James River (JRVR) 10-Q 5 May 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-36777
Entity Registrant Name	JAMES RIVER GROUP HOLDINGS, LTD.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-0585280
Entity Address, Address Line Three	Wellesley House
Entity Address, Address Line Two	2nd Floor
Entity Address, Address Line One	90 Pitts Bay Road
Entity Address, City or Town	Pembroke
Entity Address, Postal Zip Code	HM08
Entity Address, Country	BM
City Area Code	441
Local Phone Number	278-4580
Title of 12(b) Security	Common Shares, par value $0.0002 per share
Trading Symbol	JRVR
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		30,774,930
Entity Central Index Key	0001620459
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2021

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Invested assets:
Fixed maturity securities, available-for-sale, at fair value (amortized cost: 2021 – $1,755,733; 2020 – $1,690,890)	$ 1,800,151	$ 1,783,642
Equity securities, at fair value (cost:  2021 – $81,855; 2020 – $81,698)	90,877	88,975
Bank loan participations, at fair value	160,880	147,604
Short-term investments	51,198	130,289
Other invested assets	55,863	46,548
Total invested assets	2,158,969	2,197,058
Cash and cash equivalents	183,491	162,260
Restricted cash equivalents	751,668	859,920
Accrued investment income	11,634	10,980
Premiums receivable and agents’ balances, net	391,982	369,577
Reinsurance recoverable on unpaid losses, net	878,732	805,684
Reinsurance recoverable on paid losses	42,566	46,118
Prepaid reinsurance premiums	273,116	243,741
Deferred policy acquisition costs	63,606	62,953
Intangible assets, net	36,311	36,402
Goodwill	181,831	181,831
Other assets	135,801	86,548
Total assets	5,109,707	5,063,072
Liabilities:
Reserve for losses and loss adjustment expenses	2,413,846	2,192,080
Unearned premiums	674,343	630,371
Payables to reinsurers	130,593	110,431
Funds held	751,668	859,920
Senior debt	262,300	262,300
Junior subordinated debt	104,055	104,055
Accrued expenses	52,351	55,989
Other liabilities	80,923	52,318
Total liabilities	4,470,079	4,267,464
Commitments and contingent liabilities	0	0
Shareholders’ equity:
Common Shares – 2021 and 2020: $0.0002 par value; 200,000,000 shares authorized; 30,774,930 and 30,649,261 shares issued and outstanding, respectively	6	6
Preferred Shares – 2021 and 2020: $0.00125 par value; 20,000,000 shares authorized; no shares issued and outstanding	0	0
Additional paid-in capital	663,987	664,476
Retained (deficit) earnings	(63,576)	49,227
Accumulated other comprehensive income	39,211	81,899
Total shareholders’ equity	639,628	795,608
Total liabilities and shareholders’ equity	$ 5,109,707	$ 5,063,072

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed maturity securities, available-for-sale, at amortized cost	$ 1,755,733	$ 1,690,890
Equity securities, at cost	$ 81,855	$ 81,698
Common stock, par value (in dollars per share)	$ 0.0002	$ 0.0002
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	30,774,930	30,649,261
Common stock, shares outstanding (in shares)	30,774,930	30,649,261
Preferred stock, par value (in dollars per share)	$ 0.00125	$ 0.00125
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Loss and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues
Gross written premiums	$ 373,255,000	$ 283,841,000
Ceded written premiums	(198,656,000)	(149,187,000)
Net written premiums	174,599,000	134,654,000
Change in net unearned premiums	(14,006,000)	11,264,000
Net earned premiums	160,593,000	145,918,000
Net investment income	15,089,000	20,836,000
Net realized and unrealized gains (losses) on investments	6,272,000	(58,407,000)
Other income	1,026,000	1,937,000
Total revenues	182,980,000	110,284,000
Expenses
Losses and loss adjustment expenses	273,500,000	96,856,000
Other operating expenses	47,381,000	51,621,000
Other expenses	621,000	0
Interest expense	2,216,000	2,876,000
Amortization of intangible assets	91,000	149,000
Total expenses	323,809,000	151,502,000
Loss before taxes	(140,829,000)	(41,218,000)
Income tax benefit	(37,369,000)	(4,403,000)
Net loss	(103,460,000)	(36,815,000)
Other comprehensive loss:
Net unrealized losses, net of taxes of $(5,647) in 2021 and $(1,391) in 2020	(42,688,000)	(3,919,000)
Total comprehensive loss	$ (146,148,000)	$ (40,734,000)
Per share data:
Basic loss per share (in dollars per share)	$ (3.37)	$ (1.21)
Diluted loss per share (in dollars per share)	(3.37)	(1.21)
Dividend declared per share (in dollars per share)	$ 0.30	$ 0.30
Weighted-average common shares outstanding:
Basic (in shares)	30,713,986	30,476,307
Diluted (in shares)	30,713,986	30,476,307

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Loss and Comprehensive Loss (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Tax on net unrealized gains (losses)	$ (5,647)	$ (1,391)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Shares	Preferred Shares	Additional Paid-in Capital	Retained Earnings (Deficit)	Retained Earnings (Deficit)Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income
Balance (in shares) at Dec. 31, 2019			30,424,391
Balance at Dec. 31, 2019	$ 778,581		$ 6	$ 0	$ 657,875	$ 89,586		$ 31,114
Balance (ASU 2019-05) at Dec. 31, 2019		$ (7,827)					$ (7,827)
Balance (ASU 2016-13) at Dec. 31, 2019		$ (265)					$ (265)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(36,815)					(36,815)
Other comprehensive loss	(3,919)							(3,919)
Dividends	(9,267)					(9,267)
Vesting of RSUs (in shares)			96,037
Vesting of RSUs	(2,038)				(2,038)
Compensation expense under share incentive plans	1,867				1,867
Balance (in shares) at Mar. 31, 2020			30,520,428
Balance at Mar. 31, 2020	$ 720,317		$ 6	0	657,704	35,412		27,195
Balance (in shares) at Dec. 31, 2020	30,649,261		30,649,261
Balance at Dec. 31, 2020	$ 795,608		$ 6	0	664,476	49,227		81,899
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(103,460)					(103,460)
Other comprehensive loss	(42,688)							(42,688)
Dividends	$ (9,343)					(9,343)
Exercise of stock options (in shares)	16,471		16,471
Exercise of stock options	$ 159				159
Vesting of RSUs (in shares)			109,198
Vesting of RSUs	(2,553)				(2,553)
Compensation expense under share incentive plans	$ 1,905				1,905
Balance (in shares) at Mar. 31, 2021	30,774,930		30,774,930
Balance at Mar. 31, 2021	$ 639,628		$ 6	$ 0	$ 663,987	$ (63,576)		$ 39,211

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net cash (used in) operating activities	[1]	$ (81,005)	$ (65,305)
Securities available-for-sale:
Purchases – fixed maturity securities		(171,178)	(182,205)
Sales – fixed maturity securities		33,041	4,513
Maturities and calls – fixed maturity securities		73,530	34,861
Purchases – equity securities		(4,305)	(7,435)
Sales – equity securities		3,776	3,295
Bank loan participations:
Purchases		(35,832)	(18,408)
Sales		15,527	9,735
Maturities		11,190	13,220
Other invested assets:
Purchases		(9,795)	(438)
Return of capital		249	253
Redemptions		0	13,133
Short-term investments, net		79,091	85,867
Securities receivable or payable, net		10,694	(5,770)
Purchases of property and equipment		0	(342)
Net cash provided by (used in) investing activities		5,988	(49,721)
Financing activities
Senior debt issuances		0	119,000
Dividends paid		(9,610)	(9,468)
Issuance of common shares under equity incentive plans		159	0
Common share repurchases		(2,553)	(2,038)
Net cash (used in) provided by financing activities		(12,004)	107,494
Change in cash, cash equivalents, and restricted cash equivalents		(87,021)	(7,532)
Cash, cash equivalents, and restricted cash equivalents at beginning of period		1,022,180	1,406,076
Cash, cash equivalents, and restricted cash equivalents at end of period		935,159	1,398,544
Supplemental information
Interest paid		2,482	3,248
Restricted cash equivalents at beginning of period		859,920	1,199,164
Restricted cash equivalents at end of period		751,668	1,107,321
Change in restricted cash equivalents		$ (108,252)	$ (91,843)
[1]	Cash used in operating activities for the three months ended March 31, 2021 and 2020 primarily reflect $108.3 million and $91.8 million, respectively, of restricted cash equivalents returned to a former insured, per the terms of a collateral trust (see Amounts Recoverable from an Indemnifying Party in Liquidity and Capital Resources ). Excluding the reduction in the collateral funds, cash provided by operating activities was $27.2 million and $26.5 million for the three months ended March 31, 2021 and 2020, respectively.

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Cash Flows [Abstract]
Change in restricted cash equivalents	$ (108,252)	$ (91,843)
Cash provided by operating activities excluding reduction in collateral funds	$ 27,200	$ 26,500

Accounting Policies

Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies Organization James River Group Holdings, Ltd. (referred to as “JRG Holdings” or, with its subsidiaries, the “Company”) is an exempted holding company registered in Bermuda, organized for the purpose of acquiring and managing insurance and reinsurance entities. The Company owns five insurance companies based in the United States (“U.S.”) focused on specialty insurance niches and two Bermuda-based reinsurance companies as described below: • James River Group Holdings UK Limited (“James River UK”) is an insurance holding company formed in 2015 in the United Kingdom (“U.K.”). JRG Holdings contributed James River Group, Inc. (“James River Group”), a U.S. insurance holding company, to James River UK in 2015. ▪ James River Group is a Delaware domiciled insurance holding company formed in 2002 which owns all of the Company’s U.S.-based subsidiaries, either directly or indirectly through one of its wholly-owned U.S. subsidiaries. James River Group oversees the Company’s U.S. insurance operations and maintains all of the outstanding debt in the U.S. ◦ James River Insurance Company is an Ohio domiciled excess and surplus lines insurance company that, with its wholly-owned insurance subsidiary, James River Casualty Company, a Virginia domiciled company, is authorized to write business in every state and the District of Columbia. ◦ Falls Lake National Insurance Company (“Falls Lake National”) is an Ohio domiciled insurance company which wholly owns Stonewood Insurance Company (“Stonewood Insurance”), a North Carolina domiciled company, and Falls Lake Fire and Casualty Company, a California domiciled company. Falls Lake National and its subsidiaries primarily write specialty admitted fronting and program business and individual risk workers' compensation insurance. ◦ JRG Reinsurance Company Ltd. (“JRG Re”) was formed in 2007 and commenced operations in 2008. JRG Re, a Bermuda domiciled reinsurer, primarily provides non-catastrophe casualty reinsurance to U.S. third parties and, through December 31, 2017, to the Company’s U.S.-based insurance subsidiaries. ◦ Carolina Re Ltd (“Carolina Re”) was formed in 2018 and as of January 1, 2018 provides reinsurance to the Company’s U.S.-based insurance subsidiaries. Carolina Re is also the cedent on a stop loss reinsurance treaty with JRG Re. Basis of Presentation The accompanying condensed consolidated financial statements and notes have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and do not contain all of the information and footnotes required by U.S. GAAP for complete financial statements. The condensed consolidated financial statements include the results of the Company and its subsidiaries from their respective dates of inception or acquisition, as applicable. Readers are urged to review the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 for a more complete description of the Company’s business and accounting policies. In the opinion of management, all adjustments necessary for a fair presentation of the condensed consolidated financial statements have been included. Such adjustments consist only of normal recurring items. Interim results are not necessarily indicative of results of operations for the full year. The consolidated balance sheet as of December 31, 2020 was derived from the Company’s audited annual consolidated financial statements. Intercompany transactions and balances have been eliminated. Estimates and Assumptions Preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying disclosures. Those estimates are inherently subject to change, and actual results may ultimately differ from those estimates. Variable Interest Entities Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities (“VIE”). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE’s capital structure, contractual terms, nature of the VIE’s operations and purpose, and the Company’s relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis. The Company holds interests in VIEs through certain equity method investments included in “other invested assets” in the accompanying condensed consolidated balance sheets. The Company has determined that it should not consolidate any of the VIEs as it is not the primary beneficiary in any of the relationships. Although the investments resulted in the Company holding variable interests in the entities, they did not empower the Company to direct the activities that most significantly impact the economic performance of the entities. The Company’s investments related to these VIEs totaled $29.0 million and $30.1 million at March 31, 2021 and December 31, 2020, respectively, representing the Company’s maximum exposure to loss. Income Tax Expense Our effective tax rate fluctuates from period to period based on the relative mix of income reported by country and the respective tax rates imposed by each tax jurisdiction. For U.S.-sourced income, the Company’s U.S. federal income tax expense differs from the amounts computed by applying the federal statutory income tax rate to income before taxes due primarily to interest income on tax-advantaged state and municipal securities, dividends received income, and excess tax benefits on share based compensation. The Company had a pre-tax loss of $140.8 million for the three months ended March 31, 2021 and recorded a U.S. federal income tax benefit of $37.4 million. The pre-tax loss was largely driven by the $170.1 million of net adverse reserve development on prior accident years, including $168.7 million of net adverse development from the Excess and Surplus Lines segment that was primarily related to a former commercial auto account. For the three months ended March 31, 2021, our U.S. federal income tax benefit was 26.5% of the loss before taxes. The outbreak of the coronavirus pandemic in the first quarter of 2020 led to significant unrealized losses in our investment portfolio that were recognized in earnings. As a result, the Company had a pre-tax loss of $41.2 million for the three months ended March 31, 2020 and recorded a U.S. federal income tax benefit of $4.4 million. For the three months ended March 31, 2020, our U.S. federal income tax benefit was 10.7% of the loss before taxes. The change in effective tax rate for the two periods reflects changes in reserve estimates between accident years in the commercial auto business, and the related impact on the mix of income reported by country in those respective periods.

Investments

Investments	3 Months Ended
	Mar. 31, 2021
Investments [Abstract]
Investments	Investments The Company’s available-for-sale fixed maturity securities are summarized as follows: Cost or Gross Gross Fair (in thousands) March 31, 2021 Fixed maturity securities: State and municipal $ 311,053 $ 12,249 $ (3,537) $ 319,765 Residential mortgage-backed 296,200 5,490 (1,734) 299,956 Corporate 737,756 32,160 (7,223) 762,693 Commercial mortgage and asset-backed 322,579 7,234 (1,633) 328,180 U.S. Treasury securities and obligations guaranteed by the U.S. government 88,145 1,663 (251) 89,557 Total fixed maturity securities, available-for-sale $ 1,755,733 $ 58,796 $ (14,378) $ 1,800,151 December 31, 2020 Fixed maturity securities: State and municipal $ 277,241 $ 19,203 $ (39) $ 296,405 Residential mortgage-backed 286,104 7,784 (40) 293,848 Corporate 715,145 52,098 (421) 766,822 Commercial mortgage and asset-backed 314,911 12,611 (803) 326,719 U.S. Treasury securities and obligations guaranteed by the U.S. government 97,489 2,360 (1) 99,848 Total fixed maturity securities, available-for-sale $ 1,690,890 $ 94,056 $ (1,304) $ 1,783,642 The amortized cost and fair value of available-for-sale investments in fixed maturity securities at March 31, 2021 are summarized, by contractual maturity, as follows: Cost or Fair (in thousands) One year or less $ 110,269 $ 111,427 After one year through five years 455,605 477,392 After five years through ten years 327,033 332,488 After ten years 244,047 250,708 Residential mortgage-backed 296,200 299,956 Commercial mortgage and asset-backed 322,579 328,180 Total $ 1,755,733 $ 1,800,151 Actual maturities may differ for some securities because borrowers have the right to call or prepay obligations with or without penalties. The following table shows the Company’s gross unrealized losses and fair value for available-for-sale securities aggregated by investment category and the length of time that individual securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Fair Gross Fair Gross Fair Gross (in thousands) March 31, 2021 Fixed maturity securities: State and municipal $ 113,279 $ (3,537) $ — $ — $ 113,279 $ (3,537) Residential mortgage-backed 115,899 (1,725) 342 (9) 116,241 (1,734) Corporate 162,414 (7,223) — — 162,414 (7,223) Commercial mortgage and asset-backed 85,511 (1,564) 9,013 (69) 94,524 (1,633) U.S. Treasury securities and obligations guaranteed by the U.S. government 19,020 (251) — — 19,020 (251) Total fixed maturity securities, available-for-sale $ 496,123 $ (14,300) $ 9,355 $ (78) $ 505,478 $ (14,378) December 31, 2020 Fixed maturity securities: State and municipal $ 7,193 $ (39) $ — $ — $ 7,193 $ (39) Residential mortgage-backed 3,649 (40) — — 3,649 (40) Corporate 28,607 (421) — — 28,607 (421) Commercial mortgage and asset-backed 18,427 (447) 38,802 (356) 57,229 (803) U.S. Treasury securities and obligations guaranteed by the U.S. government 2,291 (1) — — 2,291 (1) Total fixed maturity securities, available-for-sale $ 60,167 $ (948) $ 38,802 $ (356) $ 98,969 $ (1,304) At March 31, 2021, the Company held fixed maturity securities of 192 issuers that were in an unrealized loss position with a total fair value of $505.5 million and gross unrealized losses of $14.4 million. None of the fixed maturity securities with unrealized losses has ever missed, or been delinquent on, a scheduled principal or interest payment. At March 31, 2021, 99.3% of the Company’s fixed maturity security portfolio was rated “BBB-” or better (“investment grade”) by Standard & Poor’s or received an equivalent rating from another nationally recognized rating agency. Fixed maturity securities with ratings below investment grade by Standard & Poor’s or another nationally recognized rating agency at March 31, 2021 had an aggregate fair value of $11.9 million and an aggregate net unrealized gain of $114,000. The Company adopted ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments on January 1, 2020. This update changed the impairment model for available-for-sale fixed maturities and requires the Company to determine whether unrealized losses on available-for-sale fixed maturities are due to credit-related factors. An allowance for credit losses is established for any credit-related impairments, limited to the amount by which fair value is below amortized cost. Changes in the allowance for credit losses are recognized in earnings and included in n et realized and unrealized gains (losses) on investments . Unrealized losses that are not credit-related will continue to be recognized in other comprehensive income. The Company considers the extent to which fair value is below amortized cost in determining whether a credit-related loss exists. The Company also considers the credit quality rating of the security, with a special emphasis on securities downgraded below investment grade. A comparison is made between the present value of expected future cash flows for a security and its amortized cost. If the present value of future expected cash flows is less than amortized cost, a credit loss is presumed to exist and an allowance for credit losses is established. Management may conclude that a qualitative analysis is sufficient to support its conclusion that the present value of the expected cash flows equals or exceeds a security’s amortized cost. As a result of this review, management concluded that there were no credit-related impairments of fixed maturity securities at March 31, 2021, December 31, 2020, or March 31, 2020. Management does not intend to sell the securities in an unrealized loss position, and it is not “more likely than not” that the Company will be required to sell these securities before a recovery in their value to their amortized cost basis occurs. In connection with the adoption of ASU 2016-13, the Company elected the fair value option in accounting for bank loan participations effective January 1, 2020. The targeted transition relief offered by ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief was applied to elect the fair value option to account for bank loan participations already held at the January 1, 2020 date of adoption. Under the fair value option, bank loan participations are measured at fair value, and changes in unrealized gains and losses in bank loan participations are reported in our income statement as net realized and unrealized gains (losses) on investments. At adoption on January 1, 2020, the Company applied the amendments on a modified retrospective basis, reducing the carrying value of its bank loan portfolio to fair value through an $8.4 million adjustment with a $7.8 million (net of tax) cumulative effect adjustment to reduce retained earnings. Applying the fair value option to the bank loan portfolio increases volatility in the Company's financial statements, but management believes it is less subjective and less burdensome to implement and maintain than ASU 2016-13, which would have otherwise been required. At March 31, 2021, the Company's bank loan portfolio had an aggregate fair value of $160.9 million and unpaid principal of $168.6 million. Investment income on bank loan participations included in net investment income was $2.9 million and $4.1 million for the three months ended March 31, 2021 and 2020, respectively. Net realized and unrealized gains (losses) on investments includes gains of $3.9 million and losses of $43.9 million related to changes in unrealized gains and losses on bank loan participations in the three months ended March 31, 2021 and 2020, respectively. Management concluded that there were no credit-related impairments of bank loan participations at March 31, 2021. At March 31, 2020, there were $5.0 million of unrealized losses due to credit-related impairments. Losses due to credit-related impairments were determined based upon consultations and advice from the Company's specialized investment manager and consideration of any adverse situations that could affect the borrower's ability to repay, the estimated value of underlying collateral, and other relevant factors. Bank loan participations generally provide a higher yield than our portfolio of fixed maturities and have a credit rating that is below investment grade (i.e. below “BBB-” for Standard & Poor’s) at the date of purchase. These bank loans are primarily senior, secured floating-rate debt rated “BB”, “B”, or “CCC” by Standard & Poor’s or an equivalent rating from another nationally recognized rating agency. These bank loans include assignments of, and participations in, performing and non-performing senior corporate debt generally acquired through primary bank syndications and in secondary markets. Bank loans consist of, but are not limited to, term loans, the funded and unfunded portions of revolving credit loans, and other similar loans and investments. Management believed that it was probable at the time that these loans were acquired that the Company would be able to collect all contractually required payments receivable. Interest income on bank loan participations is accrued on the unpaid principal balance, and discounts and premiums on bank loan participations are amortized to income using the interest method. Generally, the accrual of interest on a bank loan participation is discontinued when the contractual payment of principal or interest has become 90 days past due or management has serious doubts about further collectability of principal or interest. A bank loan participation may remain on accrual status if it is in the process of collection and is either guaranteed or well secured. Generally, bank loan participations are restored to accrual status when the obligation is brought current, has performed in accordance with the contractual terms for a reasonable period of time, and the ultimate collectability of the total contractual principal and interest is no longer in doubt. Interest received on nonaccrual loans generally is reported as investment income. There were no bank loans on nonaccrual status at March 31, 2021 or December 31, 2020. The Company’s net realized and unrealized gains and losses on investments are summarized as follows: Three Months Ended 2021 2020 (in thousands) Fixed maturity securities: Gross realized gains $ 1,056 $ 215 Gross realized losses (22) (1) 1,034 214 Bank loan participations: Gross realized gains 198 103 Gross realized losses (260) (1,309) Changes in fair values of bank loan participations 3,911 (43,947) 3,849 (45,153) Equity securities: Gross realized gains 29 — Gross realized losses (401) (170) Changes in fair values of equity securities 1,745 (13,315) 1,373 (13,485) Short-term investments and other: Gross realized gains 5 18 Gross realized losses — (1) Changes in fair values of short-term investments and other 11 — 16 17 Total $ 6,272 $ (58,407) Realized investment gains or losses are determined on a specific identification basis. The Company invests selectively in private debt and equity opportunities. These investments, which together comprise the Company’s other invested assets, are primarily focused in renewable energy, limited partnerships, and bank holding companies. Carrying Value Investment Income March 31, December 31, Three Months Ended 2021 2020 2021 2020 (in thousands) Renewable energy LLCs (a) $ 28,965 $ 30,145 $ (915) $ 834 Renewable energy notes receivable ( b) 9,000 — 234 166 Limited partnerships (c) 13,398 11,903 929 (569) Bank holding companies (d) 4,500 4,500 86 86 Total other invested assets $ 55,863 $ 46,548 $ 334 $ 517 (a) The Company’s Corporate and Other segment owns equity interests ranging from 2.6% to 32.6% in various LLCs whose principal objective is capital appreciation and income generation from owning and operating renewable energy production facilities (wind and solar). The LLCs are managed by an entity for which two former directors served as officers, and the Company’s Non-Executive Chairman has invested in certain of these LLCs. The equity method is used to account for the Company’s LLC investments. Income for the LLCs primarily reflects adjustments to the carrying values of investments in renewable energy projects to their determined fair values. The fair value adjustments are included in revenues for the LLCs. Expenses for the LLCs are not significant and are comprised of administrative and interest expenses. The Company received cash distributions from these investments totaling $265,000 and $747,000 in the three months ended March 31, 2021 and 2020, respectively. (b) The Company's Excess and Surplus Lines and Corporate and Other segments have invested in notes receivable for renewable energy projects. At March 31, 2021, the Company held two notes issued by an entity for which two of our former directors serve as officers . Interest on the notes, which mature in 2025, is fixed at 12%. Income from the notes was $234,000 and $166,000 for the three months ended March 31, 2021 and 2020, respectively ($104,000 and $— for the Excess and Surplus Lines segment and $130,000 and $166,000 for the Corporate and Other segment in the respective periods). (c) The Company owns investments in limited partnerships that invest in concentrated portfolios including publicly-traded small cap equities, loans of middle market private equity sponsored companies, and tranches of distressed home loans. Income f rom the partnerships is recognized under the equity method of accounting. The Company’s Corporate and Other segment hold investments in limited partnerships with a total carrying value of $8.6 million at March 31, 2021. The Company recognized investment income of $754,000 and losses of $710,000 on these investments for the three months ended March 31, 2021 and 2020, respectively. The Company’s Excess and Surplus Lines segment holds investments in limited partnerships with a total carrying value of $4.8 million at March 31, 2021. Investment income of $175,000 and $141,000 was recognized on the investments for the three months ended March 31, 2021 and 2020 , respectively. At March 31, 2021, the Company’s Excess and Surplus Lines segment has outstanding commitments to invest another $7.9 million in these limited partnerships. (d) The Company's Corporate and Other segment holds $4.5 million of subordinated notes issued by a bank holding company for which the Company’s Non-Executive Chairman was previously the Lead Independent Director and an investor and for which one of the Company’s directors was an investor and is currently a holder of the subordinated notes (the "Bank Holding Company"). Interest on the notes, which mature on August 12, 2023, is fixed at 7.6% per annum. Interest income on the notes was $86,000 for both three month periods ended March 31, 2021 and 2020, respectively. At March 31, 2021 and December 31, 2020, the Company held an investment in a CLO where one of the underlying loans was issued by the Bank Holding Company. The investment, with a carrying value of $252,000 at March 31, 2021, is classified as an available-for-sale fixed maturity.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets On December 11, 2007, the Company completed an acquisition of James River Group by acquiring 100% of the outstanding shares of James River Group common stock, referred to herein as the “Merger”. The transaction was accounted for under the purchase method of accounting, and goodwill and intangible assets were recognized by the Company as a result of the transaction. Goodwill resulting from the Merger was $181.8 million at March 31, 2021 and December 31, 2020. The gross carrying amounts and accumulated amortization for each major specifically identifiable intangible asset class were as follows: March 31, 2021 December 31, 2020 Life Gross Accumulated Gross Accumulated ($ in thousands) Intangible Assets Trademarks Indefinite $ 22,200 $ — $ 22,200 $ — Insurance licenses and authorities Indefinite 8,964 — 8,964 — Identifiable intangibles not subject to amortization 31,164 — 31,164 — Broker relationships 24.6 11,611 6,464 11,611 6,373 Identifiable intangible assets subject to amortization 11,611 6,464 11,611 6,373 $ 42,775 $ 6,464 $ 42,775 $ 6,373

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following represents a reconciliation of the numerator and denominator of the basic and diluted loss per share computations contained in the condensed consolidated financial statements: Three Months Ended 2021 2020 (in thousands, except share and per share amounts) Net loss to shareholders $ (103,460) $ (36,815) Weighted average common shares outstanding: Basic 30,713,986 30,476,307 Common share equivalents — — Diluted 30,713,986 30,476,307 Loss per share: Basic $ (3.37) $ (1.21) Common share equivalents — — Diluted $ (3.37) $ (1.21) Common share equivalents of 306,712 and 309,443 were excluded from the calculation of diluted earnings per share for the three months ended March 31, 2021 and 2020, respectively, as net losses in the respective periods made the effects of all common share equivalents anti-dilutive.

Reserve for Losses and Loss Adj

Reserve for Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2021
Liability for Claims and Claims Adjustment Expense [Abstract]
Reserve for Losses and Loss Adjustment Expenses	Reserve for Losses and Loss Adjustment Expenses The following table provides a reconciliation of the beginning and ending reserve balances for losses and loss adjustment expenses, net of reinsurance, to the gross amounts reported in the condensed consolidated balance sheets. Reinsurance recoverables on unpaid losses and loss adjustment expenses are presented gross of a $335,000 allowance for credit losses on reinsurance balances at March 31, 2021 and March 31, 2020. Three Months Ended 2021 2020 (in thousands) Reserve for losses and loss adjustment expenses net of reinsurance recoverables at beginning of period $ 1,386,061 $ 1,377,461 Add: Incurred losses and loss adjustment expenses net of reinsurance: Current year 103,366 95,982 Prior years 170,134 874 Total incurred losses and loss and adjustment expenses 273,500 96,856 Deduct: Loss and loss adjustment expense payments net of reinsurance: Current year 3,194 4,271 Prior years 121,588 118,357 Total loss and loss adjustment expense payments 124,782 122,628 Reserve for losses and loss adjustment expenses net of reinsurance recoverables at end of period 1,534,779 1,351,689 Add: Reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period 879,067 691,669 Reserve for losses and loss adjustment expenses gross of reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period $ 2,413,846 $ 2,043,358 The Company experienced $170.1 million of net adverse reserve development in the three months ended March 31, 2021 on the reserve for losses and loss adjustment expenses held at December 31, 2020. This reserve development included $168.7 million of net adverse development in the Excess and Surplus Lines segment including $170.0 million on commercial auto business, almost entirely related to a previously canceled account that has been in runoff since 2019. The reported losses on this terminated commercial auto account meaningfully exceeded our expectations for the three months ended March 31, 2021. We had expected that reported losses would decline as the account moved further into runoff, but the continued heavy reported loss emergence in the first quarter of 2021 indicated more inherent severity than anticipated. In response, we meaningfully adjusted our actuarial methodology, resulting in a significant strengthening of reserves for this account at March 31, 2021. In prior quarters, our actuarial work for this terminated commercial auto account had been based on industry data, pricing data, experience data, average claims severity data, and blended methodologies. However, the continuation of the highly elevated reported losses in the first quarter of 2021 led us to conclude that using only our own loss experience in our paid and incurred reserve projections rather than the array of inputs that we had used in prior quarters, and giving greater weight to incurred methods, would give us a better estimate of ultimate losses on this account. The Company also experienced $1.0 million of net favorable development in the Specialty Admitted Insurance segment due to favorable development in the workers' compensation business for prior accident years, and $2.5 million of net adverse development in the Casualty Reinsurance segment. The Company experienced $874,000 of net adverse reserve development in the three months ended March 31, 2020 on the reserve for losses and loss adjustment expenses held at December 31, 2019. This reserve development included $3,000 of favorable development in the Excess and Surplus Lines segment, $1.0 million of favorable development in the Specialty Admitted Insurance segment experienced due to favorable development in the workers' compensation business for prior accident years, and $1.9 million of adverse development in the Casualty Reinsurance segment.

Other Comprehensive Loss

Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2021
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Loss	Other Comprehensive Loss The following table summarizes the components of other comprehensive loss: Three Months Ended 2021 2020 (in thousands) Unrealized losses arising during the period, before U.S. income taxes $ (47,300) $ (5,096) U.S. income taxes 5,453 1,378 Unrealized losses arising during the period, net of U.S. income taxes (41,847) (3,718) Less reclassification adjustment: Net realized investment gains 1,035 214 U.S. income taxes (194) (13) Reclassification adjustment for investment gains realized in net income 841 201 Other comprehensive loss $ (42,688) $ (3,919) In addition to the $1.0 million and $214,000 of net realized investment gains on available-for-sale fixed maturities for the three months ended March 31, 2021 and 2020, respectively , the Company also recognized net realized and unrealized investment gains (losses) in the respective periods of $3.8 million and $(45.2) million on its investments in bank loan participations and $1.4 million and $(13.5) million on its investments in equity securities.

Contingent Liabilities

Contingent Liabilities	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities	Contingent Liabilities The Company is involved in various legal proceedings, including commercial matters and litigation regarding insurance claims arising in the ordinary course of business. The Company believes that the outcome of such matters, individually and in the aggregate, is not reasonably likely to have a material adverse effect on its consolidated financial position, results of operations or cash flows. For a description of the potential future impacts of COVID-19 on the Company, see the “The global coronavirus outbreak could harm business and results of operations of the Company” risk factor in Part I—Item IA in our Annual Report on Form 10-K for the year ended December 31, 2020. JRG Re has entered into three letter of credit facilities with banks as security to third-party reinsureds on reinsurance assumed by JRG Re. JRG Re has established custodial accounts to secure these letters of credit. Under a $75.0 million facility, $7.3 million of letters of credit were issued through March 31, 2021 which were secured by deposits of $14.4 million. Under a $102.5 million facility, $89.7 million of letters of credit were issued through March 31, 2021 which were secured by deposits of $113.6 million. Under a $100.0 million facility, $15.2 million of letters of credit were issued through March 31, 2021 which were secured by deposits of $28.1 million. JRG Re has also established trust accounts to secure its obligations to selected reinsureds. The total amount deposited in the trust accounts for the benefit of third-party reinsureds was $304.4 million at March 31, 2021. The Company previously issued a set of insurance contracts to Rasier LLC and its affiliates (collectively, “Rasier”) under which the Company pays losses and loss adjustment expenses on the contracts. The Company has indemnity agreements with Rasier (non-insurance entities) and is contractually entitled to receive reimbursement for a significant portion of the losses and loss adjustment expenses paid on behalf of Rasier and other expenses incurred by the Company. Rasier is required to collateralize all amounts currently due to the Company and to provide additional collateral sufficient to cover the amounts that may be recoverable under the indemnity agreements, including, among other things, case loss and loss adjustment expense reserves, IBNR loss and loss adjustment expense reserves, extra contractual obligations and excess of policy limits liabilities. The collateral is provided through a collateral trust arrangement established in favor of the Company by a captive insurance company affiliate of Rasier. As permitted under our indemnification agreements with Rasier and the associated trust agreement, we have withdrawn the collateral posted to the trust account. At March 31, 2021, the Company held collateral funds of $751.7 million. The funds withdrawn from the trust account, currently invested in short term securities and included in restricted cash equivalents on the Company's consolidated balance sheet, will be used to reimburse the Company for the losses and loss adjustment expenses paid on behalf of Rasier and other related expenses incurred by the Company to the extent not paid as required under the indemnity agreements.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information The Company has four reportable segments: the Excess and Surplus Lines segment, the Specialty Admitted Insurance segment, the Casualty Reinsurance segment, and the Corporate and Other segment. Segment profit (loss) is measured by underwriting profit (loss), which is generally defined as net earned premiums less loss and loss adjustment expenses and other operating expenses of the operating segments. Gross fee income of the Excess and Surplus Lines segment and Specialty Admitted Insurance segment is included in the respective segment’s underwriting profit (loss). Gross fee income of $927,000 and $1.6 million ($— and $1.3 million for the Excess and Surplus Lines segment and $927,000 and $335,000 for the Specialty Admitted Insurance segment) was included in other income and in underwriting profit (loss) for the three months ended March 31, 2021 and 2020, respectively. Segment results are reported prior to the effects of intercompany reinsurance agreements among the Company’s insurance subsidiaries. The following table summarizes the Company’s segment results: Excess and Specialty Casualty Corporate Total (in thousands) Three Months Ended March 31, 2021 Gross written premiums $ 181,358 $ 127,036 $ 64,861 $ — $ 373,255 Net earned premiums 113,708 16,357 30,528 — 160,593 Underwriting (loss) profit of insurance segments (150,946) 1,266 (1,625) — (151,305) Net investment income 3,706 822 10,556 5 15,089 Interest expense — — — 2,216 2,216 Segment revenues 118,796 18,565 45,517 102 182,980 Segment goodwill 181,831 — — — 181,831 Segment assets 2,129,985 980,824 1,930,747 68,151 5,109,707 Three Months Ended March 31, 2020 Gross written premiums $ 136,197 $ 102,802 $ 44,842 $ — $ 283,841 Net earned premiums 99,739 13,283 32,896 — 145,918 Underwriting profit (loss) of insurance segments 8,112 (988) 207 — 7,331 Net investment income 7,941 928 11,604 363 20,836 Interest expense — — — 2,876 2,876 Segment revenues 83,829 12,673 13,280 502 110,284 Segment goodwill 181,831 — — — 181,831 Segment assets 2,293,444 829,699 1,824,729 48,938 4,996,810 The following table reconciles the underwriting (loss) profit of the operating segments by individual segment to consolidated loss before income taxes: Three Months Ended 2021 2020 (in thousands) Underwriting (loss) profit of the insurance segments: Excess and Surplus Lines $ (150,946) $ 8,112 Specialty Admitted Insurance 1,266 (988) Casualty Reinsurance (1,625) 207 Total underwriting (loss) profit of insurance segments (151,305) 7,331 Other operating expenses of the Corporate and Other segment (8,056) (8,279) Underwriting loss (159,361) (948) Net investment income 15,089 20,836 Net realized and unrealized gains (losses) on investments 6,272 (58,407) Amortization of intangible assets (91) (149) Other income and expenses (522) 326 Interest expense (2,216) (2,876) Loss before income taxes $ (140,829) $ (41,218)

Other Operating Expenses and Ot

Other Operating Expenses and Other Expenses	3 Months Ended
	Mar. 31, 2021
Other Operating Expenses and Other Expenses [Abstract]
Other Operating Expenses and Other Expenses	Other Operating Expenses and Other Expenses Other operating expenses consist of the following: Three Months Ended 2021 2020 (in thousands) Amortization of policy acquisition costs $ 21,475 $ 24,116 Other underwriting expenses of the operating segments 17,850 19,226 Other operating expenses of the Corporate and Other segment 8,056 8,279 Total $ 47,381 $ 51,621 Other expenses of $621,000 for the three months ended March 31, 2021 primarily consist of employee severance and certain legal and professional consulting fees related to various strategic initiatives. There were no expenses classified as other for the three

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Three levels of inputs are used to measure fair value of financial instruments: (1) Level 1: quoted price (unadjusted) in active markets for identical assets, (2) Level 2: inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the instrument, and (3) Level 3: inputs to the valuation methodology are unobservable for the asset or liability. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. The fair values of fixed maturity securities, equity securities, and bank loan participations have been determined using fair value prices provided by the Company's investment accounting services provider or investment managers, who utilize internationally recognized independent pricing services. The prices provided by the independent pricing services are generally based on observable market data in active markets ( e.g. broker quotes and prices observed for comparable securities). Values for U.S. Treasury and publicly-traded equity securities are generally based on Level 1 inputs which use the market approach valuation technique. The values for all other fixed maturity securities (including state and municipal securities and obligations of U.S. government corporations and agencies) and bank loan participations generally incorporate significant Level 2 inputs, and in some cases, Level 3 inputs, using the market approach and income approach valuation techniques. There have been no changes in the Company’s use of valuation techniques since December 31, 2019. The Company reviews fair value prices provided by its outside investment accounting service provider or investment managers for reasonableness by comparing the fair values provided by the managers to those provided by its investment custodian. The Company also reviews and monitors changes in unrealized gains and losses. The Company has not historically adjusted security prices. The Company obtains an understanding of the methods, models and inputs used by the investment managers and independent pricing services, and controls are in place to validate that prices provided represent fair values. The Company’s control process includes, but is not limited to, initial and ongoing evaluation of the methodologies used, a review of specific securities and an assessment for proper classification within the fair value hierarchy, and obtaining and reviewing internal control reports for our investment manager that obtains fair values from independent pricing services. Assets measured at fair value on a recurring basis as of March 31, 2021 are summarized below: Fair Value Measurements Using Quoted Prices Significant Significant Total (in thousands) Fixed maturity securities, available-for-sale: State and municipal $ — $ 319,765 $ — $ 319,765 Residential mortgage-backed — 299,956 — 299,956 Corporate — 762,693 — 762,693 Commercial mortgage and asset-backed — 328,180 — 328,180 U.S. Treasury securities and obligations guaranteed by the U.S. government 89,118 439 — 89,557 Total fixed maturity securities, available-for-sale $ 89,118 $ 1,711,033 $ — $ 1,800,151 Equity securities: Preferred stock — 62,079 — 62,079 Common stock 21,464 7,334 — 28,798 Total equity securities $ 21,464 $ 69,413 $ — $ 90,877 Bank loan participations $ — $ 160,581 $ 299 $ 160,880 Short-term investments $ — $ 51,198 $ — $ 51,198 Assets measured at fair value on a recurring basis as of December 31, 2020 are summarized below: Fair Value Measurements Using Quoted Prices Significant Significant Total (in thousands) Fixed maturity securities, available-for-sale: State and municipal $ — $ 296,405 $ — $ 296,405 Residential mortgage-backed — 293,848 — 293,848 Corporate — 766,822 — 766,822 Commercial mortgage and asset-backed — 326,719 326,719 U.S. Treasury securities and obligations guaranteed by the U.S. government 99,384 464 — 99,848 Total fixed maturity securities, available-for-sale $ 99,384 $ 1,684,258 $ — $ 1,783,642 Equity securities: Preferred stock — 67,495 — 67,495 Common stock 15,793 5,015 672 21,480 Total equity securities $ 15,793 $ 72,510 $ 672 $ 88,975 Bank loan participations $ — $ 147,296 $ 308 $ 147,604 Short-term investments $ — $ 130,289 $ — $ 130,289 A reconciliation of the beginning and ending balances of available-for-sale fixed maturity securities, equity securities, and bank loan participations measured at fair value on a recurring basis (as a result of the fair value option effective January 1, 2020) using significant unobservable inputs (Level 3) is shown below: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Beginning balance $ 980 $ 43 Transfers out of Level 3 — — Transfers in to Level 3 — 358 Purchases — 703 Sales (282) — Maturities, calls and paydowns (24) (17) Amortization of discount — 3 Total gains or losses (realized/unrealized): Included in earnings (375) (58) Included in other comprehensive income — — Ending balance $ 299 $ 1,032 The Company held one bank loan participation and one equity security at March 31, 2021 and one bank loan participation and two equity securities at December 31, 2020 for which the fair value was determined using significant unobservable inputs (Level 3). A market approach using prices in trades of comparable securities was utilized to determine a fair value for the securities of $299,000 at March 31, 2021 and $980,000 at December 31, 2020. The Company held one equity security at December 31, 2019 and three bank loan participations and two equity securities at March 31, 2020 for which the fair value was determined using significant unobservable inputs (Level 3). A market approach using prices in trades of comparable securities was utilized to determine a fair value for the securities of $1.0 million at March 31, 2020 and $43,000 at December 31, 2019. Transfers out of Level 3 occur when the Company is able to obtain reliable prices from pricing vendors for securities for which the Company was previously unable to obtain reliable prices. Transfers in to Level 3 occur when the Company is unable to obtain reliable prices for securities from pricing vendors and instead must use broker price quotes to value the securities. There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2021 or 2020. The Company recognizes transfers between levels at the beginning of the reporting period. In the determination of the fair value for bank loan participations and certain high yield bonds, the Company’s investment manager endeavors to obtain data from multiple external pricing sources. External pricing sources may include brokers, dealers and price data vendors that provide a composite price based on prices from multiple dealers. Such external pricing sources typically provide valuations for normal institutional size trading units of such securities using methods based on market transactions for comparable securities, and various relationships between securities, as generally recognized by institutional dealers. For investments in which the investment manager determines that only one external pricing source is appropriate or if only one external price is available, the relevant investment is generally recorded at fair value based on such price. Investments for which external sources are not available or are determined by the investment manager not to be representative of fair value are recorded at fair value as determined by the Company, with input from its investment managers and valuation specialists as considered necessary. In determining the fair value of such investments, the Company considers one or more of the following factors: type of security held, convertibility or exchangeability of the security, redeemability of the security (including the timing of redemptions), application of industry accepted valuation models, recent trading activity, liquidity, estimates of liquidation value, purchase cost, and prices received for securities with similar terms of the same issuer or similar issuers. At March 31, 2021 and December 31, 2020, there were no investments for which external sources were unavailable to determine fair value. The carrying values and fair values of financial instruments are summarized below: March 31, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value (in thousands) Assets Fixed maturity securities, available-for-sale $ 1,800,151 $ 1,800,151 $ 1,783,642 $ 1,783,642 Equity securities 90,877 90,877 88,975 88,975 Bank loan participations 160,880 160,880 147,604 147,604 Cash and cash equivalents 183,491 183,491 162,260 162,260 Restricted cash equivalents 751,668 751,668 859,920 859,920 Short-term investments 51,198 51,198 130,289 130,289 Other invested assets – notes receivable 13,500 17,767 4,500 5,302 Liabilities Senior debt 262,300 245,670 262,300 250,953 Junior subordinated debt 104,055 101,553 104,055 110,612 The fair values of fixed maturity securities, equity securities, and bank loan participations have been determined using quoted market prices for securities traded in the public market or prices using bid or closing prices for securities not traded in the public marketplace. The fair values of cash and cash equivalents and short-term investments approximate their carrying values due to their short-term maturity. The fair values of other invested assets-notes receivable, senior debt, and junior subordinated debt at March 31, 2021 and December 31, 2020 were determined by calculating the present value of expected future cash flows under the terms of the note agreements or debt agreements, as applicable, discounted at an estimated market rate of interest at March 31, 2021 and December 31, 2020, respectively. The fair values of senior debt and junior subordinated debt at March 31, 2021 and December 31, 2020 were determined using inputs to the valuation methodology that are unobservable (Level 3).

Senior Debt

Senior Debt	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Senior Debt	Senior Debt At March 31, 2021, the Company had a drawn balance of $185.8 million outstanding on the $212.5 million unsecured revolving facility in its $315.0 million senior revolving credit facility (as amended or amended and restated, the "2013 Facility”). The 2013 Facility contains certain financial and other covenants (including minimum net worth, maximum ratio of total adjusted debt outstanding to total capitalization, and financial strength ratings) with which the Company was in compliance at March 31, 2021. In the three months ended March 31, 2020, the Company drew $60.0 million on the unsecured revolver as a precautionary measure to increase the Company's cash position and preserve financial flexibility in light of uncertainty in the global markets resulting from the coronavirus (COVID-19) outbreak. At March 31, 2021, unsecured loans of $61.5 million and secured letters of credit totaling $15.2 million were outstanding under a credit agreement (the "2017 Facility") that provides the Company with a revolving line of credit of up to $100.0 million, which may be used for loans and letters of credit made or issued, at the borrowers' option, on a secured or unsecured basis. The 2017 Facility contains certain financial and other covenants which the Company was in compliance with at March 31, 2021. In the three months ended March 31, 2020, the Company drew $59.0 million of unsecured capacity as a precautionary measure to increase the Company's cash position and preserve financial flexibility in light of uncertainty in the global markets resulting from the coronavirus (COVID-19) outbreak.

Capital Stock and Equity Awards

Capital Stock and Equity Awards	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity Note [Abstract]
Capital Stock and Equity Awards	Capital Stock and Equity Awards The Company issued 125,669 common shares in the three months ended March 31, 2021. 16,471 of the new shares were related to stock option exercises and 109,198 were related to vesting of restricted share units (“RSUs”). The total common shares outstanding increased from 30,649,261 at December 31, 2020 to 30,774,930 at March 31, 2021. The Company declared the following dividends during the first three months of 2021 and 2020: Date of Declaration Dividend per Common Share Payable to Shareholders of Record on Payment Date Total Amount (thousands) 2021 February 24, 2021 $ 0.30 March 15, 2021 March 31, 2021 $ 9,345 2020 February 19, 2020 $ 0.30 March 16, 2020 March 31, 2020 $ 9,269 Included in the total dividends for each of the three months ended March 31, 2021 and 2020, respectively, are $113,000 of dividend equivalents on unvested RSUs. The balance of dividends payable on unvested RSUs was $396,000 at March 31, 2021 and $663,000 at December 31, 2020. Equity Incentive Plans The Company’s shareholders have approved various equity incentive plans, including the Amended and Restated 2009 Equity Incentive Plan (the “Legacy Plan”), the 2014 Long Term Incentive Plan (“2014 LTIP”), and the 2014 Non-Employee Director Incentive Plan (“2014 Director Plan”) (collectively, the “Plans”). All awards issued under the Plans are issued at the discretion of the Board of Directors. Under the Legacy Plan, employees received non-qualified stock options. Options are outstanding under the Legacy Plan; however, no additional awards may be granted. Employees are eligible to receive non-qualified stock options, incentive stock options, share appreciation rights, performance shares, restricted shares, RSUs, and other awards under the 2014 LTIP. The maximum number of shares available for issuance under the 2014 LTIP is 4,171,150, and at March 31, 2021, 1,226,493 shares are available for grant. Non-employee directors of the Company are eligible to receive non-qualified stock options, share appreciation rights, performance shares, restricted shares, RSUs, and other awards under the 2014 Director Plan. The maximum number of shares available for issuance under the 2014 Director Plan is 150,000, and at March 31, 2021, 94,781 shares are available for grant. Generally, awards issued under the 2014 LTIP and 2014 Director Plan vest immediately in the event that an award recipient is terminated without Cause (as defined in the applicable plans), and in the case of the 2014 LTIP for Good Reason (as defined in the applicable plans), at any time following a Change in Control (as defined in the applicable plans). Options The following table summarizes option activity: Three Months Ended March 31, 2021 2020 Shares Weighted- Shares Weighted- Outstanding: Beginning of period 463,324 $ 32.25 643,851 $ 30.41 Granted — $ — — $ — Exercised (29,884) $ 26.37 — $ — Forfeited — $ — — $ — End of period 433,440 $ 32.65 643,851 $ 30.41 Exercisable, end of period 433,440 $ 32.65 640,606 $ 30.35 All of the outstanding options are fully vested (vesting period of three years from date of grant) and have a contractual life of seven years from the original date of grant. All of the outstanding options have an exercise price equal to the fair value of the underlying shares at the date of grant. The weighted-average remaining contractual life of the options outstanding and exercisable at March 31, 2021 was 1.9 years. RSUs The following table summarizes RSU activity: Three Months Ended March 31, 2021 2020 Shares Weighted- Shares Weighted- Unvested, beginning of period 399,856 $ 43.59 340,368 $ 41.50 Granted 138,936 $ 50.24 179,016 $ 43.55 Vested (161,004) $ 41.89 (142,830) $ 41.16 Forfeited (1,089) $ 42.44 (1,188) $ 42.07 Unvested, end of period 376,699 $ 46.78 375,366 $ 42.61 Outstanding RSUs granted to employees vest ratably over a three year vesting period. RSUs granted to non-employee directors have a one year vesting period. The holders of RSUs are entitled to dividend equivalents. The dividend equivalents are settled in cash at the same time that the underlying RSUs vest and are subject to the same risk of forfeiture as the underlying shares. The fair value of the RSUs granted is based on the market price of the underlying shares at the date of grant. Compensation Expense Share based compensation expense is recognized on a straight line basis over the vesting period. The amount of expense and related tax benefit is summarized below: Three Months Ended 2021 2020 (in thousands) Share based compensation expense $ 1,905 $ 1,867 U.S. tax benefit on share based compensation expense 294 250 As of March 31, 2021, the Company had $16.2 million of unrecognized share based compensation expense expected to be charged to earnings over a weighted-average period of 2.3 years.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn April 27, 2021, the Board of Directors declared a cash dividend of $0.30 per common share. The dividend is payable on June 30, 2021 to shareholders of record on June 14, 2021.

Accounting Policies (Policies)

Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements and notes have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and do not contain all of the information and footnotes required by U.S. GAAP for complete financial statements. The condensed consolidated financial statements include the results of the Company and its subsidiaries from their respective dates of inception or acquisition, as applicable. Readers are urged to review the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 for a more complete description of the Company’s business and accounting policies. In the opinion of management, all adjustments necessary for a fair presentation of the condensed consolidated financial statements have been included. Such adjustments consist only of normal recurring items. Interim results are not necessarily indicative of results of operations for the full year. The consolidated balance sheet as of December 31, 2020 was derived from the Company’s audited annual consolidated financial statements. Intercompany transactions and balances have been eliminated.
Estimates and Assumptions	Estimates and Assumptions Preparation of the condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying disclosures. Those estimates are inherently subject to change, and actual results may ultimately differ from those estimates.
Variable Interest Entities	Variable Interest Entities Entities that do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities (“VIE”). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE’s capital structure, contractual terms, nature of the VIE’s operations and purpose, and the Company’s relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis.
Income Tax Expense	Income Tax ExpenseOur effective tax rate fluctuates from period to period based on the relative mix of income reported by country and the respective tax rates imposed by each tax jurisdiction. For U.S.-sourced income, the Company’s U.S. federal income tax expense differs from the amounts computed by applying the federal statutory income tax rate to income before taxes due primarily to interest income on tax-advantaged state and municipal securities, dividends received income, and excess tax benefits on share based compensation.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Investments [Abstract]
Schedule of Summary of Available-for-Sale Investments	The Company’s available-for-sale fixed maturity securities are summarized as follows: Cost or Gross Gross Fair (in thousands) March 31, 2021 Fixed maturity securities: State and municipal $ 311,053 $ 12,249 $ (3,537) $ 319,765 Residential mortgage-backed 296,200 5,490 (1,734) 299,956 Corporate 737,756 32,160 (7,223) 762,693 Commercial mortgage and asset-backed 322,579 7,234 (1,633) 328,180 U.S. Treasury securities and obligations guaranteed by the U.S. government 88,145 1,663 (251) 89,557 Total fixed maturity securities, available-for-sale $ 1,755,733 $ 58,796 $ (14,378) $ 1,800,151 December 31, 2020 Fixed maturity securities: State and municipal $ 277,241 $ 19,203 $ (39) $ 296,405 Residential mortgage-backed 286,104 7,784 (40) 293,848 Corporate 715,145 52,098 (421) 766,822 Commercial mortgage and asset-backed 314,911 12,611 (803) 326,719 U.S. Treasury securities and obligations guaranteed by the U.S. government 97,489 2,360 (1) 99,848 Total fixed maturity securities, available-for-sale $ 1,690,890 $ 94,056 $ (1,304) $ 1,783,642
Schedule of Summary of Available-for-Sale Investments by Contractual Maturity	The amortized cost and fair value of available-for-sale investments in fixed maturity securities at March 31, 2021 are summarized, by contractual maturity, as follows: Cost or Fair (in thousands) One year or less $ 110,269 $ 111,427 After one year through five years 455,605 477,392 After five years through ten years 327,033 332,488 After ten years 244,047 250,708 Residential mortgage-backed 296,200 299,956 Commercial mortgage and asset-backed 322,579 328,180 Total $ 1,755,733 $ 1,800,151
Schedule of Gross Unrealized Losses and Fair Value for Available-for-Sale Securities	The following table shows the Company’s gross unrealized losses and fair value for available-for-sale securities aggregated by investment category and the length of time that individual securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Fair Gross Fair Gross Fair Gross (in thousands) March 31, 2021 Fixed maturity securities: State and municipal $ 113,279 $ (3,537) $ — $ — $ 113,279 $ (3,537) Residential mortgage-backed 115,899 (1,725) 342 (9) 116,241 (1,734) Corporate 162,414 (7,223) — — 162,414 (7,223) Commercial mortgage and asset-backed 85,511 (1,564) 9,013 (69) 94,524 (1,633) U.S. Treasury securities and obligations guaranteed by the U.S. government 19,020 (251) — — 19,020 (251) Total fixed maturity securities, available-for-sale $ 496,123 $ (14,300) $ 9,355 $ (78) $ 505,478 $ (14,378) December 31, 2020 Fixed maturity securities: State and municipal $ 7,193 $ (39) $ — $ — $ 7,193 $ (39) Residential mortgage-backed 3,649 (40) — — 3,649 (40) Corporate 28,607 (421) — — 28,607 (421) Commercial mortgage and asset-backed 18,427 (447) 38,802 (356) 57,229 (803) U.S. Treasury securities and obligations guaranteed by the U.S. government 2,291 (1) — — 2,291 (1) Total fixed maturity securities, available-for-sale $ 60,167 $ (948) $ 38,802 $ (356) $ 98,969 $ (1,304)
Summary of Net Realized Gains and Losses on Investments	The Company’s net realized and unrealized gains and losses on investments are summarized as follows: Three Months Ended 2021 2020 (in thousands) Fixed maturity securities: Gross realized gains $ 1,056 $ 215 Gross realized losses (22) (1) 1,034 214 Bank loan participations: Gross realized gains 198 103 Gross realized losses (260) (1,309) Changes in fair values of bank loan participations 3,911 (43,947) 3,849 (45,153) Equity securities: Gross realized gains 29 — Gross realized losses (401) (170) Changes in fair values of equity securities 1,745 (13,315) 1,373 (13,485) Short-term investments and other: Gross realized gains 5 18 Gross realized losses — (1) Changes in fair values of short-term investments and other 11 — 16 17 Total $ 6,272 $ (58,407)
Summary of Net Unrealized Gains and Losses on Investments	The Company’s net realized and unrealized gains and losses on investments are summarized as follows: Three Months Ended 2021 2020 (in thousands) Fixed maturity securities: Gross realized gains $ 1,056 $ 215 Gross realized losses (22) (1) 1,034 214 Bank loan participations: Gross realized gains 198 103 Gross realized losses (260) (1,309) Changes in fair values of bank loan participations 3,911 (43,947) 3,849 (45,153) Equity securities: Gross realized gains 29 — Gross realized losses (401) (170) Changes in fair values of equity securities 1,745 (13,315) 1,373 (13,485) Short-term investments and other: Gross realized gains 5 18 Gross realized losses — (1) Changes in fair values of short-term investments and other 11 — 16 17 Total $ 6,272 $ (58,407)
Schedule of Other Invested Assets	The Company invests selectively in private debt and equity opportunities. These investments, which together comprise the Company’s other invested assets, are primarily focused in renewable energy, limited partnerships, and bank holding companies. Carrying Value Investment Income March 31, December 31, Three Months Ended 2021 2020 2021 2020 (in thousands) Renewable energy LLCs (a) $ 28,965 $ 30,145 $ (915) $ 834 Renewable energy notes receivable ( b) 9,000 — 234 166 Limited partnerships (c) 13,398 11,903 929 (569) Bank holding companies (d) 4,500 4,500 86 86 Total other invested assets $ 55,863 $ 46,548 $ 334 $ 517 (a) The Company’s Corporate and Other segment owns equity interests ranging from 2.6% to 32.6% in various LLCs whose principal objective is capital appreciation and income generation from owning and operating renewable energy production facilities (wind and solar). The LLCs are managed by an entity for which two former directors served as officers, and the Company’s Non-Executive Chairman has invested in certain of these LLCs. The equity method is used to account for the Company’s LLC investments. Income for the LLCs primarily reflects adjustments to the carrying values of investments in renewable energy projects to their determined fair values. The fair value adjustments are included in revenues for the LLCs. Expenses for the LLCs are not significant and are comprised of administrative and interest expenses. The Company received cash distributions from these investments totaling $265,000 and $747,000 in the three months ended March 31, 2021 and 2020, respectively. (b) The Company's Excess and Surplus Lines and Corporate and Other segments have invested in notes receivable for renewable energy projects. At March 31, 2021, the Company held two notes issued by an entity for which two of our former directors serve as officers . Interest on the notes, which mature in 2025, is fixed at 12%. Income from the notes was $234,000 and $166,000 for the three months ended March 31, 2021 and 2020, respectively ($104,000 and $— for the Excess and Surplus Lines segment and $130,000 and $166,000 for the Corporate and Other segment in the respective periods). (c) The Company owns investments in limited partnerships that invest in concentrated portfolios including publicly-traded small cap equities, loans of middle market private equity sponsored companies, and tranches of distressed home loans. Income f rom the partnerships is recognized under the equity method of accounting. The Company’s Corporate and Other segment hold investments in limited partnerships with a total carrying value of $8.6 million at March 31, 2021. The Company recognized investment income of $754,000 and losses of $710,000 on these investments for the three months ended March 31, 2021 and 2020, respectively. The Company’s Excess and Surplus Lines segment holds investments in limited partnerships with a total carrying value of $4.8 million at March 31, 2021. Investment income of $175,000 and $141,000 was recognized on the investments for the three months ended March 31, 2021 and 2020 , respectively. At March 31, 2021, the Company’s Excess and Surplus Lines segment has outstanding commitments to invest another $7.9 million in these limited partnerships. (d) The Company's Corporate and Other segment holds $4.5 million of subordinated notes issued by a bank holding company for which the Company’s Non-Executive Chairman was previously the Lead Independent Director and an investor and for which one of the Company’s directors was an investor and is currently a holder of the subordinated notes (the "Bank Holding Company"). Interest on the notes, which mature on August 12, 2023, is fixed at 7.6% per annum. Interest income on the notes was $86,000 for both three month periods ended March 31, 2021 and 2020, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Gross Carrying Amounts and Accumulated Amortization	The gross carrying amounts and accumulated amortization for each major specifically identifiable intangible asset class were as follows: March 31, 2021 December 31, 2020 Life Gross Accumulated Gross Accumulated ($ in thousands) Intangible Assets Trademarks Indefinite $ 22,200 $ — $ 22,200 $ — Insurance licenses and authorities Indefinite 8,964 — 8,964 — Identifiable intangibles not subject to amortization 31,164 — 31,164 — Broker relationships 24.6 11,611 6,464 11,611 6,373 Identifiable intangible assets subject to amortization 11,611 6,464 11,611 6,373 $ 42,775 $ 6,464 $ 42,775 $ 6,373
Schedule of Gross Carrying Amounts and Accumulated Amortization	The gross carrying amounts and accumulated amortization for each major specifically identifiable intangible asset class were as follows: March 31, 2021 December 31, 2020 Life Gross Accumulated Gross Accumulated ($ in thousands) Intangible Assets Trademarks Indefinite $ 22,200 $ — $ 22,200 $ — Insurance licenses and authorities Indefinite 8,964 — 8,964 — Identifiable intangibles not subject to amortization 31,164 — 31,164 — Broker relationships 24.6 11,611 6,464 11,611 6,373 Identifiable intangible assets subject to amortization 11,611 6,464 11,611 6,373 $ 42,775 $ 6,464 $ 42,775 $ 6,373

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share	The following represents a reconciliation of the numerator and denominator of the basic and diluted loss per share computations contained in the condensed consolidated financial statements: Three Months Ended 2021 2020 (in thousands, except share and per share amounts) Net loss to shareholders $ (103,460) $ (36,815) Weighted average common shares outstanding: Basic 30,713,986 30,476,307 Common share equivalents — — Diluted 30,713,986 30,476,307 Loss per share: Basic $ (3.37) $ (1.21) Common share equivalents — — Diluted $ (3.37) $ (1.21)

Reserve for Losses and Loss A_2

Reserve for Losses and Loss Adjustment Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Liability for Claims and Claims Adjustment Expense [Abstract]
Schedule of Reconciliation of Beginning and Ending Reserve Balances for Losses and Loss Adjustment Expenses	The following table provides a reconciliation of the beginning and ending reserve balances for losses and loss adjustment expenses, net of reinsurance, to the gross amounts reported in the condensed consolidated balance sheets. Reinsurance recoverables on unpaid losses and loss adjustment expenses are presented gross of a $335,000 allowance for credit losses on reinsurance balances at March 31, 2021 and March 31, 2020. Three Months Ended 2021 2020 (in thousands) Reserve for losses and loss adjustment expenses net of reinsurance recoverables at beginning of period $ 1,386,061 $ 1,377,461 Add: Incurred losses and loss adjustment expenses net of reinsurance: Current year 103,366 95,982 Prior years 170,134 874 Total incurred losses and loss and adjustment expenses 273,500 96,856 Deduct: Loss and loss adjustment expense payments net of reinsurance: Current year 3,194 4,271 Prior years 121,588 118,357 Total loss and loss adjustment expense payments 124,782 122,628 Reserve for losses and loss adjustment expenses net of reinsurance recoverables at end of period 1,534,779 1,351,689 Add: Reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period 879,067 691,669 Reserve for losses and loss adjustment expenses gross of reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period $ 2,413,846 $ 2,043,358

Other Comprehensive Loss (Table

Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2021
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Components of Comprehensive Income (Loss)	The following table summarizes the components of other comprehensive loss: Three Months Ended 2021 2020 (in thousands) Unrealized losses arising during the period, before U.S. income taxes $ (47,300) $ (5,096) U.S. income taxes 5,453 1,378 Unrealized losses arising during the period, net of U.S. income taxes (41,847) (3,718) Less reclassification adjustment: Net realized investment gains 1,035 214 U.S. income taxes (194) (13) Reclassification adjustment for investment gains realized in net income 841 201 Other comprehensive loss $ (42,688) $ (3,919)

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Schedule of Summary of Company's Segment Results	The following table summarizes the Company’s segment results: Excess and Specialty Casualty Corporate Total (in thousands) Three Months Ended March 31, 2021 Gross written premiums $ 181,358 $ 127,036 $ 64,861 $ — $ 373,255 Net earned premiums 113,708 16,357 30,528 — 160,593 Underwriting (loss) profit of insurance segments (150,946) 1,266 (1,625) — (151,305) Net investment income 3,706 822 10,556 5 15,089 Interest expense — — — 2,216 2,216 Segment revenues 118,796 18,565 45,517 102 182,980 Segment goodwill 181,831 — — — 181,831 Segment assets 2,129,985 980,824 1,930,747 68,151 5,109,707 Three Months Ended March 31, 2020 Gross written premiums $ 136,197 $ 102,802 $ 44,842 $ — $ 283,841 Net earned premiums 99,739 13,283 32,896 — 145,918 Underwriting profit (loss) of insurance segments 8,112 (988) 207 — 7,331 Net investment income 7,941 928 11,604 363 20,836 Interest expense — — — 2,876 2,876 Segment revenues 83,829 12,673 13,280 502 110,284 Segment goodwill 181,831 — — — 181,831 Segment assets 2,293,444 829,699 1,824,729 48,938 4,996,810
Schedule of Underwriting Profit of Operating Segments by Individual Segment and Reconciliation to Consolidated Income Before Taxes	The following table reconciles the underwriting (loss) profit of the operating segments by individual segment to consolidated loss before income taxes: Three Months Ended 2021 2020 (in thousands) Underwriting (loss) profit of the insurance segments: Excess and Surplus Lines $ (150,946) $ 8,112 Specialty Admitted Insurance 1,266 (988) Casualty Reinsurance (1,625) 207 Total underwriting (loss) profit of insurance segments (151,305) 7,331 Other operating expenses of the Corporate and Other segment (8,056) (8,279) Underwriting loss (159,361) (948) Net investment income 15,089 20,836 Net realized and unrealized gains (losses) on investments 6,272 (58,407) Amortization of intangible assets (91) (149) Other income and expenses (522) 326 Interest expense (2,216) (2,876) Loss before income taxes $ (140,829) $ (41,218)

Other Operating Expenses and _2

Other Operating Expenses and Other Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Other Operating Expenses and Other Expenses [Abstract]
Schedule of Other Operating Expenses	Other operating expenses consist of the following: Three Months Ended 2021 2020 (in thousands) Amortization of policy acquisition costs $ 21,475 $ 24,116 Other underwriting expenses of the operating segments 17,850 19,226 Other operating expenses of the Corporate and Other segment 8,056 8,279 Total $ 47,381 $ 51,621

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on a Recurring Basis	Assets measured at fair value on a recurring basis as of March 31, 2021 are summarized below: Fair Value Measurements Using Quoted Prices Significant Significant Total (in thousands) Fixed maturity securities, available-for-sale: State and municipal $ — $ 319,765 $ — $ 319,765 Residential mortgage-backed — 299,956 — 299,956 Corporate — 762,693 — 762,693 Commercial mortgage and asset-backed — 328,180 — 328,180 U.S. Treasury securities and obligations guaranteed by the U.S. government 89,118 439 — 89,557 Total fixed maturity securities, available-for-sale $ 89,118 $ 1,711,033 $ — $ 1,800,151 Equity securities: Preferred stock — 62,079 — 62,079 Common stock 21,464 7,334 — 28,798 Total equity securities $ 21,464 $ 69,413 $ — $ 90,877 Bank loan participations $ — $ 160,581 $ 299 $ 160,880 Short-term investments $ — $ 51,198 $ — $ 51,198 Assets measured at fair value on a recurring basis as of December 31, 2020 are summarized below: Fair Value Measurements Using Quoted Prices Significant Significant Total (in thousands) Fixed maturity securities, available-for-sale: State and municipal $ — $ 296,405 $ — $ 296,405 Residential mortgage-backed — 293,848 — 293,848 Corporate — 766,822 — 766,822 Commercial mortgage and asset-backed — 326,719 326,719 U.S. Treasury securities and obligations guaranteed by the U.S. government 99,384 464 — 99,848 Total fixed maturity securities, available-for-sale $ 99,384 $ 1,684,258 $ — $ 1,783,642 Equity securities: Preferred stock — 67,495 — 67,495 Common stock 15,793 5,015 672 21,480 Total equity securities $ 15,793 $ 72,510 $ 672 $ 88,975 Bank loan participations $ — $ 147,296 $ 308 $ 147,604 Short-term investments $ — $ 130,289 $ — $ 130,289
Reconciliation of Securities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs	A reconciliation of the beginning and ending balances of available-for-sale fixed maturity securities, equity securities, and bank loan participations measured at fair value on a recurring basis (as a result of the fair value option effective January 1, 2020) using significant unobservable inputs (Level 3) is shown below: Three Months Ended March 31, 2021 March 31, 2020 (in thousands) Beginning balance $ 980 $ 43 Transfers out of Level 3 — — Transfers in to Level 3 — 358 Purchases — 703 Sales (282) — Maturities, calls and paydowns (24) (17) Amortization of discount — 3 Total gains or losses (realized/unrealized): Included in earnings (375) (58) Included in other comprehensive income — — Ending balance $ 299 $ 1,032
Schedule of Carrying Value and Fair Value	The carrying values and fair values of financial instruments are summarized below: March 31, 2021 December 31, 2020 Carrying Fair Value Carrying Fair Value (in thousands) Assets Fixed maturity securities, available-for-sale $ 1,800,151 $ 1,800,151 $ 1,783,642 $ 1,783,642 Equity securities 90,877 90,877 88,975 88,975 Bank loan participations 160,880 160,880 147,604 147,604 Cash and cash equivalents 183,491 183,491 162,260 162,260 Restricted cash equivalents 751,668 751,668 859,920 859,920 Short-term investments 51,198 51,198 130,289 130,289 Other invested assets – notes receivable 13,500 17,767 4,500 5,302 Liabilities Senior debt 262,300 245,670 262,300 250,953 Junior subordinated debt 104,055 101,553 104,055 110,612

Capital Stock and Equity Awar_2

Capital Stock and Equity Awards (Tables)	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity Note [Abstract]
Schedule of Dividends	The Company declared the following dividends during the first three months of 2021 and 2020: Date of Declaration Dividend per Common Share Payable to Shareholders of Record on Payment Date Total Amount (thousands) 2021 February 24, 2021 $ 0.30 March 15, 2021 March 31, 2021 $ 9,345 2020 February 19, 2020 $ 0.30 March 16, 2020 March 31, 2020 $ 9,269
Schedule of Summary of Option Activity	The following table summarizes option activity: Three Months Ended March 31, 2021 2020 Shares Weighted- Shares Weighted- Outstanding: Beginning of period 463,324 $ 32.25 643,851 $ 30.41 Granted — $ — — $ — Exercised (29,884) $ 26.37 — $ — Forfeited — $ — — $ — End of period 433,440 $ 32.65 643,851 $ 30.41 Exercisable, end of period 433,440 $ 32.65 640,606 $ 30.35
Schedule of Summary of RSU Activity	The following table summarizes RSU activity: Three Months Ended March 31, 2021 2020 Shares Weighted- Shares Weighted- Unvested, beginning of period 399,856 $ 43.59 340,368 $ 41.50 Granted 138,936 $ 50.24 179,016 $ 43.55 Vested (161,004) $ 41.89 (142,830) $ 41.16 Forfeited (1,089) $ 42.44 (1,188) $ 42.07 Unvested, end of period 376,699 $ 46.78 375,366 $ 42.61
Schedule of Summary of Share Based Compensation Expense and Related Tax Benefit	Share based compensation expense is recognized on a straight line basis over the vesting period. The amount of expense and related tax benefit is summarized below: Three Months Ended 2021 2020 (in thousands) Share based compensation expense $ 1,905 $ 1,867 U.S. tax benefit on share based compensation expense 294 250

Accounting Policies - Narrative

Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)company	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Accounting Policies [Line Items]
Investment in variable interest entities	$ 29,000		$ 30,100
Pre-tax (income) loss	140,829	$ 41,218
Income tax benefit	37,369	4,403
Development on prior year loss reserves	$ 170,134	$ 874
Effective U.S. federal income tax benefit rate	26.50%	10.70%
Excess and Surplus Lines
Accounting Policies [Line Items]
Development on prior year loss reserves	$ 168,700	$ (3)
UNITED STATES
Accounting Policies [Line Items]
Number of insurance companies | company	5
BERMUDA
Accounting Policies [Line Items]
Number of insurance companies | company	2

Investments - Schedule of Avail

Investments - Schedule of Available-for-Sale Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	$ 1,755,733	$ 1,690,890
Fixed maturity securities, available-for-sale	1,800,151	1,783,642
Fixed maturity securities
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	1,755,733	1,690,890
Total investments available-for-sale, Gross Unrealized Gains	58,796	94,056
Total investments available-for-sale, Gross Unrealized Losses	(14,378)	(1,304)
Fixed maturity securities, available-for-sale	1,800,151	1,783,642
State and municipal
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	311,053	277,241
Total investments available-for-sale, Gross Unrealized Gains	12,249	19,203
Total investments available-for-sale, Gross Unrealized Losses	(3,537)	(39)
Fixed maturity securities, available-for-sale	319,765	296,405
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	296,200	286,104
Total investments available-for-sale, Gross Unrealized Gains	5,490	7,784
Total investments available-for-sale, Gross Unrealized Losses	(1,734)	(40)
Fixed maturity securities, available-for-sale	299,956	293,848
Corporate
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	737,756	715,145
Total investments available-for-sale, Gross Unrealized Gains	32,160	52,098
Total investments available-for-sale, Gross Unrealized Losses	(7,223)	(421)
Fixed maturity securities, available-for-sale	762,693	766,822
Commercial mortgage and asset-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	322,579	314,911
Total investments available-for-sale, Gross Unrealized Gains	7,234	12,611
Total investments available-for-sale, Gross Unrealized Losses	(1,633)	(803)
Fixed maturity securities, available-for-sale	328,180	326,719
U.S. Treasury securities and obligations guaranteed by the U.S. government
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities, Cost or Amortized Cost	88,145	97,489
Total investments available-for-sale, Gross Unrealized Gains	1,663	2,360
Total investments available-for-sale, Gross Unrealized Losses	(251)	(1)
Fixed maturity securities, available-for-sale	$ 89,557	$ 99,848

Investments - Schedule of Contr

Investments - Schedule of Contract Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Cost or Amortized Cost
One year or less	$ 110,269
After one year through five years	455,605
After five years through ten years	327,033
After ten years	244,047
Residential mortgage-backed	296,200
Commercial mortgage and asset-backed	322,579
Total fixed maturity securities, Cost or Amortized Cost	1,755,733	$ 1,690,890
Fair Value
One year or less	111,427
After one year through five years	477,392
After five years through ten years	332,488
After ten years	250,708
Residential mortgage-backed	299,956
Commercial mortgage and asset-backed	328,180
Total investments available-for-sale, Fair Value	$ 1,800,151	$ 1,783,642

Investments - Schedule of Gross

Investments - Schedule of Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, fair value	$ 505,500
Fixed maturity securities, gross unrealized losses	(14,400)
Fixed maturity securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	496,123	$ 60,167
Fixed maturity securities, less than 12 months, gross unrealized losses	(14,300)	(948)
Fixed maturity securities, 12 months or more, fair value	9,355	38,802
Fixed maturity securities, 12 months or more, gross unrealized losses	(78)	(356)
Fixed maturity securities, fair value	505,478	98,969
Fixed maturity securities, gross unrealized losses	(14,378)	(1,304)
State and municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	113,279	7,193
Fixed maturity securities, less than 12 months, gross unrealized losses	(3,537)	(39)
Fixed maturity securities, 12 months or more, fair value	0	0
Fixed maturity securities, 12 months or more, gross unrealized losses	0	0
Fixed maturity securities, fair value	113,279	7,193
Fixed maturity securities, gross unrealized losses	(3,537)	(39)
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	115,899	3,649
Fixed maturity securities, less than 12 months, gross unrealized losses	(1,725)	(40)
Fixed maturity securities, 12 months or more, fair value	342	0
Fixed maturity securities, 12 months or more, gross unrealized losses	(9)	0
Fixed maturity securities, fair value	116,241	3,649
Fixed maturity securities, gross unrealized losses	(1,734)	(40)
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	162,414	28,607
Fixed maturity securities, less than 12 months, gross unrealized losses	(7,223)	(421)
Fixed maturity securities, 12 months or more, fair value	0	0
Fixed maturity securities, 12 months or more, gross unrealized losses	0	0
Fixed maturity securities, fair value	162,414	28,607
Fixed maturity securities, gross unrealized losses	(7,223)	(421)
Commercial mortgage and asset-backed
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	85,511	18,427
Fixed maturity securities, less than 12 months, gross unrealized losses	(1,564)	(447)
Fixed maturity securities, 12 months or more, fair value	9,013	38,802
Fixed maturity securities, 12 months or more, gross unrealized losses	(69)	(356)
Fixed maturity securities, fair value	94,524	57,229
Fixed maturity securities, gross unrealized losses	(1,633)	(803)
U.S. Treasury securities and obligations guaranteed by the U.S. government
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	19,020	2,291
Fixed maturity securities, less than 12 months, gross unrealized losses	(251)	(1)
Fixed maturity securities, 12 months or more, fair value	0	0
Fixed maturity securities, 12 months or more, gross unrealized losses	0	0
Fixed maturity securities, fair value	19,020	2,291
Fixed maturity securities, gross unrealized losses	$ (251)	$ (1)

Investments - Narrative (Detail

Investments - Narrative (Details)	3 Months Ended
	Mar. 31, 2021USD ($)issuer	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Jan. 01, 2020USD ($)	Dec. 31, 2019USD ($)
Gain (Loss) on Securities [Line Items]
Number of issuers | issuer	192
Total fair value	$ 505,500,000
Gross unrealized losses	14,400,000
Fixed maturity securities, available-for-sale	1,800,151,000		$ 1,783,642,000
Shareholders' equity	639,628,000	$ 720,317,000	795,608,000		$ 778,581,000
Bank loan participations	160,880,000		147,604,000
Unpaid principal balance	168,600,000
Net investment income	15,089,000	20,836,000
Changes in fair values of bank loan participations	3,911,000	(43,947,000)
Losses due to credit-related impairments	0	5,000,000
Bank Loan Participations
Gain (Loss) on Securities [Line Items]
Net investment income	2,900,000	4,100,000
Retained Earnings
Gain (Loss) on Securities [Line Items]
Shareholders' equity	(63,576,000)	$ 35,412,000	49,227,000		89,586,000
Cumulative Effect, Period of Adoption, Adjustment | ASU 2019-05
Gain (Loss) on Securities [Line Items]
Bank loan participations				$ (8,400,000)
Shareholders' equity					(7,827,000)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | ASU 2019-05
Gain (Loss) on Securities [Line Items]
Shareholders' equity				$ (7,800,000)	$ (7,827,000)
Fixed maturity securities
Gain (Loss) on Securities [Line Items]
Total fair value	505,478,000		98,969,000
Gross unrealized losses	14,378,000		1,304,000
Fixed maturity securities, available-for-sale	1,800,151,000		1,783,642,000
Aggregate net unrealized gain	$ 58,796,000		$ 94,056,000
BBB- or better | Fixed maturity securities
Gain (Loss) on Securities [Line Items]
Percentage of available for sale securities	99.30%
Below BBB-
Gain (Loss) on Securities [Line Items]
Fixed maturity securities, available-for-sale	$ 11,900,000
Aggregate net unrealized gain	114,000
Bank Holding Company
Gain (Loss) on Securities [Line Items]
Carrying value of collateralized loan obligation held	$ 252,000

Investments - Summary of Realiz

Investments - Summary of Realized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Investments [Abstract]
Fixed maturity securities, gross realized gains	$ 1,056	$ 215
Fixed maturity securities, gross realized losses	(22)	(1)
Fixed maturity securities	1,034	214
Bank loan participations, gross realized gains	198	103
Bank loan participations, gross realized losses	(260)	(1,309)
Changes in fair values of bank loan participations	3,911	(43,947)
Bank loan participations	3,849	(45,153)
Equity securities, gross realized gain	29	0
Equity securities, gross realized losses	(401)	(170)
Changes in fair values of equity securities	1,745	(13,315)
Equity securities	1,373	(13,485)
Short-term investments and other, gross realized gains	5	18
Short-term investments and other, gross realized losses	0	(1)
Changes in fair values of short-term investments and other	11	0
Short-term investments and other	16	17
Total	$ 6,272	$ (58,407)

Investments - Summary of Privat

Investments - Summary of Private Debt and Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Net Investment Income [Line Items]
Total other invested assets	$ 55,863		$ 46,548
Investment income	$ 334	$ 517
Rate of interest	12.00%
Renewable energy LLCs
Net Investment Income [Line Items]
Total other invested assets	$ 28,965		30,145
Investment income	(915)	834
Renewable energy notes receivable
Net Investment Income [Line Items]
Total other invested assets	9,000		0
Investment income	234	166
Limited partnerships
Net Investment Income [Line Items]
Total other invested assets	13,398		11,903
Investment income	929	(569)
Bank holding companies
Net Investment Income [Line Items]
Total other invested assets	4,500		$ 4,500
Investment income	86	86
Corporate and Other | Renewable energy notes receivable
Net Investment Income [Line Items]
Investment income	130	166
Corporate and Other | Limited partnerships
Net Investment Income [Line Items]
Investment income (loss)	754	(710)
Carrying values of limited partnerships held	8,600
Corporate and Other | Bank holding companies
Net Investment Income [Line Items]
Interest income	86	86
Corporate and Other | Investment in LLC
Net Investment Income [Line Items]
Cash distributions from LLCs	$ 265	747
Corporate and Other | Bank Holding Company
Net Investment Income [Line Items]
Rate of interest	7.60%
Investment in private subordinated notes	$ 4,500
Excess and Surplus Lines | Renewable energy notes receivable
Net Investment Income [Line Items]
Investment income	104	0
Excess and Surplus Lines | Limited partnerships
Net Investment Income [Line Items]
Investment income (loss)	175	$ 141
Carrying values of limited partnerships held	4,800
Outstanding commitments to invest	$ 7,900
Minimum | Corporate and Other | Investment in LLC
Net Investment Income [Line Items]
Ownership percentage	2.60%
Maximum | Corporate and Other | Investment in LLC
Net Investment Income [Line Items]
Ownership percentage	32.60%

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 11, 2007
Business Acquisition [Line Items]
Goodwill	$ 181,831	$ 181,831	$ 181,831
James River Group, Inc.
Business Acquisition [Line Items]
Percentage of outstanding shares				100.00%

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Acquired Intangible Assets [Line Items]
Identifiable intangibles not subject to amortization	$ 31,164	$ 31,164
Identifiable intangible assets subject to amortization
Gross Carrying Amount	11,611	11,611
Accumulated Amortization	6,464	6,373
Total Intangible Assets, Gross	42,775	42,775
Broker relationships
Identifiable intangible assets subject to amortization
Gross Carrying Amount	11,611	11,611
Accumulated Amortization	$ 6,464	6,373
Life (Years)	24 years 7 months 6 days
Trademarks
Acquired Intangible Assets [Line Items]
Identifiable intangibles not subject to amortization	$ 22,200	22,200
Insurance licenses and authorities
Acquired Intangible Assets [Line Items]
Identifiable intangibles not subject to amortization	$ 8,964	$ 8,964

Earnings Per Share - Basic and

Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net loss to shareholders	$ (103,460)	$ (36,815)
Weighted average common shares outstanding:
Basic (in shares)	30,713,986	30,476,307
Common share equivalents (in shares)	0	0
Diluted (in shares)	30,713,986	30,476,307
Loss per share:
Basic (in dollars per share)	$ (3.37)	$ (1.21)
Common share equivalents (in dollars per share)	0	0
Diluted (in dollars per share)	$ (3.37)	$ (1.21)

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock options and restricted share units ("RSU's")
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of securities excluded from the calculations of diluted earnings per share	306,712	309,443

Reserve for Losses and Loss A_3

Reserve for Losses and Loss Adjustment Expenses - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability for Claims and Claims Adjustment Expense [Abstract]
Allowance for uncollectible reinsurance balances	$ 335	$ 335
Favorable development on prior year loss reserves
Development on prior year loss reserves	170,134	874
Excess and Surplus Lines
Favorable development on prior year loss reserves
Development on prior year loss reserves	168,700	(3)
Excess and Surplus Lines | Commercial Auto Business
Favorable development on prior year loss reserves
Development on prior year loss reserves	170,000
Specialty Admitted Insurance
Favorable development on prior year loss reserves
Development on prior year loss reserves	(1,000)	(1,000)
Casualty Reinsurance
Favorable development on prior year loss reserves
Development on prior year loss reserves	$ 2,500	$ 1,900

Reserve for Losses and Loss A_4

Reserve for Losses and Loss Adjustment Expenses - Reconciliation of Losses and Loss Adjustment Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]
Reserve for losses and loss adjustment expenses net of reinsurance recoverables at beginning of period	$ 1,386,061	$ 1,377,461
Add: Incurred losses and loss adjustment expenses net of reinsurance:
Current year	103,366	95,982
Prior years	170,134	874
Total incurred losses and loss and adjustment expenses	273,500	96,856
Deduct: Loss and loss adjustment expense payments net of reinsurance:
Current year	3,194	4,271
Prior years	121,588	118,357
Total loss and loss adjustment expense payments	124,782	122,628
Reserve for losses and loss adjustment expenses net of reinsurance recoverables at end of period	1,534,779	1,351,689
Add: Reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period	879,067	691,669
Reserve for losses and loss adjustment expenses gross of reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period	$ 2,413,846	$ 2,043,358	$ 2,192,080

Other Comprehensive Loss - Summ

Other Comprehensive Loss - Summary of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized losses arising during the period, before U.S. income taxes	$ (47,300)	$ (5,096)
U.S. income taxes	5,453	1,378
Unrealized losses arising during the period, net of U.S. income taxes	(41,847)	(3,718)
Less reclassification adjustment:
Net realized investment gains	1,035	214
U.S. income taxes	(194)	(13)
Reclassification adjustment for investment gains realized in net income	841	201
Other comprehensive loss	$ (42,688)	$ (3,919)

Other Comprehensive Loss - Narr

Other Comprehensive Loss - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net realized investment gains	$ 1,035	$ 214
Bank loan participations	3,849	(45,153)
Net realized and unrealized gains (losses) on investments in equity securities	$ 1,400	$ (13,500)

Contingent Liabilities - Narrat

Contingent Liabilities - Narrative (Details)	Mar. 31, 2021USD ($)credit_facility	Dec. 31, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Contingent Liabilities [Line Items]
Amount of collateral held	$ 751,668,000	$ 859,920,000	$ 1,107,321,000	$ 1,199,164,000
JRG Reinsurance Company, Ltd.
Contingent Liabilities [Line Items]
Number of credit facilities | credit_facility	3
JRG Reinsurance Company, Ltd. | Letter of credit 75 Million
Contingent Liabilities [Line Items]
Letters of credit facility, amount	$ 75,000,000
Amount of letters of credit issued	7,300,000
Assets deposited for securing letters of credit	14,400,000
JRG Reinsurance Company, Ltd. | Letter of credit 102.5 Million
Contingent Liabilities [Line Items]
Letters of credit facility, amount	102,500,000
Amount of letters of credit issued	89,700,000
Assets deposited for securing letters of credit	113,600,000
JRG Reinsurance Company, Ltd. | Letter of credit 100 Million
Contingent Liabilities [Line Items]
Amount of letters of credit issued	15,200,000
Assets deposited for securing letters of credit	28,100,000
Line of credit (up to)	100,000,000
Third-party Reinsureds | JRG Reinsurance Company, Ltd.
Contingent Liabilities [Line Items]
Collateral trust arrangement amount	304,400,000
Raiser
Contingent Liabilities [Line Items]
Amount of collateral held	$ 751,700,000

Segment Information - Narrative

Segment Information - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)segment	Mar. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	4
Gross fee income	$ 927	$ 1,600
Excess and Surplus Lines
Segment Reporting Information [Line Items]
Gross fee income	0	1,300
Specialty Admitted Insurance
Segment Reporting Information [Line Items]
Gross fee income	$ 927	$ 335

Segment Information - Summary o

Segment Information - Summary of Segment Results (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Gross written premiums	$ 373,255	$ 283,841
Net earned premiums	160,593	145,918
Underwriting (loss) profit of insurance segments	(151,305)	7,331
Net investment income	15,089	20,836
Interest expense	2,216	2,876
Total revenues	182,980	110,284
Segment goodwill	181,831	181,831	$ 181,831
Segment assets	5,109,707	4,996,810	$ 5,063,072
Excess and Surplus Lines
Segment Reporting Information [Line Items]
Gross written premiums	181,358	136,197
Net earned premiums	113,708	99,739
Underwriting (loss) profit of insurance segments	(150,946)	8,112
Net investment income	3,706	7,941
Interest expense	0	0
Total revenues	118,796	83,829
Segment goodwill	181,831	181,831
Segment assets	2,129,985	2,293,444
Specialty Admitted Insurance
Segment Reporting Information [Line Items]
Gross written premiums	127,036	102,802
Net earned premiums	16,357	13,283
Underwriting (loss) profit of insurance segments	1,266	(988)
Net investment income	822	928
Interest expense	0	0
Total revenues	18,565	12,673
Segment goodwill	0	0
Segment assets	980,824	829,699
Casualty Reinsurance
Segment Reporting Information [Line Items]
Gross written premiums	64,861	44,842
Net earned premiums	30,528	32,896
Underwriting (loss) profit of insurance segments	(1,625)	207
Net investment income	10,556	11,604
Interest expense	0	0
Total revenues	45,517	13,280
Segment goodwill	0	0
Segment assets	1,930,747	1,824,729
Corporate and Other
Segment Reporting Information [Line Items]
Gross written premiums	0	0
Net earned premiums	0	0
Underwriting (loss) profit of insurance segments	0	0
Net investment income	5	363
Interest expense	2,216	2,876
Total revenues	102	502
Segment goodwill	0	0
Segment assets	$ 68,151	$ 48,938

Segment Information - Reconcili

Segment Information - Reconciliation of Operating Segments by Individual Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total underwriting (loss) profit of insurance segments	$ (151,305)	$ 7,331
Other operating expenses of the Corporate and Other segment	(8,056)	(8,279)
Underwriting loss	(159,361)	(948)
Net investment income	15,089	20,836
Net realized and unrealized gains (losses) on investments	6,272	(58,407)
Amortization of intangible assets	(91)	(149)
Other income and expenses	(522)	326
Interest expense	(2,216)	(2,876)
Loss before taxes	(140,829)	(41,218)
Excess and Surplus Lines
Segment Reporting Information [Line Items]
Total underwriting (loss) profit of insurance segments	(150,946)	8,112
Net investment income	3,706	7,941
Interest expense	0	0
Specialty Admitted Insurance
Segment Reporting Information [Line Items]
Total underwriting (loss) profit of insurance segments	1,266	(988)
Net investment income	822	928
Interest expense	0	0
Casualty Reinsurance
Segment Reporting Information [Line Items]
Total underwriting (loss) profit of insurance segments	(1,625)	207
Net investment income	10,556	11,604
Interest expense	$ 0	$ 0

Other Operating Expenses and _3

Other Operating Expenses and Other Expenses (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Operating Expenses and Other Expenses [Abstract]
Amortization of policy acquisition costs	$ 21,475,000	$ 24,116,000
Other underwriting expenses of the operating segments	17,850,000	19,226,000
Other operating expenses of the Corporate and Other segment	8,056,000	8,279,000
Total	47,381,000	51,621,000
Other expenses	$ 621,000	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	$ 1,800,151	$ 1,783,642
Equity securities:
Total equity securities	90,877	88,975
Bank loan participations	160,880	147,604
Fixed maturity securities
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	1,800,151	1,783,642
State and municipal
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	319,765	296,405
Residential mortgage-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	299,956	293,848
Corporate
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	762,693	766,822
Commercial mortgage and asset-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	328,180	326,719
U.S. Treasury securities and obligations guaranteed by the U.S. government
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	89,557	99,848
Recurring basis
Equity securities:
Bank loan participations	160,880	147,604
Short-term investments	51,198	130,289
Recurring basis | Fixed maturity securities
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	1,800,151	1,783,642
Recurring basis | State and municipal
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	319,765	296,405
Recurring basis | Residential mortgage-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	299,956	293,848
Recurring basis | Corporate
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	762,693	766,822
Recurring basis | Commercial mortgage and asset-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	328,180	326,719
Recurring basis | U.S. Treasury securities and obligations guaranteed by the U.S. government
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	89,557	99,848
Recurring basis | Equity securities
Equity securities:
Total equity securities	90,877	88,975
Recurring basis | Preferred stock
Equity securities:
Total equity securities	62,079	67,495
Recurring basis | Common stock
Equity securities:
Total equity securities	28,798	21,480
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1
Equity securities:
Bank loan participations	0	0
Short-term investments	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Fixed maturity securities
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	89,118	99,384
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | State and municipal
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Residential mortgage-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Corporate
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Commercial mortgage and asset-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | U.S. Treasury securities and obligations guaranteed by the U.S. government
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	89,118	99,384
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Equity securities
Equity securities:
Total equity securities	21,464	15,793
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Preferred stock
Equity securities:
Total equity securities	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets Level 1 | Common stock
Equity securities:
Total equity securities	21,464	15,793
Recurring basis | Significant Other Observable Inputs Level 2
Equity securities:
Bank loan participations	160,581	147,296
Short-term investments	51,198	130,289
Recurring basis | Significant Other Observable Inputs Level 2 | Fixed maturity securities
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	1,711,033	1,684,258
Recurring basis | Significant Other Observable Inputs Level 2 | State and municipal
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	319,765	296,405
Recurring basis | Significant Other Observable Inputs Level 2 | Residential mortgage-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	299,956	293,848
Recurring basis | Significant Other Observable Inputs Level 2 | Corporate
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	762,693	766,822
Recurring basis | Significant Other Observable Inputs Level 2 | Commercial mortgage and asset-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	328,180	326,719
Recurring basis | Significant Other Observable Inputs Level 2 | U.S. Treasury securities and obligations guaranteed by the U.S. government
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	439	464
Recurring basis | Significant Other Observable Inputs Level 2 | Equity securities
Equity securities:
Total equity securities	69,413	72,510
Recurring basis | Significant Other Observable Inputs Level 2 | Preferred stock
Equity securities:
Total equity securities	62,079	67,495
Recurring basis | Significant Other Observable Inputs Level 2 | Common stock
Equity securities:
Total equity securities	7,334	5,015
Recurring basis | Significant Unobservable Inputs Level 3
Equity securities:
Bank loan participations	299	308
Short-term investments	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Fixed maturity securities
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | State and municipal
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Residential mortgage-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Corporate
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Commercial mortgage and asset-backed
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0
Recurring basis | Significant Unobservable Inputs Level 3 | U.S. Treasury securities and obligations guaranteed by the U.S. government
Fixed maturity securities, available-for-sale:
Total fixed maturity securities, available-for-sale	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Equity securities
Equity securities:
Total equity securities	0	672
Recurring basis | Significant Unobservable Inputs Level 3 | Preferred stock
Equity securities:
Total equity securities	0	0
Recurring basis | Significant Unobservable Inputs Level 3 | Common stock
Equity securities:
Total equity securities	$ 0	$ 672

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Securities Measured at Fair Value (Details) - Fair Value, Recurring - Available-for-sale fixed maturity securities and equity securities - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 980	$ 43
Transfers out of Level 3	0	0
Transfers in to Level 3	0	358
Purchases	0	703
Sales	(282)	0
Maturities, calls and paydowns	(24)	(17)
Amortization of discount	0	3
Total gains or losses (realized/unrealized)-Included in earnings	(375)	(58)
Total gains or losses (realized/unrealized)-Included in other comprehensive income	0	0
Ending balance	$ 299	$ 1,032

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Thousands	Mar. 31, 2021USD ($)bank_loan_participationsecurity	Dec. 31, 2020USD ($)bank_loan_participationsecurity	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Number of bank loan participations held | bank_loan_participation	1	1
Number of equity securities held | security	1	2
Recurring basis | Available-for-sale fixed maturity securities and equity securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Asset value | $	$ 299	$ 980	$ 1,032	$ 43

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Assets
Fixed maturity securities, available-for-sale	$ 1,800,151	$ 1,783,642
Equity securities	90,877	88,975
Bank loan participations	160,880	147,604
Cash and cash equivalents	183,491	162,260
Restricted cash equivalents	751,668	859,920	$ 1,107,321	$ 1,199,164
Liabilities
Senior debt	262,300	262,300
Junior subordinated debt	104,055	104,055
Carrying Value
Assets
Fixed maturity securities, available-for-sale	1,800,151	1,783,642
Equity securities	90,877	88,975
Bank loan participations	160,880	147,604
Cash and cash equivalents	183,491	162,260
Restricted cash equivalents	751,668	859,920
Short-term investments	51,198	130,289
Other invested assets – notes receivable	13,500	4,500
Liabilities
Senior debt	262,300	262,300
Junior subordinated debt	104,055	104,055
Fair Value
Assets
Fixed maturity securities, available-for-sale	1,800,151	1,783,642
Equity securities	90,877	88,975
Bank loan participations	160,880	147,604
Cash and cash equivalents	183,491	162,260
Restricted cash equivalents	751,668	859,920
Short-term investments	51,198	130,289
Other invested assets – notes receivable	17,767	5,302
Liabilities
Senior debt	245,670	250,953
Junior subordinated debt	$ 101,553	$ 110,612

Senior Debt (Details)

Senior Debt (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Drawn balance outstanding		$ 262,300,000	$ 262,300,000
2013 Facility
Debt Instrument [Line Items]
Amount drawn	$ 60,000,000
Unsecured Debt | 2013 Facility
Debt Instrument [Line Items]
Drawn balance outstanding		185,800,000
Line of credit (up to)		212,500,000
Line of Credit | 2013 Facility
Debt Instrument [Line Items]
Line of credit (up to)		315,000,000
JRG Reinsurance Company, Ltd. | 2013 Facility
Debt Instrument [Line Items]
Amount of letters of credit issued		89,700,000
JRG Reinsurance Company, Ltd. | 2017 Facility
Debt Instrument [Line Items]
Line of credit (up to)		100,000,000
Amount drawn	$ 59,000,000
Amount of letters of credit issued		15,200,000
JRG Reinsurance Company, Ltd. | Unsecured Debt | 2017 Facility
Debt Instrument [Line Items]
Drawn balance outstanding		$ 61,500,000

Capital Stock and Equity Awar_3

Capital Stock and Equity Awards - Common Shares (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of stock options (in shares)	16,471
Common stock, shares outstanding (in shares)	30,774,930		30,649,261
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit dividend equivalents	$ 113	$ 113
Dividends payable	$ 396		$ 663
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares issued during period (in shares)	125,669
Exercise of stock options (in shares)	16,471
Vesting of RSUs (in shares)	109,198	96,037
Common stock, shares outstanding (in shares)	30,774,930	30,520,428	30,649,261	30,424,391

Capital Stock and Equity Awar_4

Capital Stock and Equity Awards - Schedule of Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2021	Feb. 24, 2021	Mar. 31, 2020	Feb. 19, 2020	Mar. 31, 2021	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Dividend declared per share (in dollars per share)		$ 0.30		$ 0.30	$ 0.30	$ 0.30
Total Amount (thousands)	$ 9,345		$ 9,269

Capital Stock and Equity Awar_5

Capital Stock and Equity Awards - Equity Incentive Plans (Details) - Non-qualified stock options	Mar. 31, 2021shares
2014 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for issuance	4,171,150
Number of shares available for grant	1,226,493
2014 Director Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for issuance	150,000
Number of shares available for grant	94,781

Capital Stock and Equity Awar_6

Capital Stock and Equity Awards - Summary of Option Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Shares
Exercised (in shares)	(16,471)
Weighted- Average Exercise Price
Weighted-average remaining contractual life of options outstanding	1 year 10 months 24 days
Weighted-average remaining contractual life of options exercisable	1 year 10 months 24 days
Options
Shares
Beginning of period (in shares)	463,324	643,851
Granted (in shares)	0	0
Exercised (in shares)	(29,884)	0
Forfeited (in shares)	0	0
End of period (in shares)	433,440	643,851
Exercisable, end of period (in shares)	433,440	640,606
Weighted- Average Exercise Price
Beginning of period (in dollars per share)	$ 32.25	$ 30.41
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	26.37	0
Forfeited (in dollars per share)	0	0
End of period (in dollars per share)	32.65	30.41
Exercisable, end of period (in dollars per share)	$ 32.65	$ 30.35
Vesting period (in years)	3 years
Contractual life (in years)	7 years

Capital Stock and Equity Awar_7

Capital Stock and Equity Awards - Summary of RSU Activity (Details) - RSUs - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Shares
Unvested, beginning of period (in shares)	399,856	340,368
Granted (in shares)	138,936	179,016
Vested (in shares)	(161,004)	(142,830)
Forfeited (in shares)	(1,089)	(1,188)
Unvested, end of period (in shares)	376,699	375,366
Weighted- Average Grant Date Fair Value
Unvested, beginning of period (in dollars per share)	$ 43.59	$ 41.50
Granted (in dollars per share)	50.24	43.55
Vested (in dollars per share)	41.89	41.16
Forfeited (in dollars per share)	42.44	42.07
Unvested, end of period (in dollars per share)	$ 46.78	$ 42.61
Vesting period (in years)	3 years
Non-employee directors
Weighted- Average Grant Date Fair Value
Vesting period (in years)	1 year

Capital Stock and Equity Awar_8

Capital Stock and Equity Awards - Summary of Share Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stockholders' Equity Note [Abstract]
Share based compensation expense	$ 1,905	$ 1,867
U.S. tax benefit on share based compensation expense	$ 294	$ 250

Capital Stock and Equity Awar_9

Capital Stock and Equity Awards - Compensation Expense (Details) - RSUs $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share based compensation expense	$ 16.2
Weighted-average period of unrecognized share based compensation expense	2 years 3 months 18 days

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - $ / shares	Jun. 30, 2021	Jun. 14, 2021	Apr. 27, 2021
Subsequent Event [Line Items]
Cash dividend declared (in dollars per share)			$ 0.30
Dividends payable, date to be paid	Jun. 30, 2021
Dividend payable, record date		Jun. 14, 2021

Uncategorized Items - jrvr-2021

Label	Element	Value
Accounting Standards Update [Extensible List]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-13 [Member]