NMI (NMIH) 10-Q 7 May 20 2020 Q1 Quarterly report Financial data

COVER PAGE

COVER PAGE - shares	3 Months Ended
	Mar. 31, 2020	May 04, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	001-36174
Entity Registrant Name	NMI Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4914248
Entity Address, Address Line One	2100 Powell Street
Entity Address, City or Town	Emeryville
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94608
City Area Code	855
Local Phone Number	530-6642
Title of 12(b) Security	Class A Common Stock, par value $0.01
Trading Symbol	NMIH
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		68,874,476
Entity Central Index Key	0001547903
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets
Fixed maturities, available-for-sale, at fair value (amortized cost of $1,059,143 and $1,113,779 as of March 31, 2020 and December 31, 2019, respectively)	$ 1,070,072	$ 1,140,940
Cash and cash equivalents (including restricted cash of $2,505 and $2,662 as of March 31, 2020 and December 31, 2019, respectively)	109,821	41,089
Premiums receivable	46,872	46,085
Accrued investment income	7,192	6,831
Prepaid expenses	4,750	3,512
Deferred policy acquisition costs, net	62,634	59,972
Software and equipment, net	25,667	26,096
Intangible assets and goodwill	3,634	3,634
Prepaid reinsurance premiums	13,100	15,488
Other assets	44,085	21,171
Total assets	1,387,827	1,364,818
Liabilities
Term loan	145,521	145,764
Unearned premiums	126,908	136,642
Accounts payable and accrued expenses	20,745	39,904
Reserve for insurance claims and claim expenses	29,479	23,752
Reinsurance funds withheld	12,735	14,310
Warrant liability, at fair value	1,461	7,641
Deferred tax liability, net	66,831	56,360
Other liabilities	9,257	10,025
Total liabilities	412,937	434,398
Commitments and contingencies
Shareholders' equity
Common stock - class A shares, $0.01 par value; 68,873,540 and 68,358,074 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively (250,000,000 shares authorized)	689	684
Additional paid-in capital	706,021	707,003
Accumulated other comprehensive income, net of tax	4,464	17,288
Retained earnings	263,716	205,445
Total shareholders' equity	974,890	930,420
Total liabilities and shareholders' equity	$ 1,387,827	$ 1,364,818

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities, available-for-sale, amortized cost	$ 1,059,143	$ 1,113,779
Restricted cash	$ 2,505	$ 2,662
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	68,873,540	68,358,074
Common stock, outstanding (in shares)	68,873,540	68,358,074
Common stock, authorized (in shares)	250,000,000	250,000,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenues
Net premiums earned	$ 98,717	$ 73,868
Net investment income	8,104	7,383
Net realized investment losses	(72)	(187)
Other revenues	900	42
Total revenues	107,649	81,106
Expenses
Insurance claims and claim expenses	5,697	2,743
Underwriting and operating expenses	32,277	30,800
Service expenses	734	49
Interest expense	2,744	3,061
(Gain) loss from change in fair value of warrant liability	(5,959)	5,479
Total expenses	35,493	42,132
Income before income taxes	72,156	38,974
Income tax expense	13,885	6,075
Net income	$ 58,271	$ 32,899
Earnings per share
Basic (in dollars per share)	$ 0.85	$ 0.49
Diluted (in dollars per share)	$ 0.74	$ 0.48
Weighted average common shares outstanding
Basic (in shares)	68,563	66,692
Diluted (in shares)	70,401	68,996
Comprehensive income:
Net income	$ 58,271	$ 32,899
Other comprehensive (loss) income, net of tax:
Unrealized (losses) gains in accumulated other comprehensive income, net of tax (benefit) expense of ($3,424) and $3,953 for the quarters ended March 31, 2020 and 2019, respectively	(12,881)	14,868
Reclassification adjustment for realized losses included in net income, net of tax (benefit) of ($15) and ($39) for the quarters ended March 31, 2020 and 2019, respectively	57	148
Other comprehensive (loss) income, net of tax	(12,824)	15,016
Comprehensive income	$ 45,447	$ 47,915

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net unrealized (losses) gains in accumulated other comprehensive income, tax (benefit) expense	$ (3,424)	$ 3,953
Reclassification adjustment for realized losses (gains) included in net income, tax expense (benefit)	$ (15)	$ (39)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock - Class A	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance at Dec. 31, 2018	$ 701,500	$ 663	$ 682,181	$ (14,832)	$ 33,488
Beginning balance (in shares) at Dec. 31, 2018		66,319,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock: class A shares issued related to warrant exercises	$ 944		944
Common stock: class A shares issued related to warrants (in shares)	39,195	39,000
Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes	$ (1,459)	$ 12	(1,471)
Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes (in shares)		1,144,000
Share-based compensation expense	2,981		2,981
Change in unrealized investment gains/losses, net of tax benefit/expense	15,016			15,016
Net income	32,899				32,899
Ending balance at Mar. 31, 2019	751,881	$ 675	684,635	184	66,387
Ending balance (in shares) at Mar. 31, 2019		67,502,000
Beginning balance at Dec. 31, 2019	930,420	$ 684	707,003	17,288	205,445
Beginning balance (in shares) at Dec. 31, 2019		68,358,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock: class A shares issued related to warrant exercises	$ 221		221
Common stock: class A shares issued related to warrants (in shares)	6,474	6,000
Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes	$ (3,750)	$ 5	(3,755)
Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes (in shares)		510,000
Share-based compensation expense	2,552		2,552
Change in unrealized investment gains/losses, net of tax benefit/expense	(12,824)			(12,824)
Net income	58,271				58,271
Ending balance at Mar. 31, 2020	$ 974,890	$ 689	$ 706,021	$ 4,464	$ 263,716
Ending balance (in shares) at Mar. 31, 2020		68,874,000

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Stockholders' Equity [Abstract]
Change in unrealized investment gains/losses, tax expense (benefit)	$ (3,409)	$ 3,992
Common stock: class A shares issued related to warrants (in shares)	6,474	39,195
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net income	$ 58,271	$ 32,899
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment losses	72	187
(Gain) loss from change in fair value of warrant liability	(5,959)	5,479
Depreciation and amortization	2,441	2,103
Net amortization of premium on investment securities	318	314
Amortization of debt discount and debt issuance costs	258	248
Deferred income taxes	13,880	6,038
Share-based compensation expense	2,552	2,981
Changes in operating assets and liabilities:
Premiums receivable	(787)	(2,472)
Accrued investment income	(361)	(859)
Prepaid expenses	(1,238)	(1,407)
Deferred policy acquisition costs, net	(2,662)	(1,980)
Other assets	(157)	191
Unearned premiums	(9,734)	(4,568)
Reserve for insurance claims and claim expenses	5,727	2,726
Reinsurance balances, net	(691)	(148)
Accounts payable and accrued expenses	(14,078)	(13,453)
Net cash provided by operating activities	47,852	28,279
Cash flows from investing activities
Purchase of short-term investments	(41,872)	(47,994)
Purchase of fixed-maturity investments, available-for-sale	(58,427)	(72,586)
Proceeds from maturity of short-term investments	81,207	81,311
Proceeds from redemptions, maturities and sale of fixed-maturity investments, available-for-sale	46,368	29,043
Software and equipment	(1,493)	(1,751)
Net cash provided by used in investing activities	25,783	(11,977)
Cash flows from financing activities
Proceeds from issuance of common stock related to employee equity plans	3,367	11,017
Taxes paid related to net share settlement of equity awards	(7,117)	(12,477)
Repayments of term loan	(375)	(375)
Payments of debt issuance/modification costs	(778)	0
Net cash (used in) financing activities	(4,903)	(1,835)
Net increase in cash, cash equivalents and restricted cash	68,732	14,467
Cash, cash equivalents and restricted cash, beginning of period	41,089	25,294
Cash, cash equivalents and restricted cash, end of period	109,821	$ 39,761
Supplemental disclosures of cash flow information
Interest paid	2,403		$ 2,617
Income taxes refunded	$ 0		$ 209

Organization, Basis of Presenta

Organization, Basis of Presentation and Summary of Accounting Principles	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Basis of Presentation and Summary of Accounting Principles	Organization, Basis of Presentation and Summary of Accounting Principles NMI Holdings, Inc. (NMIH) is a Delaware corporation, incorporated in May 2011, to provide private mortgage guaranty insurance (which we refer to as mortgage insurance or MI) through its wholly-owned insurance subsidiaries, National Mortgage Insurance Corporation (NMIC) and National Mortgage Reinsurance Inc One (Re One). Our common stock is listed on the NASDAQ exchange under the ticker symbol "NMIH." In April 2013, NMIC, our primary insurance subsidiary, issued its first mortgage insurance policy. NMIC is licensed to write mortgage insurance in all 50 states and D.C. In August 2015, NMIH capitalized a wholly-owned subsidiary, NMI Services, Inc. (NMIS), through which we offer outsourced loan review services to mortgage loan originators. Basis of Presentation The accompanying unaudited condensed consolidated financial statements, which include the results of NMIH and its wholly-owned subsidiaries, have been prepared in accordance with the instructions to Form 10-Q as prescribed by the SEC for interim reporting and include other information and disclosures required by accounting principles generally accepted in the U.S. (GAAP). Our accounts are maintained in U.S. dollars. These statements should be read in conjunction with our consolidated financial statements and notes thereto for the year ended December 31, 2019, included in our 2019 10-K. All intercompany transactions have been eliminated. The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, as well as disclosure of contingent assets and liabilities as of the balance sheet date. Estimates also affect the reported amounts of income and expenses for the reporting period. Actual results could differ from those estimates. Certain reclassifications to previously reported financial information have been made to conform to current period presentation. The results of operations for the interim period may not be indicative of the results that may be expected for the full year ending December 31, 2020. Significant Accounting Principles There have been no changes to our significant accounting principles as described in Item 8, " Financial Statements and Supplementary Data - Notes to Consolidated Financial Statements - Note 2 - Summary of Accounting Principles " of our 2019 10-K, other than as noted in " Investments, " " Premium Receivables, " " Reinsurance " and " Recent Accounting Pronouncements - Adopted " below. Investments We evaluate our investments each quarter to determine whether declines in fair value are below amortized cost. For any impaired debt security we evaluate if we either intend to sell the security or it is more likely than not that we will be required to sell the security before recovery. If our intent is to sell a security and its fair value is below amortized cost, the securities amortized cost basis is written down to fair value and a loss is recognized in earnings. For available for sale debt securities that do not meet the aforementioned criteria, we evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider several factors including, but not limited to: • the severity of the decline in fair value; • the financial condition of the issuer; • the failure of the issuer to make scheduled interest or principal payments; • recent credit downgrades of the applicable security or the issuer; and • adverse conditions specifically related to the security, an industry, or a geographic area. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of the cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through the allowance for credit losses is recognized in other comprehensive income. Changes in allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance for credit losses when management believes the uncollectibility of a security is met. We have elected to present accrued interest receivable separately from available for sale securities on the consolidated balance sheet in " Accrued Investment Income. " Accrued interest receivable was $7.2 million as of March 31, 2020 relating almost entirely to available for sale debt securities. We have also elected not to measure an allowance for credit losses for accrued interest receivable on available for sale securities. For all classes of available for sale securities, the accrual of interest is discontinued when the contractual payment of principal or interest has become 90 days past due and write-off of accrued interest receivable is recognized by reversing interest income. We did not write off any accrued interest receivable during the three months ended March 31, 2020. Premiums Receivable Premiums receivable consists of premiums due on our mortgage insurance policies. If a mortgage insurance premium is unpaid for more than 120 days, the receivable is written off against earned premium and the related insurance policy is canceled. We recognize an allowance for credit losses for premiums receivable based on credit losses expected to arise over the life of the receivable. Due to the nature of our insurance policies and the short-term duration of the related receivables an allowance for credit loss was not required at March 31, 2020. Reinsurance NMIC has entered into quota share reinsurance treaties effective September 1, 2016 (the 2016 QSR Transaction) and January 1, 2018 (the 2018 QSR Transaction), which we refer to collectively as the QSR Transactions. Under the QSR Transactions, we cede a portion of claims and claim expense reserves to our reinsurers, and account for such ceded reserves as reinsurance recoverables in "Other Assets" on the consolidated balance sheets and as reductions to claims expenses on the consolidated statements of operations. The company actively manages and monitors its credit risk associated with its reinsurance recoverables and recognizes an allowance for credit losses based on losses expected to arise over the life of the asset. As it relates to its QSR transactions, each of the third-party reinsurance providers has an insurer financial strength rating of A- or better by Standard & Poor's Rating Service (S&P), A.M. Best Company, Inc. (A.M.Best) or both. In accordance with the terms of the 2016 QSR Transaction, rather than making a cash payment or transferring investments for ceded premiums written, NMIC established a funds withheld liability, which also includes amounts due to NMIC for ceding and profit commissions. Any loss recoveries and any potential profit commission to NMIC will be realized from this account until exhausted. In accordance with the terms of the 2018 QSR Transaction, cash payments for ceded premiums earned are settled on a quarterly basis, offset by amounts due to NMIC for ceding and profit commissions. Any loss recoveries and any potential profit commission to NMIC are also settled quarterly. NMIC's reinsurance recoverable balances are further supported by trust accounts established and maintained by each reinsurer in accordance with the private mortgage insurer eligibility requirements (PMIERs) funding requirements for risk ceded to non-affiliates. The reinsurance recoverable on loss reserves related to our QSR Transactions was $6.2 million as of March 31, 2020 and an allowance for credit losses was not required. Recent Accounting Pronouncements - Adopted In June 2016, the Financial Accounting Standard Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments-Credit Losses (Topic 326) and subsequently issued amendments to the initial guidance: ASU 2019-04, Codification Improvements to Topic 326 , Financial Instruments-Credit Losses (Topic 815) , Derivatives and Hedging , and Topic 825, Financial Instruments , ASU 2019-05, Financial Instruments-Credit Losses: Targeted Transition Relief , and ASU 2019-11, C odification Improvements to Topic 326, Financial Instruments-Credit Losses . These updates will require companies to measure and establish reserves for lifetime expected credit losses on many financial assets held at a given reporting date. Under the guidance, the methodology for measuring lifetime credit losses shifts from an incurred loss model, whereby losses are only recognized once probable and estimable, to a current expected credit loss (CECL) model, whereby losses are recognized upfront based on a future economic forecast. Credit losses relating to available-for-sale fixed maturity securities are recorded through an allowance for credit losses, rather than a write-down of the asset as was required, with the amount of the allowance limited to the amount by which fair value is less than amortized cost. The length of time an available-for sale fixed maturity security has been held in an unrealized loss position will no longer impact its credit loss determination. We adopted these updates on January 1, 2020. Adoption of the updated standards did not have a material impact on our consolidated financial statements, and had no impact on our accounting for insurance claims and claim expenses as these items are not in scope of the guidance. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) . This update modifies the fair value measurement disclosure requirements of ASC 820. We adopted this ASU on January 1, 2020 and determined it did not have a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) . This update applies to cloud computing arrangements structured as service contracts, and provides companies with guidance on the criteria for capitalizing implementation, set-up and other up-front costs incurred in association with these arrangements. We adopted this ASU on January 1, 2020 and applied it on a prospective basis for eligible costs incurred after the effective date. The adoption of this ASU did not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements - Not Yet Adopted In August 2018, the FASB issued ASU 2018-12, Targeted Improvements to the Accounting for Long-Duration Contracts . This update provides guidance to the existing recognition, measurement, presentation and disclosure requirements for long-duration contracts issued by an insurance entity. The FASB subsequently issued ASU 2019-09 in November 2019, which amended the effective date for this standard. The standard will now take effect for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. We are currently evaluating the impact the adoption of this ASU will have, if any, on our consolidated financial statements. In November 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) . This update eliminates certain exceptions for recognizing deferred taxes for investments, performing intra-period allocations and calculating income taxes in interim periods. The ASU also includes guidance to reduce complexity in certain income tax areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. The standard will take effect for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. We are currently evaluating the impact the adoption of this ASU will have, if any, on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) . This update provides optional guidance to ease the potential burden in accounting for reference rate reform on financial reporting. Reference rate reform refers to the global transition away from referencing the London Interbank Offered Rate (LIBOR) in financial contracts, which is expected to be discontinued in 2021. The ASU includes optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The standard is effective immediately through December 31, 2022 for all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. We are currently evaluating the impact the adoption of this ASU would have, if any, to our contract modifications that are affected by the discontinuation of LIBOR.

Investments

Investments	3 Months Ended
	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Investments	Investments We have designated our investment portfolio as available-for-sale and report it at fair value. The related unrealized gains and losses are, after considering the related tax expense or benefit, recognized through comprehensive income and loss, and on an accumulated basis in shareholders' equity. Net realized investment gains and losses are reported in earnings based on specific identification of securities sold or any impairment that has been recorded through the allowance for credit losses. If our intent is to sell a security and its fair value is below amortized cost, the security's amortized cost basis is written down to fair value and a loss is recognized in earnings. Fair Values and Gross Unrealized Gains and Losses on Investments Amortized Gross Unrealized Fair Gains Losses As of March 31, 2020 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,207 $ 3,519 $ — $ 51,726 Municipal debt securities 196,750 3,853 (668) 199,935 Corporate debt securities 628,834 18,272 (6,658) 640,448 Asset-backed securities 180,514 404 (7,811) 173,107 Total bonds 1,054,305 26,048 (15,137) 1,065,216 Short-term investments 4,838 18 — 4,856 Total investments $ 1,059,143 $ 26,066 $ (15,137) $ 1,070,072 Amortized Gross Unrealized Fair Gains Losses As of December 31, 2019 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,203 $ 784 $ (58) $ 48,929 Municipal debt securities 189,530 1,721 (1,035) 190,216 Corporate debt securities 661,719 23,373 (211) 684,881 Asset-backed securities 170,153 2,603 (114) 172,642 Total bonds 1,069,605 28,481 (1,418) 1,096,668 Short-term investments 44,174 98 — 44,272 Total investments $ 1,113,779 $ 28,579 $ (1,418) $ 1,140,940 We did not own any mortgage-backed securities in our asset-backed securities portfolio at March 31, 2020 o r December 31, 2019. The following table presents a breakdown of the fair value of our corporate debt securities by issuer industry group as of March 31, 2020 and December 31, 2019: March 31, 2020 December 31, 2019 Financial 40 % 38 % Consumer 23 26 Communications 11 10 Utilities 10 9 Industrial 9 8 Technology 7 7 Energy — 2 Total 100 % 100 % As of March 31, 2020 and December 31, 2019, approximately $5.7 million and $5.5 million, respectively, of our cash and investments were held in the form of U.S. Treasury securities on deposit with various state insurance departments to satisfy regulatory requirements. Scheduled Maturities The amortized cost and fair values of available-for-sale securities as of March 31, 2020 and December 31, 2019, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in a separate category. As of March 31, 2020 Amortized Fair (In Thousands) Due in one year or less $ 83,740 $ 83,736 Due after one through five years 408,063 415,419 Due after five through ten years 373,220 383,838 Due after ten years 13,606 13,972 Asset-backed securities 180,514 173,107 Total investments $ 1,059,143 $ 1,070,072 As of December 31, 2019 Amortized Fair (In Thousands) Due in one year or less $ 138,776 $ 139,113 Due after one through five years 406,986 417,208 Due after five through ten years 380,737 394,180 Due after ten years 17,127 17,797 Asset-backed securities 170,153 172,642 Total investments $ 1,113,779 $ 1,140,940 Aging of Unrealized Losses We evaluate our investments each quarter to determine whether declines in fair value are below amortized costs. As of March 31, 2020, the investment portfolio had gross unrealized losses of $15.1 million, of which $0.1 million had been in an unrealized loss position for a period of 12 months or greater. For any impaired security we evaluate if we either intend to sell the security or it is more likely than not that we will be required to sell the security before recovery of its amortized cost. If either of the criteria regarding intent or requirement to sell is met, the security's amortized cost basis is written down to fair value through earnings. For securities that do not meet the aforementioned criteria, we evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider the extent to which fair value is less than amortized cost, any changes to the rating of the securities by a rating agency, and any adverse condition specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, and an allowance for credit losses is recorded. Any impairment that has not been recorded through an allowance for credit loss is recognized in other comprehensive income. The following table summarizes the investment portfolio in an unrealized loss position for which an allowance is not recorded, aggregated by major security type and length of time in a continuous unrealized loss position: Less Than 12 Months 12 Months or Greater Total # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses As of March 31, 2020 (Dollars in Thousands) U.S. Treasury securities and obligations of U.S. government agencies — $ — $ — — $ — $ — — $ — $ — Municipal debt securities 14 46,936 (668) — — — 14 46,936 (668) Corporate debt securities 87 178,776 (6,630) 5 3,294 (28) 92 182,070 (6,658) Asset-backed securities 60 133,997 (7,745) 1 2,934 (66) 61 136,931 (7,811) Total 161 $ 359,709 $ (15,043) 6 $ 6,228 $ (94) 167 $ 365,937 $ (15,137) Less Than 12 Months 12 Months or Greater Total # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses As of December 31, 2019 (Dollars in Thousands) U.S. Treasury securities and obligations of U.S. government agencies 4 $ 12,001 $ (58) — $ — $ — 4 $ 12,001 $ (58) Municipal debt securities 26 92,844 (1,034) 1 999 (1) 27 93,843 (1,035) Corporate debt securities 10 30,481 (140) 14 23,976 (71) 24 54,457 (211) Asset-backed securities 9 19,236 (102) 1 2,988 (12) 10 22,224 (114) Total 49 $ 154,562 $ (1,334) 16 $ 27,963 $ (84) 65 $ 182,525 $ (1,418) Allowance of credit losses As of March 31, 2020, we did not recognize an allowance of credit losses on our investment portfolio. The increase in securities in an unrealized loss position as of March 31, 2020 can be attributed to a widening of credit spreads and surging demand for liquidity across the broader debt markets, partially offset by interest rate movements since the purchase date. We evaluated the securities in an unrealized loss position as of March 31, 2020 and assessed the credit ratings and any ratings changes as well as any adverse conditions specifically related to the security. Based on our estimate of the amount and timing of cash flows to be collected we expect to recover the amortized cost basis of these securities. For the three months ended March 31, 2019, we recognized a $0.4 million other than temporarily impaired (OTTI) loss in earnings related to the planned sale of a security in a loss position in April 2019. There were no credit losses recognized in earnings for which a portion of an OTTI loss was recognized in accumulated other comprehensive income (loss) for the three months ended March 31, 2019. Net Investment Income The following table presents the components of net investment income: For the three months ended March 31, 2020 2019 (In Thousands) Investment income $ 8,349 $ 7,496 Investment expenses (245) (113) Net investment income $ 8,104 $ 7,383 The following table presents the components of net realized investment gains (losses): For the three months ended March 31, 2020 2019 (In Thousands) Gross realized investment gains $ 540 $ 195 Gross realized investment losses (612) (382) Net realized investment (losses) $ (72) $ (187)

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The following describes the valuation techniques used by us to determine the fair value of our financial instruments: We established a fair value hierarchy by prioritizing the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under this standard are described below: Level 1 - Fair value measurements based on quoted prices in active markets that we have the ability to access for identical assets or liabilities. Market price data generally is obtained from exchange or dealer markets. We do not adjust the quoted price for such instruments. Level 2 - Fair value measurements based on inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 - Fair value measurements based on valuation techniques that use significant inputs that are unobservable. Both observable and unobservable inputs may be used to determine the fair values of positions classified in Level 3. The circumstances for using these measurements include those in which there is little, if any, market activity for the asset or liability. Therefore, we must make certain assumptions, which require significant management judgment or estimation about the inputs a hypothetical market participant would use to value that asset or liability. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Assets classified as Level 1 and Level 2 To determine the fair value of securities available-for-sale in Level 1 and Level 2 of the fair value hierarchy, independent pricing sources have been utilized. One price is provided per security based on observable market data. To ensure securities are appropriately classified in the fair value hierarchy, we review the pricing techniques and methodologies of the independent pricing sources and believe that their policies adequately consider market activity, either based on specific transactions for the issue valued or based on modeling of securities with similar credit quality, duration, yield and structure that were recently traded. A variety of inputs are utilized by the independent pricing sources including benchmark yields, reported trades, non-binding broker/dealer quotes, issuer spreads, two sided markets, benchmark securities, bids, offers and reference data including data published in market research publications. Inputs may be weighted differently for any security, and not all inputs are used for each security evaluation. Market indicators, industry and economic events are also considered. This information is evaluated using a multidimensional pricing model. Quality controls are performed by the independent pricing sources throughout this process, which include reviewing tolerance reports, trading information and data changes, and directional moves compared to market moves. This model combines all inputs to arrive at a value assigned to each security. We have not made any adjustments to the prices obtained from the independent pricing sources. Liabilities classified as Level 3 We calculate the fair value of outstanding warrants utilizing Level 3 inputs, including a Black-Scholes option-pricing model, in combination with a binomial model, and we value the pricing protection features within the warrants using a Monte-Carlo simulation model. Variables in the model include the risk-free rate of return, dividend yield, expected life and expected volatility of our stock price. The following tables present the level within the fair value hierarchy at which our financial instruments were measured: Fair Value Measurements Using Quoted Prices in Significant Other Significant Fair Value As of March 31, 2020 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 51,726 $ — $ — $ 51,726 Municipal debt securities — 199,935 — 199,935 Corporate debt securities — 640,448 — 640,448 Asset-backed securities — 173,107 — 173,107 Cash, cash equivalents and short-term investments 114,677 — — 114,677 Total assets $ 166,403 $ 1,013,490 $ — $ 1,179,893 Warrant liability — — 1,461 1,461 Total liabilities $ — $ — $ 1,461 $ 1,461 Fair Value Measurements Using Quoted Prices in Significant Other Significant Fair Value As of December 31, 2019 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,929 $ — $ — $ 48,929 Municipal debt securities — 190,216 — 190,216 Corporate debt securities — 684,881 — 684,881 Asset-backed securities — 172,642 — 172,642 Cash, cash equivalents and short-term investments 85,361 — — 85,361 Total assets $ 134,290 $ 1,047,739 $ — $ 1,182,029 Warrant liability — — 7,641 7,641 Total liabilities $ — $ — $ 7,641 $ 7,641 There were no transfers between Level 2 and Level 3 of the fair value hierarchy during the three months ended March 31, 2020, or the year ended December 31, 2019. The following is a roll-forward of Level 3 liabilities measured at fair value: For the three months ended March 31, Warrant Liability 2020 2019 (In Thousands) Balance, January 1 $ 7,641 $ 7,296 Change in fair value of warrant liability included in earnings (5,959) 5,479 Issuance of common stock on warrant exercise (221) (944) Balance, March 31 $ 1,461 $ 11,831 The following table outlines the key inputs and assumptions used to calculate the fair value of the warrant liability in the Black-Scholes option-pricing model as of the dates indicated. As of March 31, 2020 2019 Common stock price $ 11.61 $ 25.87 Risk free interest rate 0.23 % 2.21 - 2.31% Expected life 2.06 years 1.67 - 3.06 years Expected volatility 61.4 % 42.3 - 45.7% Dividend yield 0 % 0 % The changes in fair value of the warrant liability for the three months ended March 31, 2020 and 2019 are primarily attributable to changes in the price of our common stock and exercises of outstanding warrants during the respective periods, with additional impact related to changes in other Black-Scholes model inputs.

Debt

Debt	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	DebtOn May 24, 2018, we entered into a credit agreement (2018 Credit Agreement), which provides for (i) a $150 million five three under the facility. 2018 Term Loan The 2018 Term Loan bears interest at the LIBOR, as defined in the 2018 Credit Agreement and subject to a 1.00% floor, plus an annual margin rate of 4.75%, representing an all-in rate of 5.75% as of March 31, 2020, payable monthly based on our current interest period election. Quarterly principal payments of $0.4 million are also required. As of March 31, 2020, the outstanding principal balance of the 2018 Term Loan was $147.4 million. Interest expense for the 2018 Term Loan includes interest and the amortization of issuance costs, an original issue discount and capitalized modification costs related to the 2015 Term Loan. For the three months ended March 31, 2020, we recorded $2.5 million of interest expense. Remaining unamortized issuance costs and original issue discount were $1.9 million as of March 31, 2020 and are being amortized to interest expense using the effective interest method over the contractual life of the 2018 Term Loan. We are subject to certain covenants under the 2018 Term Loan (as defined in the 2018 Credit Agreement), including (but not limited to) a maximum debt-to-total capitalization ratio (as defined in the 2018 Credit Agreement) of 35% under the 2018 Term Loan. We were in compliance with all covenants as of March 31, 2020. Future principal payments due under the 2018 Term Loan as of March 31, 2020 are as follows: As of March 31, 2020 Principal (In thousands) 2020 1,125 2021 1,500 2022 1,500 2023 143,250 Total $ 147,375 2020 Revolving Credit Facility Borrowings under the 2020 Revolving Credit Facility accrue interest at a variable rate equal to, at our discretion, based on the applicable corporate credit rating at the time, (i) a base rate (as defined in the 2018 Credit Agreement, subject to a floor of 1.00% per annum) plus a margin of 0.375% to 1.875% per annum, which is reduced from a margin of 1.00% to 2.50% prior to the amendment, or (ii) the Eurodollar Rate (subject to a floor of 0.00% per annum) plus a margin of 1.375% to 2.875% per annum, which is reduced from a margin of 2.00% to 3.50% prior to the amendment. As of March 31, 2020, no borrowings had been made under the 2020 Revolving Credit Facility. Under the 2020 Revolving Credit Facility, we are required to pay a quarterly commitment fee on the average daily undrawn amount, which ranges from 0.175% to 0.525%, reduced from ranges of 0.30% to 0.60% prior to the amendment, based on the applicable corporate credit rating at the time. As of March 31, 2020, the applicable commitment fee was 0.35%. For the three months ended March 31, 2020, we recorded $0.1 million of commitment fees in interest expense. We incurred issuance costs of $0.8 million in connection with the 2020 Revolving Credit Facility, which together with the remaining issuance cost of $0.6 million prior to the amendment, are amortized through interest expense over the extent contractual life of the 2020 Revolving Credit Facility, on a straight-line basis. For the three months ended March 31, 2020, we recognized $0.1 million of interest expense from the amortization of deferred issuance costs. At March 31, 2020, remaining deferred issuance costs were $1.4 million, net of accumulated amortization. We are subject to certain covenants under the 2020 Revolving Credit Facility, including (but not limited to) the following: a maximum debt-to-total capitalization ratio of 35%, a minimum liquidity requirement, compliance with the PMIERs financial requirements (subject to any Fannie Mae and Freddie Mac (collectively, the GSEs) approved waivers), and minimum consolidated net worth and statutory capital requirements (respectively, as defined therein). We were in compliance with all covenants as of March 31, 2020.

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2020
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance We enter into third-party reinsurance transactions to actively manage our risk, ensure compliance with PMIERs, state regulatory and other applicable capital requirements, and support the growth of our business. The GSEs and the Wisconsin Office of the Commissioner of Insurance (Wisconsin OCI) have approved all such transactions (subject to certain conditions and ongoing review, including levels of approved capital credit). The effect of our reinsurance agreements on premiums written and earned is as follows: For the three months ended March 31, 2020 March 31, 2019 (In Thousands) Net premiums written Direct $ 103,453 $ 81,730 Ceded (1) (12,082) (9,807) Net premiums written $ 91,371 $ 71,923 Net premiums earned Direct $ 113,187 $ 86,298 Ceded (1) (14,470) (12,430) Net premiums earned $ 98,717 $ 73,868 (1) Net of profit commission. Excess-of-loss reinsurance NMIC entered into excess-of-loss reinsurance agreements with Oaktown Re Ltd., Oaktown Re II Ltd. and Oaktown Re III Ltd. (special purpose reinsurance entities collectively referred to as the Oaktown Re Vehicles) effective May 2, 2017, July 25, 2018 and July 30, 2019, respectively. Each agreement provides NMIC with aggregate excess-of-loss reinsurance coverage on a defined portfolio of mortgage insurance policies written during a discrete period. Under each agreement, NMIC retains a first layer of aggregate loss exposure on covered policies and the respective Oaktown Re Vehicle then provides second layer loss protection up to a defined reinsurance coverage amount. NMIC then retains losses in excess of the respective reinsurance coverage amounts. The respective reinsurance coverage amounts provided by the Oaktown Re Vehicles decrease from the inception of each agreement over a 10 year period as the underlying insured mortgages are amortized or repaid, and/or the mortgage insurance coverage is canceled. The respective outstanding reinsurance coverage amounts stop amortizing if certain credit enhancement or delinquency thresholds, as defined in each agreement, are triggered. NMIC makes risk premium payments to the Oaktown Re Vehicles for the applicable outstanding reinsurance coverage amount and pays an additional amount for anticipated operating expenses (capped at $300 thousand per year to Oaktown Re Ltd. and $250 thousand per year to Oaktown Re II, Ltd. and Oaktown Re III, Ltd.). NMIC ceded aggregate premiums to the Oaktown Re Vehicles of $3.9 million and $3.0 million during the three months ended March 31, 2020 and three months ended March 31, 2019, respectively. NMIC applies claims paid on covered policies against its first layer aggregate retained loss exposure under each excess-of-loss agreement. NMIC did not cede any incurred losses on covered policies to the Oaktown Re Vehicles during the three months ended March 31, 2020 and 2019, as the aggregate first layer risk retention was not exhausted for each applicable agreement during such periods. Under the terms of each excess-of-loss reinsurance agreement, the Oaktown Re Vehicles are required to fully collateralize their outstanding reinsurance coverage amount to NMIC with funds deposited into segregated reinsurance trusts. Such trust funds are required to be invested in short-term U.S. Treasury money market funds at all times. Each Oaktown Re Vehicle financed its respective collateral requirement through the issuance of mortgage insurance-linked notes to unaffiliated investors. Such insurance-linked notes mature 10 years from the inception date of each reinsurance agreement. We refer to NMIC's reinsurance agreements with and the insurance-linked note issuances by Oaktown Re Ltd., Oaktown Re II, Ltd. and Oaktown Re III, Ltd. individually as the 2017 ILN Transaction, 2018 ILN Transaction and 2019 ILN Transaction, and collectively as the ILN Transactions. The following table presents the inception date, covered production period, initial and current reinsurance coverage amount, and initial and current first layer retained aggregate loss under each of the ILN Transactions. ( $ values in thousands) Inception Date Covered Production Initial Reinsurance Coverage Current Reinsurance Coverage Initial First Layer Retained Loss Current First Layer Retained Loss 2017 ILN Transaction May 2, 2017 1/1/2013 - 12/31/2016 $ 211,320 $ 46,990 $ 126,793 $ 122,810 2018 ILN Transaction July 25, 2018 1/1/2017 - 5/31/2018 264,545 174,340 125,312 124,311 2019 ILN Transaction July 30, 2019 6/1/2018 - 6/30/2019 326,905 259,047 123,424 123,424 NMIC holds optional termination rights under each ILN Transaction, including, among others, an optional call feature which provides NMIC the discretion to terminate the transaction on or after a prescribed date, and a clean-up call if the outstanding reinsurance coverage amount amortizes to 10% or less of the reinsurance coverage amount at inception or if NMIC reasonably determines that changes to GSE or rating agency asset requirements would cause a material and adverse effect on the capital treatment afforded to NMIC under a given agreement. In addition, there are certain events that trigger mandatory termination of an agreement, including NMIC's failure to pay premiums or consent to reductions in a trust account to make principal payments to noteholders, among others. Under the terms of the 2018 ILN Transaction and the 2019 ILN Transaction, we are required to maintain a certain level of restricted funds in premium deposit accounts with Bank of New York Mellon until the respective notes have been redeemed in full. "Cash and cash equivalents" on our condensed consolidated balance sheet includes restricted amounts of $2.5 million as of March 31, 2020. We are not required to deposit additional funds into the premium deposit accounts in the future and the restricted balances required under these transactions will decrease over time as the outstanding principal balances of the respective insurance-linked notes decline. Quota share reinsurance Under each of the QSR Transactions, NMIC cedes a proportional share of its risk on eligible policies written during a discrete period to panels of third-party reinsurance providers. Each of the third-party reinsurance providers has an insurer financial strength rating of A- or better by S&P, A.M.Best or both. Under the 2016 QSR Transaction, NMIC cedes premiums written related to 25% of the risk on eligible primary policies written for all periods through December 31, 2017 and 100% of the risk under our pool agreement with Fannie Mae. The 2016 QSR Transaction is scheduled to terminate on December 31, 2027, except with respect to the ceded pool risk, which is scheduled to terminate on August 31, 2023. NMIC has the option, based on certain conditions and subject to a termination fee, to terminate the agreement as of December 31, 2020, or at the end of any calendar quarter thereafter, which would result in NMIC reassuming the related risk. Under the 2018 QSR Transaction, NMIC cedes premiums earned related to 25% of the risk on eligible policies written in 2018 and 20% of the risk on eligible policies written in 2019. The 2018 QSR Transaction is scheduled to terminate on December 31, 2029. NMIC has the option, based on certain conditions and subject to a termination fee, to terminate the agreement as of December 31, 2022, or at the end of any calendar quarter thereafter, which would result in NMIC reassuming the related risk. NMIC may terminate either or both of the QSR Transactions without penalty if, due to a change in PMIERs requirements, it is no longer able to take full PMIERs asset credit for the risk-in-force (RIF) ceded under the respective agreements. Additionally, under the terms of the QSR Transactions, NMIC may elect to selectively terminate its engagement with individual reinsurers on a run-off basis ( i.e. , reinsurers continue providing coverage on all risk ceded prior to the termination date, with no new cessions going forward) or cut-off basis ( i.e. , the reinsurance arrangement is completely terminated with NMIC recapturing all previously ceded risk) under certain circumstances. Such selective termination rights arise when, among other reasons, a reinsurer experiences a deterioration in its capital position below a prescribed threshold and/or a reinsurer breaches (and fails to cure) its collateral posting obligations under the relevant agreement. Effective April 1, 2019, NMIC elected to terminate its engagement with one reinsurer under the 2016 QSR Transaction on a cut-off basis. In connection with the termination, NMIC recaptured approximately $500 million of previously ceded primary RIF and stopped ceding new premiums earned or written with respect to the recaptured risk. With the termination, ceded premiums written under the 2016 QSR Transaction decreased from 25% to 20.5% on eligible policies. The termination has no effect on the cession of pool risk under the 2016 QSR Transaction. The following table shows the amounts related to the QSR Transactions: For the three months ended March 31, 2020 March 31, 2019 (In Thousands) Ceded risk-in-force $ 4,843,715 $ 4,534,353 Ceded premiums earned (23,011) (21,468) Ceded claims and claim expenses 1,532 899 Ceding commission earned 4,513 4,206 Profit commission 12,413 12,061 Ceded premiums written under the 2016 QSR Transaction are recorded on the balance sheet as prepaid reinsurance premiums and amortized to ceded premiums earned in a manner consistent with the recognition of revenue on direct premiums. Under the 2018 QSR Transaction, premiums are ceded on an earned basis as defined in the agreement. NMIC receives a 20% ceding commission for premiums ceded under the QSR Transactions. NMIC also receives a profit commission under each of the QSR Transactions, provided that the loss ratios on loans covered under the 2016 QSR Transaction and 2018 QSR Transaction generally remain below 60% and 61%, respectively, as measured annually. Ceded claims and claim expenses under each of the QSR Transactions reduce the respective profit commission received by NMIC on a dollar-for-dollar basis. In accordance with the terms of the 2016 QSR Transaction, rather than making a cash payment or transferring investments for ceded premiums written, NMIC established a funds withheld liability, which also includes amounts due to NMIC for ceding and profit commissions. Any loss recoveries and any potential profit commission to NMIC will be realized from this account until exhausted. NMIC's reinsurance recoverable balance is further supported by trust accounts established and maintained by each reinsurer in accordance with the PMIERs funding requirements for risk ceded to non-affiliates. The reinsurance recoverable on loss reserves related to our 2016 QSR Transaction was $3.1 million as of March 31, 2020. In accordance with the terms of the 2018 QSR Transaction, cash payments for ceded premiums earned are settled on a quarterly basis, offset by amounts due to NMIC for ceding and profit commissions. Any loss recoveries and any potential profit commission to NMIC are also settled quarterly. NMIC's reinsurance recoverable balance is supported by trust accounts established and maintained by each reinsurer in accordance with the PMIERs funding requirements for risk ceded to non-affiliates. The reinsurance recoverable on loss reserves related to our 2018 QSR Transaction was $3.1 million as of March 31, 2020.

Reserves for Insurance Claims a

Reserves for Insurance Claims and Claim Expenses	3 Months Ended
	Mar. 31, 2020
Insurance [Abstract]
Reserves for Insurance Claims and Claim Expenses	Reserves for Insurance Claims and Claim Expenses We establish reserves to recognize the estimated liability for insurance claims and claim expenses related to defaults on insured mortgage loans. Consistent with industry practice, we establish reserves for loans that have been reported to us by servicers as having been in default for at least 60 days, referred to as case reserves, and additional loans that we estimate (based on actuarial review) have been in default for at least 60 days that have not yet been reported to us by servicers, referred to as incurred but not reported (IBNR) reserves. We also establish claim expense reserves, which represent the estimated cost of the claim administration process, including legal and other fees, as well as other general expenses of administering the claims settlement process. As of March 31, 2020, we had reserves for insurance claims and claim expenses of $29.5 million for 1,449 primary loans in default. During the three months ended March 31, 2020, we paid 34 claims totaling $1.5 million of claims and claims expense, including 31 claims covered under the QSR Transactions representing $0.3 million of ceded claims and claim expenses. In 2013, we entered into a pool insurance transaction with Fannie Mae. The pool transaction includes a deductible, which represents the amount of claims to be absorbed by Fannie Mae before we are obligated to pay any claims. We only establish reserves for pool risk if we expect claims to exceed this deductible. At March 31, 2020, 46 loans in the pool were past due by 60 days or more. These 46 loans represented approximately $3.0 million of RIF. Due to the size of the remaining deductible, the low level of notices of defaults (NODs) reported on loans in the pool through March 31, 2020 and the expected severity (all loans in the pool have loan-to-value (LTV) ratios under 80%), we did not establish any case or IBNR reserves for pool risk at March 31, 2020. In connection with the settlement of pool claims, we applied $0.9 million to the pool deductible through March 31, 2020. At March 31, 2020, the remaining pool deductible was $9.5 million. We have not paid any pool claims to date. 100% of our pool RIF is reinsured under the 2016 QSR Transaction. The following table provides a reconciliation of the beginning and ending reserve balances for primary insurance claims and claim expenses: For the three months ended March 31, 2020 2019 (In Thousands) Beginning balance $ 23,752 $ 12,811 Less reinsurance recoverables (1) (4,939) (3,001) Beginning balance, net of reinsurance recoverables 18,813 9,810 Add claims incurred: Claims and claim expenses incurred: Current year (2) 7,558 3,909 Prior years (3) (1,861) (1,166) Total claims and claim expenses incurred 5,697 2,743 Less claims paid: Claims and claim expenses paid: Current year (2) — — Prior years (3) 1,224 694 Total claims and claim expenses paid 1,224 694 Reserve at end of period, net of reinsurance recoverables 23,286 11,859 Add reinsurance recoverables (1) 6,193 3,678 Ending balance $ 29,479 $ 15,537 (1) Related to ceded losses recoverable under the QSR Transactions, included in "Other assets" on the Condensed Consolidated Balance Sheets. See Note 5, " Reinsurance " for additional information. (2) Related to insured loans with their most recent defaults occurring in the current year. For example, if a loan defaulted in a prior year and subsequently cured and later re-defaulted in the current year, the default would be included in the current year. Amounts are presented net of reinsurance. (3) Related to insured loans with defaults occurring in prior years, which have been continuously in default before the start of the current year. Amounts are presented net of reinsurance. The "claims incurred" section of the table above shows claims and claim expenses incurred on NODs for current and prior years, including IBNR reserves and is presented net of reinsurance. The amount of claims incurred relating to current year NODs represents the estimated amount of claims and claim expenses to be ultimately paid on such loans in default. We recognized $1.9 million and $1.2 million of favorable prior year development during the three months ended March 31, 2020 and 2019, respectively, due to NOD cures and ongoing analysis of recent loss development trends. We may increase or decrease our original estimates as we learn additional information about individual defaults and claims and continue to observe and analyze loss development trends in our portfolio. Gross reserves of $19.9 million related to prior year defaults remained as of March 31, 2020.

Earnings per Share (EPS)

Earnings per Share (EPS)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share (EPS)	Earnings per Share (EPS)Basic EPS is based on the weighted average number of shares of common stock outstanding. Diluted EPS is based on the weighted average number of shares of common stock outstanding and common stock equivalents that would be issuable upon the vesting of service based and performance and service based restricted stock units (RSUs), and the exercise of vested and unvested stock options and outstanding warrants. The number of shares issuable for RSUs subject to performance and service based vesting requirements are only included in diluted shares if the relevant performance measurement period has commenced and results during such period meet the necessary performance criteria. The following table reconciles the net income and the weighted average shares of common stock outstanding used in the computations of basic and diluted EPS of common stock. For the three months ended March 31, 2020 2019 (In Thousands, except for per share data) Net income $ 58,271 $ 32,899 Basic weighted average shares outstanding 68,563 66,692 Basic earnings per share $ 0.85 $ 0.49 Net income $ 58,271 $ 32,899 Gain from change in fair value of warrant liability (5,959) — Diluted net income $ 52,312 $ 32,899 Basic weighted average shares outstanding 68,563 66,692 Dilutive effect of issuable shares 1,838 2,304 Diluted weighted average shares outstanding 70,401 68,996 Diluted earnings per share $ 0.74 $ 0.48 Anti-dilutive shares 15 754

Warrants

Warrants	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Warrants	Warrants We issued 992 thousand warrants in connection with a private placement of our common stock in April 2012. Each warrant gives the holder thereof the right to purchase one share of common stock at an exercise price equal to $10.00. The warrants were issued with an aggregate fair value of $5.1 million. During the three months ended March 31, 2020, nine thousand warrants were exercised resulting in the issuance of six thousand shares of common stock. Upon exercise, we reclassified approximately $0.2 million of warrant fair value from warrant liability to additional paid-in capital, of which $8 thousand related to changes in fair value during the three months ended March 31, 2020. During the three months ended March 31, 2019, 67 thousand warrants were exercised resulting in the issuance of 39 thousand shares of common stock. Upon exercise, we reclassified approximately $0.9 million of warrant fair value from warrant liability to additional paid-in capital, of which $0.3 million related to changes in fair value during the three months ended March 31, 2019.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesWe are a U.S. taxpayer and are subject to a statutory U.S. federal corporate income tax rate of 21%. NMIH files a consolidated U.S. federal and various state income tax returns on behalf of itself and its subsidiaries. Our effective tax rate on our pre-tax income was 19.2% for the three months ended March 31, 2020 compared to 15.6% for the three months ended March 31, 2019. Our provision for income taxes for interim reporting periods is established based on our estimated annual effective tax rate for a given year. Our effective tax rate may fluctuate between interim periods due to the impact of discrete items not included in our estimated annual effective tax rate, including the tax effects associated with the vesting of RSUs and exercise of options, and the change in fair value of our warrant liability. Such items are treated on a discrete basis in the reporting period in which they occur.As a mortgage guaranty insurance company, we are eligible to claim a tax deduction for our statutory contingency reserve balance, subject to certain limitations outlined under IRC Section 832(e), and only to the extent we acquire tax and loss bonds in an amount equal to the tax benefit derived from the claimed deduction, which is our intent. As a result, our interim provision for income taxes for the three months ended March 31, 2020 represents a change in our net deferred tax liability. As of March 31, 2020, we held $7.6 million of tax and loss bonds in "Other assets" in our condensed consolidated balance sheet.

Regulatory Information

Regulatory Information	3 Months Ended
	Mar. 31, 2020
Insurance [Abstract]
Regulatory Information	Regulatory Information Statutory Requirements Our insurance subsidiaries, NMIC and Re One, file financial statements in conformity with statutory accounting principles (SAP) prescribed or permitted by the Wisconsin OCI, NMIC's principal regulator. Prescribed SAP includes state laws, regulations and general administrative rules, as well as a variety of publications of the National Association of Insurance Commissioners. The Wisconsin OCI recognizes only statutory accounting practices prescribed or permitted by the state of Wisconsin for determining and reporting the financial condition and results of operations of an insurance company and for determining its solvency under Wisconsin insurance laws. NMIC and Re One's combined statutory net income (loss) was as follows: For the three months ended March 31, 2020 2019 (In Thousands) Statutory net gain (loss) $ 7,691 $ (927) NMIC and Re One's combined statutory surplus, contingency reserve and risk-to-capital (RTC) ratio were as follows: March 31, 2020 December 31, 2019 (In Thousands) Statutory surplus $ 457,790 $ 449,602 Contingency reserve 588,418 531,825 RTC ratio 17.2:1 15.8:1 NMIH is not subject to any limitations on its ability to pay dividends except those generally applicable to corporations that are incorporated in Delaware. Delaware corporate law provides that dividends are only payable out of a corporation's capital surplus or, subject to certain limitations, recent net profits. NMIC and Re One are subject to certain capital and dividend rules and regulations prescribed by jurisdictions in which they are authorized to operate and the GSEs. NMIC and Re One have never paid dividends to NMIH. NMIC and Re One have the capacity to pay aggregate ordinary dividends of $16.1 million to NMIH during the 12-month period ending December 31, 2020.

COVID-19 Developments and Coron

COVID-19 Developments and Coronavirus Aid, Relief, and Economic Security (CARES) Act	3 Months Ended
	Mar. 31, 2020
Unusual or Infrequent Items, or Both [Abstract]
COVID-19 Developments and Coronavirus Aid, Relief, and Economic Security (CARES) Act	COVID-19 Developments and Coronavirus Aid, Relief, and Economic Security (CARES) Act COVID-19 Developments On January 30, 2020, the World Health Organization (WHO) declared the outbreak of a novel coronavirus strain (COVID-19) a global health emergency and characterized the outbreak as a global pandemic on March 11, 2020. In an effort to stem contagion and control the COVID-19 pandemic the population at large has severely curtailed day-to-day activity and local, state and federal regulators have imposed a broad set of restrictions on personal and business conduct nationwide. The COVID-19 pandemic, along with the widespread public and regulatory response, has caused a dramatic slowdown in U.S. and global economic activity. In the weeks following the outbreak, non-essential businesses across the U.S. have been shuttered and capital markets have experienced a significant spike in volatility and sell-off in valuations. A record number of Americans have been furloughed or laid-off, and unemployment claims have increased dramatically. The global dislocation caused by COVID-19 is unprecedented and, while there is broad hope for a medical advance that relieves the crisis and provides for a quick return to normalized activity, it is not known how long the dislocation will persist. In response to the COVID-19 outbreak and continuing uncertainties, we activated our business continuity program to ensure our employees were safe and able to continue serving our customers and their borrowers without interruption. We expect the COVID-19 outbreak will have a direct effect on the U.S. housing market, with existing homeowners facing challenges related to COVID-19, and the volume and timing of future housing transactions negatively impacted as potential sellers re-evaluate or postpone planned sales (housing supply) and potential buyers reassess their ability and willingness to purchase homes (demand). We are currently assessing the potential impact the COVID-19 outbreak will have on the U.S economy and housing market, the mortgage insurance market, and our business performance and financial position, including our new business production, defaults and claims experience and investment portfolio returns, of which the ultimate outcome cannot be estimated at this time. CARES Act On March 27, 2020, the President signed into law the CARES Act. The CARES Act, among other things, includes provisions relating to refundable payroll tax credits, deferment of employer side social security payments, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations, increased limitations on qualified charitable contributions, and technical corrections to tax depreciation methods for qualified improvement property. We currently are eligible but have not taken advantage of the payroll protection program, emergency grants and business loans under the CARES Act. We will continue to monitor the impact that the CARES Act may have on our business, financial condition and results of operations.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On March 2 0, 2

Organization, Basis of Presen_2

Organization, Basis of Presentation and Summary of Accounting Principles (Policies)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation        The accompanying unaudited condensed consolidated financial statements, which include the results of NMIH and its wholly-owned subsidiaries, have been prepared in accordance with the instructions to Form 10-Q as prescribed by the SEC for interim reporting and include other information and disclosures required by accounting principles generally accepted in the U.S. (GAAP). Our accounts are maintained in U.S. dollars. These statements should be read in conjunction with our consolidated financial statements and notes thereto for the year ended December 31, 2019, included in our 2019 10-K. All intercompany transactions have been eliminated. The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, as well as disclosure of contingent assets and liabilities as of the balance sheet date. Estimates also affect the reported amounts of income and expenses for the reporting period. Actual results could differ from those estimates. Certain reclassifications to previously reported financial information have been made to conform to current period presentation. The results of operations for the interim period may not be indicative of the results that may be expected for the full year ending December 31, 2020.
Investments	Investments We evaluate our investments each quarter to determine whether declines in fair value are below amortized cost. For any impaired debt security we evaluate if we either intend to sell the security or it is more likely than not that we will be required to sell the security before recovery. If our intent is to sell a security and its fair value is below amortized cost, the securities amortized cost basis is written down to fair value and a loss is recognized in earnings. For available for sale debt securities that do not meet the aforementioned criteria, we evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider several factors including, but not limited to: • the severity of the decline in fair value; • the financial condition of the issuer; • the failure of the issuer to make scheduled interest or principal payments; • recent credit downgrades of the applicable security or the issuer; and • adverse conditions specifically related to the security, an industry, or a geographic area. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of the cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through the allowance for credit losses is recognized in other comprehensive income. Changes in allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance for credit losses when management believes the uncollectibility of a security is met. We have elected to present accrued interest receivable separately from available for sale securities on the consolidated balance sheet in " Accrued Investment Income. " Accrued interest receivable was $7.2 million as of March 31, 2020 relating almost entirely to available for sale debt securities. We have also elected not to measure an allowance for credit losses for accrued interest receivable on available for sale securities. For all classes of available for sale securities, the accrual of interest is discontinued when the contractual payment of principal or interest has become 90 days past due and write-off of accrued interest receivable is recognized by reversing interest income. We did not write off any accrued interest receivable during the three months ended March 31, 2020.
Premiums Receivable	Premiums Receivable        Premiums receivable consists of premiums due on our mortgage insurance policies. If a mortgage insurance premium is unpaid for more than 120 days, the receivable is written off against earned premium and the related insurance policy is canceled. We recognize an allowance for credit losses for premiums receivable based on credit losses expected to arise over the life of the receivable. Due to the nature of our insurance policies and the short-term duration of the related receivables an allowance for credit loss was not required at March 31, 2020.
Reinsurance	Reinsurance NMIC has entered into quota share reinsurance treaties effective September 1, 2016 (the 2016 QSR Transaction) and January 1, 2018 (the 2018 QSR Transaction), which we refer to collectively as the QSR Transactions. Under the QSR Transactions, we cede a portion of claims and claim expense reserves to our reinsurers, and account for such ceded reserves as reinsurance recoverables in "Other Assets" on the consolidated balance sheets and as reductions to claims expenses on the consolidated statements of operations. The company actively manages and monitors its credit risk associated with its reinsurance recoverables and recognizes an allowance for credit losses based on losses expected to arise over the life of the asset.
Recent Accounting Pronouncements	Recent Accounting Pronouncements - Adopted In June 2016, the Financial Accounting Standard Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments-Credit Losses (Topic 326) and subsequently issued amendments to the initial guidance: ASU 2019-04, Codification Improvements to Topic 326 , Financial Instruments-Credit Losses (Topic 815) , Derivatives and Hedging , and Topic 825, Financial Instruments , ASU 2019-05, Financial Instruments-Credit Losses: Targeted Transition Relief , and ASU 2019-11, C odification Improvements to Topic 326, Financial Instruments-Credit Losses . These updates will require companies to measure and establish reserves for lifetime expected credit losses on many financial assets held at a given reporting date. Under the guidance, the methodology for measuring lifetime credit losses shifts from an incurred loss model, whereby losses are only recognized once probable and estimable, to a current expected credit loss (CECL) model, whereby losses are recognized upfront based on a future economic forecast. Credit losses relating to available-for-sale fixed maturity securities are recorded through an allowance for credit losses, rather than a write-down of the asset as was required, with the amount of the allowance limited to the amount by which fair value is less than amortized cost. The length of time an available-for sale fixed maturity security has been held in an unrealized loss position will no longer impact its credit loss determination. We adopted these updates on January 1, 2020. Adoption of the updated standards did not have a material impact on our consolidated financial statements, and had no impact on our accounting for insurance claims and claim expenses as these items are not in scope of the guidance. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) . This update modifies the fair value measurement disclosure requirements of ASC 820. We adopted this ASU on January 1, 2020 and determined it did not have a material impact on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) . This update applies to cloud computing arrangements structured as service contracts, and provides companies with guidance on the criteria for capitalizing implementation, set-up and other up-front costs incurred in association with these arrangements. We adopted this ASU on January 1, 2020 and applied it on a prospective basis for eligible costs incurred after the effective date. The adoption of this ASU did not have a material impact on our consolidated financial statements. Recent Accounting Pronouncements - Not Yet Adopted In August 2018, the FASB issued ASU 2018-12, Targeted Improvements to the Accounting for Long-Duration Contracts . This update provides guidance to the existing recognition, measurement, presentation and disclosure requirements for long-duration contracts issued by an insurance entity. The FASB subsequently issued ASU 2019-09 in November 2019, which amended the effective date for this standard. The standard will now take effect for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. We are currently evaluating the impact the adoption of this ASU will have, if any, on our consolidated financial statements. In November 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) . This update eliminates certain exceptions for recognizing deferred taxes for investments, performing intra-period allocations and calculating income taxes in interim periods. The ASU also includes guidance to reduce complexity in certain income tax areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. The standard will take effect for public business entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. We are currently evaluating the impact the adoption of this ASU will have, if any, on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) . This update provides optional guidance to ease the potential burden in accounting for reference rate reform on financial reporting. Reference rate reform refers to the global transition away from referencing the London Interbank Offered Rate (LIBOR) in financial contracts, which is expected to be discontinued in 2021. The ASU includes optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The standard is effective immediately through December 31, 2022 for all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. We are currently evaluating the impact the adoption of this ASU would have, if any, to our contract modifications that are affected by the discontinuation of LIBOR.
Earnings Per Share	Basic EPS is based on the weighted average number of shares of common stock outstanding. Diluted EPS is based on the weighted average number of shares of common stock outstanding and common stock equivalents that would be issuable upon the vesting of service based and performance and service based restricted stock units (RSUs), and the exercise of vested and unvested stock options and outstanding warrants. The number of shares issuable for RSUs subject to performance and service based vesting requirements are only included in diluted shares if the relevant performance measurement period has commenced and results during such period meet the necessary performance criteria.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Schedule of Fair Values and Gross Unrealized Gains and Losses	Fair Values and Gross Unrealized Gains and Losses on Investments Amortized Gross Unrealized Fair Gains Losses As of March 31, 2020 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,207 $ 3,519 $ — $ 51,726 Municipal debt securities 196,750 3,853 (668) 199,935 Corporate debt securities 628,834 18,272 (6,658) 640,448 Asset-backed securities 180,514 404 (7,811) 173,107 Total bonds 1,054,305 26,048 (15,137) 1,065,216 Short-term investments 4,838 18 — 4,856 Total investments $ 1,059,143 $ 26,066 $ (15,137) $ 1,070,072 Amortized Gross Unrealized Fair Gains Losses As of December 31, 2019 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,203 $ 784 $ (58) $ 48,929 Municipal debt securities 189,530 1,721 (1,035) 190,216 Corporate debt securities 661,719 23,373 (211) 684,881 Asset-backed securities 170,153 2,603 (114) 172,642 Total bonds 1,069,605 28,481 (1,418) 1,096,668 Short-term investments 44,174 98 — 44,272 Total investments $ 1,113,779 $ 28,579 $ (1,418) $ 1,140,940
Schedule of Investments by Industry Group	The following table presents a breakdown of the fair value of our corporate debt securities by issuer industry group as of March 31, 2020 and December 31, 2019: March 31, 2020 December 31, 2019 Financial 40 % 38 % Consumer 23 26 Communications 11 10 Utilities 10 9 Industrial 9 8 Technology 7 7 Energy — 2 Total 100 % 100 %
Schedule of Investments by Maturity	The amortized cost and fair values of available-for-sale securities as of March 31, 2020 and December 31, 2019, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in a separate category. As of March 31, 2020 Amortized Fair (In Thousands) Due in one year or less $ 83,740 $ 83,736 Due after one through five years 408,063 415,419 Due after five through ten years 373,220 383,838 Due after ten years 13,606 13,972 Asset-backed securities 180,514 173,107 Total investments $ 1,059,143 $ 1,070,072 As of December 31, 2019 Amortized Fair (In Thousands) Due in one year or less $ 138,776 $ 139,113 Due after one through five years 406,986 417,208 Due after five through ten years 380,737 394,180 Due after ten years 17,127 17,797 Asset-backed securities 170,153 172,642 Total investments $ 1,113,779 $ 1,140,940
Schedule of Aging Unrealized Losses	The following table summarizes the investment portfolio in an unrealized loss position for which an allowance is not recorded, aggregated by major security type and length of time in a continuous unrealized loss position: Less Than 12 Months 12 Months or Greater Total # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses As of March 31, 2020 (Dollars in Thousands) U.S. Treasury securities and obligations of U.S. government agencies — $ — $ — — $ — $ — — $ — $ — Municipal debt securities 14 46,936 (668) — — — 14 46,936 (668) Corporate debt securities 87 178,776 (6,630) 5 3,294 (28) 92 182,070 (6,658) Asset-backed securities 60 133,997 (7,745) 1 2,934 (66) 61 136,931 (7,811) Total 161 $ 359,709 $ (15,043) 6 $ 6,228 $ (94) 167 $ 365,937 $ (15,137) Less Than 12 Months 12 Months or Greater Total # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses # of Securities Fair Value Unrealized Losses As of December 31, 2019 (Dollars in Thousands) U.S. Treasury securities and obligations of U.S. government agencies 4 $ 12,001 $ (58) — $ — $ — 4 $ 12,001 $ (58) Municipal debt securities 26 92,844 (1,034) 1 999 (1) 27 93,843 (1,035) Corporate debt securities 10 30,481 (140) 14 23,976 (71) 24 54,457 (211) Asset-backed securities 9 19,236 (102) 1 2,988 (12) 10 22,224 (114) Total 49 $ 154,562 $ (1,334) 16 $ 27,963 $ (84) 65 $ 182,525 $ (1,418)
Schedule of Components of Net Investment Income	The following table presents the components of net investment income: For the three months ended March 31, 2020 2019 (In Thousands) Investment income $ 8,349 $ 7,496 Investment expenses (245) (113) Net investment income $ 8,104 $ 7,383
Schedule of Net Realized Investment Gains (Losses)	The following table presents the components of net realized investment gains (losses): For the three months ended March 31, 2020 2019 (In Thousands) Gross realized investment gains $ 540 $ 195 Gross realized investment losses (612) (382) Net realized investment (losses) $ (72) $ (187)

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value Measurements of Financial Instruments	The following tables present the level within the fair value hierarchy at which our financial instruments were measured: Fair Value Measurements Using Quoted Prices in Significant Other Significant Fair Value As of March 31, 2020 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 51,726 $ — $ — $ 51,726 Municipal debt securities — 199,935 — 199,935 Corporate debt securities — 640,448 — 640,448 Asset-backed securities — 173,107 — 173,107 Cash, cash equivalents and short-term investments 114,677 — — 114,677 Total assets $ 166,403 $ 1,013,490 $ — $ 1,179,893 Warrant liability — — 1,461 1,461 Total liabilities $ — $ — $ 1,461 $ 1,461 Fair Value Measurements Using Quoted Prices in Significant Other Significant Fair Value As of December 31, 2019 (In Thousands) U.S. Treasury securities and obligations of U.S. government agencies $ 48,929 $ — $ — $ 48,929 Municipal debt securities — 190,216 — 190,216 Corporate debt securities — 684,881 — 684,881 Asset-backed securities — 172,642 — 172,642 Cash, cash equivalents and short-term investments 85,361 — — 85,361 Total assets $ 134,290 $ 1,047,739 $ — $ 1,182,029 Warrant liability — — 7,641 7,641 Total liabilities $ — $ — $ 7,641 $ 7,641
Roll-Forward of Level 3 Liabilities Measured at Fair Value	The following is a roll-forward of Level 3 liabilities measured at fair value: For the three months ended March 31, Warrant Liability 2020 2019 (In Thousands) Balance, January 1 $ 7,641 $ 7,296 Change in fair value of warrant liability included in earnings (5,959) 5,479 Issuance of common stock on warrant exercise (221) (944) Balance, March 31 $ 1,461 $ 11,831
Schedule of Key Inputs and Assumptions in Option-Pricing Model	The following table outlines the key inputs and assumptions used to calculate the fair value of the warrant liability in the Black-Scholes option-pricing model as of the dates indicated. As of March 31, 2020 2019 Common stock price $ 11.61 $ 25.87 Risk free interest rate 0.23 % 2.21 - 2.31% Expected life 2.06 years 1.67 - 3.06 years Expected volatility 61.4 % 42.3 - 45.7% Dividend yield 0 % 0 %

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Schedule of Future Principal Payments	Future principal payments due under the 2018 Term Loan as of March 31, 2020 are as follows: As of March 31, 2020 Principal (In thousands) 2020 1,125 2021 1,500 2022 1,500 2023 143,250 Total $ 147,375

Reinsurance (Tables)

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2020
Reinsurance Disclosures [Abstract]
Schedule of Effects of Reinsurance	The effect of our reinsurance agreements on premiums written and earned is as follows: For the three months ended March 31, 2020 March 31, 2019 (In Thousands) Net premiums written Direct $ 103,453 $ 81,730 Ceded (1) (12,082) (9,807) Net premiums written $ 91,371 $ 71,923 Net premiums earned Direct $ 113,187 $ 86,298 Ceded (1) (14,470) (12,430) Net premiums earned $ 98,717 $ 73,868 (1) Net of profit commission. For the three months ended March 31, 2020 March 31, 2019 (In Thousands) Ceded risk-in-force $ 4,843,715 $ 4,534,353 Ceded premiums earned (23,011) (21,468) Ceded claims and claim expenses 1,532 899 Ceding commission earned 4,513 4,206 Profit commission 12,413 12,061
Schedule of ILN Transactions	The following table presents the inception date, covered production period, initial and current reinsurance coverage amount, and initial and current first layer retained aggregate loss under each of the ILN Transactions. ( $ values in thousands) Inception Date Covered Production Initial Reinsurance Coverage Current Reinsurance Coverage Initial First Layer Retained Loss Current First Layer Retained Loss 2017 ILN Transaction May 2, 2017 1/1/2013 - 12/31/2016 $ 211,320 $ 46,990 $ 126,793 $ 122,810 2018 ILN Transaction July 25, 2018 1/1/2017 - 5/31/2018 264,545 174,340 125,312 124,311 2019 ILN Transaction July 30, 2019 6/1/2018 - 6/30/2019 326,905 259,047 123,424 123,424

Reserves for Insurance Claims_2

Reserves for Insurance Claims and Claim Expenses (Tables)	3 Months Ended
	Mar. 31, 2020
Insurance [Abstract]
Reconciliation of Liability for Insurance Claims and Claim Expenses	The following table provides a reconciliation of the beginning and ending reserve balances for primary insurance claims and claim expenses: For the three months ended March 31, 2020 2019 (In Thousands) Beginning balance $ 23,752 $ 12,811 Less reinsurance recoverables (1) (4,939) (3,001) Beginning balance, net of reinsurance recoverables 18,813 9,810 Add claims incurred: Claims and claim expenses incurred: Current year (2) 7,558 3,909 Prior years (3) (1,861) (1,166) Total claims and claim expenses incurred 5,697 2,743 Less claims paid: Claims and claim expenses paid: Current year (2) — — Prior years (3) 1,224 694 Total claims and claim expenses paid 1,224 694 Reserve at end of period, net of reinsurance recoverables 23,286 11,859 Add reinsurance recoverables (1) 6,193 3,678 Ending balance $ 29,479 $ 15,537 (1) Related to ceded losses recoverable under the QSR Transactions, included in "Other assets" on the Condensed Consolidated Balance Sheets. See Note 5, " Reinsurance " for additional information. (2) Related to insured loans with their most recent defaults occurring in the current year. For example, if a loan defaulted in a prior year and subsequently cured and later re-defaulted in the current year, the default would be included in the current year. Amounts are presented net of reinsurance. (3) Related to insured loans with defaults occurring in prior years, which have been continuously in default before the start of the current year. Amounts are presented net of reinsurance.

Earnings per Share (EPS) (Table

Earnings per Share (EPS) (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Schedule of Earnings per Share, Basic and Diluted	The following table reconciles the net income and the weighted average shares of common stock outstanding used in the computations of basic and diluted EPS of common stock. For the three months ended March 31, 2020 2019 (In Thousands, except for per share data) Net income $ 58,271 $ 32,899 Basic weighted average shares outstanding 68,563 66,692 Basic earnings per share $ 0.85 $ 0.49 Net income $ 58,271 $ 32,899 Gain from change in fair value of warrant liability (5,959) — Diluted net income $ 52,312 $ 32,899 Basic weighted average shares outstanding 68,563 66,692 Dilutive effect of issuable shares 1,838 2,304 Diluted weighted average shares outstanding 70,401 68,996 Diluted earnings per share $ 0.74 $ 0.48 Anti-dilutive shares 15 754

Regulatory Information (Tables)

Regulatory Information (Tables)	3 Months Ended
	Mar. 31, 2020
Insurance [Abstract]
Schedule of Statutory Net Income (Loss), Surplus, Contingency Reserve and Risk-to-Capital Ratio	NMIC and Re One's combined statutory net income (loss) was as follows: For the three months ended March 31, 2020 2019 (In Thousands) Statutory net gain (loss) $ 7,691 $ (927) NMIC and Re One's combined statutory surplus, contingency reserve and risk-to-capital (RTC) ratio were as follows: March 31, 2020 December 31, 2019 (In Thousands) Statutory surplus $ 457,790 $ 449,602 Contingency reserve 588,418 531,825 RTC ratio 17.2:1 15.8:1

Organization, Basis of Presen_3

Organization, Basis of Presentation and Summary of Accounting Principles - Narrative (Details) $ in Thousands	Mar. 31, 2020USD ($)state	Dec. 31, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states in which the entity operates | state	50
Effects of Reinsurance [Line Items]
Accrued interest receivable	$ 7,200
Reinsurance recoverable on loss reserve	6,193	$ 4,939	$ 3,678	$ 3,001
Third-Party Reinsurers | QSR Transactions
Effects of Reinsurance [Line Items]
Reinsurance recoverable on loss reserve	$ 6,200

Investments - Fair Values and G

Investments - Fair Values and Gross Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,059,143	$ 1,113,779
Gross Unrealized Gains	26,066	28,579
Gross Unrealized Losses	(15,137)	(1,418)
Fair Value	1,070,072	1,140,940
U.S. Treasury securities and obligations of U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	48,207	48,203
Gross Unrealized Gains	3,519	784
Gross Unrealized Losses	0	(58)
Fair Value	51,726	48,929
Municipal debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	196,750	189,530
Gross Unrealized Gains	3,853	1,721
Gross Unrealized Losses	(668)	(1,035)
Fair Value	199,935	190,216
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	628,834	661,719
Gross Unrealized Gains	18,272	23,373
Gross Unrealized Losses	(6,658)	(211)
Fair Value	640,448	684,881
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	180,514	170,153
Gross Unrealized Gains	404	2,603
Gross Unrealized Losses	(7,811)	(114)
Fair Value	173,107	172,642
Total bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,054,305	1,069,605
Gross Unrealized Gains	26,048	28,481
Gross Unrealized Losses	(15,137)	(1,418)
Fair Value	1,065,216	1,096,668
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,838	44,174
Gross Unrealized Gains	18	98
Gross Unrealized Losses	0	0
Fair Value	$ 4,856	$ 44,272

Investments - Corporate Debt Se

Investments - Corporate Debt Securities by Industry Group (Details)	Mar. 31, 2020	Dec. 31, 2019
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	100.00%	100.00%
Financial
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	40.00%	38.00%
Consumer
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	23.00%	26.00%
Communications
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	11.00%	10.00%
Utilities
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	10.00%	9.00%
Industrial
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	9.00%	8.00%
Technology
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	7.00%	7.00%
Energy
Debt Securities By Industry [Line Items]
Corporate debt securities as component of total (percent)	0.00%	2.00%

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Unrealized loss position, accumulated loss		$ 15,137	$ 1,418
Unrealized loss position, 12 months or greater		94	84
OTTI loss in earnings	$ 400
U.S. Treasury securities and obligations of U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Cash and investments held with various state insurance departments		5,700	5,500
Unrealized loss position, accumulated loss		0	58
Unrealized loss position, 12 months or greater		$ 0	$ 0

Investments - Scheduled Maturit

Investments - Scheduled Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Due in one year or less	$ 83,740	$ 138,776
Due after one through five years	408,063	406,986
Due after five through ten years	373,220	380,737
Due after ten years	13,606	17,127
Asset-backed securities	180,514	170,153
Amortized Cost	1,059,143	1,113,779
Fair Value
Due in one year or less	83,736	139,113
Due after one through five years	415,419	417,208
Due after five through ten years	383,838	394,180
Due after ten years	13,972	17,797
Asset-backed securities	173,107	172,642
Fair Value	$ 1,070,072	$ 1,140,940

Investments - Aging of Unrealiz

Investments - Aging of Unrealized Losses (Details) $ in Thousands	Mar. 31, 2020USD ($)security	Dec. 31, 2019USD ($)security
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | security	161	49
Fair value, less than 12 months	$ 359,709	$ 154,562
Unrealized losses, less than 12 months	$ (15,043)	$ (1,334)
Number of securities,12 months or greater | security	6	16
Fair value, 12 months or greater	$ 6,228	$ 27,963
Unrealized losses, 12 months or greater	$ (94)	$ (84)
Number of securities, total | security	167	65
Fair value	$ 365,937	$ 182,525
Unrealized Losses	$ (15,137)	$ (1,418)
U.S. Treasury securities and obligations of U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | security	0	4
Fair value, less than 12 months	$ 0	$ 12,001
Unrealized losses, less than 12 months	$ 0	$ (58)
Number of securities,12 months or greater | security	0	0
Fair value, 12 months or greater	$ 0	$ 0
Unrealized losses, 12 months or greater	$ 0	$ 0
Number of securities, total | security	0	4
Fair value	$ 0	$ 12,001
Unrealized Losses	$ 0	$ (58)
Municipal debt securities
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | security	14	26
Fair value, less than 12 months	$ 46,936	$ 92,844
Unrealized losses, less than 12 months	$ (668)	$ (1,034)
Number of securities,12 months or greater | security	0	1
Fair value, 12 months or greater	$ 0	$ 999
Unrealized losses, 12 months or greater	$ 0	$ (1)
Number of securities, total | security	14	27
Fair value	$ 46,936	$ 93,843
Unrealized Losses	$ (668)	$ (1,035)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | security	87	10
Fair value, less than 12 months	$ 178,776	$ 30,481
Unrealized losses, less than 12 months	$ (6,630)	$ (140)
Number of securities,12 months or greater | security	5	14
Fair value, 12 months or greater	$ 3,294	$ 23,976
Unrealized losses, 12 months or greater	$ (28)	$ (71)
Number of securities, total | security	92	24
Fair value	$ 182,070	$ 54,457
Unrealized Losses	$ (6,658)	$ (211)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Number of securities, less than 12 months | security	60	9
Fair value, less than 12 months	$ 133,997	$ 19,236
Unrealized losses, less than 12 months	$ (7,745)	$ (102)
Number of securities,12 months or greater | security	1	1
Fair value, 12 months or greater	$ 2,934	$ 2,988
Unrealized losses, 12 months or greater	$ (66)	$ (12)
Number of securities, total | security	61	10
Fair value	$ 136,931	$ 22,224
Unrealized Losses	$ (7,811)	$ (114)

Investments - Net Investment In

Investments - Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Investment Income, Net [Abstract]
Investment income	$ 8,349	$ 7,496
Investment expenses	(245)	(113)
Net investment income	$ 8,104	$ 7,383

Investments - Net Realized Inve

Investments - Net Realized Investment Gains (Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Gross realized investment gains	$ 540	$ 195
Gross realized investment losses	(612)	(382)
Net realized investment (losses)	$ (72)	$ (187)

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Assets and Liabilities at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	$ 1,070,072	$ 1,140,940
U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	51,726	48,929
Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	199,935	190,216
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	640,448	684,881
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	173,107	172,642
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and short-term investments	114,677	85,361
Total assets	1,179,893	1,182,029
Warrant liability	1,461	7,641
Total liabilities	1,461	7,641
Recurring | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	51,726	48,929
Recurring | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	199,935	190,216
Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	640,448	684,881
Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	173,107	172,642
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and short-term investments	114,677	85,361
Total assets	166,403	134,290
Warrant liability	0	0
Total liabilities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	51,726	48,929
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and short-term investments	0	0
Total assets	1,013,490	1,047,739
Warrant liability	0	0
Total liabilities	0	0
Recurring | Significant Other Observable Inputs (Level 2) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Significant Other Observable Inputs (Level 2) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	199,935	190,216
Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	640,448	684,881
Recurring | Significant Other Observable Inputs (Level 2) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	173,107	172,642
Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents and short-term investments	0	0
Total assets	0	0
Warrant liability	1,461	7,641
Total liabilities	1,461	7,641
Recurring | Significant Unobservable Inputs (Level 3) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of securities	$ 0	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Rollforward of Level 3 Liabilities (Details) - Significant Unobservable Inputs (Level 3) - Warrant liability - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Roll-forward of Level 3 liabilities:
Beginning balance	$ 7,641	$ 7,296
Change in fair value of warrant liability included in earnings	(5,959)	5,479
Issuance of common stock on warrant exercise	(221)	(944)
Ending balance	$ 1,461	$ 11,831

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Valuation Assumptions for Warrant Liabilities (Details) - Significant Unobservable Inputs (Level 3) - Valuation Technique, Option Pricing Model	Mar. 31, 2020$ / shares	Mar. 31, 2019$ / shares
Common stock price
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input	11.61	25.87
Risk free interest rate
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input	0.0023
Risk free interest rate | Minimum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input		0.0221
Risk free interest rate | Maximum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input		0.0231
Expected life
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, expected life	2 years 21 days
Expected life | Minimum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, expected life		1 year 8 months 1 day
Expected life | Maximum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, expected life		3 years 21 days
Expected volatility
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input	0.614
Expected volatility | Minimum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input		0.423
Expected volatility | Maximum
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input		0.457
Dividend yield
Key Inputs and Assumptions, Valuation Techniques
Warrant liability, measurement input	0	0

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	Mar. 31, 2020	Mar. 20, 2020	Mar. 19, 2020	May 24, 2018	Mar. 31, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Term loan	$ 147,375,000				$ 147,375,000
Interest expense					$ 2,744,000	$ 3,061,000
2015 Term Loan
Debt Instrument [Line Items]
Debt instrument face amount				$ 150,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Debt issuance costs		$ 800,000
Revolving Credit Facility | 2018 Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument term (years)				3 years
Credit facility borrowing capacity			$ 85,000,000	$ 85,000,000
Debt instrument covenant, maximum debt-to-total capitalization ratio					35.00%
Revolving Credit Facility | 2018 Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee (percent)			0.30%
Revolving Credit Facility | 2018 Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee (percent)			0.60%
Revolving Credit Facility | 2018 Revolving Credit Facility | Eurodollar | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			2.00%
Revolving Credit Facility | 2018 Revolving Credit Facility | Eurodollar | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			3.50%
Revolving Credit Facility | 2020 Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility borrowing capacity		$ 100,000,000
Borrowings outstanding	0				$ 0
Commitment fee (percent)					0.35%
Commitment fees in interest expense					$ 100,000
Interest expense from amortization of debt issuance costs					100,000
Remaining deferred issuance costs, net of accumulated amortization	$ 1,400,000				$ 1,400,000
Revolving Credit Facility | 2020 Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee (percent)	0.175%
Revolving Credit Facility | 2020 Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee (percent)	0.525%
Revolving Credit Facility | 2020 Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Variable rate floor (percent)					1.00%
Revolving Credit Facility | 2020 Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.375%
Revolving Credit Facility | 2020 Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.875%
Revolving Credit Facility | 2020 Revolving Credit Facility | Eurodollar
Debt Instrument [Line Items]
Variable rate floor (percent)		0.00%
Revolving Credit Facility | 2020 Revolving Credit Facility | Eurodollar | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.375%
Revolving Credit Facility | 2020 Revolving Credit Facility | Eurodollar | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		2.875%
2018 Revolving Credit Facility
Debt Instrument [Line Items]
Debt issuance costs	$ 600,000				$ 600,000
2018 Revolving Credit Facility | 2020 Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			1.00%
2018 Revolving Credit Facility | 2020 Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			2.50%
Secured Debt | 2018 Term Loan
Debt Instrument [Line Items]
Debt instrument face amount				$ 150,000,000
Debt instrument term (years)				5 years
Interest rate during period (percent)					5.75%
Frequency of periodic payment					Quarterly
Periodic payment of principal					$ 400,000
Interest expense					2,500,000
Unamortized issuance costs and original issue discount	$ 1,900,000				$ 1,900,000
Debt instrument covenant, maximum debt-to-total capitalization ratio					35.00%
Secured Debt | 2018 Term Loan | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate floor (percent)					1.00%
Basis spread on variable rate (percent)						4.75%

Debt - Schedule of Future Princ

Debt - Schedule of Future Principal Payments (Details) $ in Thousands	Mar. 31, 2020USD ($)
Future Principal Payments [Abstract]
2020	$ 1,125
2021	1,500
2022	1,500
2023	143,250
Total	$ 147,375

Reinsurance - Effect of Reinsur

Reinsurance - Effect of Reinsurance Agreements on Premiums Written and Earned (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net premiums written
Direct	$ 103,453	$ 81,730
Ceded	(12,082)	(9,807)
Net premiums written	91,371	71,923
Net premiums earned
Direct	113,187	86,298
Ceded	(14,470)	(12,430)
Net premiums earned	$ 98,717	$ 73,868

Reinsurance - Narrative (Detail

Reinsurance - Narrative (Details) - USD ($) $ in Thousands	Apr. 01, 2019	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Ceded Credit Risk [Line Items]
Restricted cash			$ 2,505		$ 2,662
Reinsurance recoverable on unpaid claims		$ 3,678	$ 6,193	$ 3,678	$ 4,939	$ 3,001
ILN Transactions
Ceded Credit Risk [Line Items]
Reinsurance coverage amount amortized (as a percent)			10.00%
Third-Party Reinsurers | ILN Transactions | Maximum
Ceded Credit Risk [Line Items]
Reinsurance coverage, term of underlying mortgage amortization (in years)			10 years
Third-Party Reinsurers | 2017 ILN Transaction
Ceded Credit Risk [Line Items]
Risk premiums paid			$ 3,900	$ 3,000
Third-Party Reinsurers | 2017 ILN Transaction | Maximum
Ceded Credit Risk [Line Items]
Anticipated payment related to annual operating expenses			300
Third-Party Reinsurers | 2018 ILN Transaction | Maximum
Ceded Credit Risk [Line Items]
Anticipated payment related to annual operating expenses			$ 250
Third-Party Reinsurers | QSR Transactions
Ceded Credit Risk [Line Items]
Ceding commissions under 2016 QSR Transaction			20.00%
Reinsurance recoverable on unpaid claims			$ 6,200
Third-Party Reinsurers | Risk Written Policies in 2018
Ceded Credit Risk [Line Items]
Percent of premiums earned under 2018 QSR Transaction			25.00%
Third-Party Reinsurers | Risk Written Policies in 2019
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction			20.00%
Third-Party Reinsurers | 2018 QSR Transaction
Ceded Credit Risk [Line Items]
Threshold for loss ratio on loans to qualify for profit commission			61.00%
Reinsurance recoverable on unpaid claims			$ 3,100
Third-Party Reinsurers | 2016 QSR Transaction
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction	20.50%	25.00%
Previously ceded primary RIF recaptured	$ 500,000
Threshold for loss ratio on loans to qualify for profit commission			60.00%
Reinsurance recoverable on unpaid claims			$ 3,100
Third-Party Reinsurers | Fannie Mae
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction			100.00%
Third-Party Reinsurers | Eligible Policies, Pool One
Ceded Credit Risk [Line Items]
Percent of premiums ceded under QSR Transaction			25.00%

Reinsurance - ILN Transactions

Reinsurance - ILN Transactions (Details) - USD ($) $ in Thousands	Jul. 30, 2019	Jul. 25, 2018	May 02, 2017
2017 ILN Transaction
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Initial Reinsurance Coverage			$ 211,320
Current Reinsurance Coverage			46,990
Initial First Layer Retained Loss			126,793
Current First Layer Retained Loss			$ 122,810
2018 ILN Transaction
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Initial Reinsurance Coverage		$ 264,545
Current Reinsurance Coverage		174,340
Initial First Layer Retained Loss		125,312
Current First Layer Retained Loss		$ 124,311
2019 ILN Transaction
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Initial Reinsurance Coverage	$ 326,905
Current Reinsurance Coverage	259,047
Initial First Layer Retained Loss	123,424
Current First Layer Retained Loss	$ 123,424

Reinsurance - Amounts Related t

Reinsurance - Amounts Related to QSR Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Ceded Credit Risk [Line Items]
Ceded premiums earned	$ (14,470)	$ (12,430)
Third-Party Reinsurers
Ceded Credit Risk [Line Items]
Ceded risk-in-force	4,843,715	4,534,353
Ceded premiums earned	(23,011)	(21,468)
Ceded claims and claim expenses	1,532	899
Ceding commission earned	4,513	4,206
Profit commission	$ 12,413	$ 12,061

Reserves for Insurance Claims_3

Reserves for Insurance Claims and Claim Expenses - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)claimloan	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Liability for Claims and Claims Adjustment Expense [Line Items]
IBNR, default period (at least)	60 days
Total gross liability for unpaid claims and claim adjustment expenses	$ 29,479	$ 15,537	$ 23,752	$ 12,811
Primary loans in default | loan	1,449
Number of claims paid | claim	34
Claims paid, including amounts covered by insurance	$ 1,500
Favorable prior year development	1,861	$ 1,166
Reserve for prior year insurance claims and claim expenses	$ 19,900
Fannie Mae
Liability for Claims and Claims Adjustment Expense [Line Items]
Number of loans in pool past due 60 days or more | loan	46
Risk-in-Force of loans in pool past due 60 days or more	$ 3,000
Loan-to-value ratio (less than)	0.80
Claims applied to pool deductible	$ 900
Deductible on policy	$ 9,500
QSR Transactions
Liability for Claims and Claims Adjustment Expense [Line Items]
Number of covered claims included in number of claims paid | claim	31
Component of claims paid covered under QSR Transaction	$ 300
2016 QSR Transaction | Fannie Mae
Liability for Claims and Claims Adjustment Expense [Line Items]
Percent of pool RIF reinsured	100.00%

Reserves for Insurance Claims_4

Reserves for Insurance Claims and Claim Expenses - Reconciliation of Reserve Balances for Insurance Claims and Claim Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance	$ 23,752	$ 12,811
Less reinsurance recoverables	(4,939)	(3,001)
Beginning balance, net of reinsurance recoverables	18,813	9,810
Claims and claim expenses incurred:
Current year	7,558	3,909
Prior years	(1,861)	(1,166)
Total claims and claim expenses incurred	5,697	2,743
Claims and claim expenses paid:
Current year	0	0
Prior years	1,224	694
Total claims and claim expenses paid	1,224	694
Reserve at end of period, net of reinsurance recoverables	23,286	11,859
Add reinsurance recoverables	6,193	3,678
Ending balance	$ 29,479	$ 15,537

Earnings per Share (EPS) (Detai

Earnings per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings per Share, Basic [Abstract]
Net income	$ 58,271	$ 32,899
Basic weighted average shares outstanding (in shares)	68,563	66,692
Basic earnings per share (in dollars per share)	$ 0.85	$ 0.49
Earnings per Share, Diluted [Abstract]
Net income	$ 58,271	$ 32,899
Gain from change in fair value of warrant liability	(5,959)	0
Diluted net income	$ 52,312	$ 32,899
Basic weighted average shares outstanding (in shares)	68,563	66,692
Dilutive effect of issuable shares (in shares)	1,838	2,304
Dilutive weighted average shares outstanding (in shares)	70,401	68,996
Diluted earnings per share (in dollars per share)	$ 0.74	$ 0.48
Anti-dilutive shares (in shares)	15	754

Warrants (Details)

Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Apr. 30, 2012
Debt Disclosure [Abstract]
Warrants issued (in shares)				992,000
Right to purchase, number of shares per warrant (in shares)				1
Exercise price of warrants (in dollars per warrant)				$ 10
Warrant liability, at fair value	$ 1,461		$ 7,641	$ 5,100
Warrants exercised (in shares)	9,000	67,000
Stock issued upon exercise of warrants (in shares)	6,474	39,195
Fair value of warrant liability reclassified to additional paid in capital upon exercise	$ 200	$ 900
Change in fair value of warrant liability in current period	$ 8	$ 300

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate on pre-tax income or loss	19.20%	15.60%
Tax and loss bonds	$ 7.6

Regulatory Information - Statut

Regulatory Information - Statutory Net Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
NMIC and Re One Combined
Statutory Accounting Practices [Line Items]
Statutory net gain (loss)	$ 7,691	$ (927)

Regulatory Information - Schedu

Regulatory Information - Schedule of Statutory Surplus, Contingency Reserve and RTC Ratio (Details) - NMIC and Re One Combined $ in Thousands	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Statutory Accounting Practices [Line Items]
Statutory surplus	$ 457,790	$ 449,602
Contingency reserve	$ 588,418	$ 531,825
RTC ratio	17.2	15.8

Regulatory Information - Narrat

Regulatory Information - Narrative (Details) $ in Millions	Dec. 31, 2019USD ($)
NMIC and Re One Combined
Statutory Accounting Practices [Line Items]
Aggregate dividend capacity	$ 16.1

Subsequent Event (Details)

Subsequent Event (Details) - Revolving Credit Facility - USD ($)	Apr. 30, 2020	Mar. 20, 2020	Mar. 19, 2020	May 24, 2018
Subsequent Event | Senior debt
Subsequent Event [Line Items]
Credit facility borrowing capacity	$ 400,000,000
2018 Revolving Credit Facility
Subsequent Event [Line Items]
Credit facility borrowing capacity			$ 85,000,000	$ 85,000,000
2020 Revolving Credit Facility
Subsequent Event [Line Items]
Credit facility borrowing capacity		$ 100,000,000