Safety Insurance (SAFT) 10-Q 5 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 03, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	000-50070
Entity Registrant Name	SAFETY INSURANCE GROUP, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-4181699
Entity Address, Address Line One	20 Custom House Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	617
Local Phone Number	951-0600
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	SAFT
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		14,982,202
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001172052
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Investments:
Fixed maturities, available for sale, at fair value (amortized cost: $1,235,207 and $1,189,951, allowance for expected credit losses of $729 and $1,054)	$ 1,277,402		$ 1,256,653
Short term investments, at fair value (cost: $0 and $441)			441
Equity securities, at fair value (cost: $204,243 and $168,289)	252,623		205,254
Other invested assets	66,323		45,239
Total investments	1,596,348		1,507,587
Cash and cash equivalents	44,703		53,769
Accounts receivable, net of allowance for expected credit losses of $2,409 and $1,754	183,774	$ 183,222	179,147
Receivable for securities sold	7,113		1,311
Accrued investment income	9,289		8,045
Taxes recoverable			279
Receivable from reinsurers related to paid loss and loss adjustment expenses	11,269		13,432
Receivable from reinsurers related to unpaid loss and loss adjustment expenses	99,248		106,311
Ceded unearned premiums	22,567		22,406
Deferred policy acquisition costs	76,445		74,962
Equity and deposits in pools	38,955		30,429
Operating lease right-of-use-assets	27,313		31,000
Other assets	27,704		25,595
Total assets	2,144,728		2,054,273
Liabilities
Loss and loss adjustment expense reserves	578,547		567,581
Unearned premium reserves	434,167		421,901
Accounts payable and accrued liabilities	64,413		79,486
Payable for securities purchased	28,224		7,144
Payable to reinsurers	18,623		8,236
Deferred income taxes	11,561		17,611
Taxes payable	2,643
Debt	30,000		30,000
Operating lease liabilities	27,313		31,000
Other liabilities	21,160		6,635
Total liabilities	1,216,651		1,169,594
Commitments and contingencies (Note 8)
Shareholders' equity
Common stock: $0.01 par value; 30,000,000 shares authorized; 17,813,573 and 17,724,866 shares issued	178		178
Additional paid-in capital	214,576		209,779
Accumulated other comprehensive income, net of taxes	33,909		53,527
Retained earnings	803,248		745,029
Treasury stock, at cost: 2,831,168 shares	(123,834)		(123,834)
Total shareholders' equity	928,077	$ 920,299	884,679
Total liabilities and shareholders' equity	$ 2,144,728		$ 2,054,273

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Consolidated Balance Sheets
Fixed maturity securities, amortized cost	$ 1,235,207	$ 1,189,951
Fixed maturity securities, allowance for expected credit losses	729	1,054
Short term investments, at cost	0	441
Equity securities, at cost	204,243	168,289
Allowance for expected credit losses	$ 2,409	$ 1,754
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized	30,000,000	30,000,000
Common stock shares issued	17,813,573	17,724,866
Treasury stock shares	2,831,168	2,831,168

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues
Net earned premiums	$ 194,395	$ 194,843	$ 581,542	$ 574,640
Net investment income	11,112	9,718	32,418	30,344
Earnings from partnership investments	5,720	4,699	12,625	2,589
Net realized gains (losses) on investments	2,226	669	8,507	(683)
Change in net unrealized gains on equity securities	(3,447)	7,521	11,414	(5,639)
Credit loss (expense) benefit	(49)	182	325	(2,289)
Finance and other service income	3,751	4,768	11,660	12,252
Total revenue	213,708	222,400	658,491	611,214
Expenses
Losses and loss adjustment expenses	119,129	97,054	340,785	308,774
Underwriting, operating and related expenses	63,291	68,596	193,404	195,192
Interest expense	131	131	390	308
Total expenses	182,551	165,781	534,579	504,274
Income before income taxes	31,157	56,619	123,912	106,940
Income tax expense	6,337	11,877	25,251	21,694
Net income	$ 24,820	$ 44,742	$ 98,661	$ 85,246
Earnings per weighted average common share:
Basic (in dollars per share)	$ 1.65	$ 2.99	$ 6.63	$ 5.62
Diluted (in dollars per share)	1.64	2.96	6.58	5.58
Cash dividends paid per common share (in dollars per share)	$ 0.90	$ 0.90	$ 2.70	$ 2.70
Number of shares used in computing earnings per share:
Basic (in shares)	14,982,405	14,907,809	14,826,515	15,085,914
Diluted (in shares)	15,080,029	15,030,277	14,922,870	15,204,155

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated Statements of Comprehensive Income
Net income	$ 24,820	$ 44,742	$ 98,661	$ 85,246
Other comprehensive (loss) income, net of tax:
Unrealized holding (losses) gains during the period, net of income tax (benefit) expense of ($874), $1,635, ($3,428) and $5,102.	(3,287)	6,152	(12,897)	19,195
Reclassification adjustment for net realized (gains) losses on investments included in net income, net of income tax (expense) benefit of ($467), ($140), ($1,786) and $143.	(1,759)	(529)	(6,721)	540
Other comprehensive (loss) income, net of tax:	(5,046)	5,623	(19,618)	19,735
Comprehensive income	$ 19,774	$ 50,365	$ 79,043	$ 104,981

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated Statements of Comprehensive Income.
Tax (benefit) expense on unrealized holding (losses) gains during the period	$ (874)	$ 1,635	$ (3,428)	$ 5,102
Tax (expense) benefit on reclassification adjustment for (gains) losses included in net income	$ (467)	$ (140)	$ (1,786)	$ 143

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income, Net of Taxes	Retained Earnings	Treasury Stock	Total
Balance at Dec. 31, 2019	$ 177	$ 202,321	$ 28,190	$ 661,553	$ (83,835)	$ 808,406
Net (loss) income				(1,990)		(1,990)
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			(21,786)			(21,786)
Restricted share awards issued		528				528
Recognition of employee share-based compensation, net of deferred federal income taxes		1,215				1,215
Dividends paid and accrued				(13,872)		(13,872)
Acquisition of treasury stock					(10,392)	(10,392)
Balance at Mar. 31, 2020	177	204,064	6,404	645,691	(94,227)	762,109
Balance at Dec. 31, 2019	177	202,321	28,190	661,553	(83,835)	808,406
Net (loss) income						85,246
Acquisition of treasury stock						(39,999)
Balance at Sep. 30, 2020	178	208,113	47,925	705,469	(123,834)	837,851
Balance at Mar. 31, 2020	177	204,064	6,404	645,691	(94,227)	762,109
Net (loss) income				42,494		42,494
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			35,898			35,898
Recognition of employee share-based compensation, net of deferred federal income taxes		2,066				2,066
Dividends paid and accrued				(13,836)		(13,836)
Acquisition of treasury stock					(11,753)	(11,753)
Balance at Jun. 30, 2020	177	206,130	42,302	674,349	(105,980)	816,978
Net (loss) income				44,742		44,742
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			5,623			5,623
Restricted share awards issued	1					1
Recognition of employee share-based compensation, net of deferred federal income taxes		1,983				1,983
Dividends paid and accrued				(13,622)		(13,622)
Acquisition of treasury stock					(17,854)	(17,854)
Balance at Sep. 30, 2020	178	208,113	47,925	705,469	(123,834)	837,851
Balance at Dec. 31, 2020	178	209,779	53,527	745,029	(123,834)	884,679
Net (loss) income				36,174		36,174
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			(19,000)			(19,000)
Restricted share awards issued		475				475
Recognition of employee share-based compensation, net of deferred federal income taxes		1,384				1,384
Dividends paid and accrued				(13,459)		(13,459)
Balance at Mar. 31, 2021	178	211,638	34,527	767,744	(123,834)	890,253
Balance at Dec. 31, 2020	178	209,779	53,527	745,029	(123,834)	884,679
Net (loss) income						98,661
Balance at Sep. 30, 2021	178	214,576	33,909	803,248	(123,834)	928,077
Balance at Mar. 31, 2021	178	211,638	34,527	767,744	(123,834)	890,253
Net (loss) income				37,667		37,667
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			4,428			4,428
Recognition of employee share-based compensation, net of deferred federal income taxes		1,441				1,441
Dividends paid and accrued				(13,490)		(13,490)
Balance at Jun. 30, 2021	178	213,079	38,955	791,921	(123,834)	920,299
Net (loss) income				24,820		24,820
Unrealized (losses) gains on securities available for sale, net of deferred federal income taxes			(5,046)			(5,046)
Recognition of employee share-based compensation, net of deferred federal income taxes		1,497				1,497
Dividends paid and accrued				(13,493)		(13,493)
Balance at Sep. 30, 2021	$ 178	$ 214,576	$ 33,909	$ 803,248	$ (123,834)	$ 928,077

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 98,661	$ 85,246
Adjustments to reconcile net income to net cash provided by operating activities:
Investment amortization, net	3,455	4,832
Fixed asset depreciation, net	4,993	5,318
Stock based compensation	4,798	5,793
Credit for deferred income taxes	(836)	(2,078)
Net realized (gains) losses on investments	(8,507)	683
Credit loss (benefit) expense	(325)	2,289
(Earnings) losses from partnership investments	(9,375)	2,167
Change in net unrealized gains on equity securities	(11,414)	5,639
Changes in assets and liabilities:
Accounts receivable, net	(4,627)	(598)
Accrued investment income	(1,244)	(740)
Receivable from reinsurers	9,226	8,028
Ceded unearned premiums	(161)	12,873
Deferred policy acquisition costs	(1,483)	(5,492)
Taxes recoverable/payable	2,922	1,163
Other assets	(8,773)	(7,237)
Loss and loss adjustment expense reserves	10,966	(24,077)
Unearned premium reserves	12,266	4,938
Accounts payable and accrued liabilities	(14,870)	(3,757)
Payable to reinsurers	10,387	6,424
Other liabilities	14,525	(25,302)
Net cash provided by operating activities	110,584	76,112
Cash flows from investing activities:
Fixed maturities purchased	(272,557)	(123,449)
Equity securities purchased	(48,596)	(41,386)
Other invested assets purchased	(15,221)	(7,692)
Proceeds from sales and paydowns of fixed maturities	129,593	97,498
Proceeds from maturities, redemptions, and calls of fixed maturities	113,528	52,355
Proceed from sales of equity securities	17,110	21,122
Proceeds from other invested assets redeemed	3,993	180
Fixed assets purchased	(6,855)	(8,125)
Net cash used for investing activities	(79,005)	(9,497)
Cash flows from financing activities:
Proceeds from FHLB loan		30,000
Dividends paid to shareholders	(40,645)	(41,274)
Acquisition of treasury stock		(39,999)
Net cash used for financing activities	(40,645)	(51,273)
Net (decrease) increase in cash and cash equivalents	(9,066)	15,342
Cash and cash equivalents at beginning of year	53,769	44,407
Cash and cash equivalents at end of period	44,703	59,749
Supplemental disclosure of cash flow information:
Federal and state income taxes	20,190	20,080
Interest	$ 324	$ 215

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Basis of Presentation
Basis of Presentation	1. Basis of Presentation ​ The consolidated financial statements have been prepared on the basis of accounting principles generally accepted in the United States of America (“GAAP”). The preparation of these consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from these estimates. ​ The consolidated financial statements include Safety Insurance Group, Inc. and its subsidiaries (the “Company”). The subsidiaries consist of Safety Insurance Company, Safety Indemnity Insurance Company, Safety Property and Casualty Insurance Company, Safety Asset Management Corporation (“SAMC”), and Safety Management Corporation, which is SAMC’s holding company. All intercompany transactions have been eliminated. ​ The financial information for the three and nine months ended September 30, 2021 and 2020 is unaudited; however, in the opinion of the Company, the information includes all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the financial condition, results of operations, and cash flows for the periods. The financial information as of December 31, 2020 is derived from the audited financial statements included in the Company's 2020 Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (“SEC”) on February 26, 2021. ​ These unaudited interim consolidated financial statements may not be indicative of financial results for the full year and should be read in conjunction with the audited financial statements included in the Company’s 2020 Annual Report on Form 10-K filed with the SEC on February 26, 2021. ​ The Company is a leading provider of property and casualty insurance focused primarily on the Massachusetts market. The Company’s principal product line is automobile insurance. The Company operates through its insurance company subsidiaries, Safety Insurance Company, Safety Indemnity Insurance Company, Safety Property and Casualty Insurance Company and Safety Northeast Insurance Company (together referred to as the “Insurance Subsidiaries”). ​ ​

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2021
Recent Accounting Pronouncements
Recent Accounting Pronouncements	2. Recent Accounting Pronouncements ​ In December 2019, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) 2019-12, ​Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes ​ ​ On March 20, 2019, the SEC adopted amendments to Regulation S-K and related rules and forms to modernize and simplify certain disclosure requirements for public companies. The amendments are intended to reduce the costs and burdens of the disclosure process and while continuing to require disclosure of all material information. The amended rules generally were effective on May 2, 2019 and reduced disclosures but some provisions added new requirements. On August 26, 2020, the SEC adopted additional amendments to Regulation S-K to modernize certain disclosure requirements relating to the description of business, legal proceedings and risk factors which are required to be disclosed in the Form 10-K. The amended rules were effective for filings on or after November 9, 2020. The adoption of the new rules did not have a material impact on the Company’s financial position, results of operations, cash flows, or disclosures. ​

Earnings per Weighted Average C

Earnings per Weighted Average Common Share	9 Months Ended
	Sep. 30, 2021
Earnings per Weighted Average Common Share
Earnings per Weighted Average Common Share	​ 3. Earnings per Weighted Average Common Share ​ Basic earnings per weighted average common share (“EPS”) are calculated by dividing net income by the weighted average number of basic common shares outstanding during the period. Diluted earnings per share amounts are based on the weighted average number of common shares including non-vested performance stock grants. ​ The following table sets forth the computation of basic and diluted EPS for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Earnings attributable to common shareholders - basic and diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations ​ $ 24,820 ​ $ 44,742 ​ $ 98,661 ​ $ 85,246 Allocation of income for participating shares ​ ​ (107) ​ ​ (201) ​ ​ (434) ​ ​ (392) Net income from continuing operations attributed to common shareholders ​ $ 24,713 ​ $ 44,541 ​ $ 98,227 ​ $ 84,854 Earnings per share denominator - basic and diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total weighted average common shares outstanding, including participating shares ​ ​ 15,047,779 ​ ​ 14,974,636 ​ ​ 14,892,515 ​ ​ 15,155,969 Less: weighted average participating shares ​ ​ (65,374) ​ ​ (66,827) ​ ​ (66,000) ​ ​ (70,055) Basic earnings per share denominator ​ ​ 14,982,405 ​ ​ 14,907,809 ​ ​ 14,826,515 ​ ​ 15,085,914 Common equivalent shares- non-vested performance stock grants ​ 97,624 ​ 122,468 ​ 96,355 ​ 118,241 Diluted earnings per share denominator ​ 15,080,029 ​ 15,030,277 ​ 14,922,870 ​ 15,204,155 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings per share ​ $ 1.65 ​ $ 2.99 ​ $ 6.63 ​ $ 5.62 Diluted earnings per share ​ $ 1.64 ​ $ 2.96 ​ $ 6.58 ​ $ 5.58 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Undistributed earnings attributable to common shareholders - basic and diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations attributable to common shareholders -Basic ​ $ 1.65 ​ $ 2.99 ​ $ 6.63 ​ $ 5.62 Dividends declared ​ ​ (0.90) ​ ​ (0.90) ​ ​ (2.70) ​ ​ (2.70) Undistributed earnings ​ $ 0.75 ​ $ 2.09 ​ $ 3.93 ​ $ 2.92 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations attributable to common shareholders -Diluted ​ $ 1.64 ​ $ 2.96 ​ $ 6.58 ​ $ 5.58 Dividends declared ​ ​ (0.90) ​ ​ (0.90) ​ ​ (2.70) ​ ​ (2.70) Undistributed earnings ​ $ 0.74 ​ $ 2.06 ​ $ 3.88 ​ $ 2.88 ​ Diluted EPS excludes non-vested performance stock grants with exercise prices and exercise tax benefits greater than the average market price of the Company’s common stock during the period because their inclusion would be anti-dilutive. There were no anti-dilutive shares related to non-vested stock grants for the three and nine months ended September 30, 2021. There were 4 anti-dilutive shares related to non-vested stock grants for the three months ended September 30, 2020 and no anti-dilutive shares related to non-vested stock grants for the nine months ended September 30, 2020 respectively.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2021
Share-Based Compensation
Share-Based Compensation	4. Share-Based Compensation ​ 2018 Long Term Incentive Plan ​ On April 2, 2018, the Company’s Board of Directors adopted the Safety Insurance Group, Inc. 2018 Long-Term Incentive Plan (“the 2018 Plan”), which was subsequently approved by our shareholders at the 2018 Annual Meeting of Shareholders. The 2018 Plan enables the grant of stock awards, performance shares, cash-based performance units, other stock-based awards, stock options, stock appreciation rights, and stock unit awards, each of which may be granted separately or in tandem with other awards. Eligibility to participate includes officers, directors, employees and other individuals who provide bona fide services to the Company. The 2018 Plan supersedes the Company’s 2002 Management Omnibus Incentive Plan (“the 2002 Incentive Plan”). ​ The 2018 Plan establishes an initial pool of 350,000 shares of common stock available for issuance to our employees and other eligible participants. The Board of Directors and the Compensation Committee intend to issue awards under the 2018 Plan in the future. ​ The maximum number of shares of common stock between both the 2018 Plan and 2002 Incentive Plan with respect to which awards may be granted is 2,850,000. No further grants will be allowed under the 2002 Incentive Plan. At September 30, 2021, there were 164,908 shares available for future grant. ​ Accounting and Reporting for Stock-Based Awards ​ ASC 718, Compensation — Stock Compensation, requires the Company to measure and recognize the cost of employee services received in exchange for an award of equity instruments. Under the provisions of ASC 718, share-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized as an expense over the requisite service period (generally the vesting period of the equity grant). ​ Restricted Stock ​ Service-based restricted stock awarded in the form of unvested shares is recorded at the market value of the Company’s common stock on the grant date and amortized ratably as compensation expense over the requisite service period. Service-based restricted stock awards generally vest over a three-year period and vest 30% on the first and second anniversaries of the grant date and 40% on the third anniversary of the grant date, except for non-executive employees’ restricted stock awards granted prior to 2018 which vest ratably over a five-year service period and independent directors’ stock awards which vest immediately. Our independent directors are subject to stock ownership guidelines, which require them to have a value four times their annual cash retainer. ​ In addition to service-based awards, the Company grants performance-based restricted shares to certain employees. These performance shares cliff vest after a three-year performance period provided certain performance measures are attained. A portion of these awards, which contain a market condition, vest according to the level of total shareholder return achieved by the Company compared to its property-casualty insurance peers over a three-year period. The remainder, which contain a performance condition, vest according to the level of Company’s combined ratio results compared to a target based on its property-casualty insurance peers. ​ Actual payouts can range from 0% to 200% of target shares awarded depending upon the level of achievement of the respective market and performance conditions during a three calendar-year performance period. Compensation expense for share awards with a performance condition is based on the probable number of awards expected to vest using the performance level most likely to be achieved at the end of the performance period. ​ Performance-based awards with market conditions are accounted for and measured differently from awards that have a performance or service condition. The effect of a market condition is reflected in the award’s fair value on the grant date. That fair value is recognized as compensation cost over the requisite service period regardless of whether the market-based performance objective has been satisfied. ​ All of the Company’s restricted stock awards are issued as incentive compensation and are equity classified. ​ The following table summarizes restricted stock activity under the 2018 Plan during the nine months ended September 30, 2021 assuming a target payout for the 2021 performance-based shares. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Weighted ​ Performance-based Weighted ​ ​ Under ​ Average ​ Shares Under ​ Average ​ ​ Restriction ​ Fair Value ​ Restriction ​ Fair Value Outstanding at beginning of year 66,550 ​ $ 85.16 ​ 71,964 ​ $ 84.94 Granted 39,840 ​ ​ 79.27 ​ 49,460 (1) ​ 77.56 Vested and unrestricted (40,763) ​ ​ 80.82 ​ (48,666) ​ ​ 75.05 Forfeited ​ (253) ​ ​ 79.27 ​ (340) ​ ​ 87.43 Outstanding at end of period 65,374 ​ $ 84.30 ​ 72,418 ​ $ 86.53 (1) Includes a true-up of previously awarded performance-based restricted share awards. The updated shares were calculated based on the attainment of pre-established performance objectives and granted under the 2002 Incentive Plan. ​ As of September 30, 2021, there was $7,616 of unrecognized compensation expense related to non-vested restricted stock awards that is expected to be recognized over a weighted average period of 1.6 years. The total fair value of the shares that were vested and unrestricted during the nine months ended September 30, 2021 and 2020 was $6,947 and $6,493 , respectively. For the nine months ended September 30, 2021 and 2020, the Company recorded compensation expense related to restricted stock of $3,790 and $4,576 , net of income tax benefits of $1,008 and $1,217 , respectively, within Underwriting, operating and related expenses on the Consolidated Statements of Operations.

Investments

Investments	9 Months Ended
	Sep. 30, 2021
Investments
Investments	5. Investments ​ The gross unrealized gains and losses on investments in fixed maturity securities, including redeemable preferred stocks that have characteristics of fixed maturities, short term investments and equity securities, including interests in mutual funds, and other invested assets were as follows for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost or Allowance for Gross Unrealized Estimated ​ ​ Amortized ​ Expected Credit ​ ​ ​ ​ ​ Fair ​ ​ Cost ​ Losses ​ Gains ​ Losses (3) ​ Value U.S. Treasury securities ​ $ 1,819 ​ $ — ​ $ 18 ​ $ — ​ $ 1,837 Obligations of states and political subdivisions ​ 150,839 ​ — ​ 5,243 ​ (131) ​ 155,951 Residential mortgage-backed securities (1) ​ 237,523 ​ — ​ 8,010 ​ (428) ​ 245,105 Commercial mortgage-backed securities ​ 141,471 ​ — ​ 6,252 ​ (246) ​ 147,477 Other asset-backed securities ​ 88,672 ​ — ​ 686 ​ (9) ​ 89,349 Corporate and other securities ​ 614,883 ​ (729) ​ 25,781 ​ (2,252) ​ 637,683 Subtotal, fixed maturity securities ​ 1,235,207 ​ (729) ​ 45,990 ​ (3,066) ​ 1,277,402 Equity securities (2) ​ 204,243 ​ — ​ 50,126 ​ (1,746) ​ 252,623 Other invested assets (4) ​ 66,323 ​ — ​ — ​ — ​ 66,323 Totals ​ $ 1,505,773 ​ $ (729) ​ $ 96,116 ​ $ (4,812) ​ $ 1,596,348 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost or Allowance for Gross Unrealized Estimated ​ ​ Amortized ​ Expected Credit ​ ​ ​ ​ ​ Fair ​ ​ Cost ​ Losses ​ Gains ​ Losses (3) ​ Value U.S. Treasury securities ​ $ 1,821 ​ $ — ​ $ 44 ​ $ — ​ $ 1,865 Obligations of states and political subdivisions ​ 214,647 ​ — ​ 7,745 ​ (3) ​ 222,389 Residential mortgage-backed securities (1) ​ 229,910 ​ — ​ 11,701 ​ (14) ​ 241,597 Commercial mortgage-backed securities ​ 115,575 ​ — ​ 10,460 ​ — ​ 126,035 Other asset-backed securities ​ 72,756 ​ — ​ 531 ​ (163) ​ 73,124 Corporate and other securities ​ 555,242 ​ (1,054) ​ 38,415 ​ (960) ​ 591,643 Subtotal, fixed maturity securities ​ 1,189,951 ​ (1,054) ​ 68,896 ​ (1,140) ​ 1,256,653 Short term investments ​ 441 ​ — ​ — ​ — ​ 441 Equity securities (2) ​ 168,289 ​ — ​ 38,676 ​ (1,711) ​ 205,254 Other invested assets (4) ​ 45,239 ​ — ​ — ​ — ​ 45,239 Totals ​ $ 1,403,920 ​ $ (1,054) ​ $ 107,572 ​ $ (2,851) ​ $ 1,507,587 (1) Residential mortgage-backed securities consisted primarily of obligations of U.S. Government agencies including collateralized mortgage obligations issued, guaranteed and/or insured by the following issuers: Government National Mortgage Association (GNMA), Federal Home Loan Mortgage Corporation (FHLMC), Federal National Mortgage Association (FNMA) and the Federal Home Loan Bank (FHLB). (2) Equity securities included common stock, preferred stock, mutual funds and interests in mutual funds held to fund the Company’s executive deferred compensation plan. (3) The Company’s investment portfolio included 390 and 270 securities in an unrealized loss position at September 30, 2021 and December 31, 2020, respectively. (4) Other invested assets are accounted for under the equity method which approximated fair value. ​ ​ The amortized cost and the estimated fair value of fixed maturity securities, by maturity, are shown below for the period indicated. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ Amortized Estimated ​ ​ Cost ​ Fair Value Due in one year or less ​ $ 87,046 ​ $ 87,422 Due after one year through five years ​ 247,204 ​ 256,908 Due after five years through ten years ​ 381,212 ​ 395,777 Due after ten years through twenty years ​ 49,917 ​ 52,662 Due after twenty years ​ 2,162 ​ 2,702 Asset-backed securities ​ 467,666 ​ 481,931 Totals ​ $ 1,235,207 ​ $ 1,277,402 ​ The gross realized gains and losses on sales of investments were as follows for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 Gross realized gains ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturity securities ​ $ 527 ​ $ 461 ​ $ 2,660 ​ $ 1,489 Equity securities ​ 1,826 ​ 1,405 ​ 6,978 ​ 4,276 Gross realized losses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturity securities ​ (31) ​ (753) ​ (941) ​ (2,150) Equity securities ​ (96) ​ (444) ​ (190) ​ (4,298) Net realized gains (loss) on investments ​ $ 2,226 ​ $ 669 ​ $ 8,507 ​ $ (683) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In the normal course of business, the Company enters into transactions involving various types of financial instruments, including investments in fixed maturities and equity securities. Investment transactions have credit exposure to the extent that a counter party may default on an obligation to the Company. Credit risk is a consequence of carrying, trading and investing in securities. To manage credit risk, the Company focuses on higher quality fixed income securities, reviews the credit strength of all companies in which it invests, limits its exposure in any one investment and monitors the portfolio quality, taking into account credit ratings assigned by recognized statistical rating organizations. ​ The following tables as of September 30, 2021 and December 31, 2020 present the gross unrealized losses included in the Company’s investment portfolio and the fair value of those securities aggregated by investment category. The tables also present the length of time that they have been in a continuous unrealized loss position. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ Estimated Unrealized Estimated Unrealized Estimated Unrealized ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses U.S. Treasury securities ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Obligations of states and political subdivisions ​ 3,994 ​ 131 ​ — ​ — ​ 3,994 ​ 131 Residential mortgage-backed securities ​ 43,795 ​ 427 ​ 17 ​ 1 ​ 43,812 ​ 428 Commercial mortgage-backed securities ​ 10,100 ​ 246 ​ — ​ — ​ 10,100 ​ 246 Other asset-backed securities ​ 12,374 ​ ​ 9 ​ ​ — ​ ​ — ​ ​ 12,374 ​ ​ 9 Corporate and other securities ​ 162,449 ​ 2,187 ​ 8,601 ​ 65 ​ 171,050 ​ 2,252 Subtotal, fixed maturity securities ​ 232,712 ​ 3,000 ​ 8,618 ​ 66 ​ 241,330 ​ 3,066 Equity securities ​ 34,998 ​ 1,514 ​ 632 ​ 232 ​ 35,630 ​ 1,746 Total temporarily impaired securities ​ $ 267,710 ​ $ 4,514 ​ $ 9,250 ​ $ 298 ​ $ 276,960 ​ $ 4,812 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ Estimated Unrealized Estimated Unrealized Estimated Unrealized ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses U.S. Treasury securities ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Obligations of states and political subdivisions ​ 1,047 ​ 3 ​ — ​ — ​ 1,047 ​ 3 Residential mortgage-backed securities ​ 8,569 ​ 14 ​ 9 ​ — ​ 8,578 ​ 14 Commercial mortgage-backed securities ​ — ​ — ​ — ​ — ​ — ​ — Other asset-backed securities ​ 26,959 ​ ​ 84 ​ ​ 9,004 ​ ​ 79 ​ 35,963 ​ 163 Corporate and other securities ​ 62,882 ​ 863 ​ 6,774 ​ 97 ​ 69,656 ​ 960 Subtotal, fixed maturity securities ​ 99,457 ​ 964 ​ 15,787 ​ 176 ​ 115,244 ​ 1,140 Equity securities ​ 10,708 ​ 986 ​ 2,293 ​ 725 ​ 13,001 ​ 1,711 Total temporarily impaired securities ​ $ 110,165 ​ $ 1,950 ​ $ 18,080 ​ $ 901 ​ $ 128,245 ​ $ 2,851 ​ ​ At September 30, 2021, U.S. Government residential mortgage backed securities with a fair value of $32,239 are pledged as collateral for a borrowing with the Federal Home Loan Bank of Boston (“FHLB-Boston”) as described in Note 9 – Debt. These securities are included in fixed maturity securities on the Company’s consolidated balance sheets. ​ Impairments ​ For fixed maturities that the Company does not intend to sell or for which it is more likely than not that the Company would not be required to sell before an anticipated recovery in value, the Company separates the expected credit loss component of the impairment from the amount related to all other factors. The expected credit loss component is recognized as an allowance for expected credit losses. The allowance is adjusted for any additional credit losses and subsequent recoveries, which are booked in income as either credit loss expense or credit loss benefit, respectively. Upon recognizing a credit loss, the cost basis is not adjusted. The impairment related to all other factors (non-credit factors) is reported in other comprehensive income. ​ For fixed maturities where the Company records a credit loss, a determination is made as to the cause of the impairment and whether the Company expects a recovery in the value. For fixed maturities where the Company expects a recovery in value, the constant effective yield method is utilized, and the investment is amortized to par. ​ For fixed maturity investments the Company intends to sell or for which it is more likely than not that the Company will be required to sell before an anticipated recovery in value, the full amount of the impairment is included in credit loss expense. The new cost basis of the investment is the previous amortized cost basis less the impairment recognized in credit loss expense. The new cost basis is not adjusted for any subsequent recoveries in fair value. ​ The Company uses a systematic methodology to evaluate declines in fair values below cost or amortized cost of our investments. Some of the factors considered in assessing impairment of fixed maturities due to credit losses include the extent to which the fair value is less than amortized cost, the financial condition of and the near and long-term prospects of the issuer, whether the debtor is current on its contractually obligated interest and principal payments, changes to the rating of the security by a rating agency, the historical volatility of the fair value of the security and whether it is more like than not that the Company will be required to sell the investment prior to an anticipated recovery in value. ​ As of September 30, 2021, the Company concluded that $729 of unrealized losses were due to credit factors and were recorded as an allowance for expected credit losses expense as of September 30, 2021, compared to $1,054 as of December 31, 2020. The Company concluded that outside of the securities that were recognized as credit impaired, the unrealized losses recorded on the fixed maturity portfolio at September 30, 2021 and December 31, 2020 resulted from fluctuations in market interest rates and other temporary market conditions as opposed to fundamental changes in the credit quality of the issuers of such securities. Based upon the analysis performed, the Company’s decision to hold these securities, the Company’s current level of liquidity and our history of positive operating cash flows, management believes it is more likely than not that it will not be required to sell any of its securities before the anticipated recovery in the fair value to its amortized cost basis. ​ The following tables represent a reconciliation of the beginning and ending balances of the allowance for expected credit losses on fixed maturities classified as available for sale. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ ​ 2021 ​ ​ 2020 ​ 2021 2020 Balance, beginning of period ​ $ 680 ​ $ 2,471 ​ $ 1,054 ​ $ — Credit losses on securities with no previously recorded credit losses ​ ​ — ​ ​ 113 ​ ​ 9 ​ ​ 2,289 Net increases (decreases) in allowance on previously impaired securities ​ 51 ​ ​ (110) ​ (172) ​ — Reduction due to sales ​ (2) ​ ​ (185) ​ ​ (162) ​ ​ — Writeoffs charged against allowance ​ — ​ ​ — ​ — ​ — Recoveries of amounts previously written off ​ — ​ ​ — ​ — ​ — Balance, end of period ​ $ 729 ​ $ 2,289 ​ $ 729 ​ $ 2,289 ​ The Company holds no subprime mortgage debt securities. All of the Company’s holdings in mortgage-backed securities are either U.S. Government or Agency guaranteed or are rated investment grade by either Moody’s or Standard & Poor’s . ​ ​ ​ Net Investment Income ​ The components of net investment income were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 Interest on fixed maturity securities ​ $ 9,636 ​ $ 9,331 ​ $ 27,320 ​ $ 28,757 Dividends on equity securities ​ 1,327 ​ 1,097 ​ 3,746 ​ 3,337 Equity in earnings of other invested assets ​ 987 ​ 24 ​ 3,834 ​ 549 Interest on other assets ​ 6 ​ 6 ​ 17 ​ 20 Total investment income ​ 11,956 ​ 10,458 ​ 34,917 ​ 32,663 Investment expenses ​ 844 ​ 740 ​ 2,499 ​ 2,319 Net investment income ​ $ 11,112 ​ $ 9,718 ​ $ 32,418 ​ $ 30,344 ​ Fair Value of Financial Instruments ​ ASC 820, Fair Value Measurements and Disclosure, ​ Level 1 — Valuations based on quoted prices in active markets for identical assets and liabilities; ​ Level 2 — Valuations based on observable inputs that do not meet the criteria for Level 1, including quoted prices in inactive markets and quoted prices in active markets for similar, but not identical instruments; and ​ Level 3 — Valuations based on unobservable inputs. ​ Fair values for the Company’s fixed maturity securities are based on prices provided by its custodian bank and its investment managers. Both the Company’s custodian bank and investment managers use a variety of independent, nationally recognized pricing services to determine market valuations. If the pricing service cannot provide fair value determinations, the Company obtains non-binding price quotes from broker-dealers. A minimum of two quoted prices is obtained for the majority of the Company’s available-for-sale fixed maturity securities in its investment portfolio. The Company uses a third-party pricing service as its primary provider of quoted prices from third-party pricing services and broker-dealers. To provide reasonable assurance of the validity of each price or quote, a secondary third-party pricing service or broker-dealer quote is obtained from the Company’s custodian or investment managers. An examination of the pricing data is then performed for each security. If the variance between the primary and secondary price quotes for a security is within an accepted tolerance level, the quoted price obtained from the Company’s primary source is used for the security. If the variance between the primary and secondary price quotes exceeds an accepted tolerance level, the Company obtains a quote from an alternative source, if possible, and documents and resolves any differences between the pricing sources. In addition, the Company may request that its investment managers and its traders provide input as to which vendor is providing prices that its traders believe are reflective of fair value for the security. Following this process, the Company may decide to value the security in its financial statements using the secondary or alternative source if it believes that pricing is more reflective of the security’s value than the primary pricing provided by its custodian bank. The Company analyzes market valuations received to verify reasonableness, to understand the key assumptions used and their sources, and to determine an appropriate ASC 820 fair value hierarchy level based upon trading activity and the observability of market inputs. Based on this evaluation and investment class analysis, each price is classified into Level 1, 2 or 3. The Company classifies the financial asset or liability by level based upon the lowest level input that is significant to the determination of fair value. ​ Fair values of instruments are based on (i) quoted prices in active markets for identical assets (Level 1), (ii) quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs are observable in active markets (Level 2) or (iii) valuations derived from valuation techniques in which one or more significant inputs are unobservable in the marketplace (Level 3). ​ The Company’s Level 1 securities consist of equity securities whose values are based on quoted prices in active markets for identical assets. The Company’s Level 2 securities are comprised of available-for-sale fixed maturity securities whose fair value was determined using observable market inputs. The Company’s Level 3 security consists of an investment in the FHLB-Boston related to Safety Insurance Company’s membership stock, which is not redeemable in a short-term time frame. Fair values for securities for which quoted market prices were unavailable were estimated based upon reference to observable inputs such as benchmark interest rates, market comparables, and other relevant inputs. Investments valued using these inputs include U.S. Treasury securities, obligations of states and political subdivisions, corporate and other securities, commercial and residential mortgage-backed securities, and other asset-backed securities. Inputs into the fair value application that are utilized by asset class include but are not limited to: ​ ● Obligations of states and political subdivisions : overall credit quality, including assessments of market sectors and the level and variability of sources of payment such as general obligation, revenue or lease; credit support such as insurance, state or local economic and political base, prefunded and escrowed to maturity covenants. ​ ● Corporate and other securities : overall credit quality, the establishment of a risk adjusted credit spread over the applicable risk-free yield curve for discounted cash flow valuations; assessments of the level of industry economic sensitivity, company financial policies, indenture restrictive covenants, and/or security and collateral. ​ ● Residential mortgage-backed securities , U.S. agency pass-throughs, collateralized mortgage obligations (“CMOs”), non U.S. agency CMOs : estimates of prepayment speeds based upon historical prepayment rate trends, underlying collateral interest rates, original weighted average maturity, vintage year, borrower credit quality characteristics, interest rate and yield curve forecasts, U.S. government support programs, tax policies, and delinquency/default trends. ​ ● Commercial mortgage-backed securities : overall credit quality, including assessments of the level and variability of credit support and collateral type such as office, retail, or lodging, predictability of cash flows for the deal structure, prevailing economic market conditions. ​ ● Other asset-backed securities : overall credit quality, estimates of prepayment speeds based upon historical trends and characteristics of underlying loans, including assessments of the level and variability of collateral, revenue generating agreements, area licenses agreements, product sourcing agreements and equipment and property leases. ​ ● FHLB-Boston : value is equal to the cost of the member stock purchased. ​ In order to ensure the fair value determination is representative of an exit price (consistent with ASC 820), the Company’s procedures for validating quotes or prices obtained from third parties include, but are not limited to, obtaining a minimum of two price quotes for each fixed maturity security if possible, as discussed above, the periodic testing of sales activity to determine if there are any significant differences between the market price used to value the security as of the balance sheet date and the sales price of the security for sales that occurred around the balance sheet date, and the periodic review of reports provided by its external investment manager regarding those securities with ratings changes and securities placed on its “Watch List.” In addition, valuation techniques utilized by pricing services and prices obtained from external sources are reviewed by the Company’s external investment manager, whose investment professionals are familiar with the securities being priced and the markets in which they trade, to ensure the fair value determination is representative of an exit price (consistent with ASC 820). ​ All unadjusted estimates of fair value for our fixed maturities priced by the pricing services as described above are included in the amounts disclosed in Level 2. With the exception of the FHLB-Boston security, which is categorized as a Level 3 security, the Company’s entire portfolio was priced based upon quoted market prices or other observable inputs as of September 30, 2021. There were no significant changes to the valuation process during the nine months ended September 30, 2021. As of September 30, 2021 and December 31, 2020, no quotes or prices obtained were adjusted by management. All broker quotes obtained were non-binding. ​ At September 30, 2021 and December 31, 2020, investments in fixed maturities classified as available-for-sale had a fair value which equaled carrying value of $1,277,402 and $1,256,653 , respectively. At September 30, 2021, the Company held ​ The following tables summarize the Company’s total fair value measurements for investments for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ Total Level 1 Inputs Level 2 Inputs Level 3 Inputs U.S. Treasury securities ​ $ 1,837 ​ $ — ​ $ 1,837 ​ $ — Obligations of states and political subdivisions ​ 155,951 ​ — ​ 155,951 ​ — Residential mortgage-backed securities ​ 245,105 ​ — ​ 245,105 ​ — Commercial mortgage-backed securities ​ 147,477 ​ — ​ 147,477 ​ — Other asset-backed securities ​ 89,349 ​ — ​ 89,349 ​ — Corporate and other securities ​ 637,683 ​ — ​ 637,683 ​ — Equity securities ​ 217,499 ​ 215,801 ​ — ​ 1,698 Total investment securities ​ $ 1,494,901 ​ $ 215,801 ​ $ 1,277,402 ​ $ 1,698 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ Total Level 1 Inputs Level 2 Inputs Level 3 Inputs U.S. Treasury securities ​ $ 1,865 ​ $ — ​ $ 1,865 ​ $ — Obligations of states and political subdivisions ​ 222,389 ​ — ​ 222,389 ​ — Residential mortgage-backed securities ​ 241,597 ​ — ​ 241,597 ​ — Commercial mortgage-backed securities ​ 126,035 ​ — ​ 126,035 ​ — Other asset-backed securities ​ 73,124 ​ — ​ 73,124 ​ — Corporate and other securities ​ 591,643 ​ — ​ 591,643 ​ — Short term investments ​ 441 ​ — ​ 441 ​ — Equity securities ​ 173,096 ​ 171,398 ​ — ​ 1,698 Total investment securities ​ $ 1,430,190 ​ $ 171,398 ​ $ 1,257,094 ​ $ 1,698 ​ As of September 30, 2021 and December 31, 2020, there were approximately $35,124 and $32,158 , respectively, in a real estate investment trust (“REIT”). The REIT is excluded from the fair value hierarchy because the fair value is recorded using the net asset value per share practical expedient. The net asset value per share of this REIT is derived from member ownership in the capital venture to which a proportionate share of independently appraised net assets is attributed. The fair value was determined using the trust’s net asset value obtained from its audited financial statements. The Company is required to submit a request 45 days before a quarter end to dispose of the security. ​ There were no transfers between Level 1 and Level 2 during the three and nine months ended September 30, 2021 and 2020. The following table summarizes the changes in the Company’s Level 3 fair value securities for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 ​ ​ Level 3 ​ Level 3 Level 3 ​ Level 3 ​ ​ Fair Value ​ Fair Value Fair Value ​ Fair Value ​ ​ Securities ​ Securities Securities ​ Securities Balance at beginning of period ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 ​ $ 516 Net gains and losses included in earnings ​ — ​ — ​ — ​ — Net gains included in other comprehensive income ​ — ​ — ​ — ​ — Purchases ​ — ​ — ​ — ​ 1,182 Sales ​ ​ — ​ ​ — ​ ​ — ​ ​ — Transfers into Level 3 ​ ​ — ​ — ​ — ​ — Transfers out of Level 3 ​ — ​ — ​ — ​ — Balance at end of period ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 Amount of total losses included in earnings attributable to the change in unrealized losses related to assets still held at end of period ​ $ — ​ $ — ​ $ — ​ $ — ​ Transfers in and out of Level 3 are attributable to changes in the ability to observe significant inputs in determining fair value exit pricing. As noted in the table above, no transfers were made in or out of Level 3 during the three and nine months ended September 30, 2021 and 2020. The Company held one Level 3 security at September 30, 2021 and 2020.

Allowance for Expected Credit L

Allowance for Expected Credit Losses	9 Months Ended
	Sep. 30, 2021
Allowance for Expected Credit Losses
Allowance for Expected Credit Losses	6. Allowance for Expected Credit Losses ​ The Company’s financial instruments measured at amortized cost include premiums and accounts receivable, and reinsurance recoverables. ​ Premiums and accounts receivable are reported net of an allowance for expected credit losses. The allowance is based upon the Company’s ongoing review of amounts outstanding, historical loss data, including delinquencies and write-offs, current and forecasted economic conditions and other relevant factors. Credit risk is partially mitigated by the Company’s ability to cancel the policy if the policyholder does not pay the premium and the Company writes off premiums receivable balances that are more than 90 days overdue. ​ The following tables present the balances of premiums receivable, net of the allowance for expected credit losses and changes in the allowance for expected credit losses for the three and nine months ended September 30, 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At and For the ​ ​ At and For the ​ ​ ​ Three Months Ended September 30, 2021 ​ ​ Three Months Ended September 30, 2020 ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losse ​ ​ Allowance for Expected Credit Losses Balance, beginning of period ​ $ 183,222 ​ $ 2,192 ​ $ 199,356 ​ $ 914 Current period change for expected credit losses ​ ​ ​ 370 ​ ​ ​ 296 Writeoffs of uncollectable accounts receivable ​ ​ ​ (153) ​ ​ ​ (251) Balance, end of period ​ $ 183,774 ​ $ 2,409 ​ $ 193,967 ​ $ 959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At and For the ​ ​ At and For the ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Nine Months Ended September 30, 2020 ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses Balance, beginning of period ​ $ 179,147 ​ $ 1,754 ​ $ 193,369 ​ $ 578 Current period change for expected credit losses ​ ​ ​ 2,469 ​ ​ ​ 2,498 Writeoffs of uncollectable accounts receivable ​ ​ ​ (1,814) ​ ​ ​ (2,117) Balance, end of period ​ $ 183,774 ​ $ 2,409 ​ $ 193,967 ​ $ 959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reinsurance recoverables include amounts due from reinsurers for both paid and unpaid losses. The Company cedes insurance to Commonwealth Automobile Reinsurers (“CAR”) and to other reinsurers. The Company has a property catastrophe excess of loss agreement and a casualty excess of loss agreement that qualify as reinsurance treaties and are designed to protect against large or unusual loss and loss adjustment expenses (“LAE”) activity. Reinsurance contracts do not relieve the Company from its obligations to policyholders. Failure of reinsurers to honor their obligations could result in losses to the Company. The Company evaluates the financial condition of its reinsurers and monitors economic characteristics of the reinsurers to minimize its exposure to significant losses from reinsurer insolvencies. The Company reports its reinsurance recoverables net of an allowance for estimated uncollectable reinsurance. A probability-of-default methodology which reflects current and forecasted economic conditions is used to estimate the amount of uncollectible reinsurance due to credit-related factors and the estimate is reported in an allowance for estimated uncollectible reinsurance. Amounts deemed to be uncollectible, including amounts due from known insolvent reinsurers, are written off against the allowance. Changes in the allowance, as well as any subsequent collections of amounts previously written off, are reported as part of losses and loss adjustment expenses. ​ The majority of the Company’s reinsurance recoverable on paid and unpaid losses is a result of our participation as a servicing carrier in the CAR Commercial Automobile Program and the Taxi/Limo Program, which represents 98% of the total reinsurance recoverable on paid and unpaid losses at September 30, 2021 and December 31, 2020. The remaining 2% of amounts due from reinsurers are related to our other excess of loss and quota share contracts. For amounts due under these contracts, the Company utilizes updated A.M. Best credit ratings on a quarterly basis to determine the allowance for expected credit losses. As of September 30, 2021 and December 31, 2020, all reinsurers under these programs are rated “A” or better by A.M. Best. Certain of the Company's reinsurance recoverables are collateralized by letters of credit, funds held or trust agreements. The Company’s analysis concludes that there are no expected credit losses at September 30, 2021 or December 31, 2020.

Loss and Loss Adjustment Expens

Loss and Loss Adjustment Expense Reserves	9 Months Ended
	Sep. 30, 2021
Loss and Loss Adjustment Expense Reserves
Loss and Loss Adjustment Expense Reserves	7. Loss and Loss Adjustment Expense Reserves ​ The following table sets forth a reconciliation of beginning and ending reserves for losses and LAE, as shown in the Company’s consolidated financial statements for the periods indicated. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2021 2020 Reserves for losses and LAE at beginning of year ​ $ 567,581 ​ $ 610,566 Less receivable from reinsurers related to unpaid losses and LAE ​ (106,311) ​ (122,372) Net reserves for losses and LAE at beginning of year ​ 461,270 ​ 488,194 Incurred losses and LAE, related to: ​ ​ ​ ​ ​ ​ Current year ​ 381,996 ​ 343,393 Prior years ​ (41,211) ​ (34,619) Total incurred losses and LAE ​ 340,785 ​ 308,774 Paid losses and LAE related to: ​ ​ ​ ​ ​ ​ Current year ​ 211,048 ​ 180,649 Prior years ​ 111,708 ​ 137,613 Total paid losses and LAE ​ 322,756 ​ 318,262 Net reserves for losses and LAE at end of period ​ 479,299 ​ 478,706 Plus receivable from reinsurers related to unpaid losses and LAE ​ 99,248 ​ 107,783 Reserves for losses and LAE at end of period ​ $ 578,547 ​ $ 586,489 ​ At the end of each period, the reserves were re-estimated for all prior accident years. The Company’s prior year reserves decreased by 30, 2021 and 2020, respectively, and resulted from re-estimations of prior year’s ultimate loss and LAE liabilities. The decreases in prior years reserves during the nine months ended September 30, 2021 and 2020, are primarily composed of reductions in our retained automobile and retained homeowners lines reserves. ​

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies
Commitments and Contingencies	8. Commitments and Contingencies ​ As part of the Company’s investment activity, we have committed $135,000 to investments in limited partnerships. The Company has contributed $76,676 to these commitments as of September 30, 2021. As of September 30, 2021, the remaining committed capital that could be called is $62,770, which includes potential recallable capital distributions. ​ Various claims, generally incidental to the conduct of normal business, are pending or alleged against the Company from time to time. In the opinion of management, based in part on the advice of legal counsel, the ultimate resolution of such claims will not have a material adverse effect on the Company’s consolidated financial statements. However, if estimates of the ultimate resolutions of those proceedings are revised, liabilities related to those proceedings could be adjusted in the near term. ​ The Company has been named in a lawsuit alleging that the Company improperly denied coverage to commercial insureds for loss of business income resulting from the COVID-19 pandemic. Our business owner policies serve eligible small and medium sized commercial accounts including but not limited to apartments and condominiums; mercantile establishments; limited cooking restaurants; offices; and special trade contractors. The majority of these business owner policies do not contain a specific exclusion for viruses. However, as viruses do not produce direct physical damage or loss to property, our position is that no coverage exists for this peril. As a result, the Company accrued a reserve of $6,500 for legal defense costs during the year ended December 31, 2020. This amount is still accrued as of September 30, 2021. ​ On October 19, 2021, the Supreme Judicial Court of Massachusetts (the “Court”) unanimously ruled that property and casualty insurers must compensate third-party claimants under property damage coverage, part 4 of the standard Massachusetts automobile insurance policy, 2008 edition (standard policy), for the inherent diminished value (“IDV”) that occurs when their vehicles are damaged in a crash. This ruling overturned a previous decision by the Massachusetts Superior Court, which found that a Massachusetts auto insurance policy did not provide property damage coverage for inherent diminished value damages for third-party claimants. The Court placed the burden of proof on the individual claimant by explicitly specifying that the claimant must establish that the vehicle has suffered IDV damages and also the amount of IDV damages at issue. The Court further ruled that an insurer’s previous denial of coverage for such damages could not serve as the basis for a claim of unfair business practices. Based on the Court’s rulings, at this time the Company does not expect any claims for IDV damages to be material, and therefore has not accrued for a specific loss contingency. ​ Massachusetts law requires that insurers licensed to do business in Massachusetts participate in the Massachusetts Insurers Insolvency Fund (“Insolvency Fund”). Members of the Insolvency Fund are assessed a proportionate share of the obligations and expenses of the Insolvency Fund in connection with an insolvent insurer. It is anticipated that there will be additional assessments from time to time relating to various insolvencies. Although the timing and amounts of any future assessments are not known, based upon existing knowledge, management’s opinion is that such future assessments are not expected to have a material effect upon the financial position of the Company.

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt
Debt	9. Debt ​ On August 10, 2018, the Company extended its Revolving Credit Agreement (the “Credit Agreement”) with Citizens Bank, N.A. (formerly known as RBS Citizens, N.A. (“Citizens Bank”)) to a maturity date of August 10, 2023. The Credit Agreement provides a $30,000 revolving credit facility with an accordion feature allowing for future expansion of the committed amount up to $50,000 . Loans under the credit facility bear interest at the Company’s option at either (i) the LIBOR rate plus 1.25% per annum or (ii) the higher of Citizens Bank prime rate or 0.5% above the federal funds rate plus 1.25% per annum. Interest only is payable prior to maturity. ​ The Company’s obligations under the credit facility are secured by pledges of its assets and the capital stock of its operating subsidiaries. The credit facility is guaranteed by the Company’s non-insurance company subsidiaries. The credit facility contains covenants including requirements to maintain minimum risk-based capital ratios and statutory surplus of Safety Insurance Company as well as limitations or restrictions on indebtedness, liens, and other matters. As of September 30, 2021, the Company was in compliance with all covenants. In addition, the credit facility includes customary events of default, including a cross-default provision permitting the lenders to accelerate the facility if the Company (i) defaults in any payment obligation under debt having a principal amount in excess of ​ The Company had no amounts outstanding on its credit facility at September 30, 2021 and December 31, 2020. The credit facility commitment fee included in interest expense was computed at a rate of ​ The Company is a member of the FHLB-Boston. Membership in the FHLB-Boston allows the Company to borrow money at competitive interest rates provided the loan is collateralized by specific U.S Government residential mortgage backed securities. At September 30, 2021, the Company has the ability to borrow using eligible invested assets that would be used as collateral. ​ On March 17, 2020, the Company borrowed $30,000 from the FHLB-Boston for a term of five-years , bearing interest at a rate of 1.42% . Interest is payable monthly and the principal is due on the maturity date of March 17, 2025 but may be prepaid in whole or in part by the Company in advance with a minor penalty for prepayment. ​ The Company estimates the fair value of the FHLB-Boston loan by discounting cash flows using the interest rate stated in the loan agreement, which is an observable input. As such, the loan is categorized as Level 2 within the fair value hierarchy. The fair value of the loan is $31,123 and $31,291 at September 30, 2021 and December 31, 2020, respectively. The loan is fully collateralized by specific U.S. Government residential mortgage-backed securities with a fair value of $32,239 and $37,467 at September 30, 2021 and December 31, 2020, respectively. The borrowing is outstanding from the FHLB-Boston at September 30, 2021 and December 31, 2020. ​ Interest expense on the FHLB-Boston borrowing was $109 for the three months ended September 30, 2021 and 2020, respectively. Interest expense on the FHLB-Boston borrowing was $323 and $234 for the nine months ended September 30, 2021 and 2020, respectively.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Taxes
Income Taxes	10. Income Taxes ​ Federal income tax expense for the nine months ended September 30, 2021 and 2020 has been computed using estimated effective tax rates. These rates are revised, if necessary, at the end of each successive interim period to reflect the current estimates of the annual effective tax rates. The effective rate in 2021 was lower than the statutory rate primarily due to effects of tax-exempt investment income and the impact of stock-based compensation. ​ The Company believes that the positions taken on its income tax returns for open tax years will be sustained upon examination by the Internal Revenue Service (“IRS”). Therefore, the Company has not recorded any liability for uncertain tax positions under ASC 740, Income Taxes ​ During the nine months ended September 30, 2021, there were no material changes to the amount of the Company’s unrecognized tax benefits or to any assumptions regarding the amount of its ASC 740 liability. ​ All tax years prior to 2018 are closed. There are no current examinations ongoing. ​ In the Company’s opinion, adequate tax liabilities have been established for all open years. However, the amount of these tax liabilities could be revised in the near term if estimates of the Company’s ultimate liability are revised. ​

Share Repurchase Program

Share Repurchase Program	9 Months Ended
	Sep. 30, 2021
Share Repurchase Program
Share Repurchase Program	11. Share Repurchase Program ​ On August 3, 2007, the Board of Directors approved a share repurchase program of up to $30,000 of the Company’s outstanding common shares. The Board of Directors had cumulatively authorized increases to the existing share repurchase program of up to ​ No share purchases were made by Company under the program during the three and nine months ended September 30, 2021. During the three and nine months ended September 30, 2020, the Company purchased 249,754 and 551,598 shares, respectively, at a cost of $17,854, and $39,999, respectively. As of September 30, 2021 and December 31, 2020, the Company has purchased 2,831,168 shares at a cost of $123,834.

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases
Leases	12. Leases ​ The Company has various non-cancelable, long-term operating leases, the largest of which are for office space including the corporate headquarters, VIP claims centers and law offices. Other operating leases consist of auto leases and various office equipment. The Company has no finance leases. Our leases have remaining lease terms of one year to eight years , some of which include options to extend the leases for up to five years . ​ In calculating lease liabilities the Company uses its incremental borrowing rate as of the application date based on original lease terms. The components of lease expense were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ 2021 ​ ​ 2020 Operating lease cost ​ $ 1,117 ​ $ 1,140 ​ $ 3,413 ​ $ 3,438 ​ Other information related to leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ 2021 ​ ​ 2020 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases $ 1,235 ​ $ 1,258 ​ $ 3,768 ​ $ 3,803 Weighted average remaining lease term ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ 6.98 Years ​ ​ 7.79 Years Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ 2.36% ​ ​ 2.36% ​ ​ Maturities of lease liabilities were as follows: ​ ​ ​ ​ ​ ​ Operating Leases 2021 ​ $ 1,211 2022 ​ ​ 4,406 2023 ​ ​ 3,979 2024 ​ ​ 3,901 2025 ​ ​ 3,835 Thereafter ​ ​ 11,572 Total lease payments ​ ​ 28,904 Less imputed interest ​ ​ (1,591) Total ​ $ 27,313 ​

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2021
Subsequent Events
Subsequent Events	​ 13. Subsequent Events ​

Earnings per Weighted Average_2

Earnings per Weighted Average Common Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings per Weighted Average Common Share
Computation of basic and diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Earnings attributable to common shareholders - basic and diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations ​ $ 24,820 ​ $ 44,742 ​ $ 98,661 ​ $ 85,246 Allocation of income for participating shares ​ ​ (107) ​ ​ (201) ​ ​ (434) ​ ​ (392) Net income from continuing operations attributed to common shareholders ​ $ 24,713 ​ $ 44,541 ​ $ 98,227 ​ $ 84,854 Earnings per share denominator - basic and diluted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total weighted average common shares outstanding, including participating shares ​ ​ 15,047,779 ​ ​ 14,974,636 ​ ​ 14,892,515 ​ ​ 15,155,969 Less: weighted average participating shares ​ ​ (65,374) ​ ​ (66,827) ​ ​ (66,000) ​ ​ (70,055) Basic earnings per share denominator ​ ​ 14,982,405 ​ ​ 14,907,809 ​ ​ 14,826,515 ​ ​ 15,085,914 Common equivalent shares- non-vested performance stock grants ​ 97,624 ​ 122,468 ​ 96,355 ​ 118,241 Diluted earnings per share denominator ​ 15,080,029 ​ 15,030,277 ​ 14,922,870 ​ 15,204,155 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings per share ​ $ 1.65 ​ $ 2.99 ​ $ 6.63 ​ $ 5.62 Diluted earnings per share ​ $ 1.64 ​ $ 2.96 ​ $ 6.58 ​ $ 5.58 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Undistributed earnings attributable to common shareholders - basic and diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations attributable to common shareholders -Basic ​ $ 1.65 ​ $ 2.99 ​ $ 6.63 ​ $ 5.62 Dividends declared ​ ​ (0.90) ​ ​ (0.90) ​ ​ (2.70) ​ ​ (2.70) Undistributed earnings ​ $ 0.75 ​ $ 2.09 ​ $ 3.93 ​ $ 2.92 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income from continuing operations attributable to common shareholders -Diluted ​ $ 1.64 ​ $ 2.96 ​ $ 6.58 ​ $ 5.58 Dividends declared ​ ​ (0.90) ​ ​ (0.90) ​ ​ (2.70) ​ ​ (2.70) Undistributed earnings ​ $ 0.74 ​ $ 2.06 ​ $ 3.88 ​ $ 2.88

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-Based Compensation
Schedule of restricted stock and performance-based restricted stock activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Weighted ​ Performance-based Weighted ​ ​ Under ​ Average ​ Shares Under ​ Average ​ ​ Restriction ​ Fair Value ​ Restriction ​ Fair Value Outstanding at beginning of year 66,550 ​ $ 85.16 ​ 71,964 ​ $ 84.94 Granted 39,840 ​ ​ 79.27 ​ 49,460 (1) ​ 77.56 Vested and unrestricted (40,763) ​ ​ 80.82 ​ (48,666) ​ ​ 75.05 Forfeited ​ (253) ​ ​ 79.27 ​ (340) ​ ​ 87.43 Outstanding at end of period 65,374 ​ $ 84.30 ​ 72,418 ​ $ 86.53

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments
Gross unrealized gains and losses on investments in securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost or Allowance for Gross Unrealized Estimated ​ ​ Amortized ​ Expected Credit ​ ​ ​ ​ ​ Fair ​ ​ Cost ​ Losses ​ Gains ​ Losses (3) ​ Value U.S. Treasury securities ​ $ 1,819 ​ $ — ​ $ 18 ​ $ — ​ $ 1,837 Obligations of states and political subdivisions ​ 150,839 ​ — ​ 5,243 ​ (131) ​ 155,951 Residential mortgage-backed securities (1) ​ 237,523 ​ — ​ 8,010 ​ (428) ​ 245,105 Commercial mortgage-backed securities ​ 141,471 ​ — ​ 6,252 ​ (246) ​ 147,477 Other asset-backed securities ​ 88,672 ​ — ​ 686 ​ (9) ​ 89,349 Corporate and other securities ​ 614,883 ​ (729) ​ 25,781 ​ (2,252) ​ 637,683 Subtotal, fixed maturity securities ​ 1,235,207 ​ (729) ​ 45,990 ​ (3,066) ​ 1,277,402 Equity securities (2) ​ 204,243 ​ — ​ 50,126 ​ (1,746) ​ 252,623 Other invested assets (4) ​ 66,323 ​ — ​ — ​ — ​ 66,323 Totals ​ $ 1,505,773 ​ $ (729) ​ $ 96,116 ​ $ (4,812) ​ $ 1,596,348 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost or Allowance for Gross Unrealized Estimated ​ ​ Amortized ​ Expected Credit ​ ​ ​ ​ ​ Fair ​ ​ Cost ​ Losses ​ Gains ​ Losses (3) ​ Value U.S. Treasury securities ​ $ 1,821 ​ $ — ​ $ 44 ​ $ — ​ $ 1,865 Obligations of states and political subdivisions ​ 214,647 ​ — ​ 7,745 ​ (3) ​ 222,389 Residential mortgage-backed securities (1) ​ 229,910 ​ — ​ 11,701 ​ (14) ​ 241,597 Commercial mortgage-backed securities ​ 115,575 ​ — ​ 10,460 ​ — ​ 126,035 Other asset-backed securities ​ 72,756 ​ — ​ 531 ​ (163) ​ 73,124 Corporate and other securities ​ 555,242 ​ (1,054) ​ 38,415 ​ (960) ​ 591,643 Subtotal, fixed maturity securities ​ 1,189,951 ​ (1,054) ​ 68,896 ​ (1,140) ​ 1,256,653 Short term investments ​ 441 ​ — ​ — ​ — ​ 441 Equity securities (2) ​ 168,289 ​ — ​ 38,676 ​ (1,711) ​ 205,254 Other invested assets (4) ​ 45,239 ​ — ​ — ​ — ​ 45,239 Totals ​ $ 1,403,920 ​ $ (1,054) ​ $ 107,572 ​ $ (2,851) ​ $ 1,507,587 (1) Residential mortgage-backed securities consisted primarily of obligations of U.S. Government agencies including collateralized mortgage obligations issued, guaranteed and/or insured by the following issuers: Government National Mortgage Association (GNMA), Federal Home Loan Mortgage Corporation (FHLMC), Federal National Mortgage Association (FNMA) and the Federal Home Loan Bank (FHLB). (2) Equity securities included common stock, preferred stock, mutual funds and interests in mutual funds held to fund the Company’s executive deferred compensation plan. (3) The Company’s investment portfolio included 390 and 270 securities in an unrealized loss position at September 30, 2021 and December 31, 2020, respectively. (4) Other invested assets are accounted for under the equity method which approximated fair value.
Amortized cost and the estimated fair value of fixed maturity securities, by maturity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ Amortized Estimated ​ ​ Cost ​ Fair Value Due in one year or less ​ $ 87,046 ​ $ 87,422 Due after one year through five years ​ 247,204 ​ 256,908 Due after five years through ten years ​ 381,212 ​ 395,777 Due after ten years through twenty years ​ 49,917 ​ 52,662 Due after twenty years ​ 2,162 ​ 2,702 Asset-backed securities ​ 467,666 ​ 481,931 Totals ​ $ 1,235,207 ​ $ 1,277,402
Gross realized gains and losses on sales of investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 Gross realized gains ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturity securities ​ $ 527 ​ $ 461 ​ $ 2,660 ​ $ 1,489 Equity securities ​ 1,826 ​ 1,405 ​ 6,978 ​ 4,276 Gross realized losses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed maturity securities ​ (31) ​ (753) ​ (941) ​ (2,150) Equity securities ​ (96) ​ (444) ​ (190) ​ (4,298) Net realized gains (loss) on investments ​ $ 2,226 ​ $ 669 ​ $ 8,507 ​ $ (683) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Gross unrealized losses included in the Company's investment portfolio and the fair value of those securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ Estimated Unrealized Estimated Unrealized Estimated Unrealized ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses U.S. Treasury securities ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Obligations of states and political subdivisions ​ 3,994 ​ 131 ​ — ​ — ​ 3,994 ​ 131 Residential mortgage-backed securities ​ 43,795 ​ 427 ​ 17 ​ 1 ​ 43,812 ​ 428 Commercial mortgage-backed securities ​ 10,100 ​ 246 ​ — ​ — ​ 10,100 ​ 246 Other asset-backed securities ​ 12,374 ​ ​ 9 ​ ​ — ​ ​ — ​ ​ 12,374 ​ ​ 9 Corporate and other securities ​ 162,449 ​ 2,187 ​ 8,601 ​ 65 ​ 171,050 ​ 2,252 Subtotal, fixed maturity securities ​ 232,712 ​ 3,000 ​ 8,618 ​ 66 ​ 241,330 ​ 3,066 Equity securities ​ 34,998 ​ 1,514 ​ 632 ​ 232 ​ 35,630 ​ 1,746 Total temporarily impaired securities ​ $ 267,710 ​ $ 4,514 ​ $ 9,250 ​ $ 298 ​ $ 276,960 ​ $ 4,812 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ ​ Less than 12 Months ​ 12 Months or More ​ Total ​ Estimated Unrealized Estimated Unrealized Estimated Unrealized ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses U.S. Treasury securities ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — Obligations of states and political subdivisions ​ 1,047 ​ 3 ​ — ​ — ​ 1,047 ​ 3 Residential mortgage-backed securities ​ 8,569 ​ 14 ​ 9 ​ — ​ 8,578 ​ 14 Commercial mortgage-backed securities ​ — ​ — ​ — ​ — ​ — ​ — Other asset-backed securities ​ 26,959 ​ ​ 84 ​ ​ 9,004 ​ ​ 79 ​ 35,963 ​ 163 Corporate and other securities ​ 62,882 ​ 863 ​ 6,774 ​ 97 ​ 69,656 ​ 960 Subtotal, fixed maturity securities ​ 99,457 ​ 964 ​ 15,787 ​ 176 ​ 115,244 ​ 1,140 Equity securities ​ 10,708 ​ 986 ​ 2,293 ​ 725 ​ 13,001 ​ 1,711 Total temporarily impaired securities ​ $ 110,165 ​ $ 1,950 ​ $ 18,080 ​ $ 901 ​ $ 128,245 ​ $ 2,851
Reconciliation of beginning and ending balances of allowance for expected credit losses on fixed maturities classified as available for sale	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ ​ 2021 ​ ​ 2020 ​ 2021 2020 Balance, beginning of period ​ $ 680 ​ $ 2,471 ​ $ 1,054 ​ $ — Credit losses on securities with no previously recorded credit losses ​ ​ — ​ ​ 113 ​ ​ 9 ​ ​ 2,289 Net increases (decreases) in allowance on previously impaired securities ​ 51 ​ ​ (110) ​ (172) ​ — Reduction due to sales ​ (2) ​ ​ (185) ​ ​ (162) ​ ​ — Writeoffs charged against allowance ​ — ​ ​ — ​ — ​ — Recoveries of amounts previously written off ​ — ​ ​ — ​ — ​ — Balance, end of period ​ $ 729 ​ $ 2,289 ​ $ 729 ​ $ 2,289
Components of net investment income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 Interest on fixed maturity securities ​ $ 9,636 ​ $ 9,331 ​ $ 27,320 ​ $ 28,757 Dividends on equity securities ​ 1,327 ​ 1,097 ​ 3,746 ​ 3,337 Equity in earnings of other invested assets ​ 987 ​ 24 ​ 3,834 ​ 549 Interest on other assets ​ 6 ​ 6 ​ 17 ​ 20 Total investment income ​ 11,956 ​ 10,458 ​ 34,917 ​ 32,663 Investment expenses ​ 844 ​ 740 ​ 2,499 ​ 2,319 Net investment income ​ $ 11,112 ​ $ 9,718 ​ $ 32,418 ​ $ 30,344
Fair value measurements for investments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2021 ​ Total Level 1 Inputs Level 2 Inputs Level 3 Inputs U.S. Treasury securities ​ $ 1,837 ​ $ — ​ $ 1,837 ​ $ — Obligations of states and political subdivisions ​ 155,951 ​ — ​ 155,951 ​ — Residential mortgage-backed securities ​ 245,105 ​ — ​ 245,105 ​ — Commercial mortgage-backed securities ​ 147,477 ​ — ​ 147,477 ​ — Other asset-backed securities ​ 89,349 ​ — ​ 89,349 ​ — Corporate and other securities ​ 637,683 ​ — ​ 637,683 ​ — Equity securities ​ 217,499 ​ 215,801 ​ — ​ 1,698 Total investment securities ​ $ 1,494,901 ​ $ 215,801 ​ $ 1,277,402 ​ $ 1,698 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ Total Level 1 Inputs Level 2 Inputs Level 3 Inputs U.S. Treasury securities ​ $ 1,865 ​ $ — ​ $ 1,865 ​ $ — Obligations of states and political subdivisions ​ 222,389 ​ — ​ 222,389 ​ — Residential mortgage-backed securities ​ 241,597 ​ — ​ 241,597 ​ — Commercial mortgage-backed securities ​ 126,035 ​ — ​ 126,035 ​ — Other asset-backed securities ​ 73,124 ​ — ​ 73,124 ​ — Corporate and other securities ​ 591,643 ​ — ​ 591,643 ​ — Short term investments ​ 441 ​ — ​ 441 ​ — Equity securities ​ 173,096 ​ 171,398 ​ — ​ 1,698 Total investment securities ​ $ 1,430,190 ​ $ 171,398 ​ $ 1,257,094 ​ $ 1,698
Changes in the Company's Level 3 fair value securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, Nine Months Ended September 30, ​ 2021 2020 2021 2020 ​ ​ Level 3 ​ Level 3 Level 3 ​ Level 3 ​ ​ Fair Value ​ Fair Value Fair Value ​ Fair Value ​ ​ Securities ​ Securities Securities ​ Securities Balance at beginning of period ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 ​ $ 516 Net gains and losses included in earnings ​ — ​ — ​ — ​ — Net gains included in other comprehensive income ​ — ​ — ​ — ​ — Purchases ​ — ​ — ​ — ​ 1,182 Sales ​ ​ — ​ ​ — ​ ​ — ​ ​ — Transfers into Level 3 ​ ​ — ​ — ​ — ​ — Transfers out of Level 3 ​ — ​ — ​ — ​ — Balance at end of period ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 ​ $ 1,698 Amount of total losses included in earnings attributable to the change in unrealized losses related to assets still held at end of period ​ $ — ​ $ — ​ $ — ​ $ —

Allowance for Expected Credit_2

Allowance for Expected Credit Losses (Tables)	9 Months Ended
	Sep. 30, 2021
Allowance for Expected Credit Losses
Accounts receivable, net of allowance for expected credit losses	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At and For the ​ ​ At and For the ​ ​ ​ Three Months Ended September 30, 2021 ​ ​ Three Months Ended September 30, 2020 ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losse ​ ​ Allowance for Expected Credit Losses Balance, beginning of period ​ $ 183,222 ​ $ 2,192 ​ $ 199,356 ​ $ 914 Current period change for expected credit losses ​ ​ ​ 370 ​ ​ ​ 296 Writeoffs of uncollectable accounts receivable ​ ​ ​ (153) ​ ​ ​ (251) Balance, end of period ​ $ 183,774 ​ $ 2,409 ​ $ 193,967 ​ $ 959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ At and For the ​ ​ At and For the ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Nine Months Ended September 30, 2020 ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses ​ ​ Accounts Receivable Net of Allowance for Expected Credit Losses ​ ​ Allowance for Expected Credit Losses Balance, beginning of period ​ $ 179,147 ​ $ 1,754 ​ $ 193,369 ​ $ 578 Current period change for expected credit losses ​ ​ ​ 2,469 ​ ​ ​ 2,498 Writeoffs of uncollectable accounts receivable ​ ​ ​ (1,814) ​ ​ ​ (2,117) Balance, end of period ​ $ 183,774 ​ $ 2,409 ​ $ 193,967 ​ $ 959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Loss and Loss Adjustment Expe_2

Loss and Loss Adjustment Expense Reserves (Tables)	9 Months Ended
	Sep. 30, 2021
Loss and Loss Adjustment Expense Reserves
Schedule of reconciliation of beginning and ending reserves for losses and loss adjustment expenses (LAE)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ 2021 2020 Reserves for losses and LAE at beginning of year ​ $ 567,581 ​ $ 610,566 Less receivable from reinsurers related to unpaid losses and LAE ​ (106,311) ​ (122,372) Net reserves for losses and LAE at beginning of year ​ 461,270 ​ 488,194 Incurred losses and LAE, related to: ​ ​ ​ ​ ​ ​ Current year ​ 381,996 ​ 343,393 Prior years ​ (41,211) ​ (34,619) Total incurred losses and LAE ​ 340,785 ​ 308,774 Paid losses and LAE related to: ​ ​ ​ ​ ​ ​ Current year ​ 211,048 ​ 180,649 Prior years ​ 111,708 ​ 137,613 Total paid losses and LAE ​ 322,756 ​ 318,262 Net reserves for losses and LAE at end of period ​ 479,299 ​ 478,706 Plus receivable from reinsurers related to unpaid losses and LAE ​ 99,248 ​ 107,783 Reserves for losses and LAE at end of period ​ $ 578,547 ​ $ 586,489

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases
Schedule of operating lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ 2021 ​ ​ 2020 Operating lease cost ​ $ 1,117 ​ $ 1,140 ​ $ 3,413 ​ $ 3,438
Schedule of other information related to leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ 2021 ​ ​ 2020 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases $ 1,235 ​ $ 1,258 ​ $ 3,768 ​ $ 3,803 Weighted average remaining lease term ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ 6.98 Years ​ ​ 7.79 Years Weighted average discount rate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ ​ ​ 2.36% ​ ​ 2.36%
Schedule of the maturities of lease liabilities	​ ​ ​ ​ ​ ​ Operating Leases 2021 ​ $ 1,211 2022 ​ ​ 4,406 2023 ​ ​ 3,979 2024 ​ ​ 3,901 2025 ​ ​ 3,835 Thereafter ​ ​ 11,572 Total lease payments ​ ​ 28,904 Less imputed interest ​ ​ (1,591) Total ​ $ 27,313

Earnings per Weighted Average_3

Earnings per Weighted Average Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings per Weighted Average Common Share
Net income from continuing operations	$ 24,820	$ 37,667	$ 36,174	$ 44,742	$ 42,494	$ (1,990)	$ 98,661	$ 85,246
Allocation of income for participating shares	(107)			(201)			(434)	(392)
Net income from continuing operations attributed to common shareholders	$ 24,713			$ 44,541			$ 98,227	$ 84,854
Total weighted average common shares outstanding, including participating shares	15,047,779			14,974,636			14,892,515	15,155,969
Less: weighted average participating shares	(65,374)			(66,827)			(66,000)	(70,055)
Basic earnings per share denominator	14,982,405			14,907,809			14,826,515	15,085,914
Common equivalent shares- non-vested performance stock grants	97,624			122,468			96,355	118,241
Diluted earnings per share denominator	15,080,029			15,030,277			14,922,870	15,204,155
Basic earnings per share (in dollars per share)	$ 1.65			$ 2.99			$ 6.63	$ 5.62
Diluted earnings per share (in dollars per share)	1.64			2.96			6.58	5.58
Undistributed earnings attributable to common shareholders - basic and diluted:
Net income from continuing operations attributable to common shareholders -Basic	1.65			2.99			6.63	5.62
Dividends declared	(0.90)			(0.90)			(2.70)	(2.70)
Undistributed earnings	0.75			2.09			3.93	2.92
Undistributed earnings attributable to common shareholders - diluted
Net income from continuing operations attributable to common shareholders -Diluted	1.64			2.96			6.58	5.58
Dividends declared	(0.90)			(0.90)			(2.70)	(2.70)
Undistributed earnings	$ 0.74			$ 2.06			$ 3.88	$ 2.88
Antidilutive common shares	0			4			0	0

Share-Based Compensation (Detai

Share-Based Compensation (Details) - shares	Sep. 30, 2021	Apr. 02, 2018
Maximum number of shares of common stock with respect to which awards may be granted	2,850,000
Number of shares available for future grant	164,908
The 2018 Plan
Maximum number of shares of common stock with respect to which awards may be granted		350,000

Share-Based Compensation Restri

Share-Based Compensation Restricted Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Weighted Average Fair Value
Unrecognized compensation expense related to non-vested restricted stock awards	$ 7,616
Weighted average period expected for recognition of compensation expense related to non-vested restricted stock awards	1 year 7 months 6 days
Total fair value of the shares that were vested and unrestricted during the period	$ 6,947	$ 6,493
Compensation Expense, Net of Tax	3,790	4,576
Income tax benefits from compensation expense	$ 1,008	$ 1,217
Performance-based Shares Under Restriction
Share-Based Compensation
Vesting period	3 years
Shares Under Restriction
Outstanding at beginning of year (in shares)	71,964
Granted (in shares)	49,460
Vested and unrestricted (in shares)	(48,666)
Forfeited (in shares)	(340)
Outstanding at end of period (in shares)	72,418
Weighted Average Fair Value
Outstanding at beginning of year (in dollars per share)	$ 84.94
Granted (in dollars per share)	77.56
Vested and unrestricted (in dollars per share)	75.05
Forfeited (in dollars per share)	87.43
Outstanding at end of period (in dollars per share)	$ 86.53
Performance-based Shares Under Restriction | Minimum
Share-Based Compensation
Actual Payouts (as a percent)	0.00%
Performance-based Shares Under Restriction | Maximum
Share-Based Compensation
Actual Payouts (as a percent)	200.00%
Restricted Stock
Shares Under Restriction
Outstanding at beginning of year (in shares)	66,550
Granted (in shares)	39,840
Vested and unrestricted (in shares)	(40,763)
Forfeited (in shares)	(253)
Outstanding at end of period (in shares)	65,374
Weighted Average Fair Value
Outstanding at beginning of year (in dollars per share)	$ 85.16
Granted (in dollars per share)	79.27
Vested and unrestricted (in dollars per share)	80.82
Forfeited (in dollars per share)	79.27
Outstanding at end of period (in dollars per share)	$ 84.30
Restricted Stock | Non-executive grants prior to 2018
Share-Based Compensation
Vesting period	5 years
Restricted Stock | Executives and non-executives (2018 and after)
Share-Based Compensation
Vesting period	3 years
Restricted Stock | First anniversary of grant date | Executives and non-executives (2018 and after)
Share-Based Compensation
Actual Payouts (as a percent)	30.00%
Restricted Stock | Second anniversary of grant date | Executives and non-executives (2018 and after)
Share-Based Compensation
Actual Payouts (as a percent)	30.00%
Restricted Stock | Third anniversary of grant date | Executives and non-executives (2018 and after)
Share-Based Compensation
Actual Payouts (as a percent)	40.00%

Investments (Details)

Investments (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)security	Dec. 31, 2020USD ($)security	Jun. 30, 2021USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)
Marketable Securities
Fixed maturity securities, amortized cost	$ 1,235,207	$ 1,189,951
Fixed maturity securities, allowance for expected credit losses	(729)	(1,054)
Fixed maturity securities, Gross Unrealized Gains	45,990	68,896
Fixed maturity securities, Gross Unrealized Losses	(3,066)	(1,140)
Fixed maturity securities, Estimated Fair Value	1,277,402	1,256,653
Short term investments, at cost	0	441
Short term investments	0	441
Equity securities, Cost or Amortized Cost	204,243	168,289
Equity securities, Estimated Fair Value	252,623	205,254
Other invested assets, Cost or Amortized Cost	66,323	45,239
Cost or Amortized Cost	1,505,773	1,403,920
Gross Unrealized Gains	96,116	107,572
Gross Unrealized Losses	(4,812)	(2,851)
Estimated Fair Value	$ 1,596,348	$ 1,507,587
Number of securities in an unrealized loss position | security	390	270
U.S. Treasury securities
Marketable Securities
Fixed maturity securities, amortized cost	$ 1,819	$ 1,821
Fixed maturity securities, Gross Unrealized Gains	18	44
Fixed maturity securities, Estimated Fair Value	1,837	1,865
Obligations of states and political subdivisions
Marketable Securities
Fixed maturity securities, amortized cost	150,839	214,647
Fixed maturity securities, Gross Unrealized Gains	5,243	7,745
Fixed maturity securities, Gross Unrealized Losses	(131)	(3)
Fixed maturity securities, Estimated Fair Value	155,951	222,389
Residential mortgage-backed securities
Marketable Securities
Fixed maturity securities, amortized cost	237,523	229,910
Fixed maturity securities, Gross Unrealized Gains	8,010	11,701
Fixed maturity securities, Gross Unrealized Losses	(428)	(14)
Fixed maturity securities, Estimated Fair Value	245,105	241,597
Commercial mortgage-backed securities
Marketable Securities
Fixed maturity securities, amortized cost	141,471	115,575
Fixed maturity securities, Gross Unrealized Gains	6,252	10,460
Fixed maturity securities, Gross Unrealized Losses	(246)
Fixed maturity securities, Estimated Fair Value	147,477	126,035
Other asset-backed securities
Marketable Securities
Fixed maturity securities, amortized cost	88,672	72,756
Fixed maturity securities, Gross Unrealized Gains	686	531
Fixed maturity securities, Gross Unrealized Losses	(9)	(163)
Fixed maturity securities, Estimated Fair Value	89,349	73,124
Corporate and other securities
Marketable Securities
Fixed maturity securities, amortized cost	614,883	555,242
Fixed maturity securities, allowance for expected credit losses	(729)	(1,054)	$ (680)	$ (2,289)	$ (2,471)
Fixed maturity securities, Gross Unrealized Gains	25,781	38,415
Fixed maturity securities, Gross Unrealized Losses	(2,252)	(960)
Fixed maturity securities, Estimated Fair Value	637,683	591,643
Short term Investments.
Marketable Securities
Fixed maturity securities, amortized cost		441
Fixed maturity securities, Estimated Fair Value		441
Equity securities
Marketable Securities
Equity securities, Cost or Amortized Cost	204,243	168,289
Equity securities, Gross Unrealized Gains	50,126	38,676
Equity securities, Gross Unrealized Losses	(1,746)	(1,711)
Equity securities, Estimated Fair Value	252,623	205,254
Other invested assets
Marketable Securities
Other invested assets, Cost or Amortized Cost	66,323	45,239
Other invested assets, Estimated Fair Value	$ 66,323	$ 45,239

Investments Amortized Cost and

Investments Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less, Amortized Cost	$ 87,046
Due after one year through five years, Amortized Cost	247,204
Due after five years though ten years, Amortized Cost	381,212
Due after ten years through twenty years, Amortized Cost	49,917
Due after twenty years, Amortized Cost	2,162
Asset-backed securities, Amortized Cost	467,666
Totals, Amortized Cost	1,235,207	$ 1,189,951
Estimated Fair Value
Due in one year or less, Fair Value	87,422
Due after one year through five years, Fair Value	256,908
Due after five years through ten years, Fair Value	395,777
Due after ten years through twenty years, Fair Value	52,662
Due after twenty years, Fair Value	2,702
Asset-backed securities, Fair Value	481,931
Totals, Fair Value	$ 1,277,402	$ 1,256,653

Investments Gross Realized Gain

Investments Gross Realized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Marketable Securities [Line Items]
Net realized gains (loss) on investments	$ 2,226	$ 669	$ 8,507	$ (683)
Subtotal, fixed maturity securities
Marketable Securities [Line Items]
Gross realized gains fixed maturity securities	527	461	2,660	1,489
Gross realized losses fixed maturities	(31)	(753)	(941)	(2,150)
Equity securities
Marketable Securities [Line Items]
Gross realized gains equity securities	1,826	1,405	6,978	4,276
Gross realized losses equity securities	$ (96)	$ (444)	$ (190)	$ (4,298)

Investments Gross Unrealized Lo

Investments Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Marketable Securities
Estimated Fair Value, Less than 12 Months	$ 267,710	$ 110,165
Estimated Fair Value, 12 Months or More	9,250	18,080
Estimated Fair Value, Total	276,960	128,245
Unrealized Losses, Less than 12 Months	4,514	1,950
Unrealized Losses, 12 Months or More	298	901
Unrealized Losses, Total	4,812	2,851
Subtotal, fixed maturity securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	232,712	99,457
Estimated Fair Value, 12 Months or More	8,618	15,787
Estimated Fair Value, Total	241,330	115,244
Unrealized Losses, Less than 12 Months	3,000	964
Unrealized Losses, 12 Months or More	66	176
Unrealized Losses, Total	3,066	1,140
Obligations of states and political subdivisions
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	3,994	1,047
Estimated Fair Value, Total	3,994	1,047
Unrealized Losses, Less than 12 Months	131	3
Unrealized Losses, Total	131	3
Residential mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	43,795	8,569
Estimated Fair Value, 12 Months or More	17	9
Estimated Fair Value, Total	43,812	8,578
Unrealized Losses, Less than 12 Months	427	14
Unrealized Losses, 12 Months or More	1
Unrealized Losses, Total	428	14
Marketable Securities
Pledged as collateral for a borrowing	32,239	37,467
Commercial mortgage-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	10,100
Estimated Fair Value, Total	10,100
Unrealized Losses, Less than 12 Months	246
Unrealized Losses, Total	246
Other asset-backed securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	12,374	26,959
Estimated Fair Value, 12 Months or More		9,004
Estimated Fair Value, Total	12,374	35,963
Unrealized Losses, Less than 12 Months	9	84
Unrealized Losses, 12 Months or More		79
Unrealized Losses, Total	9	163
Corporate and other securities
Fixed Maturity Securities
Estimated Fair Value, Less than 12 Months	162,449	62,882
Estimated Fair Value, 12 Months or More	8,601	6,774
Estimated Fair Value, Total	171,050	69,656
Unrealized Losses, Less than 12 Months	2,187	863
Unrealized Losses, 12 Months or More	65	97
Unrealized Losses, Total	2,252	960
Equity securities
Equity Securities
Estimated Fair Value, Less than 12 Months	34,998	10,708
Estimated Fair Value, 12 Months or More	632	2,293
Estimated Fair Value, Total	35,630	13,001
Unrealized Losses, Less than 12 Months	1,514	986
Unrealized Losses, 12 Months or More	232	725
Unrealized Losses, Total	$ 1,746	$ 1,711

Investments Allowance for Expec

Investments Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Marketable Securities
Balance, beginning of period			$ 1,054
Balance, end of period	$ 729		729
Corporate and other securities
Marketable Securities
Balance, beginning of period	680	$ 2,471	1,054
Credit losses on securities with no previously recorded credit losses		113	9	$ 2,289
Net increases (decreases) in allowance on previously impaired securities	51	(110)	(172)
Reduction due to sales	(2)	(185)	(162)
Balance, end of period	$ 729	$ 2,289	$ 729	$ 2,289

Investments Components of Net I

Investments Components of Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of net investment income
Interest on fixed maturity securities	$ 9,636	$ 9,331	$ 27,320	$ 28,757
Dividends on equity securities	1,327	1,097	3,746	3,337
Equity in earnings of other invested assets	987	24	3,834	549
Interest on other assets	6	6	17	20
Total investment income	11,956	10,458	34,917	32,663
Investment expenses	844	740	2,499	2,319
Net investment income	$ 11,112	$ 9,718	$ 32,418	$ 30,344

Investments Other (Details)

Investments Other (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021USD ($)item	Dec. 31, 2020USD ($)	Sep. 30, 2020item
Other-Than-Temporary Impairments
Available-for-sale investments	$ 1,277,402	$ 1,256,653
Short term Investments	$ 0	$ 441
Level 3 Securities Held Number | item	1		1

Investments Fair Value Measurem

Investments Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	$ 1,277,402	$ 1,256,653
Short term investments, Estimated Fair Value	0	441
Equity securities, Estimated Fair Value	252,623	205,254
Level 1 Inputs
Fair value of financial instruments
Marketable Securities, Total	215,801	171,398
Level 1 Inputs | Equity securities
Fair value of financial instruments
Equity securities, Estimated Fair Value	215,801	171,398
Level 2 Inputs
Fair value of financial instruments
Marketable Securities, Total	1,277,402	1,257,094
Level 2 Inputs | U.S. Treasury securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	1,837	1,865
Level 2 Inputs | Obligations of states and political subdivisions
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	155,951	222,389
Level 2 Inputs | Residential mortgage-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	245,105	241,597
Level 2 Inputs | Commercial mortgage-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	147,477	126,035
Level 2 Inputs | Other asset-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	89,349	73,124
Level 2 Inputs | Corporate and other securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	637,683	591,643
Level 2 Inputs | Short term Investments.
Fair value of financial instruments
Short term investments, Estimated Fair Value		441
Level 3 Inputs
Fair value of financial instruments
Marketable Securities, Total	1,698	1,698
Level 3 Inputs | Equity securities
Fair value of financial instruments
Equity securities, Estimated Fair Value	1,698	1,698
Total
Fair value of financial instruments
Marketable Securities, Total	1,494,901	1,430,190
Total | U.S. Treasury securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	1,837	1,865
Total | Obligations of states and political subdivisions
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	155,951	222,389
Total | Residential mortgage-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	245,105	241,597
Total | Commercial mortgage-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	147,477	126,035
Total | Other asset-backed securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	89,349	73,124
Total | Corporate and other securities
Fair value of financial instruments
Fixed maturity securities, Estimated Fair Value	637,683	591,643
Total | Short term Investments.
Fair value of financial instruments
Short term investments, Estimated Fair Value		441
Total | Equity securities
Fair value of financial instruments
Equity securities, Estimated Fair Value	$ 217,499	$ 173,096

Investments Level 3 and Other (

Investments Level 3 and Other (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Transfers between Levels
Transfers from Level 1 to Level 2	$ 0	$ 0	$ 0	$ 0
Transfers from Level 2 to Level 1	0	0	0	0
Changes in the Company's Level 3 fair value securities
Balance at beginning of period	1,698	1,698	1,698	516
Purchases				1,182
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0
Balance at end of period	1,698	$ 1,698	1,698	$ 1,698
Alternative investments fair value	$ 35,124		$ 35,124		$ 32,158
Period of advance notice before quarter end			45 days

Allowance for Expected Credit_3

Allowance for Expected Credit Losses Balances of Premiums Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Balance, beginning of period	$ 183,222	$ 199,356	$ 179,147	$ 193,369
Balance, end of period	183,774	193,967	183,774	193,967
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	2,192	914	1,754	578
Current period change for expected credit losses	370	296	2,469	2,498
Writeoffs of uncollectable accounts receivable	(153)	(251)	(1,814)	(2,117)
Balance, end of period	$ 2,409	$ 959	$ 2,409	$ 959

Allowance for Expected Credit_4

Allowance for Expected Credit Losses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Expected credit losses	$ 0	$ 0
CAR Commercial Automobile Program and the Taxi/Limo Program
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of reinsurance recoverable	98.00%	98.00%
Other Contracts
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of reinsurance recoverable	2.00%

Loss and Loss Adjustment Expe_3

Loss and Loss Adjustment Expense Reserves (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Loss and Loss Adjustment Expense Reserves
Reserves for losses and LAE at beginning of year	$ 567,581	$ 610,566
Less receivable from reinsurers related to unpaid losses and LAE	(106,311)	(122,372)
Net reserves for losses and LAE at beginning of year	461,270	488,194
Incurred losses and LAE, related to:
Current year	381,996	343,393
Prior years	(41,211)	(34,619)
Total incurred losses and LAE	340,785	308,774
Paid losses and LAE related to:
Current year	211,048	180,649
Prior years	111,708	137,613
Total paid losses and LAE	322,756	318,262
Net reserves for losses and LAE at end of period	479,299	478,706
Plus receivable from reinsurers related to unpaid losses and LAE	99,248	107,783	$ 106,311
Reserves for losses and LAE at end of period	$ 578,547	$ 586,489

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Sep. 30, 2021USD ($)
Loss Contingencies [Line Items]
Legal Defense Reserve	$ 6,500
Limited partnership commitments
Commitments and Contingencies
Investment in limited partnership, committed amount	135,000
Contributions to be made	62,770
Contribution made	$ 76,676

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Mar. 17, 2020
Debt
Outstanding amount	$ 30,000		$ 30,000		$ 30,000
Advance term			5 years
Interest Expense, Borrowings	109	$ 109	$ 323	$ 234
Residential mortgage-backed securities
Debt
Pledged as collateral for a borrowing	$ 32,239		$ 32,239		37,467
Interest-bearing FHLB
Debt
Interest rate percentage	1.42%		1.42%
Revolving Credit Agreement | LIBOR rate
Debt
Variable interest rate basis			LIBOR
Spread on variable rate (as a percent)			1.25%
Revolving Credit Agreement | Prime rate
Debt
Variable interest rate basis			prime rate
Revolving Credit Agreement | Federal Funds Effective Swap Rate
Debt
Variable interest rate basis			federal funds rate
Spread on variable rate (as a percent)			1.25%
Additional spread on variable rate (as a percent)	0.50%		0.50%
RBS Citizens | Revolving Credit Agreement
Debt
Current borrowing capacity	$ 30,000	$ 30,000	$ 30,000	$ 30,000
Maximum borrowing capacity	50,000		50,000
Default trigger, principal amount	10,000		10,000
Outstanding amount	0		$ 0		$ 0
Commitment fee (as a percent)			0.25%		0.25%
F H L B Boston
Debt
Outstanding amount						$ 30,000
Maximum borrowing capacity using eligible invested assets as collateral	228,608		$ 228,608
Level 2 Inputs | F H L B Boston
Debt
Fair value of loan	$ 31,123		$ 31,123		$ 31,291

Share Repurchase Program (Detai

Share Repurchase Program (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Aug. 03, 2007
Share Repurchase Program
Share Repurchase Program				$ 150,000			$ 30,000
Acquisition of treasury stock	$ 17,854	$ 11,753	$ 10,392		$ 39,999
Number of common shares purchased during period under the program	249,754			0	551,598
Treasury stock shares				2,831,168		2,831,168
Treasury stock, at cost				$ 123,834		$ 123,834

Leases - Remaining Lease Term (

Leases - Remaining Lease Term (Details)	9 Months Ended
	Sep. 30, 2021
Leases
Operating lease, existence of option to extend	true
Minimum
Leases
Operating lease, remaining lease term	1 year
Maximum
Leases
Operating lease, remaining lease term	8 years
Operating lease, renewal term	5 years

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases
Operating lease cost	$ 1,117	$ 1,140	$ 3,413	$ 3,438
Operating cash flows from operating leases	$ 1,235	$ 1,258	$ 3,768	$ 3,803
Weighted average remaining lease term Operating leases	6 years 11 months 23 days	7 years 9 months 14 days	6 years 11 months 23 days	7 years 9 months 14 days
Weighted average discount rate Operating leases	2.36%	2.36%	2.36%	2.36%

Leases (Maturities) (Details)

Leases (Maturities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases
2021	$ 1,211
2022	4,406
2023	3,979
2024	3,901
2025	3,835
Thereafter	11,572
Total lease payments	28,904
Less imputed interest	(1,591)
Total	$ 27,313	$ 31,000