ProAssurance (PRA) 10-Q 9 May 23 2023 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2023	May 04, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
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)		54,027,685
Entity Central Index Key	0001127703
Amendment Flag	false
Document Fiscal Year Focus	2023
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, 2023	Dec. 31, 2022
Investments
Fixed maturities, available-for-sale, at fair value (amortized cost, $3,796,870 and $3,852,411, respectively; allowance for expected credit losses, $424 as of March 31, 2023 and $427 as of December 31, 2022)	$ 3,470,027	$ 3,472,472
Fixed maturities, trading, at fair value (cost, $45,869 and $45,048, respectively)	44,818	43,434
Equity investments, at fair value (cost, $161,814 and $162,429, respectively)	146,868	143,738
Short-term investments	251,027	245,313
Business owned life insurance	82,402	81,746
Investment in unconsolidated subsidiaries	297,537	305,210
Other investments (at fair value, $85,938 and $92,447, respectively, otherwise at cost or amortized cost)	88,969	95,770
Total Investments	4,381,648	4,387,683
Cash and cash equivalents	56,434	29,959
Premiums receivable (allowance for expected credit losses, $7,897 as of March 31, 2023 and $7,658 as of December 31, 2022)	266,631	246,094
Receivable from reinsurers on paid losses and loss adjustment expenses	14,370	15,313
Receivable from reinsurers on unpaid losses and loss adjustment expenses	447,693	431,889
Prepaid reinsurance premiums	34,662	29,120
Deferred policy acquisition costs	63,978	58,148
Deferred tax asset, net	202,056	209,535
Real estate, net	30,435	29,968
Operating lease ROU assets	17,992	18,987
Intangible assets, net	65,203	66,835
Goodwill	49,610	49,610
Other assets	117,151	126,858
Total Assets	5,747,863	5,699,999
Policy liabilities and accruals
Reserve for losses and loss adjustment expenses	3,469,279	3,471,147
Unearned premiums	473,696	422,950
Reinsurance premiums payable	26,370	28,514
Total Policy Liabilities and Accruals	3,969,345	3,922,611
Operating lease liabilities	18,969	20,008
Other liabilities	193,733	226,379
Debt less unamortized debt issuance costs	427,526	426,983
Total Liabilities	4,609,573	4,595,981
Shareholders' Equity
Common shares (par value $0.01 per share, 100,000,000 shares authorized, 63,491,323 and 63,427,796 shares issued, respectively)	635	634
Additional paid-in capital	398,436	397,919
Accumulated other comprehensive income (loss) (net of deferred tax expense (benefit) of ($70,025) and ($80,810), respectively)	(255,978)	(298,607)
Retained earnings	1,414,411	1,423,286
Treasury shares, at cost (9,464,160 shares as of each respective period end)	(419,214)	(419,214)
Total Shareholders' Equity	1,138,290	1,104,018
Total Liabilities and Shareholders' Equity	$ 5,747,863	$ 5,699,999

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 3,796,870	$ 3,852,411
Allowance for expected credit losses	424	427
Trading securities, cost	45,869	45,048
Equity investments at fair value, cost	161,814	162,429
Other investments, portion carried at fair value	85,938	92,447
Premium receivable, allowance for credit loss	$ 7,897	$ 7,658
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)	63,491,323	63,427,796
Deferred tax expense (benefit) on accumulated other comprehensive income (loss)	$ (70,025)	$ (80,810)
Treasury shares (in shares)	9,464,160	9,464,160

Condensed Consolidated Statemen

Condensed Consolidated Statements of Changes in Capital (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Increase (Decrease) in Stockholders' Equity:
Beginning balance	$ 1,104,018	$ 1,428,387
Common shares issued for compensation	10	7
Share-based compensation	1,146	1,342
Net effect of restricted and performance shares issued	(638)	(856)
Dividends to shareholders	(2,701)	(2,702)
Other comprehensive income (loss)	42,629	(140,850)
Net income (loss)	(6,174)	(3,560)
Ending balance	1,138,290	1,281,768
Common Stock
Increase (Decrease) in Stockholders' Equity:
Beginning balance	634	633
Net effect of restricted and performance shares issued	1	1
Ending balance	635	634
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity:
Beginning balance	397,919	392,941
Common shares issued for compensation	10	7
Share-based compensation	1,146	1,342
Net effect of restricted and performance shares issued	(639)	(857)
Ending balance	398,436	393,433
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity:
Beginning balance	(298,607)	16,284
Other comprehensive income (loss)	42,629	(140,850)
Ending balance	(255,978)	(124,566)
Retained Earnings
Increase (Decrease) in Stockholders' Equity:
Beginning balance	1,423,286	1,434,491
Dividends to shareholders	(2,701)	(2,702)
Net income (loss)	(6,174)	(3,560)
Ending balance	1,414,411	1,428,229
Treasury Stock
Increase (Decrease) in Stockholders' Equity:
Beginning balance	(419,214)	(415,962)
Ending balance	$ (419,214)	$ (415,962)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues
Net premiums earned	$ 239,787	$ 265,711
Net investment income	30,310	20,443
Equity in earnings (loss) of unconsolidated subsidiaries	(1,121)	7,620
Net investment gains (losses):
Impairment losses	2,933	0
Portion of impairment losses recognized in other comprehensive income (loss) before taxes	0	0
Net impairment losses recognized in earnings	2,933	0
Other net investment gains (losses)	5,845	(13,506)
Total net investment gains (losses)	2,912	(13,506)
Other income	787	2,804
Total revenues	272,675	283,072
Expenses
Net losses and loss adjustment expenses	205,296	209,423
Underwriting, policy acquisition and operating expenses:
Operating expense	35,084	38,810
DPAC amortization	32,704	32,966
SPC U.S. federal income tax expense	532	642
SPC dividend expense (income)	1,942	2,367
Interest expense	5,463	4,441
Total expenses	281,021	288,649
Income (loss) before income taxes	(8,346)	(5,577)
Provision for income taxes:
Current expense (benefit)	458	(607)
Deferred expense (benefit)	(2,630)	(1,410)
Total income tax expense (benefit)	(2,172)	(2,017)
Net income (loss)	(6,174)	(3,560)
Other comprehensive income (loss), after tax, net of reclassification adjustments	42,629	(140,850)
Comprehensive income (loss)	$ 36,455	$ (144,410)
Earnings (loss) per share:
Basic (in usd per share)	$ (0.11)	$ (0.07)
Diluted (in usd per share)	$ (0.11)	$ (0.07)
Weighted average number of common shares outstanding:
Basic (in shares)	53,987	54,012
Diluted (in shares)	54,117	54,143
Cash dividends declared per common share (in usd per share)	$ 0.05	$ 0.05

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating Activities
Net income (loss)	$ (6,174)	$ (3,560)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization, net of accretion	7,677	10,350
(Increase) decrease in cash surrender value of BOLI	(656)	888
Net investment (gains) losses	(2,912)	13,506
Share-based compensation	1,146	1,343
Deferred income tax expense (benefit)	(2,630)	(1,410)
Policy acquisition costs, net of amortization (net deferral)	(5,830)	(6,551)
Equity in (earnings) loss of unconsolidated subsidiaries	1,121	(7,620)
Distributed earnings from unconsolidated subsidiaries	3,176	14,176
Other, net	(35)	(1,056)
Change in:
Premiums receivable	(20,537)	(19,834)
Reinsurance related assets and liabilities	(22,547)	(18,113)
Other assets	163	12,367
Reserve for losses and loss adjustment expenses	(1,868)	23,306
Unearned premiums	50,746	52,732
Other liabilities	(30,683)	(56,259)
Net cash provided (used) by operating activities	(29,843)	14,265
Purchases of:
Fixed maturities, available-for-sale	(68,755)	(231,557)
Equity investments	(170)	(28,129)
Other investments	(11,749)	(12,757)
Investment in unconsolidated subsidiaries	(9,381)	(9,685)
Proceeds from sales or maturities of:
Fixed maturities, available-for-sale	119,447	176,820
Equity investments	868	27,305
Other investments	18,338	9,205
Net sales or (purchases) of fixed maturities, trading	(1,395)	(6,119)
Return of invested capital from unconsolidated subsidiaries	12,756	17,302
Net sales or maturities (purchases) of short-term investments	(5,432)	(16,632)
Unsettled security transactions, net change	3,407	(2,076)
Purchases of capital assets	(930)	(811)
Other	2,659	0
Net cash provided (used) by investing activities	59,663	(77,134)
Financing Activities
Dividends to shareholders	(2,688)	(2,691)
Capital contribution received from (return of capital to) external segregated portfolio cell participants	(18)	(5,085)
Other	(639)	(856)
Net cash provided (used) by financing activities	(3,345)	(8,632)
Increase (decrease) in cash and cash equivalents	26,475	(71,501)
Cash and cash equivalents at beginning of period	29,959	143,602
Cash and cash equivalents at end of period	56,434	72,101
Significant Non-Cash Transactions
Dividends declared and not yet paid	2,701	2,702
Increase (decrease) in fair value of contingent consideration issued in NORCAL acquisition	$ (2,000)	$ 0

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2023
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 9 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, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes contained in ProAssurance’s December 31, 2022 report on Form 10-K. ProAssurance operates in five reportable segments as follows: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance, Lloyd's Syndicates 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 11. 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, 2022 report on Form 10-K. Accounting Changes Adopted Reference Rate Reform - Deferral of LIBOR Sunset Date (ASU 2022-06) Effective for fiscal years beginning after December 31, 2022 and interim periods within those fiscal years, the FASB amended guidance which defers the LIBOR transition date from December 31, 2022 to December 31, 2024. ProAssurance has exposure to LIBOR in its available-for-sale fixed maturities portfolio which represented approximately 6% of total investments, or $246 million as of March 31, 2023; 63% of these investments with exposure to LIBOR were issued since 2020 and include provisions for an alternative benchmark rate. ProAssurance adopted the guidance beginning January 1, 2023, and adoption had no material effect on ProAssurance's results of operations, financial position or cash flows. Accounting Changes Not Yet Adopted ProAssurance is not aware of any accounting changes not yet adopted as of March 31, 2023 that could have a material impact on its results of operations, financial position or cash flows. Employee Retention Credit In response to COVID-19, the CARES Act was signed into law on March 27, 2020 and contains several provisions for corporations, including the initial version of the ERC. In December 2020 and March 2021, the ERC was extended and expanded from 50% of qualified wages to 70%. The 2020 rules limited qualified wages to $10,000 per employee and applied to employers with 100 or fewer full-time employees in 2019. The rules were expanded in 2021 to raise the qualified wage limit to $10,000 per employee, per quarter. As an eligible employer, NORCAL expects to file a claim during 2023 for a payroll tax refund of approximately $3.8 million. The Company recorded the expected payroll tax refund as a component of operating expenses on the Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and as a component of other assets on the Condensed Consolidated Balance Sheets as of March 31, 2023.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2023
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, 2023 and December 31, 2022 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 3 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2022 report on Form 10-K. March 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 $ — $ 233,026 $ — $ 233,026 U.S. Government-sponsored enterprise obligations — 19,147 — 19,147 State and municipal bonds — 450,220 — 450,220 Corporate debt, multiple observable inputs — 1,675,524 — 1,675,524 Corporate debt, limited observable inputs — — 76,157 76,157 Residential mortgage-backed securities — 391,834 289 392,123 Agency commercial mortgage-backed securities — 9,607 — 9,607 Other commercial mortgage-backed securities — 197,146 — 197,146 Other asset-backed securities — 412,312 4,765 417,077 Fixed maturities, trading — 44,818 — 44,818 Equity investments Financial 9,924 2,232 300 12,456 Utilities/Energy 956 — — 956 Industrial — — 2,500 2,500 Bond funds 114,618 — — 114,618 All other 16,338 — — 16,338 Short-term investments 156,871 94,156 — 251,027 Other investments 1,914 83,524 500 85,938 Total assets categorized within the fair value hierarchy $ 300,621 $ 3,613,546 $ 84,511 3,998,678 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 259,530 Total assets at fair value $ 4,258,208 Liabilities: Other liabilities $ — $ — $ 13,000 $ 13,000 Total liabilities categorized within the fair value hierarchy $ — $ — $ 13,000 $ 13,000 December 31, 2022 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 $ — $ 221,608 $ — $ 221,608 U.S. Government-sponsored enterprise obligations — 19,934 — 19,934 State and municipal bonds — 439,450 — 439,450 Corporate debt, multiple observable inputs — 1,717,479 — 1,717,479 Corporate debt, limited observable inputs — — 63,973 63,973 Residential mortgage-backed securities — 389,291 249 389,540 Agency commercial mortgage-backed securities — 9,704 — 9,704 Other commercial mortgage-backed securities — 194,090 — 194,090 Other asset-backed securities — 413,989 2,705 416,694 Fixed maturities, trading — 43,434 — 43,434 Equity investments Financial 9,850 2,219 303 12,372 Utilities/Energy 854 — — 854 Industrial — — 2,500 2,500 Bond funds 112,136 — — 112,136 All other 15,876 — — 15,876 Short-term investments 181,937 63,376 — 245,313 Other investments 1,881 88,783 1,783 92,447 Total assets categorized within the fair value hierarchy $ 322,534 $ 3,603,357 $ 71,513 3,997,404 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 262,485 Total assets at fair value $ 4,259,889 Liabilities: Other liabilities $ — $ — $ 15,000 $ 15,000 Total liabilities categorized within the fair value hierarchy $ — $ — $ 15,000 $ 15,000 Level 3 Valuations See Note 3 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2022 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 a quantitative information regarding securities in the Level 3 category, by security type: Fair Value at ($ in thousands) March 31, 2023 December 31, 2022 Valuation Technique Unobservable Input Range Assets: Corporate debt, limited observable inputs $76,157 $63,973 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Residential mortgage-backed securities $289 $249 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Other asset-backed securities $4,765 $2,705 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Equity investments $2,800 $2,803 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Other investments $500 $1,783 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Liabilities: Other liabilities $13,000 $15,000 Stochastic Model/Discounted Cash Flows Weighted Average Cost of Capital 0% - 10% (9%) 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, 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) $ — $ — March 31, 2022 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, 2021 $ 47,129 $ 6,502 $ 2,500 $ 1,434 $ 57,565 $ (24,000) $ (24,000) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment income (loss) — 1 — — 1 — — Net investment gains (losses) — — — 110 110 — — Included in other comprehensive income (loss) (993) (260) — — (1,253) — — Purchases 9,711 5,585 — 1,483 16,779 — — Sales (1,019) (5) — (116) (1,140) — — Transfers in 1,000 — — 529 1,529 — — Transfers out (2,503) (2,520) — — (5,023) — — Balance, March 31, 2022 $ 53,325 $ 9,303 $ 2,500 $ 3,440 $ 68,568 $ (24,000) $ (24,000) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ — $ 64 $ 64 $ — $ — 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, 2023 and 2022 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, 2023 and December 31, 2022, 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 commitments related to these investments as of March 31, 2023 and fair values of these investments as of March 31, 2023 and December 31, 2022 were as follows: Unfunded Fair Value (In thousands) March 31, March 31, December 31, Investment in unconsolidated subsidiaries: Private debt funds (1) $1,958 $ 19,731 $ 19,620 Long/short equity funds (2) None 4,611 5,089 Non-public equity funds (3) $49,373 142,438 144,560 Credit funds (4) $34,482 49,600 49,245 Strategy focused funds (5) $14,162 43,150 43,971 Total investments carried at NAV $ 259,530 $ 262,485 Below is additional information regarding each of the investments listed in the table above as of March 31, 2023. (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. For both funds, redemptions are not permitted. The remaining funds are real estate focused LPs, one of which allows 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, 2023 or December 31, 2022. 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, 2023 December 31, 2022 (In thousands) Carrying Fair Carrying Fair Financial assets: BOLI $ 82,402 $ 82,402 $ 81,746 $ 81,746 Other investments $ 3,031 $ 3,031 $ 3,322 $ 3,322 Other assets $ 29,804 $ 29,776 $ 28,819 $ 28,790 Financial liabilities: Senior notes due 2023* $ 250,000 $ 248,668 $ 250,000 $ 248,153 Contribution Certificates $ 177,974 $ 141,551 $ 177,525 $ 134,479 Other liabilities $ 28,560 $ 28,560 $ 27,905 $ 27,905 * 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 $28.9 million and $27.9 million at March 31, 2023 and December 31, 2022, 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 $28.6 million and $27.9 million at March 31, 2023 and December 31, 2022, 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.

Investments

Investments	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Available-for-sale fixed maturities at March 31, 2023 and December 31, 2022 included the following: March 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 $ 251,162 $ — $ 297 $ 18,433 $ 233,026 U.S. Government-sponsored enterprise obligations 20,466 — 5 1,324 19,147 State and municipal bonds 485,284 — 460 35,524 450,220 Corporate debt 1,925,268 — 1,267 174,854 1,751,681 Residential mortgage-backed securities 446,317 227 1,047 55,014 392,123 Agency commercial mortgage-backed securities 10,488 — — 881 9,607 Other commercial mortgage-backed securities 218,754 — 55 21,663 197,146 Other asset-backed securities 439,131 197 538 22,395 417,077 $ 3,796,870 $ 424 $ 3,669 $ 330,088 $ 3,470,027 December 31, 2022 (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 $ 243,999 $ — $ 8 $ 22,399 $ 221,608 U.S. Government-sponsored enterprise obligations 21,562 — — 1,628 19,934 State and municipal bonds 483,584 — 177 44,311 439,450 Corporate debt 1,980,579 — 735 199,862 1,781,452 Residential mortgage-backed securities 450,870 229 555 61,656 389,540 Agency commercial mortgage-backed securities 10,576 — — 872 9,704 Other commercial mortgage-backed securities 217,021 — 63 22,994 194,090 Other asset-backed securities 444,220 198 289 27,617 416,694 $ 3,852,411 $ 427 $ 1,827 $ 381,339 $ 3,472,472 The recorded cost basis and estimated fair value of available-for-sale fixed maturities at March 31, 2023, 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 $ 251,162 $ 22,216 $ 173,595 $ 34,426 $ 2,789 $ 233,026 U.S. Government-sponsored enterprise obligations 20,466 2,786 12,184 4,177 — 19,147 State and municipal bonds 485,284 36,714 149,950 151,348 112,208 450,220 Corporate debt 1,925,268 195,164 847,544 618,778 90,195 1,751,681 Residential mortgage-backed securities 446,317 392,123 Agency commercial mortgage-backed securities 10,488 9,607 Other commercial mortgage-backed securities 218,754 197,146 Other asset-backed securities 439,131 417,077 $ 3,796,870 $ 3,470,027 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, 2023. Cash and securities with a carrying value of $54.3 million at March 31, 2023 were on deposit with various state insurance departments to meet regulatory requirements. ProAssurance also held securities with a carrying value of $31.6 million at March 31, 2023 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 underwriting by Syndicate 1729. At March 31, 2023, ProAssurance's FAL investments were comprised of available-for-sale fixed maturities with a fair value of $20.5 million and cash and cash equivalents of $4.6 million 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, 2023 and December 31, 2022, including the length of time the investment had been held in a continuous unrealized loss position. March 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 $ 219,842 $ 18,433 $ 30,688 $ 769 $ 189,154 $ 17,664 U.S. Government-sponsored enterprise obligations 18,849 1,324 7,044 490 11,805 834 State and municipal bonds 421,764 35,524 80,956 2,651 340,808 32,873 Corporate debt 1,650,437 174,854 313,062 11,674 1,337,375 163,180 Residential mortgage-backed securities 348,127 55,014 86,565 7,891 261,562 47,123 Agency commercial mortgage-backed securities 9,607 881 1,983 78 7,624 803 Other commercial mortgage-backed securities 195,923 21,663 21,224 690 174,699 20,973 Other asset-backed securities 374,159 22,395 53,135 1,449 321,024 20,946 $ 3,238,708 $ 330,088 $ 594,657 $ 25,692 $ 2,644,051 $ 304,396 December 31, 2022 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 $ 220,991 $ 22,399 $ 53,199 $ 2,393 $ 167,792 $ 20,006 U.S. Government-sponsored enterprise obligations 19,934 1,628 8,082 663 11,852 965 State and municipal bonds 421,769 44,311 177,393 12,352 244,376 31,959 Corporate debt 1,708,529 199,862 687,947 42,977 1,020,582 156,885 Residential mortgage-backed securities 363,945 61,656 155,212 15,275 208,733 46,381 Agency commercial mortgage-backed securities 9,704 872 3,086 110 6,618 762 Other commercial mortgage-backed securities 192,359 22,994 53,270 4,087 139,089 18,907 Other asset-backed securities 396,452 27,617 162,192 7,050 234,260 20,567 $ 3,333,683 $ 381,339 $ 1,300,381 $ 84,907 $ 2,033,302 $ 296,432 As of March 31, 2023, excluding U.S. Government or U.S. Government-sponsored enterprise obligations, there were 2,809 debt securities (72.6% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 1,416 issuers. The greatest and second greatest unrealized loss positions among those securities were approximately $5.2 million and $3.5 million, respectively. The securities were evaluated for impairment as of March 31, 2023. As of December 31, 2022, excluding U.S. Government or U.S. Government-sponsored enterprise obligations, there were 2,901 debt securities (74.4% of all available-for-sale fixed maturity securities held) in an unrealized loss position representing 1,433 issuers. The greatest and second greatest unrealized loss positions among those securities were approximately $5.7 million and $4.1 million, respectively. The securities were evaluated for impairment as of December 31, 2022. 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, 2022 report on Form 10-K. Fixed maturity securities held in an unrealized loss position at March 31, 2023, 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, 2023 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 table presents a roll forward of the allowance for expected credit losses on available-for-sale fixed maturities for the three months ended March 31, 2023. There was no allowance for expected credit losses for the three months ended March 31, 2022. 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) 2023 2022 Proceeds from sales (exclusive of maturities and paydowns) $ 3.8 $ 63.5 Purchases $ 68.8 $ 231.6 Net Investment Income Net investment income (loss) by investment category was as follows: Three Months Ended (In thousands) 2023 2022 Fixed maturities $ 27,327 $ 21,544 Equities 807 701 Short-term investments, including Other 3,350 426 BOLI 657 (47) Investment fees and expenses (1,831) (2,181) Net investment income $ 30,310 $ 20,443 Investment in Unconsolidated Subsidiaries ProAssurance's investment in unconsolidated subsidiaries were as follows: March 31, 2023 Carrying Value (In thousands) Percentage March 31, December 31, Qualified affordable housing project tax credit partnerships See below $ 2,727 $ 4,088 All other investments, primarily investment fund LPs/LLCs See below 294,810 301,122 $ 297,537 $ 305,210 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, 2023 and December 31, 2022, ProAssurance did not have an ownership percentage greater than 20% in any tax credit partnership interests. ProAssurance's ownership percentage relative to the tax credit partnership interests is less than 20%; these interests had a carrying value of $2.7 million at March 31, 2023 and $4.1 million at December 31, 2022. 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 9. 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 and three of the LPs/LLCs is greater than 25% at March 31, 2023 and December 31, 2022, respectively, which is likely to be reduced as the funds mature and other investors participate in the funds; these investments had a carrying value of $46.0 million at March 31, 2023 and $36.0 million at December 31, 2022. ProAssurance's ownership percentage relative to the remaining investments and LPs/LLCs is less than 25%; these interests had a carrying value of $248.8 million at March 31, 2023 and $265.1 million at December 31, 2022. 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. 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) 2023 2022 Qualified affordable housing project tax credit partnerships Losses recorded $ 354 $ 2,388 Tax credits recognized $ 43 $ 1,205 For the three months ended March 31, 2023 the Company generated a nominal amount of tax credits from its tax credit partnership investments which were deferred for use in future periods due to the Company's expected consolidated loss calculated on a tax basis. For the three months ended March 31, 2022, the tax credits generated from the Company's tax credit partnership investments of $1.2 million were deferred and are expected to be utilized in future periods. Not included in the table above is $2.3 million and $2.0 million of tax credits recaptured from the 2019 tax year during the three months ended March 31, 2023 and 2022, respectively, due to the carryback of the Company's estimated NOL for both periods to the 2021 tax year. The recaptured tax credits were earned in 2019 but not utilized until 2021 due to NOL's generated in both 2019 and 2020. As of March 31, 2023, the Company had approximately $53.6 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. Significant Equity Method Investees As previously discussed, ProAssurance holds certain investments that are measured using the equity method of accounting, primarily investments in LPs/LLCs, which are carried as a part of investment in unconsolidated subsidiaries on the Condensed Consolidated Balance Sheets. Each quarter, ProAssurance assesses the significance of its equity method investees. As of March 31, 2023, ProAssurance determined A&M Capital Opportunities Fund to be significant, which is a private equity fund that is focused on middle-market investments. The following table presents aggregated gross summarized financial information for the fund that ProAssurance determined to be significant as of March 31, 2023, including the portion not attributable to ProAssurance, derived from the fund's financial statements which are prepared in accordance with GAAP. As the majority of ProAssurance's equity method investments report their results to the Company on a one quarter lag, the majority of the summarized financial information below is for the three months ended December 31, 2022 and 2021. (In thousands) Three Months Ended March 31 2023 2022 Net investment income (loss) $ (2,890) $ (3,582) Net investment gains (losses) (58,387) 42 Net change in unrealized appreciation (depreciation) (31,458) 41,585 Net gain (loss) $ (92,735) $ 38,045 Net gain (loss) attributable to ProAssurance (1) $ (3,174) $ 1,299 (1) Represents ProAssurance's share of the fund's aggregate income or loss, which is included as a component of equity in earnings (loss) of unconsolidated subsidiaries in its Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and 2022. 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) 2023 2022 Total impairment losses: Corporate debt $ (2,936) $ — Asset-backed securities 3 — Net impairment losses recognized in earnings (2,933) — Gross realized gains, available-for-sale fixed maturities 79 1,187 Gross realized (losses), available-for-sale fixed maturities (457) (1,124) Net realized gains (losses), trading fixed maturities (108) (75) Net realized gains (losses), equity investments 84 (220) Net realized gains (losses), other investments 229 650 Change in unrealized holding gains (losses), trading fixed maturities 97 (326) Change in unrealized holding gains (losses), equity investments 3,746 (11,485) Change in unrealized holding gains (losses), convertible securities, carried at fair value 1,132 (2,476) Other (1) 1,043 363 Net investment gains (losses) $ 2,912 $ (13,506) (1) Includes a gain of $1.0 million recognized during the 2023 three-month period reflecting 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 discussion on the Company's accounting policy in Note 1 in its December 31, 2022 report on Form 10-K. For the three months ended March 31, 2023, ProAssurance recognized credit-related impairment losses in earnings of $2.9 million. The Company did not recognize any non-credit impairment losses in OCI during the three months ended March 31, 2023. The credit-related impairment losses recognized during the three months ended March 31, 2023 related to two corporate bonds in the financial sector. ProAssurance did not recognize any credit-related impairment losses in earnings or non-credit impairment losses in OCI during the three months ended March 31, 2022. There was no change in cumulative credit losses recorded in earnings related to impaired debt securities for which a portion of the impairment was recorded in OCI from December 31, 2022 to March 31, 2023. For more information see Note 4 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2022 report on Form 10-K.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2023
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, 2023, ProAssurance utilized the estimated annual effective tax rate method. Under the estimated annual effective tax rate 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, 2022, ProAssurance utilized the discrete effective tax rate method for recording income taxes after the estimated annual effective tax rate method produced an unreliable estimated annual effective tax rate. See further discussion on this method in Note 4 of the Notes to Condensed Consolidated Financial Statements included in ProAssurance's March 31, 2022 report on Form 10-Q. In calculating the Company's year-to-date income tax expense (benefit) under the estimated annual effective tax rate method, it includes the estimated benefit of tax credits for the year-to-date period based on the most recently available information provided by the tax credit partnerships; the actual amounts of credits provided by the tax credit partnerships may prove to be different than the Company's estimates. The effect of such a difference is recognized in the period identified. For the three months ended March 31, 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 for the three months ended March 31, 2023 and the Company's projected annual effective tax rate as of March 31, 2023 as calculated under the estimated annual effective tax rate method. In addition, the provision for income taxes is also different from that which would be obtained by applying the statutory federal income tax rate to income (loss) before income taxes due to the $2 million decrease in the contingent consideration liability related to the NORCAL acquisition, all of which was non-taxable. See further discussion on the contingent consideration in Note 2. ProAssurance had a liability for U.S. federal and U.K. income taxes carried as a part of other liabilities of $4.5 million as of March 31, 2023 and a receivable of $8.0 million as of December 31, 2022 carried as a part of other assets. At March 31, 2023 and December 31, 2022, the liability for unrecognized tax benefits, which is included in the total liability for U.S. federal and U.K. income taxes, was $4.1 million in each period which included an accrued liability for interest of approximately $0.5 million in each period. Coronavirus Aid, Relief and Economic Security Act

Reserve for Losses and Loss Adj

Reserve for Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2023
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 8 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2022 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, 2023 Three Months Ended March 31, 2022 Year Ended December 31, 2022 Balance, beginning of year $ 3,471,147 $ 3,579,940 $ 3,579,940 Less reinsurance recoverables on unpaid losses and loss adjustment expenses 431,889 451,741 451,741 Net balance, beginning of year 3,039,258 3,128,199 3,128,199 Net losses: Current year (1) 198,240 214,753 813,515 (Favorable) unfavorable development of reserves established in prior years, net (2) 7,056 (5,330) (36,753) Total 205,296 209,423 776,762 Paid related to: Current year (11,052) (13,179) (108,139) Prior years (211,916) (185,977) (757,564) Total paid (222,968) (199,156) (865,703) Net balance, end of period 3,021,586 3,138,466 3,039,258 Plus reinsurance recoverables on unpaid losses and loss adjustment expenses 447,693 464,780 431,889 Balance, end of period $ 3,469,279 $ 3,603,246 $ 3,471,147 (1) Current year net losses for the three months ended March 31, 2022 and year ended December 31, 2022 included $2.5 million and $4.9 million, respectively, of purchase accounting amortization of the negative VOBA associated with NORCAL's assumed unearned premium, which was amortized over a period in proportion to the earn-out of the associated premium as a reduction to current accident year net losses (see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2022 report on Form 10-K). As of June 30, 2022, the negative VOBA was fully amortized. (2) Net prior year reserve development recognized for the three months ended March 31, 2023 and 2022 as well as the year ended December 31, 2022 included $2.5 million, $2.9 million and $10.8 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 (see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2022 report on Form 10-K). 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 unfavorable prior year reserve development recognized in the three months ended March 31, 2023 primarily reflected the continued challenging loss environment in Specialty P&C segment, as claim costs are pressured by social inflation and higher than anticipated loss severity trends which started to emerge in the fourth quarter of 2022. During the first quarter of 2023, the Company strengthened case reserves in its Specialty P&C segment related to four large claims resulting in net unfavorable prior year reserve development of $10.1 million recognized during the three months ended March 31, 2023, $7.5 million of which related to NORCAL's accident years 2016 and 2020. The consolidated net unfavorable loss development also reflected unfavorable development recognized in the Workers' Compensation Insurance segment primarily attributable to one large claim from the 1997 accident year. Consolidated net unfavorable loss development recognized in the three months ended March 31, 2023 was partially offset by favorable reserve development recognized in the Segregated Portfolio Cell Reinsurance and Lloyd's Syndicates segments. The favorable loss development recognized in the Segregated Portfolio Cell Reinsurance segment reflected overall favorable trends in claim closing patterns primarily in accident years 2016 through 2020. The favorable reserve development recognized in the Lloyd's Syndicates segment was driven by lower than expected loss development on certain large items, primarily catastrophe related losses. The net favorable loss development recognized in the three months ended March 31, 2022 primarily reflected overall favorable trends in claim closing patterns in the Workers' Compensation Insurance and Segregated Portfolio Cell Reinsurance segments. The net favorable loss development recognized in the Workers' Compensation Insurance segment is primarily related to the 2019 accident year and prior. The net favorable loss development recognized in the Segregated Portfolio Cell Reinsurance segment is primarily related to the 2019 and 2020 accident years. Net favorable development recognized during the three months ended March 31, 2022 was net of an increase to the Company's reserve for potential ECO/XPL claims of $4.0 million in the Specialty P&C segment. Excluding the increase in the ECO/XPL reserve and amortization of purchase accounting adjustments (see footnote 2 in the table above), ProAssurance recognized net favorable prior accident year reserve development of $5.0 million in the Specialty P&C segment, principally related to accident years 2019 through 2021. Consolidated net favorable loss development recognized in the three months ended March 31, 2022 was partially offset by unfavorable reserve development recognized in the Lloyd's Syndicates segment driven by certain catastrophe related losses. As of March 31, 2022, ProAssurance did not recognize any development related to NORCAL's accident years 2020 or prior since the date of acquisition on May 5, 2021. The net favorable loss development recognized for the year ended December 31, 2022 primarily reflected a lower than anticipated loss emergence in the Specialty P&C segment related to the 2017, 2020 and 2021 accident years, primarily attributable to NORCAL's 2021 accident year, and, to a lesser extent, the Medical Technology Liability line of business. The net favorable development recognized in the Specialty P&C segment also included a $9.0 million reduction in the Company's prior accident year IBNR reserve for COVID-19 as early first notices of potential claims related to anticipated COVID losses have not turned into claims. Further, the net favorable development recognized in the Specialty P&C segment was partially offset by higher than anticipated loss severity trends in select jurisdictions in the HCPL line of business, which emerged primarily in the fourth quarter of 2022. As of December 31, 2022, ProAssurance did not recognize any development related to NORCAL's accident years 2020 or prior since the date of acquisition on May 5, 2021. The net favorable development also reflected overall favorable trends in claim closing patterns in the Workers' Compensation Insurance and Segregated Portfolio Cell Reinsurance segments. The net favorable loss development recognized in the Workers' Compensation Insurance segment is primarily related to the 2017 through 2020 accident years. The net favorable loss development recognized in the Segregated Portfolio Cell Reinsurance segment is primarily related to the 2016 through 2021 accident years. Consolidated net favorable loss development recognized in 2022 was partially offset by unfavorable reserve development recognized in the Lloyd's Syndicates segment driven by higher than expected loss development on certain large claims, primarily catastrophe related losses.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2023
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, 2022 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, 2023, there were no material reserves established for corporate legal actions. As a member of Lloyd's, ProAssurance has obligations to Syndicate 1729 including a Syndicate Credit Agreement and FAL requirements. The Syndicate Credit Agreement is an unconditional revolving credit agreement to the Premium Trust Fund of Syndicate 1729 for the purpose of providing working capital. At March 31, 2023, the maximum permitted borrowings under the Syndicate Credit Agreement were approximately £15.0 million (approximately $18.5 million at March 31, 2023). The Syndicate Credit Agreement has a maturity date of June 30, 2023 and contains an annual auto-renewal feature which allows for ProAssurance to elect to non-renew if notice is given at least 30 days prior to the next auto-renewal date, which is one year prior to the maturity date. On May 23, 2022, ProAssurance provided such notice of termination of the Syndicate Credit Agreements. As a result, the Syndicate Credit Agreements will expire on June 30, 2023. Under the Syndicate Credit Agreement, advances bear interest at 3.8% annually and may be repaid at any time. As of March 31, 2023, there were no outstanding borrowings under the Syndicate Credit Agreement. ProAssurance provides FAL to support underwriting by Syndicate 1729 which is comprised of investment securities and cash and cash equivalents deposited with Lloyd's with a total fair value of approximately $25.1 million at March 31, 2023 (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, 2023, ProAssurance had total funding commitments related to non-public investment entities as well as the short-term loan commitment of approximately $184.8 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, 2023. ProAssurance entered into a services agreement with a company to provide data analytics services for certain product lines within the Company's HCPL 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. ProAssurance incurred operating expenses associated with this services agreement of $0.9 million for each of the three months ended March 31, 2023 and 2022. As of March 31, 2023, the remaining commitment under this agreement was estimated to be approximately $5.4 million.

Debt

Debt	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Debt	Debt ProAssurance’s outstanding debt consisted of the following: ($ in thousands) March 31, December 31, Senior Notes due 2023, unsecured, interest at 5.3% annually $ 250,000 $ 250,000 Contribution Certificates due 2031, interest at 3.0% (effective interest rate at 4.35%) paid annually in April 177,974 177,525 Total principal 427,974 427,525 Less unamortized debt issuance costs 448 542 Debt less unamortized debt issuance costs $ 427,526 $ 426,983 Revolving Credit Agreement and Term Loan On April 28, 2023, ProAssurance executed an amendment to the Revolving Credit Agreement, which extended the expiration from November 2024 to April 2028 and includes a $125 million delayed draw term loan ("Term Loan"). The Term Loan is available to be drawn during a five years period after closing, subject to customary borrowing conditions. The Company intends to draw on the amended Revolving Credit Agreement, including the Term Loan, to refinance its Senior Notes that mature November 2023 (see additional information on the Company's Senior Notes in Note 11 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2022 report on Form 10-K). The amended Revolving Credit Agreement may be used for general corporate purposes, including, but not limited to, short-term working capital, share repurchases as authorized by the Board and support for other activities. ProAssurance's amended Revolving Credit Agreement permits borrowings up to $250 million, and has available a $50 million accordion feature which, if successfully subscribed, would expand the permitted borrowings to a maximum of $300 million. As of March 31, 2023 and December 31, 2022, there were no outstanding borrowings on the Revolving Credit Agreement. The amended Revolving Credit Agreement permits ProAssurance to borrow, repay and reborrow from the lenders during the term of the amended Revolving Credit Agreement. All borrowings are required to be repaid prior to the expiration date of the amended Revolving Credit Agreement. ProAssurance is required to pay a commitment fee, ranging from 0.20% to 0.45% based on ProAssurance’s debt to capitalization ratio, on the average unused portion of the amended Revolving Credit Agreement during the term of the agreement. Borrowings under the agreements may be secured or unsecured and accrue interest at a selected base rate, adjusted by a margin, which can vary from 0% to 2.375%, based on ProAssurance’s debt to capitalization ratio and whether the borrowing is secured or unsecured. The base rate selected may either be the current one-, three- or six-month SOFR, with the SOFR term selected fixing the interest period for which the rate is effective. If no selection is made, the base rate defaults to the highest of (1) Zero, (2) the Prime rate, (3) the Federal Funds rate plus 0.5% or (4) the one-month SOFR Adjusted Screen Rate plus 1.0%, determined daily. Rates are reset each successive interest period until the borrowing is repaid. The amended Revolving Credit Agreement contains customary representations, covenants and events constituting default, and remedies for default. Additionally, the agreement carries the following financial covenants: (1) ProAssurance is not permitted to have a leverage ratio of consolidated funded indebtedness (principally, obligations for borrowed money, obligations evidenced by instruments such as notes or acceptances, standby and commercial letters of credit, and contingent obligations) to consolidated total capitalization (principally, total non-trade liabilities on a consolidated basis plus consolidated shareholders’ equity, exclusive of AOCI) greater than 0.35 to 1.0, determined at the end of each fiscal quarter. (2) ProAssurance is required to maintain a minimum net worth, excluding AOCI, of at least $912 million. (3) ProAssurance is required to maintain minimum liquidity, which will include cash, securities, and capacity on its revolving line, of at least $25 million. As of March 31, 2023, ProAssurance is in compliance with all covenants of the Revolving Credit Agreement. Interest Rate Swaps To manage the Company's exposure to interest rate risk due to variability in the base rate on borrowings under the amended 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 maturity date of March 31, 2028. The Interest Rate Swap associated with the amended Revolving Credit Agreement will have a constant $125 million notional amount and the Interest Rate Swap associated with the Term Loan will have an amortizing $125 million notional amount. As previously discussed, borrowings under the amended Revolving Credit Agreement and Term Loan accrue interest at a selected base rate, adjusted by a margin. The base rate selected for borrowings may either be the current one-, three- or six-month SOFR. The Company intends to select three-month SOFR for all borrowings and the Interest Rate Swaps effectively fix the base rate on borrowings under the amended 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 as it's based on ProAssurance’s debt to capitalization ratio. ProAssurance may be required to deposit collateral with the lender from time to time in order to secure the net present value of future cash flows associated with the Interest Rate Swaps which will be measured quarterly. Covenant Compliance There are no financial covenants associated with the Senior Notes, the Contribution Certificates or the Interest Rate Swaps due 2023, 2031 and 2028, respectively. The amended Revolving Credit Agreement contains customary representations, covenants and events constituting default, and remedies for default, as previously discussed. As of March 31, 2023, ProAssurance is in compliance with all covenants of the Revolving Credit Agreement. Additional Information For additional information regarding ProAssurance's debt, see Note 11 of the Notes to Consolidated Financial Statements included in ProAssurance's December 31, 2022 report on Form 10-K.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2023
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity At March 31, 2023 and December 31, 2022, 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 both 2023 and 2022, totaling $2.7 million for each three-month period. 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, 2022 report on Form 10-K for additional information. At March 31, 2023, Board authorizations for the repurchase of common shares or the retirement of outstanding debt of $106.4 million remained available for use. ProAssurance did not repurchase any common shares during the three months ended March 31, 2023 or 2022. 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 deferred tax expense of $10.8 million and a deferred tax benefit of $38.2 million for the three months ended March 31, 2023 and 2022, respectively. The changes in the balance of each component of AOCI for the three months ended March 31, 2023 and 2022 were as follows: (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) (In thousands) Unrealized Investment Gains (Losses) Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2021 $ 14,929 $ 1,355 $ 16,284 OCI, before reclassifications, net of tax (140,808) — (140,808) Amounts reclassified from AOCI, net of tax (28) (14) (42) Net OCI, current period (140,836) (14) (140,850) Balance, March 31, 2022 $ (125,907) $ 1,341 $ (124,566)

Variable Interest Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2023
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 $271.1 million at March 31, 2023 and $277.5 million at December 31, 2022. 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, 2023, 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 the 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, 2023 and December 31, 2022, approximately $143 million and $154 million of ProAssurance's assets, respectively, and approximately $143 million and $154 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, 2023
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 2023 2022 Weighted average number of common shares outstanding, basic 53,987 54,012 Dilutive effect of securities: Restricted Share Units 103 114 Performance Share Units 27 17 Weighted average number of common shares outstanding, diluted 54,117 54,143 Effect of dilutive shares on earnings (loss) per share $ — $ —

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2023
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. The Company operates in five segments that are organized around the nature of the products and services provided: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance, Lloyd's Syndicates 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, 2022 report on Form 10-K. A description of each of ProAssurance's five operating and reportable segments follows. • Specialty P&C includes professional liability insurance and medical technology liability insurance. • 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. • Lloyd's Syndicates includes the results from ProAssurance's participation in Lloyd's of London Syndicate 1729 and Syndicate 6131. ProAssurance's participation in the results of Syndicate 1729 for the 2023 underwriting year remains unchanged from the 2022 underwriting year at 5% and the Company ceased participation in Syndicate 6131 beginning with the 2022 underwriting year. Due to the quarter lag, the Company's ceased participation in Syndicate 6131 was not reflected in its results until the second quarter of 2022. • Corporate includes ProAssurance's investment operations excluding those reported in the Company's Segregated Portfolio Cell Reinsurance and Lloyd's Syndicates segments. In addition, this segment includes corporate expenses, interest expense, U.S. 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, 2022 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 Lloyd's Syndicates segment is evaluated based on operating profit or loss, which includes investment results of investment assets solely allocated to Lloyd's Syndicate operations, net of U.K. income tax expense. 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 and Lloyd's Syndicates segments, 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 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, 2023 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Lloyd's Syndicates Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 179,344 $ 40,803 $ 15,300 $ 4,340 $ — $ — $ 239,787 Net investment income — — 420 188 29,702 — 30,310 Equity in earnings (loss) of unconsolidated subsidiaries — — — — (1,121) — (1,121) Net investment gains (losses) — — 1,160 (11) 763 — 1,912 Other income (expense) (1) 993 581 1 (3) 327 (1,112) 787 Net losses and loss adjustment expenses (164,051) (30,844) (8,423) (1,978) — — (205,296) Underwriting, policy acquisition and operating expenses (1) (40,961) (12,980) (5,035) (1,720) (8,204) 1,112 (67,788) SPC U.S. federal income tax 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 $ (24,675) $ (2,440) $ 949 $ 816 $ 18,176 $ — (7,174) Reconciliation of segments to consolidated results: Contingent Consideration Adjustment (3) 1,000 Net income (loss) $ (6,174) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,640 $ 869 $ 64 $ 1 $ 4,103 $ — $ 7,677 Three Months Ended March 31, 2022 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Lloyd's Syndicates Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 197,967 $ 40,684 $ 19,314 $ 7,746 $ — $ — $ 265,711 Net investment income — — 112 211 20,120 — 20,443 Equity in earnings (loss) of unconsolidated subsidiaries — — — — 7,620 — 7,620 Net investment gains (losses) — — (711) (399) (12,396) — (13,506) Other income (expense) (1) 1,019 682 1 134 2,065 (1,097) 2,804 Net losses and loss adjustment expenses (165,958) (27,211) (11,491) (4,763) — — (209,423) Underwriting, policy acquisition and operating expenses (1) (42,878) (13,001) (4,369) (2,709) (8,739) 1,097 (70,599) SPC U.S. federal income tax expense (2) — — (642) — — — (642) SPC dividend (expense) income — — (2,367) — — — (2,367) Interest expense — — — — (4,441) — (4,441) Income tax benefit (expense) — — — — 1,770 — 1,770 Segment results $ (9,850) $ 1,154 $ (153) $ 220 $ 5,999 $ — (2,630) Reconciliation of segments to consolidated results: Transaction-related costs (4) (930) Net income (loss) $ (3,560) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,592 $ 874 $ 370 $ 14 $ 6,500 $ — $ 10,350 (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 Consolidated Statements of Income and Comprehensive Income. See further discussion on the contingent consideration in Note 2. (4) Represents the transaction-related costs, after-tax, associated with the acquisition of NORCAL. For the three months ended March 31, 2022 pre-tax transaction-related costs of approximately $1.2 million were included as a component of consolidated operating expense and the associated income tax benefit of approximately $0.3 million were included as a component of consolidated income tax benefit (expense) on the Condensed Consolidated Statements of Income and Comprehensive Income. 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) 2023 2022 Specialty P&C Segment Gross premiums earned: HCPL $ 162,387 $ 175,547 Small Business Unit 26,074 26,538 Medical Technology Liability 10,546 10,000 Other — 194 Ceded premiums earned (19,663) (14,312) Segment net premiums earned 179,344 197,967 Workers' Compensation Insurance Segment Gross premiums earned: Traditional business 43,540 43,156 Alternative market business 17,626 17,878 Ceded premiums earned (20,363) (20,350) Segment net premiums earned 40,803 40,684 Segregated Portfolio Cell Reinsurance Segment Gross premiums earned: Workers' compensation (1) 16,304 17,178 HCPL (2) 1,299 4,486 Ceded premiums earned (2,303) (2,350) Segment net premiums earned 15,300 19,314 Lloyd's Syndicates Segment Gross premiums earned: Property and casualty 5,046 9,232 Ceded premiums earned (706) (1,486) Segment net premiums earned 4,340 7,746 Consolidated net premiums earned $ 239,787 $ 265,711 (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.

Benefit Plans

Benefit Plans	3 Months Ended
	Mar. 31, 2023
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans ProAssurance sponsors a defined benefit pension plan which covers substantially all NORCAL employees (except those that were previous employees of Medicus Insurance Company and FD Insurance Company, employees of PPM RRG as well as new hires after December 31, 2013). Benefits are based on years of service and the employee’s average of the highest five years of annual compensation. Annual contributions to the defined benefit pension plan are above the minimum funding standards outlined in the Employee Retirement Income Security Act of 1974, as amended. ProAssurance makes contributions to the defined benefit pension plan with the goal of ensuring that it is adequately funded to meet its future obligations. ProAssurance did not make any contributions to the pension plan during the three months ended March 31, 2023 and does not anticipate making any contributions for the remainder of 2023. The defined benefit pension plan no longer has future service accruals or compensation increases because this plan was frozen effective December 31, 2015. See Note 17 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2022 report on Form 10-K for more information regarding the defined benefit pension plan. The components of the net periodic benefit cost (income) for the three months ended March 31, 2023 and 2022 were as follows: ($ in thousands) Three Months Ended 2023 2022 Components of net periodic benefit cost (income): Interest cost $ 904 $ 711 Expected return on Plan assets (874) (989) Total net periodic benefit cost (income)* $ 30 $ (278) *Net periodic benefit cost (income) is included as a component of operating expense on the Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and 2022.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe 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 9 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, 2023 are not necessarily indicative of the results that may be expected for the year ending December 31, 2023. The accompanying Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes contained in ProAssurance’s December 31, 2022 report on Form 10-K. ProAssurance operates in five reportable segments as follows: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance, Lloyd's Syndicates and Corporate.
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, 2022 report on Form 10-K.
Accounting Changes Adopted and Not Yet Adopted	Accounting Changes Adopted Reference Rate Reform - Deferral of LIBOR Sunset Date (ASU 2022-06) Effective for fiscal years beginning after December 31, 2022 and interim periods within those fiscal years, the FASB amended guidance which defers the LIBOR transition date from December 31, 2022 to December 31, 2024. ProAssurance has exposure to LIBOR in its available-for-sale fixed maturities portfolio which represented approximately 6% of total investments, or $246 million as of March 31, 2023; 63% of these investments with exposure to LIBOR were issued since 2020 and include provisions for an alternative benchmark rate. ProAssurance adopted the guidance beginning January 1, 2023, and adoption had no material effect on ProAssurance's results of operations, financial position or cash flows. Accounting Changes Not Yet Adopted ProAssurance is not aware of any accounting changes not yet adopted as of March 31, 2023 that could have a material impact on its results of operations, financial position or cash flows.
Employee Retention Credit	Employee Retention Credit In response to COVID-19, the CARES Act was signed into law on March 27, 2020 and contains several provisions for corporations, including the initial version of the ERC. In December 2020 and March 2021, the ERC was extended and expanded from 50% of qualified wages to 70%. The 2020 rules limited qualified wages to $10,000 per employee and applied to employers with 100 or fewer full-time employees in 2019. The rules were expanded in 2021 to raise the qualified wage limit to $10,000 per employee, per quarter. As an eligible employer, NORCAL expects to file a claim during 2023 for a payroll tax refund of approximately $3.8 million. The Company recorded the expected payroll tax refund as a component of operating expenses on the Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and as a component of other assets on the Condensed Consolidated Balance Sheets as of March 31, 2023.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2023
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, 2023 and December 31, 2022 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 3 of the Notes to Consolidated Financial Statements in ProAssurance’s December 31, 2022 report on Form 10-K. March 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 $ — $ 233,026 $ — $ 233,026 U.S. Government-sponsored enterprise obligations — 19,147 — 19,147 State and municipal bonds — 450,220 — 450,220 Corporate debt, multiple observable inputs — 1,675,524 — 1,675,524 Corporate debt, limited observable inputs — — 76,157 76,157 Residential mortgage-backed securities — 391,834 289 392,123 Agency commercial mortgage-backed securities — 9,607 — 9,607 Other commercial mortgage-backed securities — 197,146 — 197,146 Other asset-backed securities — 412,312 4,765 417,077 Fixed maturities, trading — 44,818 — 44,818 Equity investments Financial 9,924 2,232 300 12,456 Utilities/Energy 956 — — 956 Industrial — — 2,500 2,500 Bond funds 114,618 — — 114,618 All other 16,338 — — 16,338 Short-term investments 156,871 94,156 — 251,027 Other investments 1,914 83,524 500 85,938 Total assets categorized within the fair value hierarchy $ 300,621 $ 3,613,546 $ 84,511 3,998,678 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 259,530 Total assets at fair value $ 4,258,208 Liabilities: Other liabilities $ — $ — $ 13,000 $ 13,000 Total liabilities categorized within the fair value hierarchy $ — $ — $ 13,000 $ 13,000 December 31, 2022 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 $ — $ 221,608 $ — $ 221,608 U.S. Government-sponsored enterprise obligations — 19,934 — 19,934 State and municipal bonds — 439,450 — 439,450 Corporate debt, multiple observable inputs — 1,717,479 — 1,717,479 Corporate debt, limited observable inputs — — 63,973 63,973 Residential mortgage-backed securities — 389,291 249 389,540 Agency commercial mortgage-backed securities — 9,704 — 9,704 Other commercial mortgage-backed securities — 194,090 — 194,090 Other asset-backed securities — 413,989 2,705 416,694 Fixed maturities, trading — 43,434 — 43,434 Equity investments Financial 9,850 2,219 303 12,372 Utilities/Energy 854 — — 854 Industrial — — 2,500 2,500 Bond funds 112,136 — — 112,136 All other 15,876 — — 15,876 Short-term investments 181,937 63,376 — 245,313 Other investments 1,881 88,783 1,783 92,447 Total assets categorized within the fair value hierarchy $ 322,534 $ 3,603,357 $ 71,513 3,997,404 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 262,485 Total assets at fair value $ 4,259,889 Liabilities: Other liabilities $ — $ — $ 15,000 $ 15,000 Total liabilities categorized within the fair value hierarchy $ — $ — $ 15,000 $ 15,000
Schedule of Quantitative Information Regarding Level 3 Valuations	Quantitative Information Regarding Level 3 Valuations Below is a quantitative information regarding securities in the Level 3 category, by security type: Fair Value at ($ in thousands) March 31, 2023 December 31, 2022 Valuation Technique Unobservable Input Range Assets: Corporate debt, limited observable inputs $76,157 $63,973 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Residential mortgage-backed securities $289 $249 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Other asset-backed securities $4,765 $2,705 Market Comparable Comparability Adjustment 0% - 5% (2.5%) Discounted Cash Flows Comparability Adjustment 0% - 5% (2.5%) Equity investments $2,800 $2,803 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Other investments $500 $1,783 Discounted Cash Flows Comparability Adjustment 0% - 10% (5%) Liabilities: Other liabilities $13,000 $15,000 Stochastic Model/Discounted Cash Flows Weighted Average Cost of Capital 0% - 10% (9%)
Schedule of Fair Value Measurements - Level 3 Assets	The following tables present summary information regarding changes in the fair value of assets and liabilities measured using Level 3 inputs. 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) $ — $ — March 31, 2022 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, 2021 $ 47,129 $ 6,502 $ 2,500 $ 1,434 $ 57,565 $ (24,000) $ (24,000) Total gains (losses) realized and unrealized: Included in earnings, as a part of: Net investment income (loss) — 1 — — 1 — — Net investment gains (losses) — — — 110 110 — — Included in other comprehensive income (loss) (993) (260) — — (1,253) — — Purchases 9,711 5,585 — 1,483 16,779 — — Sales (1,019) (5) — (116) (1,140) — — Transfers in 1,000 — — 529 1,529 — — Transfers out (2,503) (2,520) — — (5,023) — — Balance, March 31, 2022 $ 53,325 $ 9,303 $ 2,500 $ 3,440 $ 68,568 $ (24,000) $ (24,000) Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end $ — $ — $ — $ 64 $ 64 $ — $ —
Schedule of Investments in LLCs and Limited Partnerships	The amount of ProAssurance's unfunded commitments related to these investments as of March 31, 2023 and fair values of these investments as of March 31, 2023 and December 31, 2022 were as follows: Unfunded Fair Value (In thousands) March 31, March 31, December 31, Investment in unconsolidated subsidiaries: Private debt funds (1) $1,958 $ 19,731 $ 19,620 Long/short equity funds (2) None 4,611 5,089 Non-public equity funds (3) $49,373 142,438 144,560 Credit funds (4) $34,482 49,600 49,245 Strategy focused funds (5) $14,162 43,150 43,971 Total investments carried at NAV $ 259,530 $ 262,485 Below is additional information regarding each of the investments listed in the table above as of March 31, 2023. (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. For both funds, redemptions are not permitted. The remaining funds are real estate focused LPs, one of which allows 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, 2023 December 31, 2022 (In thousands) Carrying Fair Carrying Fair Financial assets: BOLI $ 82,402 $ 82,402 $ 81,746 $ 81,746 Other investments $ 3,031 $ 3,031 $ 3,322 $ 3,322 Other assets $ 29,804 $ 29,776 $ 28,819 $ 28,790 Financial liabilities: Senior notes due 2023* $ 250,000 $ 248,668 $ 250,000 $ 248,153 Contribution Certificates $ 177,974 $ 141,551 $ 177,525 $ 134,479 Other liabilities $ 28,560 $ 28,560 $ 27,905 $ 27,905 * Carrying value excludes unamortized debt issuance costs.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-For-Sale Fixed Maturities	Available-for-sale fixed maturities at March 31, 2023 and December 31, 2022 included the following: March 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 $ 251,162 $ — $ 297 $ 18,433 $ 233,026 U.S. Government-sponsored enterprise obligations 20,466 — 5 1,324 19,147 State and municipal bonds 485,284 — 460 35,524 450,220 Corporate debt 1,925,268 — 1,267 174,854 1,751,681 Residential mortgage-backed securities 446,317 227 1,047 55,014 392,123 Agency commercial mortgage-backed securities 10,488 — — 881 9,607 Other commercial mortgage-backed securities 218,754 — 55 21,663 197,146 Other asset-backed securities 439,131 197 538 22,395 417,077 $ 3,796,870 $ 424 $ 3,669 $ 330,088 $ 3,470,027 December 31, 2022 (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 $ 243,999 $ — $ 8 $ 22,399 $ 221,608 U.S. Government-sponsored enterprise obligations 21,562 — — 1,628 19,934 State and municipal bonds 483,584 — 177 44,311 439,450 Corporate debt 1,980,579 — 735 199,862 1,781,452 Residential mortgage-backed securities 450,870 229 555 61,656 389,540 Agency commercial mortgage-backed securities 10,576 — — 872 9,704 Other commercial mortgage-backed securities 217,021 — 63 22,994 194,090 Other asset-backed securities 444,220 198 289 27,617 416,694 $ 3,852,411 $ 427 $ 1,827 $ 381,339 $ 3,472,472
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, 2023, 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 $ 251,162 $ 22,216 $ 173,595 $ 34,426 $ 2,789 $ 233,026 U.S. Government-sponsored enterprise obligations 20,466 2,786 12,184 4,177 — 19,147 State and municipal bonds 485,284 36,714 149,950 151,348 112,208 450,220 Corporate debt 1,925,268 195,164 847,544 618,778 90,195 1,751,681 Residential mortgage-backed securities 446,317 392,123 Agency commercial mortgage-backed securities 10,488 9,607 Other commercial mortgage-backed securities 218,754 197,146 Other asset-backed securities 439,131 417,077 $ 3,796,870 $ 3,470,027
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, 2023 and December 31, 2022, including the length of time the investment had been held in a continuous unrealized loss position. March 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 $ 219,842 $ 18,433 $ 30,688 $ 769 $ 189,154 $ 17,664 U.S. Government-sponsored enterprise obligations 18,849 1,324 7,044 490 11,805 834 State and municipal bonds 421,764 35,524 80,956 2,651 340,808 32,873 Corporate debt 1,650,437 174,854 313,062 11,674 1,337,375 163,180 Residential mortgage-backed securities 348,127 55,014 86,565 7,891 261,562 47,123 Agency commercial mortgage-backed securities 9,607 881 1,983 78 7,624 803 Other commercial mortgage-backed securities 195,923 21,663 21,224 690 174,699 20,973 Other asset-backed securities 374,159 22,395 53,135 1,449 321,024 20,946 $ 3,238,708 $ 330,088 $ 594,657 $ 25,692 $ 2,644,051 $ 304,396 December 31, 2022 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 $ 220,991 $ 22,399 $ 53,199 $ 2,393 $ 167,792 $ 20,006 U.S. Government-sponsored enterprise obligations 19,934 1,628 8,082 663 11,852 965 State and municipal bonds 421,769 44,311 177,393 12,352 244,376 31,959 Corporate debt 1,708,529 199,862 687,947 42,977 1,020,582 156,885 Residential mortgage-backed securities 363,945 61,656 155,212 15,275 208,733 46,381 Agency commercial mortgage-backed securities 9,704 872 3,086 110 6,618 762 Other commercial mortgage-backed securities 192,359 22,994 53,270 4,087 139,089 18,907 Other asset-backed securities 396,452 27,617 162,192 7,050 234,260 20,567 $ 3,333,683 $ 381,339 $ 1,300,381 $ 84,907 $ 2,033,302 $ 296,432
Schedule of a Roll Forward of Cumulative Credit Losses Recorded in Earnings Related to Impaired Debt Securities	The following table presents a roll forward of the allowance for expected credit losses on available-for-sale fixed maturities for the three months ended March 31, 2023. There was no allowance for expected credit losses for the three months ended March 31, 2022. 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
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) 2023 2022 Proceeds from sales (exclusive of maturities and paydowns) $ 3.8 $ 63.5 Purchases $ 68.8 $ 231.6
Schedule of Net Investment Income	Net investment income (loss) by investment category was as follows: Three Months Ended (In thousands) 2023 2022 Fixed maturities $ 27,327 $ 21,544 Equities 807 701 Short-term investments, including Other 3,350 426 BOLI 657 (47) Investment fees and expenses (1,831) (2,181) Net investment income $ 30,310 $ 20,443
Schedule of Investment in Unconsolidated Subsidiaries	ProAssurance's investment in unconsolidated subsidiaries were as follows: March 31, 2023 Carrying Value (In thousands) Percentage March 31, December 31, Qualified affordable housing project tax credit partnerships See below $ 2,727 $ 4,088 All other investments, primarily investment fund LPs/LLCs See below 294,810 301,122 $ 297,537 $ 305,210
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) 2023 2022 Qualified affordable housing project tax credit partnerships Losses recorded $ 354 $ 2,388 Tax credits recognized $ 43 $ 1,205 The following table presents aggregated gross summarized financial information for the fund that ProAssurance determined to be significant as of March 31, 2023, including the portion not attributable to ProAssurance, derived from the fund's financial statements which are prepared in accordance with GAAP. As the majority of ProAssurance's equity method investments report their results to the Company on a one quarter lag, the majority of the summarized financial information below is for the three months ended December 31, 2022 and 2021. (In thousands) Three Months Ended March 31 2023 2022 Net investment income (loss) $ (2,890) $ (3,582) Net investment gains (losses) (58,387) 42 Net change in unrealized appreciation (depreciation) (31,458) 41,585 Net gain (loss) $ (92,735) $ 38,045 Net gain (loss) attributable to ProAssurance (1) $ (3,174) $ 1,299 (1) Represents ProAssurance's share of the fund's aggregate income or loss, which is included as a component of equity in earnings (loss) of unconsolidated subsidiaries in its Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and 2022.
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) 2023 2022 Total impairment losses: Corporate debt $ (2,936) $ — Asset-backed securities 3 — Net impairment losses recognized in earnings (2,933) — Gross realized gains, available-for-sale fixed maturities 79 1,187 Gross realized (losses), available-for-sale fixed maturities (457) (1,124) Net realized gains (losses), trading fixed maturities (108) (75) Net realized gains (losses), equity investments 84 (220) Net realized gains (losses), other investments 229 650 Change in unrealized holding gains (losses), trading fixed maturities 97 (326) Change in unrealized holding gains (losses), equity investments 3,746 (11,485) Change in unrealized holding gains (losses), convertible securities, carried at fair value 1,132 (2,476) Other (1) 1,043 363 Net investment gains (losses) $ 2,912 $ (13,506) (1) Includes a gain of $1.0 million recognized during the 2023 three-month period reflecting 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 discussion on the Company's accounting policy in Note 1 in its December 31, 2022 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, 2023
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, 2023 Three Months Ended March 31, 2022 Year Ended December 31, 2022 Balance, beginning of year $ 3,471,147 $ 3,579,940 $ 3,579,940 Less reinsurance recoverables on unpaid losses and loss adjustment expenses 431,889 451,741 451,741 Net balance, beginning of year 3,039,258 3,128,199 3,128,199 Net losses: Current year (1) 198,240 214,753 813,515 (Favorable) unfavorable development of reserves established in prior years, net (2) 7,056 (5,330) (36,753) Total 205,296 209,423 776,762 Paid related to: Current year (11,052) (13,179) (108,139) Prior years (211,916) (185,977) (757,564) Total paid (222,968) (199,156) (865,703) Net balance, end of period 3,021,586 3,138,466 3,039,258 Plus reinsurance recoverables on unpaid losses and loss adjustment expenses 447,693 464,780 431,889 Balance, end of period $ 3,469,279 $ 3,603,246 $ 3,471,147 (1) Current year net losses for the three months ended March 31, 2022 and year ended December 31, 2022 included $2.5 million and $4.9 million, respectively, of purchase accounting amortization of the negative VOBA associated with NORCAL's assumed unearned premium, which was amortized over a period in proportion to the earn-out of the associated premium as a reduction to current accident year net losses (see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2022 report on Form 10-K). As of June 30, 2022, the negative VOBA was fully amortized. (2) Net prior year reserve development recognized for the three months ended March 31, 2023 and 2022 as well as the year ended December 31, 2022 included $2.5 million, $2.9 million and $10.8 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 (see Note 2 of the Notes to Consolidated Financial Statements in ProAssurance's December 31, 2022 report on Form 10-K).

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2023
Debt Disclosure [Abstract]
Schedule of Outstanding Debt	ProAssurance’s outstanding debt consisted of the following: ($ in thousands) March 31, December 31, Senior Notes due 2023, unsecured, interest at 5.3% annually $ 250,000 $ 250,000 Contribution Certificates due 2031, interest at 3.0% (effective interest rate at 4.35%) paid annually in April 177,974 177,525 Total principal 427,974 427,525 Less unamortized debt issuance costs 448 542 Debt less unamortized debt issuance costs $ 427,526 $ 426,983

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2023
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, 2023 and 2022 were as follows: (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) (In thousands) Unrealized Investment Gains (Losses) Unrecognized Change in Defined Benefit Plan Liabilities Accumulated Other Comprehensive Income (Loss) Balance, December 31, 2021 $ 14,929 $ 1,355 $ 16,284 OCI, before reclassifications, net of tax (140,808) — (140,808) Amounts reclassified from AOCI, net of tax (28) (14) (42) Net OCI, current period (140,836) (14) (140,850) Balance, March 31, 2022 $ (125,907) $ 1,341 $ (124,566)

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2023
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 2023 2022 Weighted average number of common shares outstanding, basic 53,987 54,012 Dilutive effect of securities: Restricted Share Units 103 114 Performance Share Units 27 17 Weighted average number of common shares outstanding, diluted 54,117 54,143 Effect of dilutive shares on earnings (loss) per share $ — $ —

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2023
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 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, 2023 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Lloyd's Syndicates Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 179,344 $ 40,803 $ 15,300 $ 4,340 $ — $ — $ 239,787 Net investment income — — 420 188 29,702 — 30,310 Equity in earnings (loss) of unconsolidated subsidiaries — — — — (1,121) — (1,121) Net investment gains (losses) — — 1,160 (11) 763 — 1,912 Other income (expense) (1) 993 581 1 (3) 327 (1,112) 787 Net losses and loss adjustment expenses (164,051) (30,844) (8,423) (1,978) — — (205,296) Underwriting, policy acquisition and operating expenses (1) (40,961) (12,980) (5,035) (1,720) (8,204) 1,112 (67,788) SPC U.S. federal income tax 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 $ (24,675) $ (2,440) $ 949 $ 816 $ 18,176 $ — (7,174) Reconciliation of segments to consolidated results: Contingent Consideration Adjustment (3) 1,000 Net income (loss) $ (6,174) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,640 $ 869 $ 64 $ 1 $ 4,103 $ — $ 7,677 Three Months Ended March 31, 2022 (In thousands) Specialty P&C Workers' Compensation Insurance Segregated Portfolio Cell Reinsurance Lloyd's Syndicates Corporate Inter-segment Eliminations Consolidated Net premiums earned $ 197,967 $ 40,684 $ 19,314 $ 7,746 $ — $ — $ 265,711 Net investment income — — 112 211 20,120 — 20,443 Equity in earnings (loss) of unconsolidated subsidiaries — — — — 7,620 — 7,620 Net investment gains (losses) — — (711) (399) (12,396) — (13,506) Other income (expense) (1) 1,019 682 1 134 2,065 (1,097) 2,804 Net losses and loss adjustment expenses (165,958) (27,211) (11,491) (4,763) — — (209,423) Underwriting, policy acquisition and operating expenses (1) (42,878) (13,001) (4,369) (2,709) (8,739) 1,097 (70,599) SPC U.S. federal income tax expense (2) — — (642) — — — (642) SPC dividend (expense) income — — (2,367) — — — (2,367) Interest expense — — — — (4,441) — (4,441) Income tax benefit (expense) — — — — 1,770 — 1,770 Segment results $ (9,850) $ 1,154 $ (153) $ 220 $ 5,999 $ — (2,630) Reconciliation of segments to consolidated results: Transaction-related costs (4) (930) Net income (loss) $ (3,560) Significant non-cash items: Depreciation and amortization, net of accretion $ 2,592 $ 874 $ 370 $ 14 $ 6,500 $ — $ 10,350 (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 Consolidated Statements of Income and Comprehensive Income. See further discussion on the contingent consideration in Note 2. (4) Represents the transaction-related costs, after-tax, associated with the acquisition of NORCAL. For the three months ended March 31, 2022 pre-tax transaction-related costs of approximately $1.2 million were included as a component of consolidated operating expense and the associated income tax benefit of approximately $0.3 million were included as a component of consolidated income tax benefit (expense) on the Condensed Consolidated Statements of Income and Comprehensive Income.
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) 2023 2022 Specialty P&C Segment Gross premiums earned: HCPL $ 162,387 $ 175,547 Small Business Unit 26,074 26,538 Medical Technology Liability 10,546 10,000 Other — 194 Ceded premiums earned (19,663) (14,312) Segment net premiums earned 179,344 197,967 Workers' Compensation Insurance Segment Gross premiums earned: Traditional business 43,540 43,156 Alternative market business 17,626 17,878 Ceded premiums earned (20,363) (20,350) Segment net premiums earned 40,803 40,684 Segregated Portfolio Cell Reinsurance Segment Gross premiums earned: Workers' compensation (1) 16,304 17,178 HCPL (2) 1,299 4,486 Ceded premiums earned (2,303) (2,350) Segment net premiums earned 15,300 19,314 Lloyd's Syndicates Segment Gross premiums earned: Property and casualty 5,046 9,232 Ceded premiums earned (706) (1,486) Segment net premiums earned 4,340 7,746 Consolidated net premiums earned $ 239,787 $ 265,711 (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.

Benefit Plans (Tables)

Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2023
Retirement Benefits [Abstract]
Schedule of Net Periodic Benefit Cost	The components of the net periodic benefit cost (income) for the three months ended March 31, 2023 and 2022 were as follows: ($ in thousands) Three Months Ended 2023 2022 Components of net periodic benefit cost (income): Interest cost $ 904 $ 711 Expected return on Plan assets (874) (989) Total net periodic benefit cost (income)* $ 30 $ (278) *Net periodic benefit cost (income) is included as a component of operating expense on the Condensed Consolidated Statements of Income and Comprehensive Income for the three months ended March 31, 2023 and 2022.

Basis of Presentation (Narrativ

Basis of Presentation (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable segments | segment	5
Percent of investments with exposure to LIBOR	6%
Investments with exposure to LIBOR	$ 246
Percent of investments with exposure to LIBOR, with provision for alternative benchmark rate	63%
Refund payments	$ 3.8

Fair Value Measurement (Assets

Fair Value Measurement (Assets Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets:
Fixed maturities, available-for-sale	$ 3,470,027	$ 3,472,472
Fixed maturities, trading	44,818	43,434
Equity investments	146,868	143,738
Level 3
Liabilities:
Other liabilities	13,000	15,000
U.S. Treasury obligations
Assets:
Fixed maturities, available-for-sale	233,026	221,608
U.S. Government-sponsored enterprise obligations
Assets:
Fixed maturities, available-for-sale	19,147	19,934
State and municipal bonds
Assets:
Fixed maturities, available-for-sale	450,220	439,450
Corporate debt, limited observable inputs | Level 3
Assets:
Fixed maturities, available-for-sale	76,157	63,973
Residential mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	392,123	389,540
Agency commercial mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	9,607	9,704
Other commercial mortgage-backed securities
Assets:
Fixed maturities, available-for-sale	197,146	194,090
Other asset-backed securities
Assets:
Fixed maturities, available-for-sale	417,077	416,694
Recurring
Assets:
Total assets categorized within the fair value hierarchy	4,258,208	4,259,889
Recurring | Level 1
Assets:
Fixed maturities, trading	0	0
Total assets categorized within the fair value hierarchy	300,621	322,534
Liabilities:
Other liabilities	0	0
Total liabilities categorized within the fair value hierarchy	0	0
Recurring | Level 2
Assets:
Fixed maturities, trading	44,818	43,434
Total assets categorized within the fair value hierarchy	3,613,546	3,603,357
Liabilities:
Other liabilities	0	0
Total liabilities categorized within the fair value hierarchy	0	0
Recurring | Level 3
Assets:
Fixed maturities, trading	0	0
Total assets categorized within the fair value hierarchy	84,511	71,513
Liabilities:
Other liabilities	13,000	15,000
Total liabilities categorized within the fair value hierarchy	13,000	15,000
Recurring | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, trading	44,818	43,434
Total assets categorized within the fair value hierarchy	3,998,678	3,997,404
Liabilities:
Other liabilities	13,000	15,000
Total liabilities categorized within the fair value hierarchy	13,000	15,000
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	233,026	221,608
Recurring | U.S. Treasury obligations | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | U.S. Treasury obligations | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	233,026	221,608
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	19,147	19,934
Recurring | U.S. Government-sponsored enterprise 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	19,147	19,934
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	450,220	439,450
Recurring | State and municipal bonds | 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	450,220	439,450
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	1,675,524	1,717,479
Recurring | Corporate debt, multiple observable inputs | 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	1,675,524	1,717,479
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	76,157	63,973
Recurring | Corporate debt, limited observable inputs | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	76,157	63,973
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	391,834	389,291
Recurring | Residential mortgage-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	289	249
Recurring | Residential mortgage-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	392,123	389,540
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	9,607	9,704
Recurring | Agency commercial mortgage-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	0	0
Recurring | Agency commercial mortgage-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	9,607	9,704
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	197,146	194,090
Recurring | Other 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	197,146	194,090
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	412,312	413,989
Recurring | Other asset-backed securities | Level 3
Assets:
Fixed maturities, available-for-sale	4,765	2,705
Recurring | Other asset-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Fixed maturities, available-for-sale	417,077	416,694
Recurring | Financial | Level 1
Assets:
Equity investments	9,924	9,850
Recurring | Financial | Level 2
Assets:
Equity investments	2,232	2,219
Recurring | Financial | Level 3
Assets:
Equity investments	300	303
Recurring | Financial | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	12,456	12,372
Recurring | Utilities/Energy | Level 1
Assets:
Equity investments	956	854
Recurring | Utilities/Energy | Level 2
Assets:
Equity investments	0	0
Recurring | Utilities/Energy | Level 3
Assets:
Equity investments	0	0
Recurring | Utilities/Energy | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	956	854
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	2,500	2,500
Recurring | Industrial | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	2,500	2,500
Recurring | Bond funds | Level 1
Assets:
Equity investments	114,618	112,136
Recurring | Bond funds | Level 2
Assets:
Equity investments	0	0
Recurring | Bond funds | Level 3
Assets:
Equity investments	0	0
Recurring | Bond funds | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	114,618	112,136
Recurring | All other | Level 1
Assets:
Equity investments	16,338	15,876
Recurring | All other | Level 2
Assets:
Equity investments	0	0
Recurring | All other | Level 3
Assets:
Equity investments	0	0
Recurring | All other | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Equity investments	16,338	15,876
Recurring | Short-term investments | Level 1
Assets:
Short-term and other investments	156,871	181,937
Recurring | Short-term investments | Level 2
Assets:
Short-term and other investments	94,156	63,376
Recurring | Short-term investments | Level 3
Assets:
Short-term and other investments	0	0
Recurring | Short-term investments | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Short-term and other investments	251,027	245,313
Recurring | Other investments | Level 1
Assets:
Short-term and other investments	1,914	1,881
Recurring | Other investments | Level 2
Assets:
Short-term and other investments	83,524	88,783
Recurring | Other investments | Level 3
Assets:
Short-term and other investments	500	1,783
Recurring | Other investments | Fair Value, Inputs, Level 1, 2 and 3
Assets:
Short-term and other investments	85,938	92,447
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	$ 259,530	$ 262,485

Fair Value Measurement (Quantit

Fair Value Measurement (Quantitative Information Regarding Level 3 Valuations) (Details) $ in Thousands	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Assets:
Estimated Fair Value	$ 3,470,027	$ 3,472,472
Other investments	259,530	262,485
Level 3
Assets:
Equity investments	2,800	2,803
Other investments	500	1,783
Liabilities:
Other liabilities	$ 13,000	15,000
Level 3 | Comparability Adjustment | Minimum
Assets:
Equity securities measured at fair value	0
Level 3 | Comparability Adjustment | Maximum
Assets:
Equity securities measured at fair value	0.10
Level 3 | Comparability Adjustment | Weighted Average
Assets:
Equity securities measured at fair value	0.05
Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Other investments, measurement input	0
Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Other investments, measurement input	0.10
Level 3 | Comparability Adjustment | Discounted Cash Flows | Weighted Average
Assets:
Other investments, measurement input	0.05
Level 3 | Comparability Adjustment | Stochastic Model/Discounted Cash Flows | Minimum
Liabilities:
Other liabilities, measurement input	0%
Level 3 | Comparability Adjustment | Stochastic Model/Discounted Cash Flows | Maximum
Liabilities:
Other liabilities, measurement input	10%
Level 3 | Comparability Adjustment | Stochastic Model/Discounted Cash Flows | Weighted Average
Liabilities:
Other liabilities, measurement input	9%
Corporate debt, limited observable inputs | Level 3
Assets:
Estimated Fair Value	$ 76,157	63,973
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 securities | Level 3
Assets:
Estimated Fair Value	$ 289	249
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Minimum
Assets:
Assets measured at fair value	0
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Maximum
Assets:
Assets measured at fair value	0.05
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Weighted Average
Assets:
Assets measured at fair value	0.025
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Assets measured at fair value	0
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Assets measured at fair value	0.05
Residential mortgage-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Weighted Average
Assets:
Assets measured at fair value	0.025
Other asset-backed securities | Level 3
Assets:
Estimated Fair Value	$ 4,765	$ 2,705
Other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Minimum
Assets:
Assets measured at fair value	0
Other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Maximum
Assets:
Assets measured at fair value	0.05
Other asset-backed securities | Level 3 | Comparability Adjustment | Market Comparable Securities | Weighted Average
Assets:
Assets measured at fair value	0.025
Other asset-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Minimum
Assets:
Assets measured at fair value	0
Other asset-backed securities | Level 3 | Comparability Adjustment | Discounted Cash Flows | Maximum
Assets:
Assets measured at fair value	0.05
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, 2023	Mar. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 71,513	$ 57,565
Included in earnings, as a part of:
Included in earnings	13
Operating expense	0
Included in other comprehensive income (loss)	248	$ (1,253)
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
Purchases	8,185	$ 16,779
Sales	(432)	(1,140)
Transfers in	12,999	1,529
Transfers out	(8,015)	(5,023)
Ending balance	84,511	68,568
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	$ (3)	$ 64
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	$ (15,000)	$ (24,000)
Total gains (losses) realized and unrealized:
Net investment gains (losses)	1,000	0
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	(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
Net Investment Income
Included in earnings, as a part of:
Included in earnings		$ 1
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Net investment income (loss)
Net investment gains (losses)
Included in earnings, as a part of:
Included in earnings		$ 110
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Gain (Loss) on Investments
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	63,973	$ 47,129
Included in earnings, as a part of:
Included in earnings	16	0
Operating expense	0
Included in other comprehensive income (loss)	209	(993)
Purchases	6,322	9,711
Sales	(432)	(1,019)
Transfers in	11,220	1,000
Transfers out	(5,151)	(2,503)
Ending balance	76,157	53,325
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	2,954	6,502
Included in earnings, as a part of:
Included in earnings	0	1
Operating expense	0
Included in other comprehensive income (loss)	39	(260)
Purchases	1,863	5,585
Sales	0	(5)
Transfers in	1,779	0
Transfers out	(1,581)	(2,520)
Ending balance	5,054	9,303
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	2,803	2,500
Included in earnings, as a part of:
Included in earnings	(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	2,800	2,500
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	(3)	0
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,783	1,434
Included in earnings, as a part of:
Included in earnings	0	110
Operating expense	0
Included in other comprehensive income (loss)	0	0
Purchases	0	1,483
Sales	0	(116)
Transfers in	0	529
Transfers out	(1,283)	0
Ending balance	500	3,440
Change in unrealized gains (losses) included in earnings for the above period for Level 3 assets and liabilities held at period-end	0	64
Other Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(15,000)	(24,000)
Total gains (losses) realized and unrealized:
Net investment gains (losses)	1,000	0
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	(13,000)	(24,000)
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, 2023 USD ($) fund	Dec. 31, 2022 USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 259,530	$ 262,485
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 Commitments	$ 1,958
Fair Value	$ 19,731	19,620
Long/short equity funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
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 Commitments	$ 0
Fair Value	$ 4,611	5,089
Non-public equity funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
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 Commitments	$ 49,373
Fair Value	$ 142,438	144,560
Credit funds
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Number of limited partners to allow redemption by special consent | fund	1
Investment redemption notice period	180 days
Credit funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	$ 34,482
Fair Value	49,600	49,245
Strategy focused funds | Investment in unconsolidated subsidiaries
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Unfunded Commitments	14,162
Fair Value	$ 43,150	$ 43,971

Fair Value Measurement (Narrati

Fair Value Measurement (Narrative) (Details)	Mar. 31, 2023 USD ($) subsidiary	Dec. 31, 2022 USD ($)
Credit Derivatives [Line Items]
Fair value of funded deferred compensation assets	$ 28,900,000	$ 27,900,000
FHLB
Credit Derivatives [Line Items]
Number of proassurance's insurance subsidiaries | subsidiary	3
Fair Value
Credit Derivatives [Line Items]
Deferred compensation liabilities	$ 28,600,000	27,900,000
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, 2023	Dec. 31, 2022
Carrying Value
Financial assets:
Other assets	$ 29,804	$ 28,819
Financial liabilities:
Long-term Debt and Contribution Certificates, Fair Value Disclosure	177,974
Other liabilities	28,560	27,905
Carrying Value | Senior Notes
Financial liabilities:
Debt instruments	250,000	250,000
Carrying Value | Contribution Certificates
Financial liabilities:
Long-term Debt and Contribution Certificates, Fair Value Disclosure		177,525
Carrying Value | BOLI
Financial assets:
Short-term and other investments	82,402	81,746
Carrying Value | Other investments
Financial assets:
Short-term and other investments	3,031	3,322
Fair Value
Financial assets:
Other assets	29,776	28,790
Financial liabilities:
Long-term Debt and Contribution Certificates, Fair Value Disclosure	141,551
Other liabilities	28,560	27,905
Fair Value | Senior Notes
Financial liabilities:
Debt instruments	248,668	248,153
Fair Value | Contribution Certificates
Financial liabilities:
Long-term Debt and Contribution Certificates, Fair Value Disclosure		134,479
Fair Value | BOLI
Financial assets:
Short-term and other investments	82,402	81,746
Fair Value | Other investments
Financial assets:
Short-term and other investments	$ 3,031	$ 3,322

Investments (Available-For-Sale

Investments (Available-For-Sale Fixed Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 3,796,870	$ 3,852,411
Allowance for Expected Credit Losses	424	427
Gross Unrealized Gains	3,669	1,827
Gross Unrealized Losses	330,088	381,339
Estimated Fair Value	3,470,027	3,472,472
U.S. Treasury obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	251,162	243,999
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	297	8
Gross Unrealized Losses	18,433	22,399
Estimated Fair Value	233,026	221,608
U.S. Government-sponsored enterprise obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	20,466	21,562
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	5	0
Gross Unrealized Losses	1,324	1,628
Estimated Fair Value	19,147	19,934
State and municipal bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	485,284	483,584
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	460	177
Gross Unrealized Losses	35,524	44,311
Estimated Fair Value	450,220	439,450
Corporate debt
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,925,268	1,980,579
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	1,267	735
Gross Unrealized Losses	174,854	199,862
Estimated Fair Value	1,751,681	1,781,452
Residential mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	446,317	450,870
Allowance for Expected Credit Losses	227	229
Gross Unrealized Gains	1,047	555
Gross Unrealized Losses	55,014	61,656
Estimated Fair Value	392,123	389,540
Agency commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	10,488	10,576
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	881	872
Estimated Fair Value	9,607	9,704
Other commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	218,754	217,021
Allowance for Expected Credit Losses	0	0
Gross Unrealized Gains	55	63
Gross Unrealized Losses	21,663	22,994
Estimated Fair Value	197,146	194,090
Other asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	439,131	444,220
Allowance for Expected Credit Losses	197	198
Gross Unrealized Gains	538	289
Gross Unrealized Losses	22,395	27,617
Estimated Fair Value	$ 417,077	$ 416,694

Investments (Available-For-Sa_2

Investments (Available-For-Sale Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 3,796,870	$ 3,852,411
Total Fair Value	3,470,027	3,472,472
U.S. Treasury obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	251,162	243,999
Due in one year or less	22,216
Due after one year through five years	173,595
Due after five years through ten years	34,426
Due after ten years	2,789
Total Fair Value	233,026	221,608
U.S. Government-sponsored enterprise obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	20,466	21,562
Due in one year or less	2,786
Due after one year through five years	12,184
Due after five years through ten years	4,177
Due after ten years	0
Total Fair Value	19,147	19,934
State and municipal bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	485,284	483,584
Due in one year or less	36,714
Due after one year through five years	149,950
Due after five years through ten years	151,348
Due after ten years	112,208
Total Fair Value	450,220	439,450
Corporate debt
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	1,925,268	1,980,579
Due in one year or less	195,164
Due after one year through five years	847,544
Due after five years through ten years	618,778
Due after ten years	90,195
Total Fair Value	1,751,681	1,781,452
Residential mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	446,317	450,870
Total Fair Value	392,123	389,540
Agency commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	10,488	10,576
Total Fair Value	9,607	9,704
Other commercial mortgage-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	218,754	217,021
Total Fair Value	197,146	194,090
Other asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	439,131	444,220
Total Fair Value	$ 417,077	$ 416,694

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) business security investment issuer	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) issuer security business
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	$ 54,300
Investment in unconsolidated subsidiaries	$ 297,537		$ 305,210
Number of LPs / LLCs with investment ownership percent over 25% (in businesses) | business	4		3
Net impairment losses recognized in earnings	$ (2,933)	$ 0
Asset Pledged as Collateral
Debt Securities, Available-for-Sale [Line Items]
Securities on deposit with state insurance departments	31,600
Tax Year 2019
Debt Securities, Available-for-Sale [Line Items]
Tax credit partnership investments	2,300	2,000
Tax Year 2039
Debt Securities, Available-for-Sale [Line Items]
Tax credit carryforwards	53,600
Tax Credit Partnership Investment Tax Credit Carryforward | Tax Year 2020
Debt Securities, Available-for-Sale [Line Items]
Tax credit partnership investments		$ 1,200
Tax Credit Partnerships Less Than 20% Ownership
Debt Securities, Available-for-Sale [Line Items]
Investment in unconsolidated subsidiaries	$ 2,700		$ 4,100
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	$ 46,000		36,000
Other Limited Partnerships and Limited Liability Company Less than 25% Ownership
Debt Securities, Available-for-Sale [Line Items]
Investment in unconsolidated subsidiaries	248,800		$ 265,100
Fixed maturities
Debt Securities, Available-for-Sale [Line Items]
Required FAL deposit	20,500
Cash and cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Required FAL deposit	$ 4,600
Non government-backed
Debt Securities, Available-for-Sale [Line Items]
Debt securities in unrealized loss position (in securities) | security	2,809		2,901
Debt securities in unrealized loss position as percentage of total debt securities held	72.60%		74.40%
Issuers in unrealized loss position (in issuers) | issuer	1,416		1,433
Single greatest unrealized loss position	$ 5,200		$ 5,700
Second greatest unrealized loss position	$ 3,500		$ 4,100

Investments (Investments Held i

Investments (Investments Held in a Loss Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair value
Fair Value	$ 3,238,708	$ 3,333,683
Less than 12 months, Fair Value	594,657	1,300,381
12 months or longer, Fair Value	2,644,051	2,033,302
Unrealized Loss
Unrealized Loss	330,088	381,339
Less than 12 months, Unrealized Loss	25,692	84,907
12 months or longer, Unrealized Loss	304,396	296,432
U.S. Treasury obligations
Fair value
Fair Value	219,842	220,991
Less than 12 months, Fair Value	30,688	53,199
12 months or longer, Fair Value	189,154	167,792
Unrealized Loss
Unrealized Loss	18,433	22,399
Less than 12 months, Unrealized Loss	769	2,393
12 months or longer, Unrealized Loss	17,664	20,006
U.S. Government-sponsored enterprise obligations
Fair value
Fair Value	18,849	19,934
Less than 12 months, Fair Value	7,044	8,082
12 months or longer, Fair Value	11,805	11,852
Unrealized Loss
Unrealized Loss	1,324	1,628
Less than 12 months, Unrealized Loss	490	663
12 months or longer, Unrealized Loss	834	965
State and municipal bonds
Fair value
Fair Value	421,764	421,769
Less than 12 months, Fair Value	80,956	177,393
12 months or longer, Fair Value	340,808	244,376
Unrealized Loss
Unrealized Loss	35,524	44,311
Less than 12 months, Unrealized Loss	2,651	12,352
12 months or longer, Unrealized Loss	32,873	31,959
Corporate debt
Fair value
Fair Value	1,650,437	1,708,529
Less than 12 months, Fair Value	313,062	687,947
12 months or longer, Fair Value	1,337,375	1,020,582
Unrealized Loss
Unrealized Loss	174,854	199,862
Less than 12 months, Unrealized Loss	11,674	42,977
12 months or longer, Unrealized Loss	163,180	156,885
Residential mortgage-backed securities
Fair value
Fair Value	348,127	363,945
Less than 12 months, Fair Value	86,565	155,212
12 months or longer, Fair Value	261,562	208,733
Unrealized Loss
Unrealized Loss	55,014	61,656
Less than 12 months, Unrealized Loss	7,891	15,275
12 months or longer, Unrealized Loss	47,123	46,381
Agency commercial mortgage-backed securities
Fair value
Fair Value	9,607	9,704
Less than 12 months, Fair Value	1,983	3,086
12 months or longer, Fair Value	7,624	6,618
Unrealized Loss
Unrealized Loss	881	872
Less than 12 months, Unrealized Loss	78	110
12 months or longer, Unrealized Loss	803	762
Other commercial mortgage-backed securities
Fair value
Fair Value	195,923	192,359
Less than 12 months, Fair Value	21,224	53,270
12 months or longer, Fair Value	174,699	139,089
Unrealized Loss
Unrealized Loss	21,663	22,994
Less than 12 months, Unrealized Loss	690	4,087
12 months or longer, Unrealized Loss	20,973	18,907
Other asset-backed securities
Fair value
Fair Value	374,159	396,452
Less than 12 months, Fair Value	53,135	162,192
12 months or longer, Fair Value	321,024	234,260
Unrealized Loss
Unrealized Loss	22,395	27,617
Less than 12 months, Unrealized Loss	1,449	7,050
12 months or longer, Unrealized Loss	$ 20,946	$ 20,567

Investments (Credit Losses Rela

Investments (Credit Losses Related to Debt Securities) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	$ 427
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(3)
Allowance for credit loss ending balance	424
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	229
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(2)
Allowance for credit loss ending balance	227
Other asset-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss beginning balance	198
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(1)
Allowance for credit loss ending balance	$ 197

Investments (Sales and Purchase

Investments (Sales and Purchases of Available-for-Sale Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Information regarding sales and purchases of available-for-sale securities
Proceeds from sales (exclusive of maturities and paydowns)	$ 3,800	$ 63,500
Purchases	$ 68,755	$ 231,557

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net Investment Income
Investment fees and expenses	$ (1,831)	$ (2,181)
Net investment income	30,310	20,443
Fixed maturities
Net Investment Income
Net investment income (loss)	27,327	21,544
Equities
Net Investment Income
Net investment income (loss)	807	701
Short-term investments, including Other
Net Investment Income
Net investment income (loss)	3,350	426
BOLI
Net Investment Income
BOLI	$ 657	$ (47)

Investments (Unconsolidated Sub

Investments (Unconsolidated Subsidiaries) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	$ 297,537	$ 305,210
Qualified affordable housing project tax credit partnerships
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	2,727	4,088
All other investments, primarily investment fund LPs/LLCs
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated subsidiaries	$ 294,810	$ 301,122

Investments (Equity in Earnings

Investments (Equity in Earnings (Loss) of Unconsolidated Subsidiaries) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Losses recorded	$ 354	$ 2,388
Tax credits recognized	$ 43	$ 1,205

Investments (Summarized Financi

Investments (Summarized Financial Information for Significant Investment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Schedule of Equity Method Investments [Line Items]
Net investment income (loss)	$ 30,310	$ 20,443
Total net investment gains (losses)	2,912	(13,506)
Net gain (loss) attributable to proassurance	(6,174)	(3,560)
Significant Equity Method Investees
Schedule of Equity Method Investments [Line Items]
Net investment income (loss)	(2,890)	(3,582)
Net investment gains (losses)	(58,387)	42
Net change in unrealized appreciation (depreciation)	(31,458)	41,585
Total net investment gains (losses)	(92,735)	38,045
Net gain (loss) attributable to proassurance	$ (3,174)	$ 1,299

Investments (Net Realized Inves

Investments (Net Realized Investment Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	$ (2,933)	$ 0
Net impairment losses recognized in earnings	(2,933)	0
Gross realized gains, available-for-sale fixed maturities	79	1,187
Gross realized (losses), available-for-sale fixed maturities	(457)	(1,124)
Net realized gains (losses), trading fixed maturities	(108)	(75)
Net realized gains (losses), equity investments	84	(220)
Net realized gains (losses), other investments	229	650
Change in unrealized holding gains (losses), trading fixed maturities	97	(326)
Change in unrealized holding gains (losses), equity investments	3,746	(11,485)
Change in unrealized holding gains (losses), convertible securities, carried at fair value	1,132	(2,476)
Other	1,043	363
Total net investment gains (losses)	2,912	(13,506)
Corporate Debt
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	(2,936)	0
Asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Total impairment losses:	(3)	$ 0
NORCAL Group
Debt Securities, Available-for-Sale [Line Items]
Gain on fair value of contingent consideration	$ 1,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Decrease in contingent consideration liability	$ 2
Income taxes payable	(4.5)
Income taxes receivable		$ 8
Unrecognized tax benefits	4.1
Accrued liability for interest related to unrecognized tax benefits	0.5
Tax Year 2020
Income Tax Contingency [Line Items]
Operating loss carryforwards	33.3
Income tax refund, CARES Act	$ 11.7

Reserve for Losses and Loss A_3

Reserve for Losses and Loss Adjustment Expenses (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023 USD ($) claim	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
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	$ 3,471,147	$ 3,579,940	$ 3,579,940
Less reinsurance recoverables on unpaid losses and loss adjustment expenses	431,889	451,741	451,741
Net balance, beginning of year	3,039,258	3,128,199	3,128,199
Net losses:
Current year	198,240	214,753	813,515
Favorable development of reserves established in prior years, net	7,056	(5,330)	(36,753)
Total	205,296	209,423	776,762
Paid related to:
Current year	(11,052)	(13,179)	(108,139)
Prior years	(211,916)	(185,977)	(757,564)
Total paid	(222,968)	(199,156)	(865,703)
Net balance, end of period	3,021,586	3,138,466	3,039,258
Plus reinsurance recoverables on unpaid losses and loss adjustment expenses	447,693	464,780	431,889
Balance, end of period	$ 3,469,279	3,603,246	3,471,147
Number of claims | claim	4
Net unfavorable prior year reserve development	$ 10,100
Net unfavorable prior year reserve development, years 2016 and 2020	$ 7,500
Number of claims, net unfavorable prior year reserve development, from 1997 accident year | claim	1
Specialty P&C Segment
Net losses:
Favorable development of reserves established in prior years, net	$ 5,000		9,000
Paid related to:
Increase in reserve for potential ECO/XPL claims	4,000
NORCAL Group
Net losses:
Current year		2,500	4,900
Favorable development of reserves established in prior years, net	$ 2,500	$ 2,900	$ 10,800

Commitments and Contingencies (

Commitments and Contingencies (Details) £ in Millions	1 Months Ended	3 Months Ended
	Nov. 30, 2021 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2023 GBP (£)	Dec. 31, 2022 USD ($)	May 05, 2021 USD ($)
NORCAL Group
Other Commitments [Line Items]
Contingent consideration, maximum estimate						$ 84,000,000
Fair value of contingent consideration in NORCAL acquisition		$ (13,000,000)			$ (15,000,000)
Data Analytics Services
Other Commitments [Line Items]
Non-renew notice, period		6 months
Purchase commitment, period	3 years
Annual fee	$ 3,500,000
Extension period for long-term purchase commitment		1 year
Operating expense		$ 900,000	$ 900,000
Purchase obligation		5,400,000
Funding Commitments
Other Commitments [Line Items]
Commitments total		184,800,000
Lloyd's Syndicates
Other Commitments [Line Items]
Current lending capacity under revolving credit agreement		$ 18,500,000		£ 15
Non-renew notice, period		30 days
Auto-renewal period prior to maturity date		1 year
Interest rate on revolving credit agreement		3.80%		3.80%
Outstanding borrowings		$ 0
Required FAL deposit		$ 25,100,000

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Gross debt	$ 427,974	$ 427,525
Less unamortized debt issuance costs	448	542
Debt less unamortized debt issuance costs	427,526	426,983
Senior notes due 2023 | Senior Notes
Debt Instrument [Line Items]
Gross debt	$ 250,000	250,000
Stated interest rate on debt	5.30%
Contribution Certificates
Debt Instrument [Line Items]
Gross debt	$ 177,974	$ 177,525
Stated interest rate on debt	3%
Effective interest rate on debt	4.35%

Debt (Narrative) (Details)

Debt (Narrative) (Details)		3 Months Ended
	Apr. 28, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Derivative, notional amount		$ 125,000,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit borrowing capacity		250,000,000
Accordion feature borrowing capacity		50,000,000
Line of credit, borrowing capacity including accordion feature		300,000,000
Outstanding borrowing		$ 0	$ 0
Maximum allowable consolidated funded indebtedness ratio (percent)		0.35
Minimum net worth required		$ 912,000,000
Minimum liquidity required		$ 25,000,000
Line of Credit | Revolving Credit Facility | Subsequent event
Debt Instrument [Line Items]
Construction loan	$ 125,000,000
Delayed term loan period	5 years
Line of Credit | Revolving Credit Facility | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate for debt		0.50%
Line of Credit | Revolving Credit Facility | One Month LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate for debt		1%
Line of Credit | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee percentages (percent)		0.20%
Basis spread on variable rate for debt		0%
Line of Credit | Revolving Credit Facility | Minimum | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Derivative, fixed interest rate		3.187%
Line of Credit | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee percentages (percent)		0.45%
Basis spread on variable rate for debt		2.375%
Line of Credit | Revolving Credit Facility | Maximum | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Derivative, fixed interest rate		3.207%

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
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)	$ 0.05	$ 0.05
Dividend declared	$ 2.7	$ 2.7
Total authorizations which remain available for use	106.4
Common shares acquired (in shares)		0
Deferred tax (benefit) expense included in OCI	$ 10.8	$ (38.2)

Shareholders' Equity (Roll Forw

Shareholders' Equity (Roll Forward of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,104,018	$ 1,428,387
OCI, before reclassifications, net of tax	40,007	(140,808)
Amounts reclassified from AOCI, net of tax	2,622	(42)
Net OCI, current period	42,629	(140,850)
Ending balance	1,138,290	1,281,768
Unrealized Investment Gains (Losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(297,142)	14,929
OCI, before reclassifications, net of tax	40,007	(140,808)
Amounts reclassified from AOCI, net of tax	2,622	(28)
Net OCI, current period	42,629	(140,836)
Ending balance	(254,513)	(125,907)
Non-credit Impairments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11)
OCI, before reclassifications, net of tax	0
Amounts reclassified from AOCI, net of tax	0
Net OCI, current period	0
Ending balance	(11)
Unrecognized Change in Defined Benefit Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,454)	1,355
OCI, before reclassifications, net of tax	0	0
Amounts reclassified from AOCI, net of tax	0	(14)
Net OCI, current period	0	(14)
Ending balance	(1,454)	1,341
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(298,607)	16,284
Ending balance	$ (255,978)	$ (124,566)

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
VIEs carrying value	$ 5,747,863	$ 5,699,999
Liabilities	4,609,573	4,595,981
Variable Interest Entity, Primary Beneficiary | PPM RRG
Variable Interest Entity [Line Items]
VIEs carrying value	143,000	154,000
Surplus Notes	5,000
Liabilities	143,000	154,000
Equity investments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIEs carrying value	$ 271,100	$ 277,500

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average number of common shares outstanding, basic (in shares)	53,987	54,012
Weighted average number of common shares outstanding, diluted (in shares)	54,117	54,143
Effect of dilutive shares on earnings (loss) per share (in usd per share)	$ 0	$ 0
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive securities (in shares)	103	114
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive securities (in shares)	27	17

Segment Information (Narrative)

Segment Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2023 segment
Segment Reporting Information [Line Items]
Number of reportable segments	5
Number of operating segments	5
Syndicate 1729
Segment Reporting Information [Line Items]
Proportion of capital provided to support Lloyd's Syndicate	5%

Segment Information (Financial

Segment Information (Financial Data by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Net premiums earned	$ 239,787	$ 265,711
Net investment income	30,310	20,443
Equity in earnings (loss) of unconsolidated subsidiaries	(1,121)	7,620
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	1,912
Net investment gains (losses)	2,912	(13,506)
Other income (expense)	787	2,804
Net losses and loss adjustment expenses	(205,296)	(209,423)
Underwriting, policy acquisition and operating expenses	(67,788)	(70,599)
SPC U.S. federal income taxes expense	(532)	(642)
SPC dividend (expense) income	(1,942)	(2,367)
Interest expense	(5,463)	(4,441)
Income tax benefit (expense)	2,172	1,770
Segment results	(7,174)	(2,630)
Contingent Consideration Adjustment	(2,000)	0
Net income (loss)	(6,174)	(3,560)
Depreciation and amortization, net of accretion	7,677	10,350
Income tax expense (benefit)	(2,172)	(2,017)
NORCAL Group
Segment Reporting Information [Line Items]
Transaction-related costs		(1,200)
Income tax expense (benefit)		300
Specialty P&C
Segment Reporting Information [Line Items]
Net premiums earned	179,344	197,967
Workers' Compensation Insurance
Segment Reporting Information [Line Items]
Net premiums earned	40,803	40,684
Segregated Portfolio Cell Reinsurance
Segment Reporting Information [Line Items]
Net premiums earned	15,300	19,314
Lloyd's Syndicates
Segment Reporting Information [Line Items]
Net premiums earned	4,340	7,746
Operating segments | Specialty P&C
Segment Reporting Information [Line Items]
Net premiums earned	179,344	197,967
Net investment income	0	0
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	0
Net investment gains (losses)		0
Other income (expense)	993	1,019
Net losses and loss adjustment expenses	(164,051)	(165,958)
Underwriting, policy acquisition and operating expenses	(40,961)	(42,878)
SPC U.S. federal income taxes expense	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	(24,675)	(9,850)
Depreciation and amortization, net of accretion	2,640	2,592
Operating segments | Workers' Compensation Insurance
Segment Reporting Information [Line Items]
Net premiums earned	40,803	40,684
Net investment income	0	0
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	0
Net investment gains (losses)		0
Other income (expense)	581	682
Net losses and loss adjustment expenses	(30,844)	(27,211)
Underwriting, policy acquisition and operating expenses	(12,980)	(13,001)
SPC U.S. federal income taxes expense	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	(2,440)	1,154
Depreciation and amortization, net of accretion	869	874
Operating segments | Segregated Portfolio Cell Reinsurance
Segment Reporting Information [Line Items]
Net premiums earned	15,300	19,314
Net investment income	420	112
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	1,160
Net investment gains (losses)		(711)
Other income (expense)	1	1
Net losses and loss adjustment expenses	(8,423)	(11,491)
Underwriting, policy acquisition and operating expenses	(5,035)	(4,369)
SPC U.S. federal income taxes expense	(532)	(642)
SPC dividend (expense) income	(1,942)	(2,367)
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	949	(153)
Depreciation and amortization, net of accretion	64	370
Operating segments | Lloyd's Syndicates
Segment Reporting Information [Line Items]
Net premiums earned	4,340	7,746
Net investment income	188	211
Equity in earnings (loss) of unconsolidated subsidiaries	0	0
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	(11)
Net investment gains (losses)		(399)
Other income (expense)	(3)	134
Net losses and loss adjustment expenses	(1,978)	(4,763)
Underwriting, policy acquisition and operating expenses	(1,720)	(2,709)
SPC U.S. federal income taxes expense	0	0
SPC dividend (expense) income	0	0
Interest expense	0	0
Income tax benefit (expense)	0	0
Segment results	816	220
Depreciation and amortization, net of accretion	1	14
Operating segments | Corporate
Segment Reporting Information [Line Items]
Net premiums earned	0	0
Net investment income	29,702	20,120
Equity in earnings (loss) of unconsolidated subsidiaries	(1,121)	7,620
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	763
Net investment gains (losses)		(12,396)
Other income (expense)	327	2,065
Net losses and loss adjustment expenses	0	0
Underwriting, policy acquisition and operating expenses	(8,204)	(8,739)
SPC U.S. federal income taxes expense	0	0
SPC dividend (expense) income	0	0
Interest expense	(5,463)	(4,441)
Income tax benefit (expense)	2,172	1,770
Segment results	18,176	5,999
Depreciation and amortization, net of accretion	4,103	6,500
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
Gain (Loss) on Investments, Excluding Contingent Consideration Adjustment	0
Net investment gains (losses)		0
Other income (expense)	(1,112)	(1,097)
Net losses and loss adjustment expenses	0	0
Underwriting, policy acquisition and operating expenses	1,112	1,097
SPC U.S. federal income taxes 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 Adjustment	$ 1,000
Transaction-related costs		$ (930)

Segment Information (Gross Prem

Segment Information (Gross Premiums Earned and Reconciliation to Net Premiums) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Segment net premiums earned	$ 239,787	$ 265,711
Specialty P&C Segment
Segment Reporting Information [Line Items]
Ceded premiums earned	(19,663)	(14,312)
Segment net premiums earned	179,344	197,967
Specialty P&C Segment | HCPL
Segment Reporting Information [Line Items]
Gross premiums earned:	162,387	175,547
Specialty P&C Segment | Small Business Unit
Segment Reporting Information [Line Items]
Gross premiums earned:	26,074	26,538
Specialty P&C Segment | Medical Technology Liability
Segment Reporting Information [Line Items]
Gross premiums earned:	10,546	10,000
Specialty P&C Segment | Other
Segment Reporting Information [Line Items]
Gross premiums earned:	0	194
Workers' Compensation Insurance Segment
Segment Reporting Information [Line Items]
Ceded premiums earned	(20,363)	(20,350)
Segment net premiums earned	40,803	40,684
Workers' Compensation Insurance Segment | Traditional business
Segment Reporting Information [Line Items]
Gross premiums earned:	43,540	43,156
Workers' Compensation Insurance Segment | Alternative market business
Segment Reporting Information [Line Items]
Gross premiums earned:	17,626	17,878
Segregated Portfolio Cell Reinsurance Segment
Segment Reporting Information [Line Items]
Ceded premiums earned	(2,303)	(2,350)
Segment net premiums earned	15,300	19,314
Segregated Portfolio Cell Reinsurance Segment | HCPL
Segment Reporting Information [Line Items]
Gross premiums earned:	1,299	4,486
Segregated Portfolio Cell Reinsurance Segment | Workers' compensation
Segment Reporting Information [Line Items]
Gross premiums earned:	16,304	17,178
Lloyd's Syndicates Segment
Segment Reporting Information [Line Items]
Gross premiums earned:	5,046	9,232
Ceded premiums earned	(706)	(1,486)
Segment net premiums earned	$ 4,340	$ 7,746

Benefit Plans (Components of Ne

Benefit Plans (Components of Net Periodic Benefit Cost Credit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined benefit pension plan, benefit basis, average of highest annual compensation period	5 years
Pension Plan
Components of net periodic benefit cost (income):
Interest cost	$ 904	$ 711
Expected return on Plan assets	(874)	(989)
Total net periodic benefit cost (income)	$ 30	$ (278)