five years	11,653
Due after five years through ten years	505
Due after ten years	1,979
Total Fair Value	18,927	18,724
State and municipal bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	502,549	482,367
Due in one year or less	30,409
Due after one year through five years	157,707
Due after five years through ten years	161,274
Due after ten years	124,875
Total Fair Value	474,265	454,381
Corporate debt
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,849,162	1,883,308
Due in one year or less	179,206
Due after one year through five years	886,529
Due after five years through ten years	569,033
Due after ten years	79,284
Total Fair Value	1,714,052	1,750,574
Residential mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	507,312	481,267
Total Fair Value	450,052	430,137
Agency commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	8,964	9,369
Total Fair Value	7,950	8,387
Other commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	248,756	210,469
Total Fair Value	229,029	189,474
Other asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	418,695	412,354
Total Fair Value	$ 408,973	$ 398,395

Investments (Narrative) (Detail

Investments (Narrative) (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) investment security issuer business	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) security issuer
Debt Securities, Available-for-Sale [Line Items]
Number of investment in any entity or affiliates greater than 10% of stockholders' equity | investment	0
Threshold limit of investments based on shareholders' equity	10%
Securities on deposit with state insurance departments	$ 53,500,000
Number of LPs / LLCs with investment ownership percent over 25% (in businesses) | business	4
Investment in unconsolidated subsidiaries	$ 278,931,000		$ 276,756,000
Net impairment losses recognized in earnings	(934,000)	$ (2,933,000)
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	576,000	$ 0
Asset Pledged as Collateral
Debt Securities, Available-for-Sale [Line Items]
Securities on deposit with state insurance departments	70,600,000
Tax Year 2019
Debt Securities, Available-for-Sale [Line Items]
Tax credit carryforwards	$ 52,700,000
Tax Credit Partnerships Less Than 20% Ownership | Maximum
Debt Securities, Available-for-Sale [Line Items]
Investment ownership percentage	20%
Other Limited Partnerships and Limited Liability Company, Greater Than 25% Ownership
Debt Securities, Available-for-Sale [Line Items]
Investment ownership percentage	25%
Investment in unconsolidated subsidiaries	$ 24,000,000		23,000,000
Other Limited Partnerships and Limited Liability Company Less than 25% Ownership
Debt Securities, Available-for-Sale [Line Items]
Investment in unconsolidated subsidiaries	$ 254,400,000		$ 253,100,000
Non government-backed
Debt Securities, Available-for-Sale [Line Items]
Debt securities in unrealized loss position (in securities) | security	2,545		2,531
Debt securities in unrealized loss position as percentage of total debt securities held	64.80%		65.60%
Issuers in unrealized loss position (in issuers) | issuer	1,328		1,319
Single greatest unrealized loss position	$ 5,300,000		$ 5,000,000
Second greatest unrealized loss position	$ 3,300,000		$ 3,200,000

Investments (Investments Held i

Investments (Investments Held in a Loss Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair value
Fair Value	$ 2,942,293	$ 2,934,215
Less than 12 months, Fair Value	958,097	293,116
12 months or longer, Fair Value	1,984,196	2,641,099
Unrealized Loss
Unrealized Loss	275,926	274,690
Less than 12 months, Unrealized Loss	75,300	21,226
12 months or longer, Unrealized Loss	200,626	253,464
U.S. Treasury obligations
Fair value
Fair Value	226,103	213,634
Less than 12 months, Fair Value	40,747	32,925
12 months or longer, Fair Value	185,356	180,709
Unrealized Loss
Unrealized Loss	17,597	16,474
Less than 12 months, Unrealized Loss	1,412	1,364
12 months or longer, Unrealized Loss	16,185	15,110
U.S. Government-sponsored enterprise obligations
Fair value
Fair Value	18,928	18,428
Less than 12 months, Fair Value	10,631	4,128
12 months or longer, Fair Value	8,297	14,300
Unrealized Loss
Unrealized Loss	1,030	1,030
Less than 12 months, Unrealized Loss	486	242
12 months or longer, Unrealized Loss	544	788
State and municipal bonds
Fair value
Fair Value	389,539	378,313
Less than 12 months, Fair Value	98,395	48,960
12 months or longer, Fair Value	291,144	329,353
Unrealized Loss
Unrealized Loss	30,020	29,871
Less than 12 months, Unrealized Loss	5,941	2,287
12 months or longer, Unrealized Loss	24,079	27,584
Corporate debt
Fair value
Fair Value	1,498,062	1,524,940
Less than 12 months, Fair Value	459,157	84,221
12 months or longer, Fair Value	1,038,905	1,440,719
Unrealized Loss
Unrealized Loss	136,791	136,759
Less than 12 months, Unrealized Loss	38,451	5,054
12 months or longer, Unrealized Loss	98,340	131,705
Residential mortgage-backed securities
Fair value
Fair Value	335,297	313,082
Less than 12 months, Fair Value	130,058	74,463
12 months or longer, Fair Value	205,239	238,619
Unrealized Loss
Unrealized Loss	59,073	53,795
Less than 12 months, Unrealized Loss	16,800	10,271
12 months or longer, Unrealized Loss	42,273	43,524
Agency commercial mortgage-backed securities
Fair value
Fair Value	7,950	7,955
Less than 12 months, Fair Value	2,652	212
12 months or longer, Fair Value	5,298	7,743
Unrealized Loss
Unrealized Loss	1,014	987
Less than 12 months, Unrealized Loss	344	1
12 months or longer, Unrealized Loss	670	986
Other commercial mortgage-backed securities
Fair value
Fair Value	214,030	184,416
Less than 12 months, Fair Value	90,586	18,092
12 months or longer, Fair Value	123,444	166,324
Unrealized Loss
Unrealized Loss	19,948	20,904
Less than 12 months, Unrealized Loss	8,120	1,140
12 months or longer, Unrealized Loss	11,828	19,764
Other asset-backed securities
Fair value
Fair Value	252,384	293,447
Less than 12 months, Fair Value	125,871	30,115
12 months or longer, Fair Value	126,513	263,332
Unrealized Loss
Unrealized Loss	10,453	14,870
Less than 12 months, Unrealized Loss	3,746	867
12 months or longer, Unrealized Loss	$ 6,707	$ 14,003

Investments (Credit Losses Rela

Investments (Credit Losses Related to Debt Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	$ 555	$ 427
No allowance for credit losses has been previously recognized	740
Securities sold during the period	(158)	(3)
Allowance for credit loss ending balance	1,137	424
Corporate Debt
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	0
No allowance for credit losses has been previously recognized	740
Securities sold during the period	0
Allowance for credit loss ending balance	740
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	211	229
No allowance for credit losses has been previously recognized	0
Securities sold during the period	(4)	(2)
Allowance for credit loss ending balance	207	227
Other commercial mortgage-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	151
No allowance for credit losses has been previously recognized	0
Securities sold during the period	(151)
Allowance for credit loss ending balance	0
Other asset-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	193	198
No allowance for credit losses has been previously recognized	0
Securities sold during the period	(3)	(1)
Allowance for credit loss ending balance	$ 190	$ 197

Investments (Sales and Purchase

Investments (Sales and Purchases of Available-for-Sale Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales (exclusive of maturities and paydowns)	$ 17,100	$ 3,800
Purchases	$ 230,549	$ 68,755

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income
Investment fees and expenses	$ (2,309)	$ (1,831)
Net investment income	33,897	30,310
Fixed maturities
Net Investment Income
Interest and dividend income, operating	31,451	27,327
Equities
Net Investment Income
Interest and dividend income, operating	892	807
Short-term investments, including Other
Net Investment Income
Interest and dividend income, operating	3,411	3,350
BOLI
Net Investment Income
BOLI	$ 452	$ 657

Investments (Unconsolidated Sub

Investments (Unconsolidated Subsidiaries) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	$ 278,931	$ 276,756
Qualified affordable housing project tax credit partnerships
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	562	666
All other investments, primarily investment fund LPs/LLCs
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	$ 278,369	$ 276,090

Investments (Equity in Earnings

Investments (Equity in Earnings (Loss) of Unconsolidated Subsidiaries) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Losses recorded	$ 103	$ 354
Tax credits recognized	$ 8	$ 43

Investments (Net Realized Inves

Investments (Net Realized Investment Gains (Losses)) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	$ (1,510,000)	$ (2,933,000)
Corporate debt	576,000	0
Net impairment losses recognized in earnings	(934,000)	(2,933,000)
Gross realized gains, available-for-sale fixed maturities	366,000	79,000
Gross realized (losses), available-for-sale fixed maturities	(1,099,000)	(457,000)
Net realized gains (losses), trading fixed maturities	15,000	(108,000)
Net realized gains (losses), equity investments	(256,000)	84,000
Net realized gains (losses), other investments	1,776,000	229,000
Change in unrealized holding gains (losses), trading fixed maturities	214,000	97,000
Change in unrealized holding gains (losses), equity investments	774,000	3,746,000
Change in unrealized holding gains (losses), convertible securities, carried at fair value	(1,119,000)	1,132,000
Other	(5,000)	1,043,000
Total net investment gains (losses)	(268,000)	2,912,000
NORCAL Group
Debt Securities, Available-for-Sale [Line Items]
Gain on fair value of contingent consideration		1,000,000
Corporate Debt
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	(1,316,000)	(2,936,000)
Asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	$ (194,000)	$ 3,000

Investments (Roll Forward of Cu

Investments (Roll Forward of Cumulative Credit Losses Recorded in Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance beginning of period	$ 57	$ 57
No impairment has been previously recognized	740	0
Balance ending of period	$ 797	$ 57

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Decrease in contingent consideration liability	$ 2
Income taxes payable	3	$ 4
Unrecognized tax benefits	5.4	5.3
Accrued liability for interest related to unrecognized tax benefits	$ 0.6	$ 0.5

Reserve for Losses and Loss A_3

Reserve for Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Liability for Claims and Claims Adjustment Expense [Line Items]
Minimum period for claims resolution	5 years
Summary of reserve for losses and loss adjustment expenses
Balance, beginning of year	$ 3,401,281	$ 3,471,147	$ 3,471,147
Less reinsurance recoverables on unpaid losses and loss adjustment expenses	445,573	431,889	431,889
Net balance, beginning of year	2,955,708	3,039,258	3,039,258
Net losses:
Current year	195,110	198,240	794,848
(Favorable) unfavorable development of reserves established in prior years, net	(416)	7,056	5,646
Total	194,694	205,296	800,494
Paid related to:
Current year	(12,867)	(11,052)	(101,996)
Prior years	(202,180)	(211,916)	(782,048)
Total paid	(215,047)	(222,968)	(884,044)
Net balance, end of period	2,935,355	3,021,586	2,955,708
Plus reinsurance recoverables on unpaid losses and loss adjustment expenses	447,157	447,693	445,573
Balance, end of period	3,382,512	3,469,279	3,401,281
Net unfavorable prior year reserve development	900
Net unfavorable reserve development attributable to parent	400
Net favorable development in workers' compensation business	500
Net unfavorable development medical professional liability business	1,400
NORCAL Group
Net losses:
Current year	1,700
(Favorable) unfavorable development of reserves established in prior years, net	$ 1,700	$ 2,500	$ 8,300

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Other Commitments [Line Items]
Period to advance funds	30 days
NORCAL Group
Other Commitments [Line Items]
Contingent consideration, maximum estimate	$ 84
Fair value of contingent consideration in NORCAL acquisition	(6.5)		$ (6.5)
Data Analytics Services
Other Commitments [Line Items]
Annual fee	$ 3.5
Purchase commitment, period	3 years
Extension period for long-term purchase commitment	1 year
Non-renew notice, period	6 months
Operating expense	$ 0.8	$ 0.9
Purchase obligation	2.2
Funding Commitments
Other Commitments [Line Items]
Commitments total	161.9
Lloyd's Syndicates
Other Commitments [Line Items]
Required FAL deposit	$ 20.2

Debt (Details)

Debt (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Gross debt	$ 429,865,000	$ 429,387,000
Less unamortized debt issuance costs	2,091,000	2,254,000
Debt less unamortized debt issuance costs	427,774,000	427,133,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Gross debt	$ 125,000,000	125,000,000
Stated interest rate on debt	7.53%
Line of credit, borrowing capacity including accordion feature	$ 300,000,000
Accordion feature borrowing capacity	50,000,000
Contribution Certificates
Debt Instrument [Line Items]
Gross debt	$ 179,865,000	179,387,000
Stated interest rate on debt	3%
Effective interest rate on debt	4.35%
Term Loan
Debt Instrument [Line Items]
Gross debt	$ 125,000,000	$ 125,000,000
Term Loan | Line of Credit
Debt Instrument [Line Items]
Effective interest rate on debt	7.65%

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) derivative_instrument	Dec. 31, 2023 USD ($)
Derivative [Line Items]
Number of instruments (in derivative instruments) | derivative_instrument	2
Interest Rate Swaps
Derivative [Line Items]
Interest rate swaps	$ 9.1	$ 4
Expected gains reclassified	4.3
Revolving Credit Agreement | Interest Rate Swaps
Derivative [Line Items]
Derivative, notional amount	125
Term Loan | Interest Rate Swaps
Derivative [Line Items]
Derivative, notional amount	$ 125
Line of Credit | Revolving Credit Agreement
Derivative [Line Items]
Basis spread on variable rate for debt	2.23%	5.42%
Line of Credit | Revolving Credit Agreement | Secured Overnight Financing Rate (SOFR)
Derivative [Line Items]
Derivative, fixed interest rate	3.187%
Line of Credit | Term Loan
Derivative [Line Items]
Basis spread on variable rate for debt	2.35%	5.56%
Line of Credit | Term Loan | Secured Overnight Financing Rate (SOFR)
Derivative [Line Items]
Derivative, fixed interest rate	3.207%
Line of Credit | Minimum | Revolving Credit Agreement
Derivative [Line Items]
Basis spread on variable rate for debt	0%
Line of Credit | Maximum | Term Loan
Derivative [Line Items]
Basis spread on variable rate for debt	2.375%

Derivatives (Volume and Fair Va

Derivatives (Volume and Fair Value) (Details) $ in Thousands	Mar. 31, 2024 USD ($) derivative_instrument	Dec. 31, 2023 USD ($) derivative_instrument
Derivative [Line Items]
Number of instruments (in derivative instruments) | derivative_instrument	2
Interest Rate Swaps | Cash Flow Hedging
Derivative [Line Items]
Number of instruments (in derivative instruments) | derivative_instrument	2	2
Aggregate Notional Amount | $	$ 250,000	$ 250,000
Estimated fair value | $	$ 7,674	$ 3,876

Derivatives (Schedule of Deriva

Derivatives (Schedule of Derivative Instruments, Gain (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Interest Rate Swaps | Interest Expense
Derivative [Line Items]
Qualifying Cash Flow Hedges - Gains (Losses) Reclassified from AOCI, net of tax, to Earnings	$ 1,073	$ 0

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Equity [Abstract]
Common shares, shares authorized (in shares)	100,000,000		100,000,000
Preferred stock, shares authorized (in shares)	50,000,000		50,000,000
Cash dividends declared per common share (in usd per share)	$ 0	$ 0.05
Dividend declared		$ 2.7
Total authorizations which remain available for use	$ 55.9
Deferred tax (benefit) expense included in OCI		$ 10.8

Shareholders' Equity (Roll Forw

Shareholders' Equity (Roll Forward of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,111,980	$ 1,104,018
OCI, before reclassifications, net of tax	(2,720)	40,007
Amounts reclassified from AOCI, net of tax	248	2,622
Net OCI, current period	(2,472)	42,629
Ending balance	1,113,065	1,138,290
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(204,489)	(298,607)
Ending balance	(206,961)	(255,978)
Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(206,327)	(297,142)
OCI, before reclassifications, net of tax	(6,339)	40,007
Amounts reclassified from AOCI, net of tax	1,321	2,622
Net OCI, current period	(5,018)	42,629
Ending balance	(211,345)	(254,513)
Cash Flow Hedging Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	3,026
OCI, before reclassifications, net of tax	4,074
Amounts reclassified from AOCI, net of tax	(1,073)
Net OCI, current period	3,001
Ending balance	6,027
Non-credit Impairments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11)	(11)
OCI, before reclassifications, net of tax	(455)	0
Amounts reclassified from AOCI, net of tax	0	0
Net OCI, current period	(455)	0
Ending balance	(466)	(11)
Unrecognized Change in Defined Benefit Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,177)	(1,454)
OCI, before reclassifications, net of tax	0	0
Amounts reclassified from AOCI, net of tax	0	0
Net OCI, current period	0	0
Ending balance	$ (1,177)	$ (1,454)

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
VIEs carrying value	$ 5,650,036	$ 5,631,925
Liabilities	4,536,971	4,519,945
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIEs carrying value	252,900	250,400
Variable Interest Entity, Primary Beneficiary | PPM RRG
Variable Interest Entity [Line Items]
VIEs carrying value	135,000	142,000
Surplus notes	5,000
Liabilities	$ 135,000	$ 142,000

Earnings (Loss) Per Share (Earn

Earnings (Loss) Per Share (Earnings Per Share) (Details) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average number of common shares outstanding, basic (in shares)	51,013	53,987
Weighted average number of common shares outstanding, diluted (in shares)	51,149	54,117
Effect of dilutive shares on earnings (loss) per share (in usd per share)	$ 0	$ 0
Antidilutive shares excluded from computation of earnings per share (in shares)	251
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect of securities (in shares)	112	103
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect of securities (in shares)	24	27

Segment Information (Narrative)

Segment Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2024 employee segment
Segment Reporting [Abstract]
Number of operating segments	4
Number of reportable segments	4
Number of employees | employee	1,000

Segment Information (Financial

Segment Information (Financial Data by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Net premiums earned	$ 244,150	$ 239,787
Net investment income	33,897	30,310
Equity in earnings (loss) of unconsolidated subsidiaries	2,963	(1,121)
Net investment gains (losses)	(268)	1,912
Other income (expense)	3,955	787
Net losses and loss adjustment expenses	(194,694)	(205,296)
Underwriting, policy acquisition and operating expenses	(78,005)	(67,788)
SPC U.S. federal income tax benefit (expense)	(416)	(532)
SPC dividend (expense) income	(607)	(1,942)
Interest expense	(5,657)	(5,463)
Income tax benefit (expense)	(692)	2,172
Segment results	4,626	(7,174)
Contingent consideration	0	(2,000)
Net income (loss)	4,626	(6,174)
Depreciation and amortization, net of accretion	5,332	7,677
Operating segments | Specialty P&C
Segment Reporting Information [Line Items]
Net premiums earned	188,888	183,684
Net investment income	0	0
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Net investment gains (losses)	0	0
Other income (expense)	1,353	990
Net losses and loss adjustment expenses	(152,994)	(166,029)
Underwriting, policy acquisition and operating expenses	(51,049)	(42,681)
SPC U.S. federal income tax benefit (expense)	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	(13,802)	(24,036)
Depreciation and amortization, net of accretion	2,429	2,640
Operating segments | Workers' Compensation Insurance
Segment Reporting Information [Line Items]
Net premiums earned	41,094	40,803
Net investment income	0	0
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Net investment gains (losses)	0	0
Other income (expense)	477	581
Net losses and loss adjustment expenses	(31,636)	(30,844)
Underwriting, policy acquisition and operating expenses	(14,490)	(12,980)
SPC U.S. federal income tax benefit (expense)	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	(4,555)	(2,440)
Depreciation and amortization, net of accretion	1,164	869
Operating segments | Segregated Portfolio Cell Reinsurance
Segment Reporting Information [Line Items]
Net premiums earned	14,168	15,300
Net investment income	693	420
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Net investment gains (losses)	1,471	1,160
Other income (expense)	(1)	1
Net losses and loss adjustment expenses	(10,064)	(8,423)
Underwriting, policy acquisition and operating expenses	(4,713)	(5,035)
SPC U.S. federal income tax benefit (expense)	(416)	(532)
SPC dividend (expense) income	(607)	(1,942)
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	531	949
Depreciation and amortization, net of accretion	(370)	64
Operating segments | Corporate
Segment Reporting Information [Line Items]
Net premiums earned	0	0
Net investment income	33,204	29,890
Equity in earnings (loss) of unconsolidated subsidiaries	2,963	(1,121)
Net investment gains (losses)	(1,739)	752
Other income (expense)	3,061	327
Net losses and loss adjustment expenses	0	0
Underwriting, policy acquisition and operating expenses	(8,688)	(8,204)
SPC U.S. federal income tax benefit (expense)	0	0
SPC dividend (expense) income	0	0
Interest expense	(5,657)	(5,463)
Income tax benefit (expense)	(692)	2,172
Segment results	22,452	18,353
Depreciation and amortization, net of accretion	2,109	4,104
Inter-segment Eliminations
Segment Reporting Information [Line Items]
Net premiums earned	0	0
Net investment income	0	0
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Net investment gains (losses)	0	0
Other income (expense)	(935)	(1,112)
Net losses and loss adjustment expenses	0	0
Underwriting, policy acquisition and operating expenses	935	1,112
SPC U.S. federal income tax benefit (expense)	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	0	0
Depreciation and amortization, net of accretion	$ 0	0
Segment reconciling items
Segment Reporting Information [Line Items]
Contingent consideration		$ 1,000

Segment Information (Gross Prem

Segment Information (Gross Premiums Earned and Reconciliation to Net Premiums) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Segment net premiums earned	$ 244,150	$ 239,787
Specialty P&C Segment | Operating segments
Segment Reporting Information [Line Items]
Ceded premiums earned	(17,739)	(20,369)
Segment net premiums earned	188,888	183,684
Specialty P&C Segment | MPL | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	184,744	181,800
Specialty P&C Segment | Medical Technology Liability | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	10,938	10,546
Specialty P&C Segment | Lloyd's Syndicates | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	4,934	5,046
Specialty P&C Segment | Other | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	6,011	6,661
Workers' Compensation Insurance Segment | Operating segments
Segment Reporting Information [Line Items]
Ceded premiums earned	(20,445)	(20,363)
Segment net premiums earned	41,094	40,803
Workers' Compensation Insurance Segment | Traditional business | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	44,376	43,540
Workers' Compensation Insurance Segment | Alternative market business | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	17,163	17,626
Segregated Portfolio Cell Reinsurance Segment | Operating segments
Segment Reporting Information [Line Items]
Ceded premiums earned	(2,242)	(2,303)
Segment net premiums earned	14,168	15,300
Segregated Portfolio Cell Reinsurance Segment | MPL | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	543	1,299
Segregated Portfolio Cell Reinsurance Segment | Workers' compensation | Operating segments
Segment Reporting Information [Line Items]
Gross premiums earned:	$ 15,867	$ 16,304