MGIC Investment (MTG) 10-Q 3 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	1-10816
Entity Registrant Name	MGIC Investment Corp
Entity Incorporation, State or Country Code	WI
Entity Tax Identification Number	39-1486475
Entity Address, Address Line One	250 E. Kilbourn Avenue
Entity Address, City or Town	Milwaukee,
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53202
City Area Code	(414)
Local Phone Number	347-6480
Title of each class	Common stock
Trading Symbol	MTG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		325,582,685
Entity Central Index Key	0000876437
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Investment portfolio:
Fixed income, available-for-sale, at fair value (amortized cost 2021 - $6,650,315; 2020 - $6,317,164)	$ 6,897,734	$ 6,661,596
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	15,361	18,215
Other invested assets, at cost	3,100	3,100
Total investment portfolio	6,916,195	6,682,911
Cash and cash equivalents	176,426	287,953
Restricted cash and cash equivalents	9,486	8,727
Accrued investment income	53,595	49,997
Reinsurance recoverable on loss reserves	107,029	95,042
Reinsurance recoverable on paid losses	526	669
Premiums receivable	56,388	56,044
Home office and equipment, net	45,303	47,144
Deferred insurance policy acquisition costs	22,284	21,561
Other assets	124,077	104,478
Total assets	7,511,309	7,354,526
Liabilities:
Loss reserves	932,909	880,537
Unearned premiums	256,517	287,099
Federal Home Loan Bank advance	155,000	155,000
Senior notes	880,976	879,379
Convertible junior subordinated debentures	208,814	208,814
Other liabilities	199,673	244,711
Total liabilities	2,633,889	2,655,540
Contingencies
Shareholders’ equity:
Common stock (one dollar par value, shares authorized 1,000,000; shares issued 2021 - 371,353; 2020 - 371,353; shares outstanding 2021 - 329,335; 2020 - 338,573)	371,353	371,353
Paid-in capital	1,789,874	1,862,042
Treasury stock at cost (shares 2021 - 42,018; 2020 - 32,779)	(534,447)	(393,326)
Accumulated other comprehensive income, net of tax	147,645	216,821
Retained earnings	3,102,995	2,642,096
Total shareholders’ equity	4,877,420	4,698,986
Total liabilities and shareholders’ equity	$ 7,511,309	$ 7,354,526

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 6,650,315	$ 6,317,164
Cost	$ 14,981	$ 17,522
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	371,353,000	371,353,000
Common stock, shares outstanding (in shares)	329,335,000	338,573,000
Treasury stock, shares at cost (in shares)	42,018,000	32,779,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Premiums written:
Direct	$ 280,172	$ 272,990	$ 846,700	$ 830,938
Assumed	2,477	2,137	6,810	8,895
Ceded	(35,039)	(47,173)	(122,664)	(144,487)
Net premiums written	247,610	227,954	730,846	695,346
Decrease in unearned premiums, net	7,234	28,159	30,582	65,230
Net premiums earned	254,844	256,113	761,428	760,576
Investment income, net of expenses	38,282	37,252	117,304	118,278
Net realized investment gains	1,009	2,259	5,397	10,851
Other revenue	1,611	380	7,426	7,160
Total revenues	295,746	296,004	891,555	896,865
Losses and expenses:
Losses incurred, net	20,766	40,686	89,566	319,016
Amortization of deferred policy acquisition costs	3,295	3,278	9,016	8,697
Other underwriting and operating expenses, net	53,942	45,250	155,763	131,785
Loss on debt extinguishment	0	26,736	0	26,736
Interest expense	18,011	15,725	53,993	41,580
Total losses and expenses	96,014	131,675	308,338	527,814
Income before tax	199,732	164,329	583,217	369,051
Provision for income taxes	41,755	33,518	122,168	74,388
Net income	$ 157,977	$ 130,811	$ 461,049	$ 294,663
Earnings per share:
Basic (in dollars per share)	$ 0.47	$ 0.39	$ 1.36	$ 0.87
Diluted (in dollars per share)	$ 0.46	$ 0.38	$ 1.33	$ 0.85
Weighted average common shares outstanding - basic (in shares)	335,938	338,598	338,045	340,408
Weighted average common shares outstanding - diluted (in shares)	353,557	357,195	355,481	360,389

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
Statement of Comprehensive Income [Abstract]
Net income	$ 157,977	$ 130,811	$ 461,049	$ 294,663
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	(27,600)	33,712	(76,675)	104,308
Benefit plan adjustments	5,963	(11,347)	7,499	(9,239)
Other comprehensive income (loss), net of tax	(21,637)	22,365	(69,176)	95,069
Comprehensive income	$ 136,340	$ 153,176	$ 391,873	$ 389,732

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock	Paid-in capital	Paid-in capitalCumulative Effect, Period of Adoption, Adjustment	Paid-in capitalCumulative Effect, Period of Adoption, Adjusted Balance	Treasury stock	Accumulated other comprehensive income (loss)	Retained earnings	Retained earningsCumulative Effect, Period of Adoption, Adjustment	Retained earningsCumulative Effect, Period of Adoption, Adjusted Balance
Balance, beginning of period at Dec. 31, 2019		$ 371,353	$ 1,869,719			$ (283,196)	$ 72,708	$ 2,278,650
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(18,807)			9,867
Reacquisition of convertible junior subordinated debentures - equity component			(2,673)
Equity compensation			8,331
Repurchase of common stock						(119,997)
Other comprehensive income (loss), net of tax	$ 95,069						95,069
Net income	294,663							294,663
Cash dividends								(62,065)
Balance, end of period at Sep. 30, 2020	4,513,622	371,353	1,856,570			(393,326)	167,777	2,511,248
Balance, beginning of period at Jun. 30, 2020		371,353	1,859,195			(393,425)	145,412	2,400,820
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(140)			99
Reacquisition of convertible junior subordinated debentures - equity component			(2,673)
Equity compensation			188
Repurchase of common stock						0
Other comprehensive income (loss), net of tax	22,365						22,365
Net income	130,811							130,811
Cash dividends								(20,383)
Balance, end of period at Sep. 30, 2020	4,513,622	371,353	1,856,570			(393,326)	167,777	2,511,248
Balance, beginning of period at Dec. 31, 2020	4,698,986	371,353	1,862,042	$ (68,289)	$ 1,793,753	(393,326)	216,821	2,642,096	$ 68,289	$ 2,710,385
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(15,956)			8,879
Reacquisition of convertible junior subordinated debentures - equity component			0
Equity compensation			12,077
Repurchase of common stock						(150,000)
Other comprehensive income (loss), net of tax	(69,176)						(69,176)
Net income	461,049							461,049
Cash dividends								(68,439)
Balance, end of period at Sep. 30, 2021	4,877,420	371,353	1,789,874			(534,447)	147,645	3,102,995
Balance, beginning of period at Jun. 30, 2021		371,353	1,786,260			(384,550)	169,282	2,972,362
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reissuance of treasury stock, net under share-based compensation plans			(211)			103
Reacquisition of convertible junior subordinated debentures - equity component			0
Equity compensation			3,825
Repurchase of common stock						(150,000)
Other comprehensive income (loss), net of tax	(21,637)						(21,637)
Net income	157,977							157,977
Cash dividends								(27,344)
Balance, end of period at Sep. 30, 2021	$ 4,877,420	$ 371,353	$ 1,789,874			$ (534,447)	$ 147,645	$ 3,102,995

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	$ 461,049	$ 294,663
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	49,820	40,660
Deferred tax expense	4,591	28,427
Loss on debt extinguishment	0	26,736
Net realized investment (gains) losses	(5,397)	(10,851)
Change in certain assets and liabilities:
Accrued investment income	(3,598)	1,923
Reinsurance recoverable on loss reserves	(11,987)	(61,502)
Reinsurance recoverable on paid losses	143	459
Premium receivable	(344)	1,616
Deferred insurance policy acquisition costs	(723)	(2,707)
Profit commission receivable	(18,564)	13,909
Loss reserves	52,372	285,115
Unearned premiums	(30,582)	(65,231)
Return premium accrual	7,200	(300)
Current income taxes	5,453	(40,855)
Other, net	2,977	(3,209)
Net cash provided by operating activities	512,410	508,853
Cash flows from investing activities:
Purchases of investments	(1,335,569)	(1,994,286)
Proceeds from sales of investments	239,483	741,732
Proceeds from maturity of fixed income securities	700,301	776,709
Additions to property and equipment	(2,388)	(2,214)
Net cash provided by (used in) investing activities	(398,173)	(478,059)
Cash flows from financing activities:
Proceeds from issuance of senior notes	0	640,250
Purchase of senior notes	0	(179,735)
Payment of original issue discount - senior notes	0	(2,969)
Purchase of convertible junior subordinated debentures	0	(36,392)
Payment of original issue discount - convertible junior subordinated debentures	0	(15,049)
Cash portion of loss on debt extinguishment	0	(25,266)
Payment of debt issuance costs	0	(1,197)
Repurchase of common stock	(150,000)	(119,997)
Dividends paid	(68,276)	(61,745)
Payment of withholding taxes related to share-based compensation net share settlement	(6,729)	(8,940)
Net cash provided by (used in) financing activities	(225,005)	188,960
Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents	(110,768)	219,754
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	296,680	169,056
Cash and cash equivalents and restricted cash and cash equivalents at end of period	$ 185,912	$ 388,810

Nature of Business and Basis of

Nature of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation MGIC Investment Corporation is a holding company which, through Mortgage Guaranty Insurance Corporation (“MGIC”), is principally engaged in the mortgage insurance business. We provide mortgage insurance to lenders throughout the United States and to government sponsored entities to protect against loss from defaults on low down payment residential mortgage loans. MGIC Assurance Corporation (“MAC”) and MGIC Indemnity Corporation (“MIC”), insurance subsidiaries of MGIC, provide insurance for certain mortgages under Fannie Mae and Freddie Mac (the “GSEs”) credit risk transfer programs. The accompanying unaudited consolidated financial statements of MGIC Investment Corporation and its wholly-owned subsidiaries have been prepared in accordance with the instructions to Form 10-Q as prescribed by the Securities and Exchange Commission (“SEC”) for interim reporting and do not include all of the other information and disclosures required by accounting principles generally accepted in the United States of America (“GAAP”). These statements should be read in conjunction with the consolidated financial statements and notes thereto for the year ended December 31, 2020 included in our 2020 Annual Report on Form 10-K. As used below, “we,” “our” and “us” refer to MGIC Investment Corporation’s consolidated operations or to MGIC Investment Corporation, as the context requires. In the opinion of management, the accompanying financial statements include all adjustments, consisting primarily of normal recurring accruals, necessary to fairly state our consolidated financial position and consolidated results of operations for the periods indicated. The consolidated results of operations for an interim period are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. The substantial majority of our NIW has been for loans purchased by the GSEs. The current private mortgage insurer eligibility requirements ("PMIERs") of the GSEs include financial requirements, as well as business, quality control and certain transactional approval requirements. The financial requirements of the PMIERs require a mortgage insurer’s "Available Assets" (generally only the most liquid assets of an insurer) to equal or exceed its "Minimum Required Assets" (which are based on an insurer's book of risk in force, calculated from tables of factors with several risk dimensions). Based on our application of the PMIERs, as of September 30, 2021, MGIC’s Available Assets are in excess of its Minimum Required Assets; and MGIC is in compliance with the PMIERs and eligible to insure loans purchased by the GSEs. Subsequent events

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
Significant Accounting Policies	Significant Accounting Policies Recent accounting and reporting developments Accounting standards effective in 2021, or early adopted, and relevant to our financial statements are described below: Simplifying the Accounting for Income Taxes: ASU 2019-12 Effective January 1, 2021, we adopted FASB guidance which simplifies Accounting for Income Taxes (Topic 740) by removing certain exceptions to Topic 740. The adoption of this guidance did not have a material impact on our consolidated financial statements. Clarification of Accounting for Equity Securities: ASU 2020-01 Effective January 1, 2021, we adopted ASU 2020-01, which clarifies certain interactions of accounting for equity securities under Topic 321, accounting for equity securities under the equity method of accounting in Topic 323, and accounting for certain forward contracts and purchased options in Topic 815. The amendment clarifies the consideration of observable transactions before applying or discounting the equity method of accounting. The adoption of this guidance did not have a material impact on our consolidated financial statements. Codification Improvements to Subtopic 310-20, Receivables - Nonrefundable Fees and Other Costs: ASU 2020-08 Effective January 1, 2021, we adopted Accounting Standards Update No. 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. FASB standard 2017-08 shortened the amortization period for certain purchased callable debt securities held at a premium by requiring that an entity amortize the premium associated with those callable debt securities within the scope of paragraph 310-20-25-33 to the earliest call date and clarified the FASB’s intent that an entity should reevaluate whether a callable debt security that has multiple call dates is within the scope of paragraph 310-20-35-33 for each reporting period. This guidance clarified that the issuer of a callable debt security should use the next call date versus the earliest call date in amortizing premium. The adoption of this guidance did not have a material impact on our consolidated financial statements. Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity: ASU 2020-06 Effective January 1, 2021, we adopted ASU 2020-06 using a modified retrospective basis. ASU 2020-06 simplifies the accounting for certain financial instruments with characteristics of liabilities and equity. It also includes amendments to EPS guidance. The updated guidance reduced the number of accounting models for convertible debt instruments and convertible preferred stock, and eliminated the cash conversion feature within ASU 470. As a result of these changes, more convertible instruments will be reported as a single unit on the balance sheet. We previously accounted for our 9% Debentures under the cash conversion feature, which required us to account for the conversion features of our 9% Debentures within Paid-in Capital. The adoption of this guidance resulted in a $68.3 million cumulative effect adjustment to our 2021 beginning Retained Earnings and Paid-in Capital to reflect the 9% Debentures as if we had always accounted for them as a liability in their entirety. The updated guidance also includes updates to the EPS calculation. It requires an entity to use the if-converted method, assume share settlement when settlement can be in cash or in shares, use an average market price for the period if the number of shares is based on an entity’s share price, and use the weighted average shares from each quarter to calculate the year to date weighted average shares. The guidance also includes improvements to the disclosures for convertible instruments and EPS. The adoption of this guidance did not have a material impact on our consolidated financial statement disclosures. Reference Rate Reform: ASU 2020-04 In March 2020, the FASB issued ASU 2020-04 to provide temporary optional guidance to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform. It provides optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. This standard may be elected and applied prospectively over time from March 12, 2020 through December 31, 2022 as reference rate reform activities occur. The adoption of, and future elections under, this standard are not expected to have a material impact on our consolidated financial statements as the standard will ease, if warranted, the requirements for accounting for the future effects of reference rate reform. We continue to monitor the impact the discontinuance of LIBOR or other reference rates will have on our contracts and other transactions.

Debt

Debt	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	Debt Debt obligations The aggregate carrying values of our long-term debt obligations and their par values, if different, as of September 30, 2021 and December 31, 2020 are presented in table 3.1 below. Long-term debt obligations Table 3.1 (In millions) September 30, 2021 December 31, 2020 FHLB Advance - 1.91%, due February 2023 $ 155.0 $ 155.0 5.75% Notes, due August 2023 (par value: $242.3 million) 241.1 240.6 5.25% Notes, due August 2028 (par value: $650 million) 639.9 638.8 9% Debentures, due April 2063 (1) 208.8 208.8 Long-term debt, carrying value $ 1,244.8 $ 1,243.2 (1) Convertible at any time prior to maturity at the holder’s option, at a conversion rate, which is subject to adjustment, of 75.5932 shares per $1,000 principal amount, representing a conversion price of approximately $13.23 per share. The payment of dividends by our holding company results in adjustments to the conversion rate, with such adjustment generally deferred until the end of the year. The 5.75% Senior Notes (“5.75% Notes”), 5.25% Senior Notes (5.25% Notes) and 9% Convertible Junior Subordinated Debentures (“9% Debentures”) are obligations of our holding company, MGIC Investment Corporation. The Federal Home Loan Bank Advance (the “FHLB Advance”) is an obligation of MGIC. See Note 7 “Debt” in our Annual Report on Form 10-K for the year ended December 31, 2020 for additional information pertaining to our debt obligations and the 2020 repurchase of a portion of our 5.75% Notes and 9% Debentures resulting in a total loss on debt extinguishment of $26.7 million .As of September 30, 2021 we are in compliance with all of our debt covenants. Interest payments Interest payments for the nine months ended September 30, 2021 and 2020 were $60.0 million and $44.2 million, respectively.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2021
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The reinsurance agreements to which we are a party, excluding captive agreements (which were immaterial), are discussed below. The effect of all of our reinsurance agreements on premiums earned and losses incurred is shown in table 4.1 below. Reinsurance Table 4.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Premiums earned: Direct $ 287,223 $ 300,557 $ 876,541 $ 896,346 Assumed 2,660 2,729 7,551 8,719 Ceded (1) (35,039) (47,173) (122,664) (144,489) Net premiums earned $ 254,844 $ 256,113 $ 761,428 $ 760,576 Losses incurred: Direct $ 17,265 $ 61,164 $ 103,319 $ 383,950 Assumed (97) 229 (43) 528 Ceded 3,598 (20,707) (13,710) (65,462) Losses incurred, net $ 20,766 $ 40,686 $ 89,566 $ 319,016 (1) Ceded premiums earned net of profit commission Quota share reinsurance We have entered into quota share reinsurance ("QSR") transactions with panels of third-party reinsurers to cede a fixed quota share percentage of premiums earned and received and losses incurred on insurance covered by the transactions. We receive the benefit of a ceding commission equal to 20% of premiums ceded before profit commission. We also receive the benefit of a profit commission through a reduction of premiums we cede. The profit commission varies inversely with the level of losses on a “dollar for dollar” basis and can be eliminated at annual loss ratios higher than we have experienced on our QSR Transactions. Each of our QSR Transactions typically have annual loss ratio caps of 300% and lifetime loss ratios of 200% . Table 4.2 below provides additional detail regarding our QSR Transactions. Reinsurance Table 4.2 Quota Share Contract Covered Policy Years Quota Share % Annual Loss Ratio to Exhaust Profit Commission (1) Contractual Termination Date 2015 QSR Prior to 2017 15.0 % 68.0 % December 31, 2031 2017 QSR 2017 30.0 % 60.0 % December 31, 2028 2018 QSR 2018 30.0 % 62.0 % December 31, 2029 2019 QSR 2019 30.0 % 62.0 % December 31, 2030 2020 QSR 2020 12.5 % 62.0 % December 31, 2031 2020 QSR and 2021 QSR 2020 - 2021 17.5 % 62.0 % December 31, 2032 2021 QSR 2021 12.5 % 57.5 % December 31, 2032 2022 QSR 2022 15.0 % 57.5 % December 31, 2033 Credit Union QSR (2) 2020-2025 65.0 % 50.0 % December 31, 2039 (1) We will receive a profit commission provided the annual loss ratio on policies covered under the transaction remains below this ratio. (2) Eligible credit union business written before April 1, 2020 was covered by our 2019 and prior QSR Transactions. We can elect to terminate the QSR Transactions under specified scenarios without penalty upon prior written notice, including if we will receive less than 90% (80% for the Credit Union QSR Transaction ) of the full credit amount under the PMIERs, full financial statement credit or full credit under applicable regulatory capital requirements for the risk ceded in any required calculation period. Table 4.3 provides additional detail regarding optional termination dates and optional reductions to our quota share percentage which can, in each case, be elected by us for a fee. The optional reduction to the quota share percentage would give us an option to reduce our quota share percentage from the original percentage shown in table 4.2 to the percentage shown in table 4.3. Reinsurance Table 4.3 Quota Share Contract Optional Termination Date (1) Optional Quota Share % Reduction Date (2) Quota Share % Reduction 2015 QSR June 30, 2021 NA NA 2017 QSR December 31, 2021 NA NA 2018 QSR December 31, 2021 NA NA 2019 QSR December 31, 2021 July 1, 2020 25% or 20% 2020 QSR December 31, 2022 July 1, 2021 10.5% or 8% 2020 QSR and 2021 QSR, 2020 Policy year December 31, 2022 July 1, 2021 14.5% or 12% 2020 QSR and 2021 QSR, 2021 Policy year December 31, 2023 July 1, 2022 14.5% or 12% 2021 QSR December 31, 2023 July 1, 2022 10.5% or 8% 2022 QSR December 31, 2024 July 1, 2023 12.5% or 10% (1) We can elect early termination of the QSR Transaction beginning on this date, and bi-annually thereafter for the 2015 QSR, 2019 QSR, 2020 QSR, 2021 QSR, and 2022 QSR. Early termination of the 2018 QSR can be elected on this date and annually thereafter. (2) We can elect to reduce the quota share percentage beginning on this date, and bi-annually thereafter. We have elected to terminate our 2017 QSR and 2018 QSR Transactions effective December 31, 2021 and will incur an early termination fee of $5 million at December 31, 2021. Table 4.4 below provides a summary of our QSR Transactions, excluding captive agreements, for the three and nine months ended September 30, 2021 and 2020. Quota Share Reinsurance Table 4.4 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Ceded premiums written and earned, net of profit commission $ 22,911 $ 43,448 $ 90,284 $ 131,651 Ceded losses incurred (3,598) 20,707 13,710 65,493 Ceding commissions (1) 13,599 12,128 39,657 35,518 Profit commission 45,078 17,191 108,000 45,939 (1) Ceding commissions are reported within Other underwriting and operating expenses, net on the consolidated statements of operations. Ceded losses incurred for the three and nine months ended September 30, 2021 reflect favorable loss reserve development on previously received notices primarily due to the decrease in the claim rate on pre-COVID-19 delinquencies notices and a decrease in new delinquency notices reported on insurance covered by our QSR Transactions. Ceded loss incurred for the three and nine months ended September 30, 2020 reflect the increase in new delinquency notices due to the impact of the COVID-19 pandemic on insurance covered by our QSR Transactions. See Note 11 - “Loss Reserves” for discussion of our loss reserves. Under the terms of our QSR Transactions, currently in effect, ceded premiums, ceding commissions, profit commission, and ceded paid loss and LAE are settled net on a quarterly basis. The ceded premiums due after deducting the related ceding commission and profit commission is reported within Other liabilities on the consolidated balance sheets. The reinsurance recoverable on loss reserves related to our QSR Transactions was $107.0 million as of September 30, 2021 and $95.0 million as of December 31, 2020. The reinsurance recoverable balance is secured by funds on deposit from the reinsurers, the minimum amount of which is based on the greater of a reinsurer’s funding requirements under PMIERs or ceded reserves. An allowance for credit losses was not required at September 30, 2021. Excess of loss reinsurance We have aggregate excess of loss reinsurance transactions (“Home Re Transactions”) with unaffiliated special purpose insurers domiciled in Bermuda (“Home Re Entities”). For the reinsurance coverage periods, we retain the first layer of the respective aggregate losses paid, and a Home Re Entity will then provide second layer coverage up to the outstanding reinsurance coverage amount. We retain losses paid in excess of the outstanding reinsurance coverage amount. Subject to certain conditions, the reinsurance coverage decreases over a period of either 10 or 12.5 years, depending on the transaction, as the underlying covered mortgages amortize or are repaid, or mortgage insurance losses are paid. The Home Re Entities financed the coverages by issuing mortgage insurance-linked notes (“ILNs”) to unaffiliated investors in an aggregate amount equal to the initial reinsurance coverage amounts. Each ILN is non-recourse to any assets of MGIC or affiliates. The proceeds of the ILNs, which were deposited into reinsurance trusts for the benefit of MGIC, will be the source of reinsurance claim payments to MGIC and principal repayments on the ILNs. When a “Trigger Event” is in effect, payment of principal on the related notes will be suspended and the reinsurance coverage available to MGIC under the transactions will not be reduced by such principal payments. As of September 30, 2021 a "Trigger Event" has occurred on our Home Re 2018-1 and Home Re 2019-1 ILN transactions because the reinsured principal balance of loans that were reported 60 or more days delinquent exceeded 4% of the total reinsured principal balance of loans under each transaction. A “Trigger Event” has also occurred on the Home Re 2021-1 and Home Re 2021-2 ILN transactions because the credit enhancement of the most senior tranche is less than the target credit enhancement. Table 4.5 provides a summary of our Home Re Transactions as of September 30, 2021 and December 31, 2020. Excess of Loss Reinsurance Table 4.5 ($ in thousands) Home Re 2021-2, Ltd. Home Re 2021-1, Ltd. Home Re 2020-1, Ltd. Home Re 2019-1, Ltd. Home Re 2018-1, Ltd. Issue Date August 3, 2021 February 2, 2021 October 29, 2020 May 25, 2019 October 30, 2018 Policy Inforce Dates January 1, 2021 - May 28, 2021 August 1, 2020 - December 31, 2020 January 1, 2020 - July 31, 2020 January 1, 2018 - March 31, 2019 July 1, 2016 - December 31, 2017 Optional Call Date (1) July 25, 2028 January 25, 2028 October 25, 2027 May 25, 2026 October 25, 2025 Legal Maturity 12.5 years 12.5 years 10 years 10 years 10 years Initial First Layer Retention 190,159 211,159 275,283 185,730 168,691 Initial Excess of Loss Reinsurance Coverage 398,429 398,848 412,917 315,739 318,636 September 30, 2021 Remaining First Layer Retention 190,159 211,159 275,268 184,007 165,434 Remaining Excess of Loss Reinsurance Coverage 398,429 398,848 288,777 208,146 218,343 December 31, 2020 Remaining First Layer Retention — — 275,283 184,514 166,005 Remaining Excess of Loss Reinsurance Coverage — — 412,917 208,146 218,343 (1) We have the right to terminate the Home Re Transactions under certain circumstances and on any payment date on or after the respective Optional Call Date. The reinsurance premiums ceded to each Home Re Entity are composed of coverage, initial expense and supplemental premiums. The coverage premiums are generally calculated as the difference between the amount of interest payable by the Home Re Entity on the remaining reinsurance coverage levels, and the investment income collected on the collateral assets held in a reinsurance trust account and used to collateralize the Home Re Entity’s reinsurance obligation to MGIC. The amount of monthly reinsurance coverage premium ceded will fluctuate due to changes in the reference rate and changes in money market rates that affect investment income collected on the assets in the reinsurance trust. The Home Re 2021-2 Transaction references SOFR, while the remaining Home Re Transactions reference the one-month LIBOR. As a result, we concluded that each Home Re transaction contains an embedded derivative that is accounted for separately as a freestanding derivative. The fair values of the derivatives at September 30, 2021, were not material to our consolidated balance sheet, and the change in fair value during the three and nine months ended September 30, 2021 was not material to our consolidated statements of operations. Total ceded premiums were $12.1 million and $32.4 million for the three and nine months ended September 30, 2021, and $3.7 million and $12.8 million for the three and nine months ended September 30, 2020, respectively. At the time the Home Re Transactions were entered into, we concluded that each Home Re Entity is a variable interest entity (“VIE”). A VIE is a legal entity that does not have sufficient equity at risk to finance its activities without additional subordinated financial support or is structured such that equity investors lack the ability to make sufficient decisions relating to the entity’s operations through voting rights or do not substantively participate in gains and losses of the entity. Given that MGIC (1) does not have the unilateral power to direct the activities that most significantly affect each Home Re Entity’s economic performance and (2) does not have the obligation to absorb losses or the right to receive benefits of each Home Re Entity that potentially could be significant to the Home Re Entity, consolidation of the Home Re Entities is not required. We are required to disclose our maximum exposure to loss, which we consider to be an amount that we could be required to record -in our statements of operations, as a result of our involvement with the VIEs under our Home Re Transactions. As of September 30, 2021, and December 31, 2020, we did not have material exposure to the VIEs as we have no investment in the VIEs and had no reinsurance claim payments due from the VIEs under our reinsurance transactions. We are unable to determine the timing or extent of claims from losses that are ceded under the reinsurance transactions. The VIE assets are deposited in reinsurance trusts for the benefit of MGIC that will be the source of reinsurance claim payments to MGIC. The purpose of the reinsurance trusts is to provide security to MGIC for the obligations of the VIEs under the reinsurance transactions. The trustee of the reinsurance trusts, a recognized provider of corporate trust services, has established segregated accounts within the reinsurance trusts for the benefit of MGIC, pursuant to the trust agreements. The trust agreements are governed by, and construed in accordance with, the laws of the State of New York. If the trustee of the reinsurance trusts failed to distribute claim payments to us as provided in the reinsurance trusts, we would incur a loss related to our losses ceded under the Home Re Transactions and deemed unrecoverable. We are also unable to determine the impact such possible failure by the trustee to perform pursuant to the reinsurance trust agreements may have on our consolidated financial statements. As a result, we are unable to quantify our maximum exposure to loss related to our involvement with the VIEs. MGIC has certain termination rights under the reinsurance transactions should its claims not be paid. We consider our exposure to loss from our reinsurance transactions with the VIEs to be remote. Table 4.6 presents the total assets of the Home Re Entities as of September 30, 2021 and December 31, 2020. Home Re total assets Table 4.6 (In thousands) Home Re Entity (Issue date) Total VIE Assets September 30, 2021 Home Re 2018-1 Ltd. $ 218,343 Home Re 2019-1 Ltd. 208,146 Home Re 2020-1 Ltd. 312,199 Home Re 2021-1 Ltd. 398,848 Home Re 2021-2 Ltd. 398,429 December 31, 2020 Home Re 2018-1 Ltd. $ 218,343 Home Re 2019-1 Ltd. 208,146 Home Re 2020-1 Ltd. 412,917 The reinsurance trust agreements provide that the trust assets may generally only be invested in certain money market funds that (i) invest at least 99.5% of their total assets in cash or direct U.S. federal government obligations, such as U.S. Treasury bills, as well as other short-term securities backed by the full faith and credit of the U.S. federal government or issued by an agency of the U.S. federal government, (ii) have a principal stability fund rating of “AAAm” by S&P or a money market fund rating of “Aaa-mf” by Moody’s as of the Closing Date and thereafter maintain any rating with either S&P or Moody’s, and (iii) are permitted investments under the applicable credit for reinsurance laws and applicable PMIERs credit for reinsurance requirements. The total calculated PMIERs credit for risk ceded under our Home Re Transactions is generally based on the PMIERs requirement of the covered policies and the attachment and detachment points of the coverage, all of which fluctuate over time. (see Note 1 - “Nature of Business and Basis of Presentation”

Litigation and Contingencies

Litigation and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Litigation and Contingencies	Litigation and Contingencies Before paying an insurance claim, generally we review the loan and servicing files to determine the appropriateness of the claim amount. When reviewing the files, we may determine that we have the right to rescind coverage or deny a claim on the loan (both referred to as “rescissions”). In addition, our insurance policies generally provide that we can reduce a claim if the servicer did not comply with its obligations under our insurance policy (such reduction referred to as a “curtailment”). In recent quarters, an immaterial percentage of claims received in a quarter have been resolved by rescissions. In the three quarters of 2021 and in 2020, curtailments reduced our average claim paid by approximately 3.9% and 3.6%, respectively. The COVID-19 related foreclosure moratoriums and forbearance plans have decreased our claims paid activity beginning in the second quarter of 2020. It is difficult to predict the level of curtailments once the foreclosure moratoriums and forbearance plans end. When the insured disputes our right to rescind coverage or curtail claims, we generally engage in discussions in an attempt to settle the dispute. If we are unable to reach a settlement, the outcome of a dispute ultimately may be determined by legal proceedings. Under ASC 450-20, until a loss associated with settlement discussions or legal proceedings becomes probable and can be reasonably estimated, we consider our claim payment or rescission resolved for financial reporting purposes and do not accrue an estimated loss. When we determine that a loss is probable and can be reasonably estimated, we record our best estimate of our probable loss, including recording a probable loss of $6.3 million in the second quarter of 2021. The probable loss is reported within Loss Reserves on the Consolidated Balance Sheet and within Losses Incurred, net on the Consolidated Statements of Operations. In those cases, until settlement negotiations or legal proceedings are concluded (including the receipt of any necessary GSE approvals), it is possible that we will record an additional loss. We are currently involved in discussions and/or proceedings with respect to our claims paying practices. Although it is possible that, if not resolved by negotiation, we will not prevail on all matters, we are unable to make a reasonable estimate or range of estimates of the potential liability. We estimate the maximum exposure where a loss is reasonably possible to be approximately $27 million more than the amount of the probable loss we have recorded. This estimate of maximum exposure is based upon currently available information; is subject to significant judgment, numerous assumptions and known and unknown uncertainties; will include an amount for matters for which we have recorded a probable loss until such matters are concluded; will include different matters from time to time; and does not include interest or consequential or exemplary damages.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic earnings per share (“EPS”) is calculated by dividing net income by the weighted average number of shares of common stock outstanding. For purposes of calculating basic EPS, vested restricted stock and restricted stock units (“RSUs”) are considered outstanding. Diluted EPS includes the components of basic EPS and also gives effect to dilutive common stock equivalents. The determination of whether components are dilutive is calculated independently for each period. We calculate diluted EPS using the treasury stock method and if-converted method. Under the treasury stock method, diluted EPS reflects the potential dilution that could occur if unvested RSUs result in the issuance of common stock. Under the if-converted method, diluted EPS reflects the potential dilution that could occur if our 9% Debentures result in the issuance of common stock. The determination of potentially issuable shares does not consider the satisfaction of the conversion requirements and the shares are included in the determination of diluted EPS as of the beginning of the period, if dilutive. Table 6.1 reconciles the numerators and denominators used to calculate basic and diluted EPS. Earnings per share Table 6.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2021 2020 2021 2020 Basic earnings per share: Net income $ 157,977 $ 130,811 $ 461,049 $ 294,663 Weighted average common shares outstanding - basic 335,938 338,598 338,045 340,408 Basic earnings per share $ 0.47 $ 0.39 $ 1.36 $ 0.87 Diluted earnings per share: Net income $ 157,977 $ 130,811 $ 461,049 $ 294,663 Interest expense, net of tax (1): 9% Debentures 3,712 4,161 11,135 13,293 Diluted income available to common shareholders $ 161,689 $ 134,972 $ 472,184 $ 307,956 Weighted average common shares outstanding - basic 335,938 338,598 338,045 340,408 Effect of dilutive securities: Unvested RSUs 1,834 1,377 1,651 1,492 9% Debentures 15,785 17,220 15,785 18,489 Weighted average common shares outstanding - diluted 353,557 357,195 355,481 360,389 Diluted earnings per share $ 0.46 $ 0.38 $ 1.33 $ 0.85 (1) Interest expense for the three and nine months ended September 30, 2021 and 2020, respectively, has been tax effected at a rate of 21%.

Investments

Investments	9 Months Ended
	Sep. 30, 2021
Investments [Abstract]
Investments	Investments Fixed income securities Our fixed income securities classified as available-for-sale at September 30, 2021 and December 31, 2020 are shown in tables 7.1a and 7.1b below. Details of fixed income securities by category as of September 30, 2021 Table 7.1a (In thousands) Amortized Cost Allowance for Expected Credit Loss Gross Unrealized Gains Gross Unrealized (Losses) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 184,578 $ — $ 434 $ (277) $ 184,735 Obligations of U.S. states and political subdivisions 2,372,020 — 146,149 (3,639) 2,514,530 Corporate debt securities 2,856,671 — 100,264 (8,438) 2,948,497 ABS 158,637 (1) 1,337 (198) 159,775 RMBS 337,353 — 3,581 (1,666) 339,268 CMBS 319,187 — 9,634 (628) 328,193 CLOs 408,121 — 913 (64) 408,970 Foreign government debt 13,748 — 58 (40) 13,766 Total fixed income securities $ 6,650,315 $ (1) $ 262,370 $ (14,950) $ 6,897,734 Details of fixed income securities by category as of December 31, 2020 Table 7.1b (In thousands) Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized (Losses) (1) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 264,531 $ — $ 1,164 $ (2) $ 265,693 Obligations of U.S. states and political subdivisions 2,083,568 — 166,557 (256) 2,249,869 Corporate debt securities 2,690,860 — 155,156 (1,728) 2,844,288 ABS 203,807 (49) 2,946 (18) 206,686 RMBS 425,532 — 6,472 (838) 431,166 CMBS 312,572 — 16,055 (1,125) 327,502 CLOs 310,616 — 566 (692) 310,490 Foreign government debt 4,485 — 224 — 4,709 Commercial paper 21,193 — — — 21,193 Total fixed income securities $ 6,317,164 $ (49) $ 349,140 $ (4,659) $ 6,661,596 We had $13.8 million and $14.1 million of investments at fair value on deposit with various states as of September 30, 2021 and December 31, 2020, respectively, due to regulatory requirements of those state insurance departments. In connection with our insurance and reinsurance activities within MAC and MIC, insurance subsidiaries of MGIC, we are required to maintain assets in trusts for the benefit of contractual counterparties, which had investments at fair value of $187.5 million and $160.3 million at September 30, 2021 and December 31, 2020, respectively. The amortized cost and fair values of fixed income securities at September 30, 2021, by contractual maturity, are shown in table 7.2 below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most ABS, RMBS, CMBS, and CLOs provide for periodic payments throughout their lives, they are listed in separate categories. Fixed income securities maturity schedule Table 7.2 September 30, 2021 (In thousands) Amortized cost Fair Value Due in one year or less $ 415,090 $ 418,673 Due after one year through five years 1,856,136 1,919,980 Due after five years through ten years 1,666,042 1,757,537 Due after ten years 1,489,749 1,565,338 5,427,017 5,661,528 ABS 158,637 159,775 RMBS 337,353 339,268 CMBS 319,187 328,193 CLOs 408,121 408,970 Total as of September 30, 2021 $ 6,650,315 $ 6,897,734 Proceeds from sales of fixed income securities classified as available-for-sale were $246.8 million and $713.1 million during the nine months ended September 30, 2021 and 2020, respectively. Gross gains of $1.4 million and $6.7 million and gross losses of $0.3 million and $1.0 million were realized during the three and nine months ended September 30, 2021. We did not record any realized losses for the three and nine months ended September 30, 2021 related to our intent to sell certain securities. During the three and nine months ended September 30, 2020 gross gains of $3.4 million and $15.9 million and gross losses of $0.8 million and $5.9 million, respectively, were realized. We recorded $0.4 million of realized losses for the three months ended September 30, 2020 and $0.7 million of realized losses for the nine months ended September 30, 2020 related to our intent to sell certain securities. Equity securities The cost and fair value of investments in equity securities at September 30, 2021 and December 31, 2020 are shown in tables 7.3a and 7.3b below. Details of equity security investments as of September 30, 2021 Table 7.3a (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 14,981 $ 395 $ (15) $ 15,361 Details of equity security investments as of December 31, 2020 Table 7.3b (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 17,522 $ 695 $ (2) $ 18,215 For the three and nine months ended September 30, 2021, we recognized $0.1 million and $0.3 million of net losses on equity securities still held as of September 30, 2021. For the three and nine months ended September 30, 2020, we recognized $0.1 million and $0.4 million of net gains, respectively, on equity securities still held as of September 30, 2020. Other invested assets Other invested assets include an investment in Federal Home Loan Bank ("FHLB") stock that is carried at cost, which due to its nature approximates fair value. Ownership of FHLB stock provides access to a secured lending facility, and our current FHLB Advance amount is secured by eligible collateral whose fair value is maintained at a minimum of 102% of the outstanding principal balance of the FHLB Advance. As of September 30, 2021 and December 31, 2020, that collateral consisted of fixed income securities included in our total investment portfolio, and cash and cash equivalents, with a total fair value of $163.7 million and $163.9 million, respectively. Unrealized investment losses Tables 7.4a and 7.4b below summarize, for all available-for-sale investments in an unrealized loss position at September 30, 2021 and December 31, 2020, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in tables 7.4a and 7.4b are estimated using the process described in Note 8 - “Fair Value Measurements” to these consolidated financial statements and in Note 3 - “Significant Accounting Policies” to the consolidated financial statements in our 2020 Annual Report on Form 10-K. Unrealized loss aging for securities by type and length of time as of September 30, 2021 Table 7.4a Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 88,312 $ (277) $ — $ — $ 88,312 $ (277) Obligations of U.S. states and political subdivisions 250,099 (3,479) 15,638 (160) 265,737 (3,639) Corporate debt securities 468,720 (8,438) — — 468,720 (8,438) ABS 58,901 (198) — — 58,901 (198) RMBS 174,094 (1,302) 26,733 (364) 200,827 (1,666) CMBS 82,653 (628) — — 82,653 (628) CLOs 127,483 (29) 21,974 (35) 149,457 (64) Foreign government debt 4,445 (40) — — 4,445 (40) Total $ 1,254,707 $ (14,391) $ 64,345 $ (559) $ 1,319,052 $ (14,950) Unrealized loss aging for securities by type and length of time as of December 31, 2020 Table 7.4b Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 2,690 $ (2) $ — $ — $ 2,690 $ (2) Obligations of U.S. states and political subdivisions 31,416 (256) — — 31,416 (256) Corporate debt securities 44,968 (1,728) — — 44,968 (1,728) ABS 14,929 (18) — — 14,929 (18) RMBS 98,409 (773) 3,566 (65) 101,975 (838) CMBS 13,212 (789) 2,799 (336) 16,011 (1,125) CLOs 95,287 (261) 73,904 (431) 169,191 (692) Total $ 300,911 $ (3,827) $ 80,269 $ (832) $ 381,180 $ (4,659) Based on current facts and circumstances, we believe the unrealized losses as of September 30, 2021 presented in table 7.4a above are not indicative of the ultimate collectability of the current amortized cost of the securities. The unrealized losses in all categories of our investments at September 30, 2021 were primarily caused by changes in interest rates between the time of purchase and the respective fair value measurement date. We also rely upon estimates of several credit and non-credit factors in our review and evaluation of individual investments to determine whether a credit impairment exists. There were 396 and 109 securities in an unrealized loss position at September 30, 2021 and December 31, 2020, respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Recurring fair value measurements The following describes the valuation methodologies generally used by the independent pricing sources, or by us, to measure financial instruments at fair value, including the general classification of such financial instruments pursuant to the valuation hierarchy. • Fixed income securities: U.S. Treasury Securities and Obligations of U.S. Government Corporations and Agencies: Securities with valuations derived from quoted prices for identical instruments in active markets that we can access are categorized in Level 1 of the fair value hierarchy. Securities valued by surveying the dealer community, obtaining relevant trade data, benchmark quotes and spreads and incorporating this information in the valuation process are categorized as Level 2 of the fair value hierarchy. Corporate Debt Bonds are valued by surveying the dealer community, obtaining relevant trade data, benchmark quotes and spreads and incorporating this information into the valuation process. These securities are generally categorized in Level 2 of the fair value hierarchy. Obligations of U.S. States & Political Subdivisions are valued by tracking, capturing, and analyzing quotes for active issues and trades reported via the Municipal Securities Rulemaking Board records. Daily briefings and reviews of current economic conditions, trading levels, spread relationships, and the slope of the yield curve provide further data for evaluation. These securities are generally categorized in Level 2 of the fair value hierarchy. Residential Mortgage-Backed Securities ("RMBS") are valued by monitoring interest rate movements, and other pertinent data daily. Incoming market data is enriched to derive spread, yield and/or price data as appropriate, enabling known data points to be extrapolated for valuation application across a range of related securities. These securities are generally categorized in Level 2 of the fair value hierarchy. Commercial Mortgage-Backed Securities ("CMBS") are valued using techniques that reflect market participants’ assumptions and maximize the use of relevant observable inputs including quoted prices for similar assets, benchmark yield curves and market corroborated inputs. Evaluation uses regular reviews of the inputs for securities covered, including executed trades, broker quotes, credit information, collateral attributes and/or cash flow waterfall as applicable. These securities are generally categorized in Level 2 of the fair value hierarchy. Asset-Backed Securities ("ABS") are valued using spreads and other information solicited from market buy-and-sell-side sources, including primary and secondary dealers, portfolio managers, and research analysts. Cash flows are generated for each tranche, benchmark yields are determined, and deal collateral performance and tranche level attributes including trade activity, bids, and offers are applied, resulting in tranche specific prices. These securities are generally categorized in Level 2 of the fair value hierarchy. Collateralized loan obligations ("CLOs") are valued by evaluating manager rating, seniority in the capital structure, assumptions about prepayment, default and recovery and their impact on cash flow generation. Loan level net asset values are determined and aggregated for tranches and as a final step prices are checked against available recent trade activity. These securities are generally categorized in Level 2 of the fair value hierarchy. Foreign government debt is valued by surveying the dealer community, obtaining relevant trade data, benchmark quotes and spreads and incorporating this information into the valuation process. These securities are generally categorized in Level 2 of the fair value hierarchy. Commercial Paper, which has an original maturity greater than 90 days , is valued using market data for comparable instruments of similar maturity and average yields. These securities are categorized in Level 2 of the fair value hierarchy. • Equity securities: Consist of actively traded, exchange-listed equity securities, including exchange traded funds (“ETFs”) and Bond Mutual Funds, with valuations derived from quoted prices for identical assets in active markets that we can access. These securities are valued in Level 1 of the fair value hierarchy. • Cash Equivalents: Consists of money market funds and treasury bills with valuations derived from quoted prices for identical assets in active markets that we can access. These securities are valued in level 1 of the fair value hierarchy. Instruments in this category valued using market data for comparable instruments are classified as level 2 in the fair value hierarchy. • Real estate acquired is valued at the lower of our acquisition cost or a percentage of the appraised value. The percentage applied to the appraised value is based upon our historical sales experience adjusted for current trends. These securities are categorized in level 3 of the fair value hierarchy. Assets measured at fair value, by hierarchy level, as of September 30, 2021 and December 31, 2020 are shown in tables 8.1a and 8.1b below. The fair value of the assets is estimated using the process described above, and more fully in Note 3 - “Significant Accounting Policies” to the consolidated financial statements in our 2020 Annual Report on Form 10-K. Assets carried at fair value by hierarchy level as of September 30, 2021 Table 8.1a (In thousands) Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 184,735 $ 124,310 $ 60,425 $ — Obligations of U.S. states and political subdivisions 2,514,530 — 2,514,530 — Corporate debt securities 2,948,497 — 2,948,497 — ABS 159,775 — 159,775 — RMBS 339,268 — 339,268 — CMBS 328,193 — 328,193 — CLOs 408,970 — 408,970 — Foreign government debt 13,766 — 13,766 — Total fixed income securities 6,897,734 124,310 6,773,424 — Equity securities 15,361 15,361 — — Cash Equivalents 168,083 168,083 — — Real estate acquired (1) 1,485 — — 1,485 Total $ 7,082,663 $ 307,754 $ 6,773,424 $ 1,485 Assets carried at fair value by hierarchy level as of December 31, 2020 Table 8.1b (In thousands) Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 265,693 $ 149,339 $ 116,354 $ — Obligations of U.S. states and political subdivisions 2,249,869 — 2,249,869 — Corporate debt securities 2,844,288 — 2,844,288 — ABS 206,686 — 206,686 — RMBS 431,166 — 431,166 — CMBS 327,502 — 327,502 — CLOs 310,490 — 310,490 — Foreign government debt 4,709 — 4,709 — Commercial paper 21,193 — 21,193 — Total fixed income securities 6,661,596 149,339 6,512,257 — Equity securities 18,215 18,215 — — Cash Equivalents 288,941 275,668 13,273 — Real estate acquired (1) 1,092 — — 1,092 Total $ 6,969,844 $ 443,222 $ 6,525,530 $ 1,092 (1) Real estate acquired through claim settlement, which is held for sale, is reported in “Other assets” on the consolidated balance sheets. Certain financial instruments, including insurance contracts, are excluded from these fair value disclosure requirements. The carrying values of cash and cash equivalents (Level 1) and accrued investment income (Level 2) approximated their fair values. Additional fair value disclosures related to our investment portfolio are included in Note 7 – “Investments.” Reconciliations of Level 3 assets For assets measured at fair value using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances for the three and nine months ended September 30, 2021 and 2020 is shown in tables 8.2a and 8.2b below. There were no losses included in earnings for those periods attributable to the change in unrealized losses on assets still held at the end of the applicable period. Fair value roll-forward for financial instruments classified as Level 3 for the three months ended September 30, Table 8.2a Real Estate Acquired (In thousands) 2021 2020 Balance at June 30, $ 572 $ 1,963 Purchases 1,178 1,990 Sales (190) (2,266) Included in earnings and reported as losses incurred, net (75) 3 Balance at September 30, $ 1,485 $ 1,690 Fair value roll-forward for financial instruments classified as Level 3 for the nine months ended September 30, Table 8.2b Real Estate Acquired (In thousands) 2021 2020 Balance at December 31, $ 1,092 $ 7,252 Purchases 3,955 7,911 Sales (3,844) (13,991) Included in earnings and reported as losses incurred, net 282 518 Balance at September 30, $ 1,485 $ 1,690 Financial assets and liabilities not measured at fair value Other invested assets include an investment in FHLB stock that is carried at cost, which due to restrictions that require it to be redeemed or sold only to the security issuer at par value, approximates fair value. The fair value of other invested assets is categorized as Level 2. Financial liabilities include our outstanding debt obligations. The fair values of our 5.75% and 5.25% Notes and 9% Debentures were based on observable market prices. The fair value of the FHLB Advance was estimated using cash flows discounted at current incremental borrowing rates for similar borrowing arrangements. In all cases the fair values of the financial liabilities below are categorized as Level 2. Table 8.3 presents the carrying value and fair value of our financial assets and liabilities disclosed, but not carried, at fair value at September 30, 2021 and December 31, 2020. Financial assets and liabilities not measured at fair value Table 8.3 September 30, 2021 December 31, 2020 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Financial assets Other invested assets $ 3,100 $ 3,100 $ 3,100 $ 3,100 Financial liabilities FHLB Advance 155,000 158,820 155,000 160,865 5.75% Senior Notes 241,090 260,349 240,597 261,752 5.25% Senior Notes 639,886 694,135 638,782 696,449 9% Convertible Junior Subordinated Debentures 208,814 279,696 208,814 273,569 Total financial liabilities $ 1,244,790 $ 1,393,000 $ 1,243,193 $ 1,392,635

Other Comprehensive Income

Other Comprehensive Income	9 Months Ended
	Sep. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other Comprehensive Income	Other Comprehensive Income The pretax and related income tax benefit (expense) components of our other comprehensive income (loss) for the three and nine months ended September 30, 2021 and 2020 are included in table 9.1 below. Components of other comprehensive income (loss) Table 9.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Net unrealized investment (losses) gains arising during the period $ (34,937) $ 42,674 $ (97,057) $ 132,036 Total income tax benefit (expense) 7,337 (8,962) 20,382 (27,728) Net of taxes (27,600) 33,712 (76,675) 104,308 Net changes in benefit plan assets and obligations 7,548 (14,364) 9,492 (11,695) Total income tax benefit (expense) (1,585) 3,017 (1,993) 2,456 Net of taxes 5,963 (11,347) 7,499 (9,239) Total other comprehensive income (loss) (27,389) 28,310 (87,565) 120,341 Total income tax benefit (expense) 5,752 (5,945) 18,389 (25,272) Total other comprehensive income (loss), net of tax $ (21,637) $ 22,365 $ (69,176) $ 95,069 The pretax and related income tax benefit (expense) components of the amounts reclassified from our accumulated other comprehensive income (loss) (“AOCI”) to our consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020 are included in table 9.2 below. Reclassifications from AOCI Table 9.2 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Reclassification adjustment for net realized (losses) gains (1) $ 1,045 $ 10,349 $ 7,462 $ 8,673 Income tax benefit (expense) (219) (2,173) (1,566) (1,821) Net of taxes 826 8,176 5,896 6,852 Reclassification adjustment related to benefit plan assets and obligations (2) (971) (1,336) (2,915) (4,005) Income tax benefit (expense) 204 280 612 841 Net of taxes (767) (1,056) (2,303) (3,164) Total reclassifications 74 9,013 4,547 4,668 Income tax benefit (expense) (15) (1,893) (954) (980) Total reclassifications, net of tax $ 59 $ 7,120 $ 3,593 $ 3,688 (1) Increases (decreases) Net realized investment gains (losses) on the consolidated statements of operations. (2) Decreases (increases) Other underwriting and operating expenses, net on the consolidated statements of operations. A rollforward of AOCI for the nine months ended September 30, 2021, including amounts reclassified from AOCI, are included in table 9.3 below. Rollforward of AOCI Table 9.3 Nine Months Ended September 30, 2021 (In thousands) Net unrealized gains and (losses) on available-for-sale securities Net benefit plan assets and (obligations) recognized in shareholders' equity Total accumulated other comprehensive income (loss) Balance at December 31, 2020, net of tax $ 272,137 $ (55,316) $ 216,821 Other comprehensive income before reclassifications (70,779) 5,196 (65,583) Less: Amounts reclassified from AOCI 5,896 (2,303) 3,593 Balance, September 30, 2021, net of tax $ 195,462 $ (47,817) $ 147,645

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans Tables 10.1 and 10.2 provide the components of net periodic benefit cost for our pension, supplemental executive retirement and other postretirement benefit plans for the three and nine months ended September 30, 2021 and 2020. Components of net periodic benefit cost Table 10.1 Three Months Ended September 30, Pension and Supplemental Executive Retirement Plans Other Postretirement Benefit Plans (In thousands) 2021 2020 2021 2020 Service cost $ 1,908 $ 1,848 $ 377 $ 316 Interest cost 2,794 3,375 163 208 Expected return on plan assets (5,229) (5,526) (2,216) (1,852) Amortization of net actuarial losses (gains) 1,403 1,580 (425) (196) Amortization of prior service cost (credit) (60) (62) 53 13 Cost of settlements 4,732 6,520 — — Net periodic benefit cost (benefit) $ 5,548 $ 7,735 $ (2,048) $ (1,511) Components of net periodic benefit cost Table 10.2 Nine Months Ended September 30, Pension and Supplemental Executive Retirement Plans Other Postretirement Benefit Plans (In thousands) 2021 2020 2021 2020 Service cost $ 5,724 $ 5,545 $ 1,131 $ 947 Interest cost 8,383 10,125 487 624 Expected return on plan assets (15,687) (16,579) (6,647) (5,556) Amortization of net actuarial losses (gains) 4,208 4,740 (1,273) (587) Amortization of prior service cost (credit) (179) (186) 159 38 Cost of settlements 4,732 6,520 — — Net periodic benefit cost (benefit) $ 7,181 $ 10,165 $ (6,143) $ (4,534) Contributions of $6.9 million have been made to our qualified pension and supplemental executive retirement plan in 2021. We recorded pension settlement accounting charges of $4.7 million and $6.5 million in 2021 and 2020, respectively.

Loss Reserves

Loss Reserves	9 Months Ended
	Sep. 30, 2021
Insurance Loss Reserves [Abstract]
Loss Reserves	Loss Reserves We establish case reserves and loss adjustment expenses (“LAE”) reserves on delinquent loans that were reported to us as two payments past due and have not become current or resulted in a claim payment. Such loans are referred to as being in our delinquency inventory. Case reserves are established by estimating the number of loans in our delinquency inventory that will result in a claim payment, which is referred to as the claim rate, and further estimating the amount of the claim payment, which is referred to as claim severity. IBNR reserves are established for estimated losses from delinquencies we estimate have occurred prior to the close of an accounting period but have not yet been reported to us. IBNR reserves are also established using estimated claim rates and claim severities. Estimation of losses is inherently judgmental. The conditions that affect the claim rate and claim severity include the current and future state of the domestic economy, including unemployment and the current and future strength of local housing markets; exposure on insured loans; the amount of time between delinquency and claim filing (all else being equal, the longer the period between delinquency and claim filing, the greater the severity); and curtailments and rescissions. The actual amount of the claim payments may be substantially different than our loss reserve estimates. Our estimates could be adversely affected by several factors, including a deterioration of regional or national economic conditions, including unemployment and the continued impact of the COVID-19 pandemic, leading to a reduction in borrowers’ income and thus their ability to make mortgage payments, the impact of past and future government initiatives and actions taken by the GSEs (including mortgage forbearance programs and foreclosure moratoriums), and a drop in housing values which may affect borrower willingness to continue to make mortgage payments when the value of the home is below the mortgage balance. Loss reserves in future periods will also be dependent on the number of loans reported to us as delinquent. Changes to our estimates could result in a material impact to our consolidated results of operations and financial position, even in a stable economic environment. It is reasonably possible that given the uncertainty of the impacts of the COVID-19 pandemic, our reserve estimate may continue to be impacted. In considering the potential sensitivity of the factors underlying our estimate of loss reserves, it is possible that even a relatively small change in our estimated claim rate or severity could have a material impact on loss reserves and, correspondingly, on our consolidated results of operations even in a stable economic environment. For example, as of September 30, 2021, assuming all other factors remain constant, a $1,000 increase/decrease in the average severity reserve factor would change the loss reserve amount by approximately +/- $17 million. A one percentage point increase/decrease in the average claim rate reserve factor would change the loss reserve amount by approximately +/- $22 million. The “Losses incurred” section of table 11.1 below shows losses incurred on delinquencies that occurred in the current year and in prior years. The amount of losses incurred relating to delinquencies that occurred in the current year represents the estimated amount to be ultimately paid on such delinquencies. The amount of losses incurred relating to delinquencies that occurred in prior years represents the difference between the actual claim rate and severity associated with those delinquencies resolved in the current year compared to the estimated claim rate and severity at the prior year-end, as well as a re-estimation of amounts to be ultimately paid on delinquencies continuing from the end of the prior year. This re-estimation of the claim rate and severity is the result of our review of current trends in the delinquency inventory, such as percentages of delinquencies that have resulted in a claim, the amount of the claims relative to the average loan exposure, changes in the relative level of delinquencies by geography and changes in average loan exposure. Losses incurred on delinquencies that occurred in the current year decreased in the first nine months of 2021 compared to the same period last year primarily due to a decrease in new delinquency notices reported. In addition, we decreased IBNR reserve estimates by $5.9 million in the nine months ending September 30, 2021, compared to a $12.6 million increase in the nine months ending September 30, 2020. New delinquency notices and IBNR reserve estimates increased in the nine months ended September 30, 2020 due to the impact of the COVID-19 pandemic. Given the uncertainty surrounding the long-term impact of COVID-19, it is difficult to predict the ultimate effect of the COVID-19 related delinquencies and forbearances on our loss incidence. For the nine months ended September 30, 2021 we experienced favorable loss development of $6.0 million on previously received notices primarily due to the decrease in the claim rate on pre-COVID-19 delinquencies. This was offset by the recognition of a probable loss of $6.3 million related to litigation of our claims paying practices and adverse development on LAE reserves and reinsurance. For the nine months ended September 30, 2020 we experienced adverse loss development of $17.3 million on previously received delinquencies primarily related to severity. The “Losses paid” section of table 11.1 below shows the amount of losses paid on delinquencies that occurred in the current year and losses paid on delinquencies that occurred in prior years. In light of the uncertainty caused by the COVID-19 pandemic, specifically the foreclosure moratoriums and forbearance plans, we expect the average time it takes to receive a claim will increase. Table 11.1 provides a reconciliation of beginning and ending loss reserves as of and for the nine months ended September 30, 2021 and 2020. Development of reserves for losses and loss adjustment expenses Table 11.1 Nine Months Ended September 30, (In thousands) 2021 2020 Reserve at beginning of period $ 880,537 $ 555,334 Less reinsurance recoverable 95,042 21,641 Net reserve at beginning of period 785,495 533,693 Losses incurred: Losses and LAE incurred in respect of delinquency notices received in: Current year 95,534 301,699 Prior years (1) (5,968) 17,317 Total losses incurred 89,566 319,016 Losses paid: Losses and LAE paid in respect of delinquency notices received in: Current year 339 1,486 Prior years 48,842 93,937 Reinsurance terminations — (20) Total losses paid 49,181 95,403 Net reserve at end of period 825,880 757,306 Plus reinsurance recoverables 107,029 83,143 Reserve at end of period $ 932,909 $ 840,449 (1) A positive number for prior year loss development indicates a deficiency of prior year reserves. A negative number for prior year loss development indicates a redundancy of prior year loss reserves. See the following table for more information about prior year loss development. The prior year development of the reserves in the first nine months of 2021 and 2020 is reflected in table 11.2 below. Reserve development on previously received delinquencies Table 11.2 Nine Months Ended September 30, (In thousands) 2021 2020 Increase (decrease) in estimated claim rate on primary defaults $ (18,147) $ (1,626) Increase (decrease) in estimated severity on primary defaults (105) 13,503 Change in estimates related to pool reserves, LAE reserves, reinsurance, and other 12,284 5,440 Total prior year loss development (1) $ (5,968) $ 17,317 (1) A positive number for prior year loss development indicates a deficiency of prior year loss reserves. A negative number for prior year loss development indicates a redundancy of prior year loss reserves. Delinquency inventory A rollforward of our primary delinquency inventory for the three and nine months ended September 30, 2021 and 2020 appears in table 11.3 below. The information concerning new notices and cures is compiled from monthly reports received from loan servicers. The level of new notice and cure activity reported in a particular month can be influenced by, among other things, the date on which a servicer generates its report, the number of business days in a month and transfers of servicing between loan servicers. Delinquency inventory rollforward Table 11.3 Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Delinquency inventory at beginning of period 42,999 69,326 57,710 30,028 New notices 9,862 20,924 31,909 90,906 Cures (14,813) (25,446) (50,901) (54,523) Paid claims (298) (375) (956) (1,933) Rescissions and denials (11) (11) (23) (60) Other items removed from inventory (360) — (360) — Delinquency inventory at end of period 37,379 64,418 37,379 64,418 During the three and nine months ended September 30, 2021, our losses paid included amounts paid upon commutation of coverage of pools of non-performing loans (“NPLs”). As a result of these payments, 360 items were removed from the delinquency inventory with an amount paid of $6.7 million. COVID-19 Activity Our delinquency inventory increased beginning in the second quarter of 2020 because of the impacts of the COVID-19 pandemic, including the high level of unemployment and economic uncertainty resulting from measures to reduce the transmission of COVID-19. Starting in the third quarter of 2020, we experienced an increase in cures associated with our COVID-19 new delinquency notices. Government initiatives and actions taken by the GSEs provide for payment forbearance on mortgages to borrowers experiencing hardship during the COVID-19 pandemic. These forbearance plans generally allow for mortgage payments to be suspended for up to 18 months: an initial forbearance period of up to six months; if requested by the borrower, an extension of up to six months; and, for loans in a COVID-19 forbearance plan as of February 28, 2021, an additional extension up to six months, subject to certain limits. Table 11.4 below shows the number of consecutive months a borrower is delinquent. Historically as a delinquency ages it is more likely to result in a claim. Primary delinquency inventory - consecutive months delinquent Table 11.4 September 30, 2021 December 31, 2020 September 30, 2020 3 months or less 6,948 11,542 15,879 4-11 months 9,371 34,620 37,702 12 months or more (1) 21,060 11,548 10,837 Total 37,379 57,710 64,418 3 months or less 19 % 20 % 25 % 4-11 months 25 % 60 % 58 % 12 months or more 56 % 20 % 17 % Total 100 % 100 % 100 % Primary claims received inventory included in ending delinquent inventory 154 159 172 (1) Approximately 17%, 31% , and 32% of the primary delinquency inventory delinquent for 12 consecutive months or more has been delinquent for at least 36 consecutive months as of September 30, 2021, December 31, 2020, and September 30, 2020, respectively. The increase in delinquency inventory that is 12 months or more consecutive months delinquent compared to September 30, 2020 and December 31, 2020 is primarily due to the number of new delinquency notices received in the second quarter of 2020 resulting from the impacts of the COVID-19 pandemic. This was partially offset by an increase in cures in the second half of 2020 and in the first nine months of 2021. Premium refunds

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2021
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Change in Accounting Policy As of January 1, 2021, we adopted the updated guidance for "A ccounting for Convertible Instruments and Contracts in an Entity’s Own Equity”. The application of this guidance resulted in a $68.3 million cumulative effect adjustment to our 2021 beginning retained earnings and paid in capital to reflect the 9% Debenture as if we had always accounted for the debt as a liability in its entirety. Share repurchase programs Repurchases of our common stock may be made from time to time on the open market (including through 10b5-1 plans) or through privately negotiated transactions. In 2020, we repurchased approximately 9.6 million shares of our common stock, at an average cost of $12.47 per share, which included commissions. After suspending stock repurchases due to the uncertainty caused by the COVID-19 pandemic, in the third quarter of 2021, we repurchased approximately 10.0 million shares at an average cost of $15.01 per share, which included commissions. At September 30, 2021 we had $141 million remaining under a share repurchase program approved by our Board of Directors in 2020. In October 2021, we received authorization to repurchase an additional $500 million of our common stock through the end of 2023. In October 2021, we repurchased an additional 3.8 million shares totaling $60 million under the remaining authorization that expires at year end 2021. Cash dividends In March and May of 2021, we paid quarterly cash dividends of $0.06 per share to shareholders which totaled $41.1 million. In August 2021, we paid a quarterly cash dividend of $0.08 per share which totaled $27.3 million. On October 28, 2021, the Board of Directors declared a quarterly cash dividend to holders of the company’s common stock of $0.08 per share payable on November 23, 2021, to shareholders of record at the close of business on November 11, 2021.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation We have certain share-based compensation plans. Under the fair value method, compensation cost is measured at the grant date based on the fair value of the award and is recognized over the service period which generally corresponds to the vesting period. Awards under our plans generally vest over periods ranging from one Table 13.1 shows the number of restricted stock units (RSUs) granted to employees and the weighted average fair value per share during the periods presented (shares in thousands). Restricted stock unit grants Table 13.1 Nine months ended September 30, 2021 2020 RSUs Granted (in thousands) Weighted Average Share Fair Value RSUs Granted (in thousands) Weighted Average Share Fair Value RSUs subject to performance conditions 966 $ 12.82 1,282 $ 12.87 RSUs subject only to service conditions 398 12.82 390 12.91

Statutory Information

Statutory Information	3 Months Ended
	Sep. 30, 2021
Statutory Capital [Abstract]
Insurance Disclosure	Statutory InformationStatutory Capital Requirements The insurance laws of 16 jurisdictions, including Wisconsin, our domiciliary state, require a mortgage insurer to maintain a minimum amount of statutory capital relative to the RIF (or a similar measure) in order for the mortgage insurer to continue to write new business. We refer to these requirements as the “State Capital Requirements” and, together with the GSE Financial Requirements, the “Financial Requirements.” While they vary among jurisdictions, the most common State Capital Requirements allow for a maximum risk-to-capital ratio of 25 to 1. A risk-to-capital ratio will increase if (i) the percentage decrease in capital exceeds the percentage decrease in insured risk, or (ii) the percentage increase in capital is less than the percentage increase in insured risk. Wisconsin does not regulate capital by using a risk-to-capital measure but instead requires a minimum policyholder position (“MPP”). The “policyholder position” of a mortgage insurer is its net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums. At September 30, 2021, MGIC’s risk-to-capital ratio was 9.0 to 1, below the maximum allowed by the jurisdictions with State Capital Requirements, and its policyholder position was $3.6 billion above the required MPP of $1.8 billion. The calculation of our risk-to-capital ratio and MPP reflect credit for the risk ceded under our reinsurance transactions. It is possible that MGIC will not be allowed full credit for the risk ceded to the reinsurers. If MGIC is not allowed an agreed level of credit under either the State Capital Requirements or the financial requirements of the PMIERs, MGIC may terminate the reinsurance transactions, without penalty. At September 30, 2021, the risk-to-capital ratio of our combined insurance operations was 9.0 to 1. Dividend restrictions In the third quarter of 2021, MGIC paid a dividend of $150 million to our holding company. MGIC is subject to statutory regulations as to payment of dividends. The maximum amount of dividends that MGIC may pay in any twelve-month period without regulatory approval by the OCI is the lesser of adjusted statutory net income or 10% of statutory ‘policyholders’ surplus as of the preceding calendar year end. Adjusted statutory net income is defined for this purpose to be the greater of statutory net income, net of realized investment gains, for the calendar year preceding the date of the dividend or statutory net income, net of realized investment gains, for the three calendar years preceding the date of the dividend less dividends paid within the first two of the preceding three calendar years. Before making any dividend payments, we will notify the OCI to ensure it does not object. Under the PMIERs guidance, any dividend paid by MGIC to our holding company, through December 31, 2021 requires GSE approval if MGIC's excess of Available Assets is or would become less than 15% of its Minimum Required Assets. GSE approval was not required for the 2021 dividend. The OCI recognizes only statutory accounting principles prescribed, or practices permitted by the State of Wisconsin for determining and reporting the financial condition and results of operations of an insurance company. The OCI has adopted certain prescribed accounting practices that differ from those found in other states. Specifically, Wisconsin domiciled companies record changes in their contingency reserves through their income statement as a change in underwriting deduction. As a result, in periods in which MGIC is increasing contingency reserves, statutory net income is reduced. Statutory Financial Information The statutory net income, policyholders’ surplus, and contingency reserve liability of our insurance subsidiaries, which agrees to amounts utilized in our risk-to-capital calculations, are shown in table 14.1. Financial information of our insurance subsidiaries Table 14.1 As of and for the Nine Months Ended September 30, (In thousands) 2021 2020 Statutory net income $ 194,614 $ 28,954 Statutory policyholders' surplus 1,354,268 1,313,952 Contingency reserve 3,987,786 3,409,778

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Standards Update and Change in Accounting Principle [Abstract]
Prospective Accounting Standards	Recent accounting and reporting developments Accounting standards effective in 2021, or early adopted, and relevant to our financial statements are described below: Simplifying the Accounting for Income Taxes: ASU 2019-12 Effective January 1, 2021, we adopted FASB guidance which simplifies Accounting for Income Taxes (Topic 740) by removing certain exceptions to Topic 740. The adoption of this guidance did not have a material impact on our consolidated financial statements. Clarification of Accounting for Equity Securities: ASU 2020-01 Effective January 1, 2021, we adopted ASU 2020-01, which clarifies certain interactions of accounting for equity securities under Topic 321, accounting for equity securities under the equity method of accounting in Topic 323, and accounting for certain forward contracts and purchased options in Topic 815. The amendment clarifies the consideration of observable transactions before applying or discounting the equity method of accounting. The adoption of this guidance did not have a material impact on our consolidated financial statements. Codification Improvements to Subtopic 310-20, Receivables - Nonrefundable Fees and Other Costs: ASU 2020-08 Effective January 1, 2021, we adopted Accounting Standards Update No. 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. FASB standard 2017-08 shortened the amortization period for certain purchased callable debt securities held at a premium by requiring that an entity amortize the premium associated with those callable debt securities within the scope of paragraph 310-20-25-33 to the earliest call date and clarified the FASB’s intent that an entity should reevaluate whether a callable debt security that has multiple call dates is within the scope of paragraph 310-20-35-33 for each reporting period. This guidance clarified that the issuer of a callable debt security should use the next call date versus the earliest call date in amortizing premium. The adoption of this guidance did not have a material impact on our consolidated financial statements. Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity: ASU 2020-06 Effective January 1, 2021, we adopted ASU 2020-06 using a modified retrospective basis. ASU 2020-06 simplifies the accounting for certain financial instruments with characteristics of liabilities and equity. It also includes amendments to EPS guidance. The updated guidance reduced the number of accounting models for convertible debt instruments and convertible preferred stock, and eliminated the cash conversion feature within ASU 470. As a result of these changes, more convertible instruments will be reported as a single unit on the balance sheet. We previously accounted for our 9% Debentures under the cash conversion feature, which required us to account for the conversion features of our 9% Debentures within Paid-in Capital. The adoption of this guidance resulted in a $68.3 million cumulative effect adjustment to our 2021 beginning Retained Earnings and Paid-in Capital to reflect the 9% Debentures as if we had always accounted for them as a liability in their entirety. The updated guidance also includes updates to the EPS calculation. It requires an entity to use the if-converted method, assume share settlement when settlement can be in cash or in shares, use an average market price for the period if the number of shares is based on an entity’s share price, and use the weighted average shares from each quarter to calculate the year to date weighted average shares. The guidance also includes improvements to the disclosures for convertible instruments and EPS. The adoption of this guidance did not have a material impact on our consolidated financial statement disclosures. Reference Rate Reform: ASU 2020-04 In March 2020, the FASB issued ASU 2020-04 to provide temporary optional guidance to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform. It provides optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. This standard may be elected and applied prospectively over time from March 12, 2020 through December 31, 2022 as reference rate reform activities occur. The adoption of, and future elections under, this standard are not expected to have a material impact on our consolidated financial statements as the standard will ease, if warranted, the requirements for accounting for the future effects of reference rate reform. We continue to monitor the impact the discontinuance of LIBOR or other reference rates will have on our contracts and other transactions.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Long-term debt	The aggregate carrying values of our long-term debt obligations and their par values, if different, as of September 30, 2021 and December 31, 2020 are presented in table 3.1 below. Long-term debt obligations Table 3.1 (In millions) September 30, 2021 December 31, 2020 FHLB Advance - 1.91%, due February 2023 $ 155.0 $ 155.0 5.75% Notes, due August 2023 (par value: $242.3 million) 241.1 240.6 5.25% Notes, due August 2028 (par value: $650 million) 639.9 638.8 9% Debentures, due April 2063 (1) 208.8 208.8 Long-term debt, carrying value $ 1,244.8 $ 1,243.2 (1) Convertible at any time prior to maturity at the holder’s option, at a conversion rate, which is subject to adjustment, of 75.5932 shares per $1,000 principal amount, representing a conversion price of approximately $13.23 per share. The payment of dividends by our holding company results in adjustments to the conversion rate, with such adjustment generally deferred until the end of the year.

Reinsurance (Tables)

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2021
Reinsurance Disclosures [Abstract]
Effect of reinsurance agreement	The effect of all of our reinsurance agreements on premiums earned and losses incurred is shown in table 4.1 below. Reinsurance Table 4.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Premiums earned: Direct $ 287,223 $ 300,557 $ 876,541 $ 896,346 Assumed 2,660 2,729 7,551 8,719 Ceded (1) (35,039) (47,173) (122,664) (144,489) Net premiums earned $ 254,844 $ 256,113 $ 761,428 $ 760,576 Losses incurred: Direct $ 17,265 $ 61,164 $ 103,319 $ 383,950 Assumed (97) 229 (43) 528 Ceded 3,598 (20,707) (13,710) (65,462) Losses incurred, net $ 20,766 $ 40,686 $ 89,566 $ 319,016 (1) Ceded premiums earned net of profit commission
Schedule Of Quota Share Reinsurance Agreements	Table 4.2 below provides additional detail regarding our QSR Transactions. Reinsurance Table 4.2 Quota Share Contract Covered Policy Years Quota Share % Annual Loss Ratio to Exhaust Profit Commission (1) Contractual Termination Date 2015 QSR Prior to 2017 15.0 % 68.0 % December 31, 2031 2017 QSR 2017 30.0 % 60.0 % December 31, 2028 2018 QSR 2018 30.0 % 62.0 % December 31, 2029 2019 QSR 2019 30.0 % 62.0 % December 31, 2030 2020 QSR 2020 12.5 % 62.0 % December 31, 2031 2020 QSR and 2021 QSR 2020 - 2021 17.5 % 62.0 % December 31, 2032 2021 QSR 2021 12.5 % 57.5 % December 31, 2032 2022 QSR 2022 15.0 % 57.5 % December 31, 2033 Credit Union QSR (2) 2020-2025 65.0 % 50.0 % December 31, 2039 (1) We will receive a profit commission provided the annual loss ratio on policies covered under the transaction remains below this ratio. (2) Eligible credit union business written before April 1, 2020 was covered by our 2019 and prior QSR Transactions. Table 4.3 provides additional detail regarding optional termination dates and optional reductions to our quota share percentage which can, in each case, be elected by us for a fee. The optional reduction to the quota share percentage would give us an option to reduce our quota share percentage from the original percentage shown in table 4.2 to the percentage shown in table 4.3. Reinsurance Table 4.3 Quota Share Contract Optional Termination Date (1) Optional Quota Share % Reduction Date (2) Quota Share % Reduction 2015 QSR June 30, 2021 NA NA 2017 QSR December 31, 2021 NA NA 2018 QSR December 31, 2021 NA NA 2019 QSR December 31, 2021 July 1, 2020 25% or 20% 2020 QSR December 31, 2022 July 1, 2021 10.5% or 8% 2020 QSR and 2021 QSR, 2020 Policy year December 31, 2022 July 1, 2021 14.5% or 12% 2020 QSR and 2021 QSR, 2021 Policy year December 31, 2023 July 1, 2022 14.5% or 12% 2021 QSR December 31, 2023 July 1, 2022 10.5% or 8% 2022 QSR December 31, 2024 July 1, 2023 12.5% or 10% (1) We can elect early termination of the QSR Transaction beginning on this date, and bi-annually thereafter for the 2015 QSR, 2019 QSR, 2020 QSR, 2021 QSR, and 2022 QSR. Early termination of the 2018 QSR can be elected on this date and annually thereafter. (2)
Effect of quota share reinsurance agreements on premiums earned and losses incurred	Table 4.4 below provides a summary of our QSR Transactions, excluding captive agreements, for the three and nine months ended September 30, 2021 and 2020. Quota Share Reinsurance Table 4.4 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Ceded premiums written and earned, net of profit commission $ 22,911 $ 43,448 $ 90,284 $ 131,651 Ceded losses incurred (3,598) 20,707 13,710 65,493 Ceding commissions (1) 13,599 12,128 39,657 35,518 Profit commission 45,078 17,191 108,000 45,939 (1) Ceding commissions are reported within Other underwriting and operating expenses, net on the consolidated statements of operations.
Schedule of coverages and retention	Table 4.5 provides a summary of our Home Re Transactions as of September 30, 2021 and December 31, 2020. Excess of Loss Reinsurance Table 4.5 ($ in thousands) Home Re 2021-2, Ltd. Home Re 2021-1, Ltd. Home Re 2020-1, Ltd. Home Re 2019-1, Ltd. Home Re 2018-1, Ltd. Issue Date August 3, 2021 February 2, 2021 October 29, 2020 May 25, 2019 October 30, 2018 Policy Inforce Dates January 1, 2021 - May 28, 2021 August 1, 2020 - December 31, 2020 January 1, 2020 - July 31, 2020 January 1, 2018 - March 31, 2019 July 1, 2016 - December 31, 2017 Optional Call Date (1) July 25, 2028 January 25, 2028 October 25, 2027 May 25, 2026 October 25, 2025 Legal Maturity 12.5 years 12.5 years 10 years 10 years 10 years Initial First Layer Retention 190,159 211,159 275,283 185,730 168,691 Initial Excess of Loss Reinsurance Coverage 398,429 398,848 412,917 315,739 318,636 September 30, 2021 Remaining First Layer Retention 190,159 211,159 275,268 184,007 165,434 Remaining Excess of Loss Reinsurance Coverage 398,429 398,848 288,777 208,146 218,343 December 31, 2020 Remaining First Layer Retention — — 275,283 184,514 166,005 Remaining Excess of Loss Reinsurance Coverage — — 412,917 208,146 218,343
Schedule of total assets of Home Re	Table 4.6 presents the total assets of the Home Re Entities as of September 30, 2021 and December 31, 2020. Home Re total assets Table 4.6 (In thousands) Home Re Entity (Issue date) Total VIE Assets September 30, 2021 Home Re 2018-1 Ltd. $ 218,343 Home Re 2019-1 Ltd. 208,146 Home Re 2020-1 Ltd. 312,199 Home Re 2021-1 Ltd. 398,848 Home Re 2021-2 Ltd. 398,429 December 31, 2020 Home Re 2018-1 Ltd. $ 218,343 Home Re 2019-1 Ltd. 208,146 Home Re 2020-1 Ltd. 412,917

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Calculation of earnings (loss) per share	Table 6.1 reconciles the numerators and denominators used to calculate basic and diluted EPS. Earnings per share Table 6.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share data) 2021 2020 2021 2020 Basic earnings per share: Net income $ 157,977 $ 130,811 $ 461,049 $ 294,663 Weighted average common shares outstanding - basic 335,938 338,598 338,045 340,408 Basic earnings per share $ 0.47 $ 0.39 $ 1.36 $ 0.87 Diluted earnings per share: Net income $ 157,977 $ 130,811 $ 461,049 $ 294,663 Interest expense, net of tax (1): 9% Debentures 3,712 4,161 11,135 13,293 Diluted income available to common shareholders $ 161,689 $ 134,972 $ 472,184 $ 307,956 Weighted average common shares outstanding - basic 335,938 338,598 338,045 340,408 Effect of dilutive securities: Unvested RSUs 1,834 1,377 1,651 1,492 9% Debentures 15,785 17,220 15,785 18,489 Weighted average common shares outstanding - diluted 353,557 357,195 355,481 360,389 Diluted earnings per share $ 0.46 $ 0.38 $ 1.33 $ 0.85 (1) Interest expense for the three and nine months ended September 30, 2021 and 2020, respectively, has been tax effected at a rate of 21%.

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
Investments [Abstract]
Amortized cost, gross unrealized gains and losses and fair value of fixed income securities	Our fixed income securities classified as available-for-sale at September 30, 2021 and December 31, 2020 are shown in tables 7.1a and 7.1b below. Details of fixed income securities by category as of September 30, 2021 Table 7.1a (In thousands) Amortized Cost Allowance for Expected Credit Loss Gross Unrealized Gains Gross Unrealized (Losses) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 184,578 $ — $ 434 $ (277) $ 184,735 Obligations of U.S. states and political subdivisions 2,372,020 — 146,149 (3,639) 2,514,530 Corporate debt securities 2,856,671 — 100,264 (8,438) 2,948,497 ABS 158,637 (1) 1,337 (198) 159,775 RMBS 337,353 — 3,581 (1,666) 339,268 CMBS 319,187 — 9,634 (628) 328,193 CLOs 408,121 — 913 (64) 408,970 Foreign government debt 13,748 — 58 (40) 13,766 Total fixed income securities $ 6,650,315 $ (1) $ 262,370 $ (14,950) $ 6,897,734 Details of fixed income securities by category as of December 31, 2020 Table 7.1b (In thousands) Amortized Cost Allowance for Expected Credit Losses Gross Unrealized Gains Gross Unrealized (Losses) (1) Fair Value U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 264,531 $ — $ 1,164 $ (2) $ 265,693 Obligations of U.S. states and political subdivisions 2,083,568 — 166,557 (256) 2,249,869 Corporate debt securities 2,690,860 — 155,156 (1,728) 2,844,288 ABS 203,807 (49) 2,946 (18) 206,686 RMBS 425,532 — 6,472 (838) 431,166 CMBS 312,572 — 16,055 (1,125) 327,502 CLOs 310,616 — 566 (692) 310,490 Foreign government debt 4,485 — 224 — 4,709 Commercial paper 21,193 — — — 21,193 Total fixed income securities $ 6,317,164 $ (49) $ 349,140 $ (4,659) $ 6,661,596
Amortized cost and fair values of fixed income securities by contractual maturity	The amortized cost and fair values of fixed income securities at September 30, 2021, by contractual maturity, are shown in table 7.2 below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most ABS, RMBS, CMBS, and CLOs provide for periodic payments throughout their lives, they are listed in separate categories. Fixed income securities maturity schedule Table 7.2 September 30, 2021 (In thousands) Amortized cost Fair Value Due in one year or less $ 415,090 $ 418,673 Due after one year through five years 1,856,136 1,919,980 Due after five years through ten years 1,666,042 1,757,537 Due after ten years 1,489,749 1,565,338 5,427,017 5,661,528 ABS 158,637 159,775 RMBS 337,353 339,268 CMBS 319,187 328,193 CLOs 408,121 408,970 Total as of September 30, 2021 $ 6,650,315 $ 6,897,734
Cost and fair value of investments in equity securities	The cost and fair value of investments in equity securities at September 30, 2021 and December 31, 2020 are shown in tables 7.3a and 7.3b below. Details of equity security investments as of September 30, 2021 Table 7.3a (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 14,981 $ 395 $ (15) $ 15,361 Details of equity security investments as of December 31, 2020 Table 7.3b (In thousands) Cost Gross Gains Gross Losses Fair Value Equity securities $ 17,522 $ 695 $ (2) $ 18,215
Aging of the fair values of securities in an unrealized loss position	Tables 7.4a and 7.4b below summarize, for all available-for-sale investments in an unrealized loss position at September 30, 2021 and December 31, 2020, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in tables 7.4a and 7.4b are estimated using the process described in Note 8 - “Fair Value Measurements” to these consolidated financial statements and in Note 3 - “Significant Accounting Policies” to the consolidated financial statements in our 2020 Annual Report on Form 10-K. Unrealized loss aging for securities by type and length of time as of September 30, 2021 Table 7.4a Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 88,312 $ (277) $ — $ — $ 88,312 $ (277) Obligations of U.S. states and political subdivisions 250,099 (3,479) 15,638 (160) 265,737 (3,639) Corporate debt securities 468,720 (8,438) — — 468,720 (8,438) ABS 58,901 (198) — — 58,901 (198) RMBS 174,094 (1,302) 26,733 (364) 200,827 (1,666) CMBS 82,653 (628) — — 82,653 (628) CLOs 127,483 (29) 21,974 (35) 149,457 (64) Foreign government debt 4,445 (40) — — 4,445 (40) Total $ 1,254,707 $ (14,391) $ 64,345 $ (559) $ 1,319,052 $ (14,950) Unrealized loss aging for securities by type and length of time as of December 31, 2020 Table 7.4b Less Than 12 Months 12 Months or Greater Total (In thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 2,690 $ (2) $ — $ — $ 2,690 $ (2) Obligations of U.S. states and political subdivisions 31,416 (256) — — 31,416 (256) Corporate debt securities 44,968 (1,728) — — 44,968 (1,728) ABS 14,929 (18) — — 14,929 (18) RMBS 98,409 (773) 3,566 (65) 101,975 (838) CMBS 13,212 (789) 2,799 (336) 16,011 (1,125) CLOs 95,287 (261) 73,904 (431) 169,191 (692) Total $ 300,911 $ (3,827) $ 80,269 $ (832) $ 381,180 $ (4,659)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair value measurements for items measured at fair value	Assets measured at fair value, by hierarchy level, as of September 30, 2021 and December 31, 2020 are shown in tables 8.1a and 8.1b below. The fair value of the assets is estimated using the process described above, and more fully in Note 3 - “Significant Accounting Policies” to the consolidated financial statements in our 2020 Annual Report on Form 10-K. Assets carried at fair value by hierarchy level as of September 30, 2021 Table 8.1a (In thousands) Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 184,735 $ 124,310 $ 60,425 $ — Obligations of U.S. states and political subdivisions 2,514,530 — 2,514,530 — Corporate debt securities 2,948,497 — 2,948,497 — ABS 159,775 — 159,775 — RMBS 339,268 — 339,268 — CMBS 328,193 — 328,193 — CLOs 408,970 — 408,970 — Foreign government debt 13,766 — 13,766 — Total fixed income securities 6,897,734 124,310 6,773,424 — Equity securities 15,361 15,361 — — Cash Equivalents 168,083 168,083 — — Real estate acquired (1) 1,485 — — 1,485 Total $ 7,082,663 $ 307,754 $ 6,773,424 $ 1,485 Assets carried at fair value by hierarchy level as of December 31, 2020 Table 8.1b (In thousands) Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) U.S. Treasury securities and obligations of U.S. government corporations and agencies $ 265,693 $ 149,339 $ 116,354 $ — Obligations of U.S. states and political subdivisions 2,249,869 — 2,249,869 — Corporate debt securities 2,844,288 — 2,844,288 — ABS 206,686 — 206,686 — RMBS 431,166 — 431,166 — CMBS 327,502 — 327,502 — CLOs 310,490 — 310,490 — Foreign government debt 4,709 — 4,709 — Commercial paper 21,193 — 21,193 — Total fixed income securities 6,661,596 149,339 6,512,257 — Equity securities 18,215 18,215 — — Cash Equivalents 288,941 275,668 13,273 — Real estate acquired (1) 1,092 — — 1,092 Total $ 6,969,844 $ 443,222 $ 6,525,530 $ 1,092 (1) Real estate acquired through claim settlement, which is held for sale, is reported in “Other assets” on the consolidated balance sheets.
Reconciliation of beginning and ending balance for assets and liabilities measured at fair value with significant unobservable inputs (level 3)	For assets measured at fair value using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances for the three and nine months ended September 30, 2021 and 2020 is shown in tables 8.2a and 8.2b below. There were no losses included in earnings for those periods attributable to the change in unrealized losses on assets still held at the end of the applicable period. Fair value roll-forward for financial instruments classified as Level 3 for the three months ended September 30, Table 8.2a Real Estate Acquired (In thousands) 2021 2020 Balance at June 30, $ 572 $ 1,963 Purchases 1,178 1,990 Sales (190) (2,266) Included in earnings and reported as losses incurred, net (75) 3 Balance at September 30, $ 1,485 $ 1,690 Fair value roll-forward for financial instruments classified as Level 3 for the nine months ended September 30, Table 8.2b Real Estate Acquired (In thousands) 2021 2020 Balance at December 31, $ 1,092 $ 7,252 Purchases 3,955 7,911 Sales (3,844) (13,991) Included in earnings and reported as losses incurred, net 282 518 Balance at September 30, $ 1,485 $ 1,690
Carrying value and fair value of financial assets and liabilities	Table 8.3 presents the carrying value and fair value of our financial assets and liabilities disclosed, but not carried, at fair value at September 30, 2021 and December 31, 2020. Financial assets and liabilities not measured at fair value Table 8.3 September 30, 2021 December 31, 2020 (In thousands) Carrying Value Fair Value Carrying Value Fair Value Financial assets Other invested assets $ 3,100 $ 3,100 $ 3,100 $ 3,100 Financial liabilities FHLB Advance 155,000 158,820 155,000 160,865 5.75% Senior Notes 241,090 260,349 240,597 261,752 5.25% Senior Notes 639,886 694,135 638,782 696,449 9% Convertible Junior Subordinated Debentures 208,814 279,696 208,814 273,569 Total financial liabilities $ 1,244,790 $ 1,393,000 $ 1,243,193 $ 1,392,635

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other comprehensive income	The pretax and related income tax benefit (expense) components of our other comprehensive income (loss) for the three and nine months ended September 30, 2021 and 2020 are included in table 9.1 below. Components of other comprehensive income (loss) Table 9.1 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Net unrealized investment (losses) gains arising during the period $ (34,937) $ 42,674 $ (97,057) $ 132,036 Total income tax benefit (expense) 7,337 (8,962) 20,382 (27,728) Net of taxes (27,600) 33,712 (76,675) 104,308 Net changes in benefit plan assets and obligations 7,548 (14,364) 9,492 (11,695) Total income tax benefit (expense) (1,585) 3,017 (1,993) 2,456 Net of taxes 5,963 (11,347) 7,499 (9,239) Total other comprehensive income (loss) (27,389) 28,310 (87,565) 120,341 Total income tax benefit (expense) 5,752 (5,945) 18,389 (25,272) Total other comprehensive income (loss), net of tax $ (21,637) $ 22,365 $ (69,176) $ 95,069
Reclassification out of accumulated other comprehensive income	The pretax and related income tax benefit (expense) components of the amounts reclassified from our accumulated other comprehensive income (loss) (“AOCI”) to our consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020 are included in table 9.2 below. Reclassifications from AOCI Table 9.2 Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2021 2020 2021 2020 Reclassification adjustment for net realized (losses) gains (1) $ 1,045 $ 10,349 $ 7,462 $ 8,673 Income tax benefit (expense) (219) (2,173) (1,566) (1,821) Net of taxes 826 8,176 5,896 6,852 Reclassification adjustment related to benefit plan assets and obligations (2) (971) (1,336) (2,915) (4,005) Income tax benefit (expense) 204 280 612 841 Net of taxes (767) (1,056) (2,303) (3,164) Total reclassifications 74 9,013 4,547 4,668 Income tax benefit (expense) (15) (1,893) (954) (980) Total reclassifications, net of tax $ 59 $ 7,120 $ 3,593 $ 3,688 (1) Increases (decreases) Net realized investment gains (losses) on the consolidated statements of operations. (2) Decreases (increases) Other underwriting and operating expenses, net on the consolidated statements of operations.
Accumulated other comprehensive income (loss)	A rollforward of AOCI for the nine months ended September 30, 2021, including amounts reclassified from AOCI, are included in table 9.3 below. Rollforward of AOCI Table 9.3 Nine Months Ended September 30, 2021 (In thousands) Net unrealized gains and (losses) on available-for-sale securities Net benefit plan assets and (obligations) recognized in shareholders' equity Total accumulated other comprehensive income (loss) Balance at December 31, 2020, net of tax $ 272,137 $ (55,316) $ 216,821 Other comprehensive income before reclassifications (70,779) 5,196 (65,583) Less: Amounts reclassified from AOCI 5,896 (2,303) 3,593 Balance, September 30, 2021, net of tax $ 195,462 $ (47,817) $ 147,645

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Components of net periodic benefit cost	Tables 10.1 and 10.2 provide the components of net periodic benefit cost for our pension, supplemental executive retirement and other postretirement benefit plans for the three and nine months ended September 30, 2021 and 2020. Components of net periodic benefit cost Table 10.1 Three Months Ended September 30, Pension and Supplemental Executive Retirement Plans Other Postretirement Benefit Plans (In thousands) 2021 2020 2021 2020 Service cost $ 1,908 $ 1,848 $ 377 $ 316 Interest cost 2,794 3,375 163 208 Expected return on plan assets (5,229) (5,526) (2,216) (1,852) Amortization of net actuarial losses (gains) 1,403 1,580 (425) (196) Amortization of prior service cost (credit) (60) (62) 53 13 Cost of settlements 4,732 6,520 — — Net periodic benefit cost (benefit) $ 5,548 $ 7,735 $ (2,048) $ (1,511) Components of net periodic benefit cost Table 10.2 Nine Months Ended September 30, Pension and Supplemental Executive Retirement Plans Other Postretirement Benefit Plans (In thousands) 2021 2020 2021 2020 Service cost $ 5,724 $ 5,545 $ 1,131 $ 947 Interest cost 8,383 10,125 487 624 Expected return on plan assets (15,687) (16,579) (6,647) (5,556) Amortization of net actuarial losses (gains) 4,208 4,740 (1,273) (587) Amortization of prior service cost (credit) (179) (186) 159 38 Cost of settlements 4,732 6,520 — — Net periodic benefit cost (benefit) $ 7,181 $ 10,165 $ (6,143) $ (4,534)

Loss Reserves (Tables)

Loss Reserves (Tables)	9 Months Ended
	Sep. 30, 2021
Insurance Loss Reserves [Abstract]
Reconciliation of beginning and ending loss reserves	Table 11.1 provides a reconciliation of beginning and ending loss reserves as of and for the nine months ended September 30, 2021 and 2020. Development of reserves for losses and loss adjustment expenses Table 11.1 Nine Months Ended September 30, (In thousands) 2021 2020 Reserve at beginning of period $ 880,537 $ 555,334 Less reinsurance recoverable 95,042 21,641 Net reserve at beginning of period 785,495 533,693 Losses incurred: Losses and LAE incurred in respect of delinquency notices received in: Current year 95,534 301,699 Prior years (1) (5,968) 17,317 Total losses incurred 89,566 319,016 Losses paid: Losses and LAE paid in respect of delinquency notices received in: Current year 339 1,486 Prior years 48,842 93,937 Reinsurance terminations — (20) Total losses paid 49,181 95,403 Net reserve at end of period 825,880 757,306 Plus reinsurance recoverables 107,029 83,143 Reserve at end of period $ 932,909 $ 840,449 (1) A positive number for prior year loss development indicates a deficiency of prior year reserves. A negative number for prior year loss development indicates a redundancy of prior year loss reserves. See the following table for more information about prior year loss development.
Prior year development of the reserves	The prior year development of the reserves in the first nine months of 2021 and 2020 is reflected in table 11.2 below. Reserve development on previously received delinquencies Table 11.2 Nine Months Ended September 30, (In thousands) 2021 2020 Increase (decrease) in estimated claim rate on primary defaults $ (18,147) $ (1,626) Increase (decrease) in estimated severity on primary defaults (105) 13,503 Change in estimates related to pool reserves, LAE reserves, reinsurance, and other 12,284 5,440 Total prior year loss development (1) $ (5,968) $ 17,317 (1) A positive number for prior year loss development indicates a deficiency of prior year loss reserves. A negative number for prior year loss development indicates a redundancy of prior year loss reserves.
Rollforward of primary delinquent inventory	A rollforward of our primary delinquency inventory for the three and nine months ended September 30, 2021 and 2020 appears in table 11.3 below. The information concerning new notices and cures is compiled from monthly reports received from loan servicers. The level of new notice and cure activity reported in a particular month can be influenced by, among other things, the date on which a servicer generates its report, the number of business days in a month and transfers of servicing between loan servicers. Delinquency inventory rollforward Table 11.3 Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 Delinquency inventory at beginning of period 42,999 69,326 57,710 30,028 New notices 9,862 20,924 31,909 90,906 Cures (14,813) (25,446) (50,901) (54,523) Paid claims (298) (375) (956) (1,933) Rescissions and denials (11) (11) (23) (60) Other items removed from inventory (360) — (360) — Delinquency inventory at end of period 37,379 64,418 37,379 64,418
Aging of the primary delinquent inventory	Table 11.4 below shows the number of consecutive months a borrower is delinquent. Historically as a delinquency ages it is more likely to result in a claim. Primary delinquency inventory - consecutive months delinquent Table 11.4 September 30, 2021 December 31, 2020 September 30, 2020 3 months or less 6,948 11,542 15,879 4-11 months 9,371 34,620 37,702 12 months or more (1) 21,060 11,548 10,837 Total 37,379 57,710 64,418 3 months or less 19 % 20 % 25 % 4-11 months 25 % 60 % 58 % 12 months or more 56 % 20 % 17 % Total 100 % 100 % 100 % Primary claims received inventory included in ending delinquent inventory 154 159 172 (1) Approximately 17%, 31% ,

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of stock-based compensation, activity	Table 13.1 shows the number of restricted stock units (RSUs) granted to employees and the weighted average fair value per share during the periods presented (shares in thousands). Restricted stock unit grants Table 13.1 Nine months ended September 30, 2021 2020 RSUs Granted (in thousands) Weighted Average Share Fair Value RSUs Granted (in thousands) Weighted Average Share Fair Value RSUs subject to performance conditions 966 $ 12.82 1,282 $ 12.87 RSUs subject only to service conditions 398 12.82 390 12.91

Statutory Information Statutory

Statutory Information Statutory Information (Tables)	9 Months Ended
	Sep. 30, 2021
Statutory Capital [Abstract]
Summary of amounts disclosed under statutory accounting practices	The statutory net income, policyholders’ surplus, and contingency reserve liability of our insurance subsidiaries, which agrees to amounts utilized in our risk-to-capital calculations, are shown in table 14.1. Financial information of our insurance subsidiaries Table 14.1 As of and for the Nine Months Ended September 30, (In thousands) 2021 2020 Statutory net income $ 194,614 $ 28,954 Statutory policyholders' surplus 1,354,268 1,313,952 Contingency reserve 3,987,786 3,409,778

Significant Accounting Polici_3

Significant Accounting Policies Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jan. 01, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 3,102,995		$ 2,642,096
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 68,300
Additional paid in capital		$ 68,300

Debt - Summary of Debt Obligati

Debt - Summary of Debt Obligations (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt, carrying value	$ 1,244,800,000	$ 1,243,200,000
Federal Home Loan Bank Advances (FHLB)
Debt Instrument [Line Items]
Long-term debt, carrying value	$ 155,000,000	155,000,000
Stated interest rate	1.91%
Senior Notes | 5.75% Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt, carrying value	$ 241,100,000	240,600,000
Stated interest rate	5.75%
Debt instrument, face amount	$ 242,300,000
Senior Notes | 5.25% Senior Notes Due 2028
Debt Instrument [Line Items]
Long-term debt, carrying value	$ 639,900,000	638,800,000
Stated interest rate	5.25%
Debt instrument, face amount	$ 650,000,000
9% Convertible Junior Subordinated Debentures
Debt Instrument [Line Items]
Long-term debt, carrying value	$ 208,800,000	$ 208,800,000
Stated interest rate	9.00%

Debt - Narrative (Details)

Debt - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)$ / shares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)$ / shares	Sep. 30, 2020USD ($)
Debt Instrument [Line Items]
Loss on debt extinguishment	$ 0	$ 26,736,000	$ 0	$ 26,736,000
Total interest payments			$ 60,000,000	$ 44,200,000
9% Convertible Junior Subordinated Debentures
Debt Instrument [Line Items]
Conversion rate (in shares per $1,000 note)			0.0755932
Principal amount of notes used in determining conversion rate	$ 1,000		$ 1,000
Convertible debt, conversion price (in dollars per share) | $ / shares	$ 13.23		$ 13.23
Stated interest rate	9.00%		9.00%
Senior Notes | 5.75% Senior Notes Due 2023
Debt Instrument [Line Items]
Stated interest rate	5.75%		5.75%
Senior Notes | 5.25% Senior Notes Due 2028
Debt Instrument [Line Items]
Stated interest rate	5.25%		5.25%

Reinsurance - Summary of Premiu

Reinsurance - Summary of Premiums Earned and Losses Incurred (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Premiums earned:
Direct	$ 287,223	$ 300,557	$ 876,541	$ 896,346
Assumed	2,660	2,729	7,551	8,719
Ceded	(35,039)	(47,173)	(122,664)	(144,489)
Net premiums earned	254,844	256,113	761,428	760,576
Losses incurred:
Direct	17,265	61,164	103,319	383,950
Assumed	(97)	229	(43)	528
Ceded	3,598	(20,707)	(13,710)	(65,462)
Losses incurred, net	$ 20,766	$ 40,686	$ 89,566	$ 319,016

Reinsurance - Narrative (Detail

Reinsurance - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Effects of Reinsurance [Line Items]
Reinsurance recoverable on loss reserves		$ 107,029	$ 83,143	$ 107,029	$ 83,143	$ 95,042	$ 21,641
Ceded premiums		$ 35,039	47,173	$ 122,664	144,489
Home Re special purpose insurers
Effects of Reinsurance [Line Items]
Percent of total trust assets invested in cash or direct U.S. federal government obligations				99.50%
Quota Share Reinsurance Agreements
Effects of Reinsurance [Line Items]
Ceding commission, percentage (as a percent)				20.00%
Reinsurance, Quota Share Reinsurance Agreement, Terms, Annual Loss Ratio Cap		300.00%		300.00%
Reinsurance, Quota Share Reinsurance Agreement, Terms, Lifetime Loss Ratio Cap		200.00%		200.00%
Threshold for private mortgage insurer eligibility requirements for termination election (less than) (as a percent)				90.00%
Reinsurance recoverable on loss reserves		$ 107,000		$ 107,000		$ 95,000
Quota Share Reinsurance Agreements | Subsequent Event
Effects of Reinsurance [Line Items]
Contingent termination fee	$ 5,000
Credit Union QSR
Effects of Reinsurance [Line Items]
Threshold for private mortgage insurer eligibility requirements for termination election (less than) (as a percent)				80.00%
Excess of Loss Reinsurance Agreement, Home Re
Effects of Reinsurance [Line Items]
Ceded premiums		$ 12,100	$ 3,700	$ 32,400	$ 12,800
Excess of Loss Reinsurance Agreement, Home Re | Minimum
Effects of Reinsurance [Line Items]
Amortization period excess of loss reinsurance coverage				10 years
Excess of Loss Reinsurance Agreement, Home Re | Maximum
Effects of Reinsurance [Line Items]
Amortization period excess of loss reinsurance coverage				12 years 6 months
Excess of Loss Reinsurance Agreement, Home Re | Financial Asset Equal To Or Greater Than 60 Days Past Due
Effects of Reinsurance [Line Items]
Percent of delinquent reinsured loans to total reinsured loans				4.00%

Reinsurance - Quota Share Agree

Reinsurance - Quota Share Agreement Terms (Details)	9 Months Ended
	Sep. 30, 2021
2015 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	15.00%
Loss ratio threshold for profit commissions (as a percent)	68.00%
2017 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	60.00%
2018 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	62.00%
2019 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	30.00%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	25.00%
Cede rate, option 2 (as a percent)	20.00%
2020 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	12.50%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	10.50%
Cede rate, option 2 (as a percent)	8.00%
2020 QSR and 2021 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	17.50%
Loss ratio threshold for profit commissions (as a percent)	62.00%
Cede rate, option 1 (as a percent)	14.50%
Cede rate, option 2 (as a percent)	12.00%
2021 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	12.50%
Loss ratio threshold for profit commissions (as a percent)	57.50%
Cede rate, option 1 (as a percent)	10.50%
Cede rate, option 2 (as a percent)	8.00%
2022 QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	15.00%
Loss ratio threshold for profit commissions (as a percent)	57.50%
Cede rate, option 1 (as a percent)	12.50%
Cede rate, option 2 (as a percent)	10.00%
Credit Union QSR
Effects of Reinsurance [Line Items]
Quota share for all policies covered (as a percent)	65.00%
Loss ratio threshold for profit commissions (as a percent)	50.00%

Reinsurance - Summary of Quota

Reinsurance - Summary of Quota Reinsurance Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Effects of Reinsurance [Line Items]
Ceded losses incurred	$ (3,598)	$ 20,707	$ 13,710	$ 65,462
Quota Share Reinsurance Agreements, Excluding Captive Agreements
Effects of Reinsurance [Line Items]
Ceded premiums written and earned, net of profit commission	22,911	43,448	90,284	131,651
Ceded losses incurred	(3,598)	20,707	13,710	65,493
Ceding commissions	13,599	12,128	39,657	35,518
Profit commission	$ 45,078	$ 17,191	$ 108,000	$ 45,939

Reinsurance - Excess of Loss Re

Reinsurance - Excess of Loss Reinsurance (Details) - USD ($) $ in Thousands	Aug. 03, 2021	Feb. 02, 2021	Oct. 29, 2020	May 25, 2019	Oct. 30, 2018	Sep. 30, 2021	Dec. 31, 2020
Home Re 2021-2
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes	12 years 6 months
Remaining First Layer Retention	$ 190,159					$ 190,159
Remaining Excess of Loss Reinsurance Coverage	$ 398,429					398,429
Home Re 2021-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes		12 years 6 months
Remaining First Layer Retention		$ 211,159				211,159
Remaining Excess of Loss Reinsurance Coverage		$ 398,848				398,848
Home Re 2020-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes			10 years
Remaining First Layer Retention			$ 275,283			275,268	$ 275,283
Remaining Excess of Loss Reinsurance Coverage			$ 412,917			288,777	412,917
Home Re 2019-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes				10 years
Remaining First Layer Retention				$ 185,730		184,007	184,514
Remaining Excess of Loss Reinsurance Coverage				$ 315,739		208,146	208,146
Home Re 2018-1
Effects of Reinsurance [Line Items]
Term of mortgage insurance-linked notes					10 years
Remaining First Layer Retention					$ 168,691	165,434	166,005
Remaining Excess of Loss Reinsurance Coverage					$ 318,636	$ 218,343	$ 218,343

Reinsurance - Variable Interest

Reinsurance - Variable Interest Entity (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Effects of Reinsurance [Line Items]
Assets	$ 7,511,309	$ 7,354,526
Home Re 2018-1
Effects of Reinsurance [Line Items]
Assets	218,343	218,343
Home Re 2019-1
Effects of Reinsurance [Line Items]
Assets	208,146	208,146
Home Re 2020-1
Effects of Reinsurance [Line Items]
Assets	312,199	$ 412,917
Home Re 2021-1
Effects of Reinsurance [Line Items]
Assets	398,848
Home Re 2021-2
Effects of Reinsurance [Line Items]
Assets	$ 398,429

Litigation and Contingencies (D

Litigation and Contingencies (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Average paid claim reduction due to curtailments (as a percent)	3.90%	3.60%
Probable loss contingency accrual			$ 6.3
Maximum exposure associated with other discussions and legal proceedings	$ 27

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic earnings per share:
Net income	$ 157,977	$ 130,811	$ 461,049	$ 294,663
Weighted average common shares outstanding - basic (in shares)	335,938	338,598	338,045	340,408
Basic earnings per share (in dollars per share)	$ 0.47	$ 0.39	$ 1.36	$ 0.87
Diluted earnings per share:
Net income	$ 157,977	$ 130,811	$ 461,049	$ 294,663
Diluted income available to common shareholders	$ 161,689	$ 134,972	$ 472,184	$ 307,956
Weighted average common shares outstanding - basic (in shares)	335,938	338,598	338,045	340,408
Effect of dilutive securities:
Weighted average common shares outstanding - diluted (in shares)	353,557	357,195	355,481	360,389
Diluted earnings per share (in dollars per share)	$ 0.46	$ 0.38	$ 1.33	$ 0.85
Federal statutory income tax rate (in hundredths)	21.00%	21.00%	21.00%	21.00%
9% Convertible Junior Subordinated Debentures
Diluted earnings per share:
Dilutive securities	$ 3,712	$ 4,161	$ 11,135	$ 13,293
Effect of dilutive securities:
Dilutive securities (in shares)	15,785	17,220	15,785	18,489
Stated interest rate	9.00%		9.00%
Unvested RSUs
Effect of dilutive securities:
Unvested RSUs (in shares)	1,834	1,377	1,651	1,492

Investments (Details)

Investments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)security	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)security	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)security
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 6,650,315		$ 6,650,315		$ 6,317,164
Fair Value	6,897,734		6,897,734		6,661,596
Assets held by insurance regulatory requirements	13,800		13,800		14,100
Assets held in trust for the benefit of contractual counterparties	187,500		$ 187,500		160,300
Collateral, market value to principal balance of FHLB (as a percent)			102.00%
FHLB advance, collateral pledged	$ 163,700		$ 163,700		$ 163,900
Number of securities in unrealized loss position (in securities) | security	396		396		109
Total fixed income securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 6,650,315		$ 6,650,315		$ 6,317,164
Allowance for Expected Credit Loss	(1)		(1)		(49)
Gross Unrealized Gains	262,370		262,370		349,140
Gross Unrealized Losses	(14,950)		(14,950)		(4,659)
Fair Value	6,897,734		6,897,734		6,661,596
Proceeds from sales of fixed income securities			246,800	$ 713,100
Gross realized gains, fixed income securities	1,400	$ 3,400	6,700	15,900
Gross realized losses, fixed income securities	(300)	(800)	(1,000)	(5,900)
Impairment charges recognized on securities with the intent to sell	0	$ (400)	0	$ (700)
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	184,578		184,578		264,531
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	434		434		1,164
Gross Unrealized Losses	(277)		(277)		(2)
Fair Value	184,735		184,735		265,693
Obligations of U.S. states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,372,020		2,372,020		2,083,568
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	146,149		146,149		166,557
Gross Unrealized Losses	(3,639)		(3,639)		(256)
Fair Value	2,514,530		2,514,530		2,249,869
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	2,856,671		2,856,671		2,690,860
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	100,264		100,264		155,156
Gross Unrealized Losses	(8,438)		(8,438)		(1,728)
Fair Value	2,948,497		2,948,497		2,844,288
ABS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	158,637		158,637		203,807
Allowance for Expected Credit Loss	(1)		(1)		(49)
Gross Unrealized Gains	1,337		1,337		2,946
Gross Unrealized Losses	(198)		(198)		(18)
Fair Value	159,775		159,775		206,686
RMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	337,353		337,353		425,532
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	3,581		3,581		6,472
Gross Unrealized Losses	(1,666)		(1,666)		(838)
Fair Value	339,268		339,268		431,166
CMBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	319,187		319,187		312,572
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	9,634		9,634		16,055
Gross Unrealized Losses	(628)		(628)		(1,125)
Fair Value	328,193		328,193		327,502
CLOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	408,121		408,121		310,616
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	913		913		566
Gross Unrealized Losses	(64)		(64)		(692)
Fair Value	408,970		408,970		310,490
Foreign government debt
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	13,748		13,748		4,485
Allowance for Expected Credit Loss	0		0		0
Gross Unrealized Gains	58		58		224
Gross Unrealized Losses	(40)		(40)		0
Fair Value	$ 13,766		$ 13,766		4,709
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost					21,193
Allowance for Expected Credit Loss					0
Gross Unrealized Gains					0
Gross Unrealized Losses					0
Fair Value					$ 21,193

Investments - Amortized Cost an

Investments - Amortized Cost and Fair Values of Debt Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Amortized cost
Due in one year or less	$ 415,090
Due after one year through five years	1,856,136
Due after five years through ten years	1,666,042
Due after ten years	1,489,749
Total debt securities with single maturity date, amortized cost	5,427,017
Amortized Cost	6,650,315	$ 6,317,164
Fair Value
Due in one year or less	418,673
Due after one year through five years	1,919,980
Due after five years through ten years	1,757,537
Due after ten years	1,565,338
Total debt securities with single maturity date, fair value	5,661,528
Total at end of period	6,897,734	6,661,596
ABS
Amortized cost
Total debt securities without single maturity date, amortized cost	158,637
Amortized Cost	158,637	203,807
Fair Value
Total debt securities without single maturity date, fair value	159,775
Total at end of period	159,775	206,686
RMBS
Amortized cost
Total debt securities without single maturity date, amortized cost	337,353
Amortized Cost	337,353	425,532
Fair Value
Total debt securities without single maturity date, fair value	339,268
Total at end of period	339,268	431,166
CMBS
Amortized cost
Total debt securities without single maturity date, amortized cost	319,187
Amortized Cost	319,187	312,572
Fair Value
Total debt securities without single maturity date, fair value	328,193
Total at end of period	328,193	327,502
CLOs
Amortized cost
Total debt securities without single maturity date, amortized cost	408,121
Amortized Cost	408,121	310,616
Fair Value
Total debt securities without single maturity date, fair value	408,970
Total at end of period	$ 408,970	$ 310,490

Investments - Equity Securities

Investments - Equity Securities (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
Equity Securities, FV-NI, Gain (Loss) [Abstract]
Cost	$ 14,981		$ 14,981		$ 17,522
Gross Gains			395		695
Gross Losses			(15)		(2)
Fair Value	15,361		15,361		$ 18,215
Unrealized Gain (Loss) on Equity Securities [Abstract]
Recognized net gains (losses) on equity securities still held	$ (100)	$ 100	$ (300)	$ 400

Investments - Securities In Unr

Investments - Securities In Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	$ 1,254,707	$ 300,911
12 Months or Greater - Fair Value	64,345	80,269
Total - Fair Value	1,319,052	381,180
Less Than 12 Months - Unrealized Losses	(14,391)	(3,827)
12 Months or Greater - Unrealized Losses	(559)	(832)
Total - Unrealized Losses	(14,950)	(4,659)
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	88,312	2,690
12 Months or Greater - Fair Value	0	0
Total - Fair Value	88,312	2,690
Less Than 12 Months - Unrealized Losses	(277)	(2)
12 Months or Greater - Unrealized Losses	0	0
Total - Unrealized Losses	(277)	(2)
Obligations of U.S. states and political subdivisions
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	250,099	31,416
12 Months or Greater - Fair Value	15,638	0
Total - Fair Value	265,737	31,416
Less Than 12 Months - Unrealized Losses	(3,479)	(256)
12 Months or Greater - Unrealized Losses	(160)	0
Total - Unrealized Losses	(3,639)	(256)
Corporate debt securities
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	468,720	44,968
12 Months or Greater - Fair Value	0	0
Total - Fair Value	468,720	44,968
Less Than 12 Months - Unrealized Losses	(8,438)	(1,728)
12 Months or Greater - Unrealized Losses	0	0
Total - Unrealized Losses	(8,438)	(1,728)
ABS
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	58,901	14,929
12 Months or Greater - Fair Value	0	0
Total - Fair Value	58,901	14,929
Less Than 12 Months - Unrealized Losses	(198)	(18)
12 Months or Greater - Unrealized Losses	0	0
Total - Unrealized Losses	(198)	(18)
RMBS
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	174,094	98,409
12 Months or Greater - Fair Value	26,733	3,566
Total - Fair Value	200,827	101,975
Less Than 12 Months - Unrealized Losses	(1,302)	(773)
12 Months or Greater - Unrealized Losses	(364)	(65)
Total - Unrealized Losses	(1,666)	(838)
CMBS
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	82,653	13,212
12 Months or Greater - Fair Value	0	2,799
Total - Fair Value	82,653	16,011
Less Than 12 Months - Unrealized Losses	(628)	(789)
12 Months or Greater - Unrealized Losses	0	(336)
Total - Unrealized Losses	(628)	(1,125)
CLOs
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	127,483	95,287
12 Months or Greater - Fair Value	21,974	73,904
Total - Fair Value	149,457	169,191
Less Than 12 Months - Unrealized Losses	(29)	(261)
12 Months or Greater - Unrealized Losses	(35)	(431)
Total - Unrealized Losses	(64)	$ (692)
Foreign government debt
Schedule of Investments [Line Items]
Less Than 12 Months - Fair Value	4,445
12 Months or Greater - Fair Value	0
Total - Fair Value	4,445
Less Than 12 Months - Unrealized Losses	(40)
12 Months or Greater - Unrealized Losses	0
Total - Unrealized Losses	$ (40)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 6,897,734	$ 6,661,596
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	15,361	18,215
Cash Equivalents	168,083	288,941
Real estate acquired	1,485	1,092
Total assets	7,082,663	6,969,844
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	168,083	275,668
Real estate acquired	0	0
Total assets	307,754	443,222
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	0	13,273
Real estate acquired	0	0
Total assets	6,773,424	6,525,530
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	0	0
Real estate acquired	1,485	1,092
Total assets	1,485	1,092
Total fixed income securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	6,897,734	6,661,596
Total fixed income securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	124,310	149,339
Total fixed income securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	6,773,424	6,512,257
Total fixed income securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	184,735	265,693
U.S. Treasury securities and obligations of U.S. government corporations and agencies | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	124,310	149,339
U.S. Treasury securities and obligations of U.S. government corporations and agencies | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	60,425	116,354
U.S. Treasury securities and obligations of U.S. government corporations and agencies | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Obligations of U.S. states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,514,530	2,249,869
Obligations of U.S. states and political subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Obligations of U.S. states and political subdivisions | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,514,530	2,249,869
Obligations of U.S. states and political subdivisions | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,948,497	2,844,288
Corporate debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Corporate debt securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2,948,497	2,844,288
Corporate debt securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
ABS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	159,775	206,686
ABS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
ABS | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	159,775	206,686
ABS | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
RMBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	339,268	431,166
RMBS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
RMBS | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	339,268	431,166
RMBS | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
CMBS
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	328,193	327,502
CMBS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
CMBS | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	328,193	327,502
CMBS | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
CLOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	408,970	310,490
CLOs | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
CLOs | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	408,970	310,490
CLOs | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Foreign government debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	13,766	4,709
Foreign government debt | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Foreign government debt | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	13,766	4,709
Foreign government debt | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		21,193
Commercial paper | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Commercial paper | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		21,193
Commercial paper | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	15,361	18,215
Equity securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	15,361	18,215
Equity securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	0	0
Equity securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value (cost 2021 - $14,981; 2020 - $17,522)	$ 0	$ 0

Fair Value Measurements - Unobs

Fair Value Measurements - Unobservable Input Reconciliation (Details) - Real Estate Acquired - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 572	$ 1,963	$ 1,092	$ 7,252
Purchases	1,178	1,990	3,955	7,911
Sales	(190)	(2,266)	(3,844)	(13,991)
Included in earnings and reported as losses incurred, net	(75)	3	282	518
Balance at end of period	$ 1,485	$ 1,690	$ 1,485	$ 1,690

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	$ 3,100	$ 3,100
FHLB Advance	155,000	155,000
9% Convertible Junior Subordinated Debentures	208,814	208,814
Total financial liabilities	1,244,790	1,243,193
Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	3,100	3,100
FHLB Advance	158,820	160,865
9% Convertible Junior Subordinated Debentures	279,696	273,569
Total financial liabilities	$ 1,393,000	1,392,635
Senior Notes | 5.75% Senior Notes Due 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.75%
Senior Notes | 5.75% Senior Notes Due 2023 | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	$ 241,090	240,597
Senior Notes | 5.75% Senior Notes Due 2023 | Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	$ 260,349	261,752
Senior Notes | 5.25% Senior Notes Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.25%
Senior Notes | 5.25% Senior Notes Due 2028 | Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	$ 639,886	638,782
Senior Notes | 5.25% Senior Notes Due 2028 | Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	$ 694,135	$ 696,449
9% Convertible Junior Subordinated Debentures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	9.00%

Other Comprehensive Income (Det

Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total other comprehensive income (loss)	$ (27,389)	$ 28,310	$ (87,565)	$ 120,341
Income tax benefit (expense)	5,752	(5,945)	18,389	(25,272)
Other comprehensive income (loss), net of tax	(21,637)	22,365	(69,176)	95,069
Amounts Reclassified From Accumulated Other Comprehensive Income [Abstract]
Income tax benefit (expense)	(41,755)	(33,518)	(122,168)	(74,388)
Total reclassifications, net of tax	157,977	130,811	461,049	294,663
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			4,698,986
Other comprehensive income before reclassifications			(65,583)
Less: Amounts reclassified from AOCI			3,593
Balance, end of period	4,877,420	4,513,622	4,877,420	4,513,622
Reclassification from Accumulated Other Comprehensive Income
Amounts Reclassified From Accumulated Other Comprehensive Income [Abstract]
Total reclassifications before tax	74	9,013	4,547	4,668
Income tax benefit (expense)	(15)	(1,893)	(954)	(980)
Total reclassifications, net of tax	59	7,120	3,593	3,688
Accumulated other comprehensive income (loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss), net of tax	(21,637)	22,365	(69,176)	95,069
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	169,282	145,412	216,821	72,708
Balance, end of period	147,645	167,777	147,645	167,777
Net unrealized gains and (losses) on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total other comprehensive income (loss)	(34,937)	42,674	(97,057)	132,036
Income tax benefit (expense)	7,337	(8,962)	20,382	(27,728)
Other comprehensive income (loss), net of tax	(27,600)	33,712	(76,675)	104,308
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			272,137
Other comprehensive income before reclassifications			(70,779)
Less: Amounts reclassified from AOCI			5,896
Balance, end of period	195,462		195,462
Net unrealized gains and (losses) on available-for-sale securities | Reclassification from Accumulated Other Comprehensive Income
Amounts Reclassified From Accumulated Other Comprehensive Income [Abstract]
Total reclassifications before tax	1,045	10,349	7,462	8,673
Income tax benefit (expense)	(219)	(2,173)	(1,566)	(1,821)
Total reclassifications, net of tax	826	8,176	5,896	6,852
Net benefit plan assets and (obligations) recognized in shareholders' equity
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total other comprehensive income (loss)	7,548	(14,364)	9,492	(11,695)
Income tax benefit (expense)	(1,585)	3,017	(1,993)	2,456
Other comprehensive income (loss), net of tax	5,963	(11,347)	7,499	(9,239)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period			(55,316)
Other comprehensive income before reclassifications			5,196
Less: Amounts reclassified from AOCI			(2,303)
Balance, end of period	(47,817)		(47,817)
Net benefit plan assets and (obligations) recognized in shareholders' equity | Reclassification from Accumulated Other Comprehensive Income
Amounts Reclassified From Accumulated Other Comprehensive Income [Abstract]
Total reclassifications before tax	(971)	(1,336)	(2,915)	(4,005)
Income tax benefit (expense)	204	280	612	841
Total reclassifications, net of tax	$ (767)	$ (1,056)	$ (2,303)	$ (3,164)

Benefit Plans (Details)

Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension and Supplemental Executive Retirement Plans
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 1,908	$ 1,848	$ 5,724	$ 5,545
Interest cost	2,794	3,375	8,383	10,125
Expected return on plan assets	(5,229)	(5,526)	(15,687)	(16,579)
Amortization of net actuarial losses (gains)	1,403	1,580	4,208	4,740
Amortization of prior service cost (credit)	(60)	(62)	(179)	(186)
Cost of settlements	4,732	6,520	4,732	6,520
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	5,548	7,735	7,181	10,165
Company contribution to pension and supplemental executive retirement plans			6,900
Other Postretirement Benefit Plans
Components of Net Periodic Benefit Cost [Abstract]
Service cost	377	316	1,131	947
Interest cost	163	208	487	624
Expected return on plan assets	(2,216)	(1,852)	(6,647)	(5,556)
Amortization of net actuarial losses (gains)	(425)	(196)	(1,273)	(587)
Amortization of prior service cost (credit)	53	13	159	38
Cost of settlements	0	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total	$ (2,048)	$ (1,511)	(6,143)	(4,534)
Pension Plan
Components of Net Periodic Benefit Cost [Abstract]
Cost of settlements			$ 4,700	$ 6,500

Loss Reserves (Details)

Loss Reserves (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021USD ($)loan	Sep. 30, 2020loan	Sep. 30, 2021USD ($)loan	Sep. 30, 2020USD ($)loan	Dec. 31, 2020USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves			$ 52,372	$ 285,115
Prior years			(5,968)	17,317
Prior years			$ 48,842	$ 93,937
Other items removed from default inventory | loan	360	0	360	0
Premium refund liability, expected claim payments	$ 37,300		$ 37,300		$ 30,100
Primary Delinquent Inventory [Roll Forward]
Delinquent inventory at the beginning of period (in loans) | loan	42,999	69,326	57,710	30,028
New notices (in loans) | loan	9,862	20,924	31,909	90,906
Cures (in loans) | loan	(14,813)	(25,446)	(50,901)	(54,523)
Paids (including those charged to a deductible or captive) (in loans) | loan	(298)	(375)	(956)	(1,933)
Rescissions and denials (in loans) | loan	(11)	(11)	(23)	(60)
Other items removed from inventory (in loans) | loan	(360)	0	(360)	0
Delinquent inventory at end of period (in loans) | loan	37,379	64,418	37,379	64,418
$1,000 Increase/Decrease In Average Severity Reserve Factor
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves			$ 17,000
One Percentage Point Increase/Decrease In Average Claim Rate Reserve Factor
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves			22,000
Change in estimates related to IBNR reserves
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves			(5,900)	$ 12,600
Probable loss on litigation claims paying practices
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			6,300
Increase (decrease) in estimated claim rate on primary defaults
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			(18,147)	(1,626)
Increase (decrease) in estimated severity on primary defaults
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			(105)	13,503
Change in estimates related to pool reserves, LAE reserves, reinsurance, and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			12,284	$ 5,440
Settlements for commutations of coverage of pools of nonperforming loans
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years	$ 6,700		$ 6,700

Loss Reserves - Reconciliation

Loss Reserves - Reconciliation of Beginning and Ending Balances (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Loss Reserve [Roll Forward]
Reserve at beginning of period	$ 880,537	$ 555,334
Less reinsurance recoverable	95,042	21,641
Net reserve at beginning of period	785,495	533,693
Losses and LAE incurred in respect of delinquency notices received in:
Current year	95,534	301,699
Prior years	(5,968)	17,317
Total losses incurred	89,566	319,016
Losses and LAE paid in respect of delinquency notices received in:
Current year	339	1,486
Prior years	48,842	93,937
Reinsurance terminations	0	(20)
Total losses paid	49,181	95,403
Net reserve at end of period	825,880	757,306
Plus reinsurance recoverables	107,029	83,143
Reserve at end of period	$ 932,909	$ 840,449

Loss Reserves - Delinquent Item

Loss Reserves - Delinquent Items (Details) - loan	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Aging of the Primary Delinquent Inventory [Abstract]
3 months or less (in loans)	6,948		11,542	15,879
4 - 11 months (in loans)	9,371		34,620	37,702
12 months or more (in loans)	21,060		11,548	10,837
Total primary delinquent inventory (in loans)	37,379	42,999	57,710	64,418	69,326	30,028
3 months or less (as a percent)	19.00%		20.00%	25.00%
4 - 11 months (as a percent)	25.00%		60.00%	58.00%
12 months or more (as a percent)	56.00%		20.00%	17.00%
Total primary delinquent inventory (as a percent)	100.00%		100.00%	100.00%
Primary claims received inventory included in ending delinquent inventory (in loans)	154		159	172
Percent of 12 months or more delinquent inventory, delinquent for more than 36 months (as a percent)	17.00%		31.00%	32.00%

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Oct. 28, 2021	Oct. 31, 2021	Aug. 31, 2021	Sep. 30, 2021	May 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jan. 01, 2021
Class of Stock [Line Items]
Retained earnings				$ 3,102,995		$ 3,102,995		$ 2,642,096
Shares repurchased in period (in shares)				10				9.6
Shares repurchased, weighted average price per share				$ 15.01				$ 12.47
Remaining authorized repurchase amount				$ 141,000		141,000
Repurchase of common stock						$ 150,000	$ 119,997
Quarterly cash dividend paid (per share)			$ 0.08		$ 0.06
Cash dividends			$ 27,300		$ 41,100
Cumulative Effect, Period of Adoption, Adjustment
Class of Stock [Line Items]
Retained earnings									$ 68,300
Additional paid in capital									$ 68,300
Subsequent Event
Class of Stock [Line Items]
Shares repurchased in period (in shares)		3.8
Stock repurchase program, authorized amount through 2023	$ 500,000
Repurchase of common stock		$ 60,000
Quarterly cash dividend declared (per share)	$ 0.08

Share-Based Compensation (Detai

Share-Based Compensation (Details) - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
RSUs subject to performance conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	966	1,282
Weighted Average Share Fair Value (in dollars per share)	$ 12.82	$ 12.87
RSUs subject only to service conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	398	390
Weighted Average Share Fair Value (in dollars per share)	$ 12.82	$ 12.91
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years

Statutory Information (Details)

Statutory Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2021	Sep. 30, 2021USD ($)jurisdiction	Sep. 30, 2021USD ($)jurisdiction
Statutory capital requirements [Abstract]
Number of jurisdictions with risk-to-capital requirements (in jurisdictions) | jurisdiction		16	16
Maximum permitted risk-to-capital ratio commonly applied			25 to 1
Risk to capital ratio of combined insurance operations at end of period			9.0 to 1
Risk-to-capital ratio for combined insurance operations		9	9
Forecast
Statutory capital requirements [Abstract]
Regulatory restrictions on payment of dividends, percentage of available assets exceeding minimum required assets	0.15
Mortgage Guaranty Insurance Corporation
Statutory capital requirements [Abstract]
Maximum risk-to-capital ratio			25
Risk to capital ratio at end of period			9.0 to 1
Risk-to-capital ratio		9	9
Amount of policyholders position above or below required MPP		$ 3,600	$ 3,600
Amount of required MPP		1,800	$ 1,800
Dividends paid to the parent company		$ 150
Percentage of statutory policyholders surplus used to determine maximum allowable dividends (as a percent)		10.00%	10.00%
Adjusted statutory net income measurement period (in years)			3 years
Adjusted statutory net income dividend payment measurement period (in years)			2 years

Statutory Information - Summary

Statutory Information - Summary of Amounts Disclosed Under Statutory Accounting Practices (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Statutory Capital [Abstract]
Statutory net income	$ 194,614	$ 28,954
Statutory policyholders' surplus	1,354,268	1,313,952
Contingency reserve	$ 3,987,786	$ 3,409,778

Uncategorized Items - mtg-20210

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2020-06 [Member]