NMI (NMIH) 10-Q 17 Dec 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Dec. 01, 2013
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'NMI HOLDINGS, INC.	'
Entity Central Index Key	'0001547903	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-13	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	58,052,480

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
Investments, available-for-sale, at fair value:	'	'
Fixed maturities (amortized cost of $419,021,671 and $0 as of September 30, 2013 and December 31, 2012, respectively)	$411,983,016	$0
Short-term investments	0	4,864,206
Total investment portfolio	411,983,016	4,864,206
Cash and cash equivalents	34,097,356	485,855,418
Accrued investment income	1,834,079	0
Prepaid expenses	1,053,057	416,861
Restricted cash	0	40,338,155
Deferred policy acquisition costs, net	4,226	0
Goodwill and other intangible assets	3,634,197	3,634,197
Software and equipment, net	9,053,995	7,550,095
Other assets	59,050	108,802
Total Assets	461,718,976	542,767,734
Liabilities	'	'
Accounts payable and accrued expenses	9,275,843	8,707,573
Placement fee payable	0	38,305,405
Purchase consideration payable	0	2,032,750
Warrant liability	5,452,428	4,841,765
Deferred tax liability	132,600	132,600
Total Liabilities	14,860,871	54,020,093
Commitments and Contingencies	'	'
Shareholders' Equity	'	'
Additional paid-in capital	524,280,385	517,032,619
Accumulated other comprehensive (loss) income	-7,038,655	559
Deficit accumulated during the development phase	-70,940,000	-28,840,538
Total Shareholders' Equity	446,858,105	488,747,641
Total Liabilities and Shareholders' Equity	461,718,976	542,767,734
Common Class A [Member]	'	'
Shareholders' Equity	'	'
Common stock, shares outstanding	556,375	552,501
Common Class B [Member]	'	'
Shareholders' Equity	'	'
Common stock, shares outstanding	$0	$2,500

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Fixed maturity, amortized cost	$419,021,671	$0
Common Class A [Member]	'	'
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares issued	55,637,480	55,250,100
Common stock, shares outstanding	55,637,480	55,250,100
Common stock, shares authorized	250,000,000	250,000,000
Common Class B [Member]	'	'
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares issued	0	250,000
Common stock, shares outstanding	0	250,000
Common stock, shares authorized	250,000	250,000

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		9 Months Ended		28 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Revenues	'	'	'	'	'
Direct premiums written	$481,529	$0	$482,566	$0	$482,566
Increase (decrease) in unearned premiums	0	0	0	0	0
Net premiums earned	481,529	0	482,566	0	482,566
Net investment income	1,519,361	874	3,336,150	874	3,341,975
Net realized investment gains (losses)	-308,418	0	172,291	0	172,291
Gain (Loss) from change in fair value of warrant liability	468,848	0	-610,663	0	-332,859
Total Revenues	2,161,320	874	3,380,344	874	3,663,973
Expenses	'	'	'	'	'
Payroll and related	7,090,357	4,085,597	20,896,375	5,914,924	32,455,289
Share-based compensation	1,967,980	2,045,215	8,827,053	3,091,096	14,942,413
Depreciation and amortization	2,045,306	0	3,892,054	0	3,894,971
Professional fees	2,348,771	1,143,135	5,576,684	2,470,368	11,079,486
Information technology	1,328,268	281,364	3,455,087	281,364	4,327,540
Travel and related costs	262,701	227,634	965,569	424,502	1,691,033
Rent and office expenses	212,040	97,852	524,849	124,690	757,841
Financial fees and interest expense	0	0	0	1,628,635	1,632,364
Loss on impairment	0	0	0	0	1,200,000
Other	778,571	232,750	1,342,135	760,118	2,623,036
Total Expenses	16,033,994	8,113,547	45,479,806	14,695,697	74,603,973
Net Loss	-13,872,674	-8,112,673	-42,099,462	-14,694,823	-70,940,000
Share Data	'	'	'	'	'
Basic and Diluted loss per share (in dollars per share)	($0.25)	($0.15)	($0.76)	($0.46)	($2.11)
Weighted average common shares (in shares)	55,637,480	55,500,100	55,589,674	32,003,750	33,585,018
Other Comprehensive Income (Loss) (net of tax)	'	'	'	'	'
Net unrealized holding gains (losses) for the period included in accumulated other comprehensive income (loss)	2,283,106	0	-7,039,214	0	-7,038,655
Other Comprehensive Income (Loss) (net of tax)	2,283,106	0	-7,039,214	0	-7,038,655
Total Comprehensive Loss	($11,589,568)	($8,112,673)	($49,138,676)	($14,694,823)	($77,978,655)

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Total	Common Class A [Member]	Common Class B [Member]	Common Stock [Member]	Common Stock [Member]	Additional paid-in capital [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (loss) [Member]	Deficit Accumulated During the Development Phase [Member]
				Common Class A [Member]	Common Class B [Member]		Common Class A [Member]
Beginning Balance at May. 18, 2011	$0	'	'	$0	$0	$0	'	$0	$0
Beginning Balance, Shares at May. 18, 2011	'	'	'	0	0	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'
Issuance of shares of common stock, Shares	'	'	'	55,137,480	250,000	'	'	'	'
Issuance of shares of common stock	'	507,391,847	2,500	551,375	2,500	'	506,840,472	'	'
Conversion of Class B shares of common stock into Class A shares of common stock, Shares	'	'	'	250,000	-250,000	'	'	'	'
Conversion of Class B shares of common stock into Class A shares of common stock	'	'	'	2,500	-2,500	'	'	'	'
Issuance of common stock related to acquisition of subsidiaries, Shares	'	'	'	250,000	'	'	'	'	'
Issuance of common stock related to acquisition of subsidiaries	2,500,000	'	'	2,500	'	2,497,500	'	'	'
Share-based compensation expense	14,942,413	'	'	'	'	14,942,413	'	'	'
Change in unrealized investment gains/losses	-7,038,655	'	'	'	'	'	'	-7,038,655	'
Net loss	-70,940,000	'	'	'	'	'	'	'	-70,940,000
Ending Balance at Sep. 30, 2013	446,858,105	'	'	556,375	0	524,280,385	'	-7,038,655	-70,940,000
Ending Balance, Shares at Sep. 30, 2013	'	55,637,480	0	55,637,480	0	'	'	'	'
Beginning Balance at Dec. 31, 2011	-1,348,824	'	'	1	0	0	'	0	-1,348,825
Beginning Balance, Shares at Dec. 31, 2011	'	'	'	100	0	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'
Issuance of shares of common stock, Shares	'	'	'	55,000,000	250,000	'	'	'	'
Issuance of shares of common stock	'	508,969,759	2,500	550,000	2,500	'	508,419,759	'	'
Issuance of common stock related to acquisition of subsidiaries, Shares	'	'	'	250,000	'	'	'	'	'
Issuance of common stock related to acquisition of subsidiaries	2,500,000	'	'	2,500	'	2,497,500	'	'	'
Share-based compensation expense	6,115,360	'	'	'	'	6,115,360	'	'	'
Change in unrealized investment gains/losses	559	'	'	'	'	'	'	559	'
Net loss	-27,491,713	'	'	'	'	'	'	'	-27,491,713
Ending Balance at Dec. 31, 2012	488,747,641	'	'	552,501	2,500	517,032,619	'	559	-28,840,538
Ending Balance, Shares at Dec. 31, 2012	'	55,250,100	250,000	55,250,100	250,000	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'	'	'
Issuance of shares of common stock, Shares	'	'	'	137,380	'	'	'	'	'
Issuance of shares of common stock	'	-1,577,913	'	1,374	'	'	-1,579,287	'	'
Conversion of Class B shares of common stock into Class A shares of common stock, Shares	'	'	'	250,000	-250,000	'	'	'	'
Conversion of Class B shares of common stock into Class A shares of common stock	'	'	'	2,500	-2,500	'	'	'	'
Share-based compensation expense	8,827,053	'	'	'	'	8,827,053	'	'	'
Change in unrealized investment gains/losses	-7,039,214	'	'	'	'	'	'	-7,039,214	'
Net loss	-42,099,462	'	'	'	'	'	'	'	-42,099,462
Ending Balance at Sep. 30, 2013	$446,858,105	'	'	$556,375	$0	$524,280,385	'	($7,038,655)	($70,940,000)
Ending Balance, Shares at Sep. 30, 2013	'	55,637,480	'	55,637,480	0	'	'	'	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended		28 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Net Cash Provided by (Used in) Operating Activities [Abstract]	'	'	'
Net Loss	($42,099,462)	($14,694,823)	($70,940,000)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'	'
Share-based compensation expense	8,827,053	3,091,096	14,942,413
Warrants issued in connection with line of credit	0	1,619,569	1,619,569
Loss from change in fair value of warrant liability	610,663	0	332,859
Net realized investment gains	-172,291	0	-172,291
Loss on impairment	0	0	1,200,000
Depreciation and other amortization	5,409,867	0	5,412,784
Accrued investment income	-1,834,079	0	-1,839,904
Changes in operating assets and liabilities:	'	'	'
Prepaid expense	-636,196	-200,211	-1,053,057
Deferred policy acquisition costs, net	-4,226	0	-4,226
Other assets	49,752	-47,716	-55,244
Accounts payable and accrued expenses	568,270	1,368,314	6,474,873
Net Cash Used in Operating Activities	-29,280,649	-8,863,771	-44,082,224
Cash Flows from Investing Activities	'	'	'
Purchase of short-term investments	-509,964	-3,457,717	-5,371,592
Purchase of fixed maturities, available-for-sale	-559,752,153	0	-559,752,153
Proceeds from maturity of short-term investments	5,375,000	0	5,375,000
Proceeds from sale of fixed maturities, available-for-sale	139,383,571	0	139,383,571
Purchase of software and equipment	-5,395,954	-654,597	-7,842,458
Acquisition of subsidiaries	0	-2,500,000	-2,500,000
Net Cash Used in Investing Activities	-420,899,500	-6,612,314	-430,707,632
Cash Flows from Financing Activities	'	'	'
Payments on line of credit	0	-205,318	0
Taxes paid related to net share settlement of equity awards	-1,577,913	0	-1,577,913
Issuance of common stock	0	510,465,124	510,465,125
Net Cash (Used in) Provided by Financing Activities	-1,577,913	510,259,806	508,887,212
Net (Decrease) Increase in Cash and Cash Equivalents	-451,758,062	494,783,721	34,097,356
Cash and Cash Equivalents, beginning of period	485,855,418	1	0
Cash and Cash Equivalents, end of period	34,097,356	494,783,722	34,097,356
Noncash Financing Activities	'	'	'
Restricted Cash	0	20,830,488	40,338,155
Noncash Financing Activities	'	'	'
Conversion of Class B shares of common stock into Class A shares of common stock	$2,500	$0	$2,500
Acquisition of subsidiaries	'	'	'
Warrants issued in connection with acquisition of subsidiaries, Shares	0	3,500,000	3,500,000
Common stock issued in connection with acquisition of subsidiaries, Shares	0	2,500,000	2,500,000

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Basis of Presentation	'
	Organization and Basis of Presentation
	NMI Holdings, Inc. (A Development Stage Company) ("the Company"), a Delaware corporation, was formed in May 2011 with the intention of providing private mortgage guaranty insurance through a wholly owned insurance subsidiary. From May 2011 through March 2013, the Company's activities were limited to raising capital, seeking to acquire the assets and approvals necessary to become a private mortgage guaranty insurance provider and hiring personnel. The accompanying consolidated financial statements include the accounts of NMI Holdings, Inc. and its wholly owned subsidiaries, MAC Financial Holding Corporation, National Mortgage Insurance Corporation ("NMIC"), previously named Mortgage Assurance Corporation, National Mortgage Reinsurance Inc One ("NMI Re One"), previously named Mortgage Assurance Reinsurance Inc One, and National Mortgage Reinsurance Inc Two ("NMI Re Two"), previously named Mortgage Assurance Reinsurance Inc Two. In April 2013, the Company, through its primary insurance subsidiary, began writing its first mortgage guaranty insurance policies. On September 30, 2013, the Company merged NMI Re Two into NMIC with NMIC surviving the merger and MAC Financial Holding Corporation merged into NMI Holdings, Inc., with NMI Holdings, Inc. surviving the merger.
	On November 30, 2011, the Company entered into an agreement with MAC Financial Ltd. to acquire MAC Financial Holding Corporation and its subsidiaries, Mortgage Assurance Corporation, Mortgage Assurance Reinsurance Inc One and Mortgage Assurance Reinsurance Inc Two, for approximately $8.5 million in cash, common stock and warrants plus the assumption of approximately $1.3 million in liabilities ("MAC Acquisition"). In addition, the Company incurred $0.1 million in tax liabilities as a result of the acquisition of certain indefinite-lived intangibles. The acquisition was completed in April 2012.
	In April 2012, the Company offered and sold 55.0 million shares of common stock at an issue price of $10.00 per share. Gross proceeds from the offering were $550.0 million. Net proceeds from the offering, after an approximate 7% underwriting fee and other offering expenses, were approximately $510 million. The fee was escrowed for the benefit of FBR Capital Markets and Co. ("FBR") and was released to FBR upon the Company's receipt of approval from Federal National Home Mortgage Association ("Fannie Mae") and Federal Home Loan Mortgage Corporation ("Freddie Mac") ("GSE Approval"). An additional $1.5 million in offering expenses were paid by the Company upon GSE Approval in January 2013.
	Under the terms of the offering, the Company had until January 17, 2013 to obtain GSE Approval ("GSE Approval Deadline"). The Company was approved as an eligible mortgage guaranty insurer by Freddie Mac and Fannie Mae, on January 15, 2013 and January 16, 2013, respectively, which approvals are conditioned upon the Company maintaining certain conditions.
	Basis of Presentation
	The accompanying consolidated financial statements include the results of the Company and its wholly owned subsidiaries. All intercompany transactions have been eliminated. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (US GAAP). The accounts of the Company and its subsidiaries are maintained in US dollars. The preparation of financial statements in accordance with generally accepted accounting principles 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.
	Basic net loss per share is based on the weighted-average number of common shares outstanding, while diluted net loss per share is based on the weighted-average number of common shares outstanding and common stock equivalents that would be issuable upon the exercise of stock options, other stock-based compensation arrangements, and the dilutive effect of outstanding warrants. As a result of the Company's net loss for the three and nine months ended September 30, 2013, 5,304,693 shares of the Company's common stock equivalents issued under stock-based compensation arrangements and warrants were not included in the calculation of diluted net loss per share as of such dates because they were anti-dilutive. As a result of the Company's net loss for the three and nine months ended September 30, 2012, 4,414,165 shares of the Company's common stock equivalents issued under stock-based compensation arrangements and warrants were not included in the calculation of diluted net loss per share as of such dates because they were anti-dilutive.

Summary_of_Accounting_Policies

Summary of Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Accounting Principles	'
	Summary of Accounting Principles
	Cash and Cash Equivalents
	The Company considers items such as certificates of deposit and money market funds with original maturities of 90 days or less to be cash equivalents.
	The Company had restricted cash as of December 31, 2012. The restricted cash balance was comprised of two escrow accounts that were initially funded on April 24, 2012 with an agreement that the funds would be released upon GSE Approval. The restricted cash was payable to FBR and MAC Financial Ltd. and was released from escrow on January 23, 2013. There was no restricted cash as of September 30, 2013.
	Investments
	The Company has designated its investment portfolio as available-for-sale and is reported at fair value. The related unrealized gains and losses are, after considering the related tax expense or benefit, recognized as a component of accumulated other comprehensive income (loss) in shareholders' equity. Net realized investment gains and losses are reported in income based upon specific identification of securities sold.
	Purchases and sales of investments are recorded on a trade date basis. Net investment income is recognized when earned and includes interest and dividend income together with amortization of market premiums and discounts using the effective yield method and is net of investment management fees and other investment related expenses. For asset-backed securities and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments.
	Each quarter the Company evaluates the investments in order to determine whether declines in fair value below amortized cost were considered other-than-temporary in accordance with applicable guidance. In evaluating whether a decline in fair value is other-than-temporary, the Company considers several factors including, but not limited to:
	•	the Company's intent to sell the security or whether it is more likely than not that the Company will be required to sell the security before recovery;
	•	severity and duration of the decline in fair value;
	•	the financial condition of the issuer;
	•	failure of the issuer to make scheduled interest or principal payments;
	•	recent credit downgrades of the applicable security or the issuer below investment grade; and
	•	adverse conditions specifically related to the security, an industry, or a geographic area.
	Under the current guidance, a debt security impairment is deemed other than temporary if (1) the Company either intends to sell the security, or it is more likely than not that the Company will be required to sell the security before recovery or (2) the Company does not expect to collect cash flows sufficient to recover the amortized cost basis of the security. In the event of the decline in fair value of a debt security, a holder of that security that does not intend to sell the debt security and for whom it is more likely than not that such holder will be required to sell the debt security before recovery of its amortized cost basis is required to separate the decline in fair value into (a) the amount representing the credit loss and (b) the amount related to other factors. The amount of total decline in fair value related to the credit loss shall be recognized in earnings as other-than-temporary impairment ("OTTI") with the amount related to other factors recognized in accumulated other comprehensive income or loss, net of tax. In periods after recognition of an OTTI on debt securities, the Company accounts for such securities as if they had been purchased on the measurement date of the OTTI at an amortized cost basis equal to the previous amortized cost basis less the OTTI recognized in earnings. For debt securities for which OTTI were recognized in earnings, the difference between the new amortized cost basis and the cash flows expected to be collected will be accreted into net investment income. The determination of OTTI is a subjective process, and different judgments and assumptions could affect the timing of the loss realization.
	Revenue Recognition
	In the mortgage guaranty insurance industry, a “book” is a group of loans that an MI ("Mortgage Insurance") company insures in a particular period, normally a calendar year. The Company sets premiums at the time a policy is issued based on the Company's expectations regarding likely performance over the term of coverage. The policies the Company writes are guaranteed renewable contracts at the policyholder's option on a single, annual or monthly premium basis. The Company generally has no ability to reunderwrite or reprice these contracts.  Premiums written on a single premium basis and an annual premium basis are initially deferred as unearned premium reserve and earned over the policy term.  Premiums written on policies covering more than one year are amortized over the policy life in accordance with the expiration of risk which is the anticipated claim payment pattern based on industry experience.  Premiums written on annual policies are earned on a monthly pro rata basis.  Premiums written on monthly policies are earned as coverage is provided. Premiums written on pool transactions are earned over the period that coverage is provided.  Upon cancellation of a policy, all premium that is non-refundable is immediately earned. Any refundable premium is returned to the policyholder. The actual return of premium for all periods affects premiums written and earned in those periods.
	Deferred Policy Acquisition Costs
	Costs directly associated with the successful acquisition of mortgage guaranty insurance business, consisting of certain employee compensation and other policy issuance and underwriting expenses, are initially deferred and reported as deferred policy acquisition costs ("DAC"). For each book year of business, these costs are amortized to income in proportion to estimated gross profits over the estimated life of the policies.
	Business Combinations, Goodwill and Intangible Assets
	Goodwill represents the excess of the purchase price over the estimated fair value of net assets acquired from a business combination. In accordance with Accounting Standards Codification ("ASC") 350, Intangibles - Goodwill and Other, the Company will test goodwill for impairment during the third quarter each year or more frequently if the Company believes indicators of impairment exist. The Company has not identified any impairments of goodwill through September 30, 2013.
	The Company's intangible assets consist of state licenses and GSE applications which have indefinite lives. The Company tests indefinite-lived intangible assets for impairment during the fourth quarter of each year or more frequently if the Company believes indicators of impairment exist. The Company does not believe that the indefinite-lived intangible assets were impaired as of September 30, 2013.
	Software and Equipment
	Software and equipment are stated at cost, less accumulated amortization and depreciation. Amortization and depreciation are calculated using the straight-line method over the estimated useful lives of the respective assets ranging typically from 3 to 7 years, unless factors indicate a shorter useful life. During the second quarter of 2013, the Company conducted an analysis on the existing Insurance Management System ("IMS"), which was acquired in connection with the MAC Acquisition, and evaluated development efforts in pursuit of designing a system that would meet the Company's business requirements. Based on that analysis, the Company made the business decision during the second quarter of 2013 to pursue the development of new modules to support policy servicing, billing and delinquency and claims management business functions. As a result of the change in approach, the Company reduced the useful life of the modules of IMS that support these business functions and shortened the amortization period of the modules to 7 and 18 months. Amortization of software and depreciation of equipment commences at the beginning of the month following the placement of the assets into use by the Company.
	Warrants
	The Company accounts for warrants to purchase common shares of the Company that were issued to FBR and MAC Financial Ltd. in conjunction with the line of credit and stock purchase agreement, respectively, in accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 470-20 Debt with Conversion and Other Options and ASC 815-40 Derivatives and Hedging - Contracts in Entity's Own Equity. These warrants may be settled by the Company using the physical settlement method or through cashless exercises in which shares subject to the warrants are reduced in lieu of cash payment of the exercise price. The exercise price and the number of warrants are subject to anti-dilution provisions whereby the existing exercise price is adjusted downward and the number of warrants increased for events that may not be dilutive and the adjustment may be in excess of any dilution suffered. As a result, the warrants are classified as a liability. The Company revalues the warrants at the end of each reporting period and any change in fair value is reported in the statements of operations in the period in which the change occurred. The fair value of the warrants is calculated using a Black-Scholes option-pricing model in combination with a binomial model and a Monte Carlo simulation model used to value the pricing protection features within the warrant.
	Stock-Based Compensation
	The Company adopted ASC 718, Compensation - Stock Compensation ("ASC 718"). ASC 718 addresses accounting for share-based awards and recognition of compensation expense, measured using grant date fair value, over the requisite service or performance period of the award. Share-based payments include restricted stock units and stock option grants under the 2012 Stock Incentive Plan. The fair value of stock option grants issued are determined based on an option pricing model which takes into account various assumptions that are subjective. Key assumptions used in the stock option valuation include the expected term of the equity award taking into account the contractual term of the award, the effects of expected exercise and post-vesting termination behavior, expected volatility, expected dividends and the risk-free interest rate for the expected term of the award. Restricted stock unit grants to employees contain a market condition and/or service condition. The fair value of restricted stock unit grants to employees with a market condition is determined based on a Monte Carlo simulation model at the date of grant. Restricted stock unit grants to employees with a service condition and restricted stock unit grants to non-employee directors are valued at the Company's stock price on the date of grant less the present value of anticipated dividends.
	Offering and Incorporation Expenses
	Offering expenses incurred in connection with the capitalization of the Company were recorded as a reduction of paid-in-capital at closing. These costs include certain investment banking fees, legal fees, printer fees and audit fees. Any incorporation and organizational expenses not related to the raising of capital are expensed as incurred and are included in the statement of operations.
	Income Taxes
	The Company accounts for income taxes using the liability method in accordance with FASB ASC Topic 740 - Income Taxes. The liability method measures the expected future tax effects of temporary differences at the enacted tax rates applicable for the period in which the deferred asset or liability is expected to be realized or settled. Temporary differences are differences between the tax basis of an asset or liability and its reported amount in the consolidated financial statements that will result in future increases or decreases in taxes owed on a cash basis compared to amounts already recognized as tax expense in the consolidated statement of operations.
	The Company evaluates the need for a valuation allowance against its deferred tax assets on a quarterly basis. In the course of its review, the Company assesses all available evidence, both positive and negative, including future sources of income, tax planning strategies, future contractual cash flows and reversing temporary differences. Additional valuation allowance benefits or charges could be recognized in the future due to changes in management's expectations regarding the realization of tax benefits. Uncertain tax positions taken or expected to be taken in a tax return by the Company are recognized in the financial statements when it is more likely than not that the position would be sustained upon examination by tax authorities. There are no tax uncertainties that are expected to result in significant increases or decreases to unrecognized tax benefits within the next twelve month period.
	In assessing the valuation of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible.
	Recent Accounting Developments Not Adopted
	Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the FASB issued an Accounting Standards Update addressing the reporting of reclassifications out of accumulated other comprehensive income. The Update requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in the statement of operations if the amount being reclassified is required under U.S. GAAP to be reclassified in its entirety to net income. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under U.S. GAAP that provide additional detail about those amounts. For public entities, the amendments are effective for reporting periods beginning after December 15, 2012. For nonpublic entities, the amendments are effective for reporting periods beginning after December 15, 2013. Early adoption is permitted. The Company expects this guidance to affect financial statement disclosures but not to have an impact on the Company's results of operations, financial position or liquidity.
	Recent Accounting Standards Updates Adopted
	Nonpublic Entity Disclosures about Financial Instruments
	In February 2013, the FASB issued an Accounting Standards Update clarifying the intended scope of the disclosures required by Update 2011-04, Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs. The amendments clarify that the requirement to disclose "the level of the fair value hierarchy within which the fair value measurements are categorized in their entirety (Level 1, 2, or 3)" does not apply to nonpublic entities for items that are not measured at fair value in the statement of financial position but for which fair value is disclosed. The amendments were effective upon issuance. The adoption of this guidance in February 2013 did not have any effect on the Company's results of operations, financial position or liquidity.
	Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities
	In January 2013, the FASB issued an Accounting Standards Update clarifying that the scope of Update 2011-11, Balance Sheet (Topic 210): Disclosures about Offsetting Assets and Liabilities, applies to derivatives accounted for in accordance with Topic 815, Derivatives and Hedging, including bifurcated embedded derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing and securities lending transactions that are either offset in accordance with Section 210-20-45 or Section 815-10-45 or subject to an enforceable master netting arrangement or similar agreement. The amendments are effective for fiscal years beginning on or after January 1, 2013, and interim periods within those annual periods. The adoption of this guidance in January 2013 did not have any effect on the Company's results of operations, financial position or liquidity.
	Reclassifications
	Certain items in the financial statements as of December 31, 2012 and for the periods ending September 30, 2012 and for the period from May 19, 2011 (inception) to September 30, 2013 have been reclassified to conform to the current period's presentation. There was no effect on net income or shareholders' equity previously reported.

Common_Stock_Offering

Common Stock Offering	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Common Stock Offering	'
	Common Stock Offering
	The Company entered into a purchase/placement agreement with FBR on April 17, 2012 and offered and sold an aggregate of 55,000,000 of its class A common shares resulting in net proceeds of approximately $510 million. In accordance with the terms of the Offering, the Company placed approximately 93% (or $476 million) of the Company's net proceeds from this offering into investment accounts established for the purpose of preserving such proceeds on a short-term basis, prior to approval from at least one of the GSEs as an eligible mortgage guaranty insurance provider to the GSE. As provided in the Company's Certificate of Incorporation, this amount was not to be disbursed (used for operating activities) until the earlier of (i) receipt by the Company of GSE Approval or (ii) the liquidation of the Company. Approximately $35 million of the net proceeds were available for paying the cash portion of the MAC Acquisition and to pay off the FBR loan. The remaining balance of approximately $32 million was placed in an operating account for the purpose of funding the Company's operations through the time of GSE Approval.
	The initial purchaser's discount and placement fee of $38.3 million was comprised of $19.5 million in common stock and $18.8 million in cash. On October 24, 2012, FBR sold the aforementioned common stock and proceeds of $19.5 million were retained in an escrow account until the Company received GSE Approval.
	In January 2013, following GSE Approval, the escrow funds were released and distributed to FBR (its initial purchasers' discount and placement fees from the escrow account) and to MAC (its cash portion of the MAC Acquisition), respectively.

Acquisition_of_MAC

Acquisition of MAC	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Acquisition of MAC	'
	Acquisition of MAC
	On November 30, 2011, the Company entered into a definitive stock purchase agreement with MAC Financial Ltd. to acquire MAC Financial Holdings Corporation and its wholly owned subsidiaries (collectively "MAC"). The transaction closed shortly after the closing of the common stock offering described above. Under the agreement, the total initial consideration paid for MAC was $8.5 million consisting of $2.5 million in cash, $2.5 million in the Company's common stock, and warrants to acquire the Company's common stock valued at $3.5 million. The consideration (net of expenses paid on MAC's behalf) was held in an escrow account until the Company received GSE Approval, upon which time it was released to MAC Financial Ltd. The total purchase consideration was allocated to the acquired assets and liabilities as follows:
	April 24, 2012
	Current assets	$	52,159
	Intangibles	1,590,000
	Capitalized software	5,000,000
	Goodwill	3,244,197
	Subtotal	9,886,356
	Current liabilities and deferred tax liabilities	(1,386,356		)
	Estimated fair value of net assets acquired	$	8,500,000
	Pursuant to the terms of the stock purchase agreement, the Company assumed approximately $1.3 million of MAC's existing liabilities, which related to outstanding payment obligations under its vendor contracts with CDW, LLC, Milliman, Inc., and Intellect/SEEC, Inc. and incurred $0.1 million in tax liabilities as a result of the acquisition of certain indefinite-lived intangibles. All other liabilities which existed at closing are the sole obligation of MAC Financial Ltd. As of September 30, 2013 and December 31, 2012, the total amount of cash held in escrow (net of expenses paid on MAC's behalf) was $0 and $2.0 million, respectively.
	Included in the acquired intangibles of $1.6 million are operational manuals valued at $1.2 million which at the time of acquisition, were a key deliverable in the Company's GSE application and were expected to be placed in service following GSE approval. Subsequently, the processes and procedures underlying the operational manuals were reengineered to be substantially different as defined by the Company's current management. Therefore, at December 31, 2012 the Company determined the carrying value of operational manuals would not be recovered and the manuals could not be sold and would be disposed of, and as a result, the Company assessed the fair value at zero and recognized a loss on impairment of $1.2 million in the fourth quarter of 2012.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'
Investments	'
	Investments
	As of September 30, 2013, there were approximately $7 million of cash and investments in the form of U.S. Treasury securities on deposit with various state insurance departments to satisfy regulatory requirements.
	Fair Values and Gross Unrealized Gains and Losses on Investments
		Amortized				Gross Unrealized								Fair
		Cost				Gains				(Losses)				Value
	As of September 30, 2013
	U.S. Treasury securities and obligations of U.S. government agencies	$	108,067,508			$	—			$	(1,178,688	)		$	106,888,820
	Municipal bonds	12,019,214				—				(103,372		)		11,915,842
	Corporate debt securities	224,245,377				150,482				(4,818,660		)		219,577,199
	Asset-backed securities	74,689,572				81,955				(1,170,372		)		73,601,155
	Total Investments	$	419,021,671			$	232,437			$	(7,271,092	)		$	411,983,016
		Amortized				Gross Unrealized								Fair
		Cost				Gains				(Losses)				Value
	As of December 31, 2012
	Short-term investments	$	4,863,647			$	559			$	—			$	4,864,206
	Total Investments	$	4,863,647			$	559			$	—			$	4,864,206
	Scheduled Maturities as of September 30, 2013
	The amortized cost and fair values of available for sale securities at September 30, 2013, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.
		Amortized				Fair
		Cost				Value
	Due in one year or less	$	—			$	—
	Due after one through five years	253,500,682				250,727,716
	Due after five through ten years	75,369,556				72,704,193
	Due after ten years	15,461,861				14,949,952
	Asset-backed securities	74,689,572				73,601,155
	Total Investments	$	419,021,671			$	411,983,016
	All investments held at December 31, 2012 had a scheduled maturity of one year or less.
	Net Realized Investment (Losses) Gains on Investments
		Three Months Ended September 30, 2013				Nine months ended September 30, 2013				For the Period from May 19, 2011 (inception) to September 30, 2013
	Corporate Bond	$	(206,875	)		$	309,234			$	309,234
	U.S. Treasury securities and obligations of U.S. government agencies	(71,700		)		(87,359		)		(87,359		)
	Mortgage-backed security	(29,843		)		(49,584		)		(49,584		)
	Total Net Realized Investment (Losses) Gains	$	(308,418	)		$	172,291			$	172,291
	There were no realized investment gains or losses for the three and nine months ended September 30, 2012.
	Aging of Unrealized Losses
	At September 30, 2013, the investment portfolio had gross unrealized losses of approximately $7 million. For those securities in an unrealized loss position, the length of time the securities were in such a position, as measured by their month-end fair values, is as follows:
		Less Than 12 Months							12 Months or Greater							Total
		Fair Value			Unrealized Losses				Fair Value			Unrealized Losses				Fair Value		Unrealized Losses
	As of September 30, 2013
	U.S. Treasury Securities and Obligations of U.S. government agencies	$	106,888,820		$	(1,178,688	)		$	—		$	—			$	106,888,820	$	(1,178,688	)
	Municipal bonds	11,915,842			(103,372		)		—			—				11,915,842		(103,372		)
	Corporate debt securities	197,641,652			(4,818,660		)		—			—				197,641,652		(4,818,660		)
	Assets-backed securities	66,012,200			(1,170,372		)		—			—				66,012,200		(1,170,372		)
	Total Investments	$	382,458,514		$	(7,271,092	)		$	—		$	—			$	382,458,514	$	(7,271,092	)
	At December 31, 2012, the investment portfolio had no unrealized losses.
	Net investment income is comprised of the following:
		Nine months ended September 30, 2013				For the Nine months ended September 30, 2012				For the Year Ended December 31, 2012				For the Period From May 19, 2011 (inception) to September 30, 2013
	Fixed maturities	$	3,663,254			$	874			$	2,019			$	3,665,273
	Cash equivalents	—				—				3,806				3,806
	Other	1,517				—				—				1,517
	Investment income	3,664,771				874				5,825				3,670,596
	Investment expenses	(328,621		)		—				—				(328,621		)
	Net Investment Income	$	3,336,150			$	874			$	5,825			$	3,341,975

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	The following describes the valuation techniques used by the Company to determine the fair value of financial instruments held at September 30, 2013 and December 31, 2012:
	The Company 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 - Unadjusted quoted prices for identical assets or liabilities in active markets that are accessible at the measurement date for identical assets or liabilities;
	Level 2 - Prices or valuations based on observable inputs other than quoted prices in active markets for identical assets and liabilities; and
	Level 3 - Unobservable inputs that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation.
	The level of market activity used to determine the fair value hierarchy is based on the availability of observable inputs market participants would use to price an asset or a liability, including market value price observations.
	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. The Company has not made any adjustments to the prices obtained from the independent pricing sources.
	Liabilities classified as Level 3
	The warrants held by FBR and MAC Financial Ltd. and are valued using a Black-Scholes option-pricing model in combination with a binomial model and Monte Carlo simulation used to value the pricing protection features within the warrant. Variables in the model include the risk-free rate of return, dividend yield, expected life and expected volatility of the Company's stock price. Any potential value associated with pricing protection features are assessed using internal models and management estimation.
	ASC 825, "Disclosures about Fair Value of Financial Instruments", requires all entities to disclose the fair value of their financial instruments, both assets and liabilities recognized and not recognized in the balance sheet, for which it is practicable to estimate fair value.
	The following is a list of those assets and liabilities that are measured at fair value by hierarchy level as of September 30, 2013 and December 31, 2012:
		Fair Value Measurements Using
	Assets and Liabilities at Fair Value	Quoted Prices in		Significant Other		Significant		Fair Value
		Active Markets for		Observable Inputs		Unobservable
		Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	As of September 30, 2013
	U.S. Treasury securities and obligations of U.S. government agencies	$	106,888,820	$	—	$	—	$	106,888,820
	Municipal bonds	—		11,915,842		—		11,915,842
	Corporate debt securities	—		219,577,199		—		219,577,199
	Asset-backed securities	—		73,601,155		—		73,601,155
	Cash and cash equivalents	34,097,356		—		—		34,097,356
	Total Assets	$	140,986,176	$	305,094,196	$	—	$	446,080,372
	Warrant liability	—		—		$	5,452,428	$	5,452,428
	Total Liabilities	$	—	$	—	$	5,452,428	$	5,452,428
		Fair Value Measurements Using
	Assets and Liabilities at Fair Value	Quoted Prices in		Significant Other		Significant		Fair Value
		Active Markets for		Observable Inputs		Unobservable
		Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	As of December 31, 2012
	U.S. Treasury securities and obligations of U.S. government agencies	$	4,864,206	$	—	$	—	$	4,864,206
	Cash and cash equivalents	526,193,573		—		—		526,193,573
	Total Assets	$	531,057,779	$	—	$	—	$	531,057,779
	Warrant liability	—		—		$	4,841,765	$	4,841,765
	Total Liabilities	$	—	$	—	$	4,841,765	$	4,841,765
	The following is a roll-forward of Level 3 liabilities measured at fair value for the nine months ended September 30, 2013:
		Total Fair Value Measurements
	Nine months ended September 30, 2013
	Level 3 Instruments Only	Warrant Liability
	Balance, January 1, 2013	$	4,841,765
	Change in fair value of warrant liability included in earnings	610,663
	Balance, September 30, 2013	$	5,452,428
		Total Fair Value Measurements
	Period from May 19, 2011 (inception) to September 30, 2013
	Level 3 Instruments Only	Warrant Liability
	Balance, May 19, 2011	$	—
	Initial fair value of warrant liability	5,119,569
	Change in fair value of warrant liability included in earnings	332,859
	Balance, September 30, 2013	$	5,452,428
	The fair value of the warrants issued to FBR and MAC Financial Ltd. was estimated on the date of grant using the Black-Scholes option-pricing model, including consideration of any potential additional value associated with pricing protection features. The volatility assumption used, 39.0%, was derived from the historical volatility of the share price of a range of publicly-traded companies with similar types of business to that of the Company. No allowance was made for any potential illiquidity associated with the private trading of the Company's shares. The Company revalues the warrant liability quarterly using a Black-Scholes option-pricing model in combination with a binomial model and a Monte-Carlo simulation model used to value the pricing protection features within the warrant. As of September 30, 2013 the assumptions used in the option pricing model were as follows: a common stock price as of September 30, 2013 of $11.40, risk free interest rate of 2.03%, expected life of 7.06 years and a dividend yield of 0%.
	The carrying value of other selected assets on our consolidated balance sheet approximates fair value.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Following is a reconciliation of the Company's net deferred income tax asset as of September 30, 2013 and December 31, 2012:
		September 30, 2013
		Gross			Tax Effected
	Deferred tax asset:
	Capitalized start-up costs	$	40,318,967		$	13,708,449
	Stock compensation	13,159,292			4,474,159
	Unrealized loss on investments	7,038,655			2,393,143
	Net operating loss carry forwards	14,825,590			5,040,701
	Other	5,647,019			1,919,986
	Total gross deferred tax assets	80,989,523			27,536,438
	Less: valuation allowance	78,544,235			26,705,040
	Total deferred tax assets	2,445,288			831,398
	Deferred tax liability:
	Capitalized Software	(2,439,542		)	(829,444		)
	Intangible Assets	(390,000		)	(132,600		)
	Other	(5,746		)	(1,954		)
	Total deferred tax liabilities	(2,835,288		)	(963,998		)
	Net deferred income tax liability	$	(390,000	)	$	(132,600	)
		December 31, 2012
		Gross			Tax Effected
	Deferred tax asset:
	Capitalized start-up costs	$	21,796,012		$	7,410,644
	Net operating loss carry forwards	7,307,344			2,484,497
	Total gross deferred tax assets	29,103,356			9,895,141
	Less: valuation allowance	24,103,356			8,195,141
	Total deferred tax assets	5,000,000			1,700,000
	Deferred tax liability:
	Capitalized Software	(5,000,000		)	(1,700,000		)
	Intangible Assets	(390,000		)	(132,600		)
	Total deferred tax liabilities	(5,390,000		)	(1,832,600		)
	Net deferred income tax liability	$	(390,000	)	$	(132,600	)
	The Company has a net deferred tax liability of approximately$0.1 million as a result of the acquisition of indefinite-lived intangibles in the MAC Acquisition for which a benefit has been reflected in the acquired net operating loss carry forwards. The tax liability incurred at the acquisition is recorded as an increase in Goodwill.
	Excluded from deferred tax assets is $1.5 million of excess stock compensation for which any benefit realized will be recorded to stockholders' equity. Additionally, Section 382 imposes annual limitations on a corporation's ability to utilize its net operating loss carry forwards ("NOLs") if it experiences an "ownership change." As a result of the MAC Acquisition, $7.3 million of NOLs are subject to annual limitations of approximately $0.8 million through 2016, then $0.3 million. The NOLs will expire in years 2029 through 2033.
	As the Company has just recently begun insurance operations and has no history to provide a basis for reliable future net income projections, a valuation allowance of $26.7 million and $8.2 million was recorded at September 30, 2013 and December 31, 2012, respectively, to reflect the amount of the deferred tax asset that may not be realized.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	GSE Approvals
	Fannie Mae and Freddie Mac have imposed certain capitalization, operational and reporting conditions in connection with their approvals of NMIC as a qualified mortgage guaranty insurer. Some of these conditions remain in effect for a three (3) year period from the date of GSE Approval while others do not expressly expire. These conditions require, among other things, that NMIC:
	•	be initially capitalized in the amount of $200 million and that its affiliate reinsurance companies, NMI Re One and NMI Re Two, be initially capitalized in the amount of $10 million each (as of September 30, 2013, NMI Re Two was merged into NMIC, with NMIC surviving the merger. See Note 1. Organization);
	•	maintain minimum capital of $150 million;
	•	operate at a risk-to-capital ratio not to exceed 15:1 for its first three (3) years and then pursuant to the GSE Eligibility Requirements then in effect;
	•	not declare or pay dividends to affiliates or to the Company for its first three (3) years, then pursuant to the Eligibility Requirements;
	•	not enter into capital support agreements or guarantees for the benefit of, or purchase or otherwise invest in the debt of, affiliates without the prior written approval of the GSEs for its first three (3) years, then pursuant to the Eligibility Requirements;
	•	not enter into reinsurance or other risk share arrangements without the GSEs' prior written approval for its first three (3) years, then pursuant to the Eligibility Requirements; and
	•	at the direction of one or both of the GSEs, re-domicile from Wisconsin to another state.
	The conditional approvals also include certain additional conditions, limitations and reporting requirements that the Company anticipates will be included in the GSEs' final Eligibility Requirements, such as limits on costs allocated to NMIC under affiliate expense sharing arrangements, risk concentration, rates of return, requirements to obtain a financial strength rating, provision of ancillary services (i.e., non-insurance) to customers, transfers of underwriting to affiliates, notification requirements regarding change of ownership and new five percent (5%) shareholders, provisions regarding underwriting policies and claims processing as well as certain other obligations.
	During the third quarter of 2013, NMIC entered into an agreement with Fannie Mae, pursuant to which NMIC insures a pool of approximately 22,000 loans with an aggregate unpaid principal balance of approximately $5.2 billion.  The effective date of the agreement and the coverage is September 1, 2013, and in September 2013, NMIC received the first premium payment from Fannie Mae.  The agreement has an expected term of 10 years from the coverage effective date.
	The initial pool risk-in-force to NMIC, as of September 1, 2013 was approximately $93.1 million which represents the amount between a deductible payable by Fannie Mae on initial losses and a stop loss, above which, losses are borne by Fannie Mae. The pool agreement obligates NMIC to maintain the greater of (1) the risk-to-capital requirements outlined in the January 2013 approval letter, or (2) a risk-to-capital ratio of 18:1 on primary business plus statutory capital equal to the amount of net risk-in-force of the pool. As of September 30, 2013, the pool risk-in-force was $93.1 million.
	In addition to the conditions noted above, the Company's insurance subsidiary, NMIC entered into risk-to-capital agreements with certain state insurance regulators. See Note 14. Statutory Financial Information.
	Office Lease
	The Company entered into an office facility lease effective July 1, 2012 for a term of two years.
	Management expects that, in the normal course of business, as of September 30, 2013, future minimum lease payments under this lease will be as follows:
	Years ending December 31,
	2013	$	205,884
	2014	416,176
	Totals	$	622,060
	The Company incurred rent expense, related to this lease, of approximately $0.2 million, and $0.4 million for the three and nine months ended September 30, 2013, respectively. Rent expense for the three and nine months ended September 30, 2012 was approximately $0.1 million.

Stock_Compensation

Stock Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock Compensation	'
	Stock Compensation
	The 2012 Stock Incentive Plan (the "Plan") was approved by the Board of Directors (the "Board") on April 16, 2012, and authorized 5.5 million shares be reserved for issuance under the Plan with 3.85 million shares available for stock options and 1.65 million shares available for restricted stock unit grants ("RSUs"). Options granted under the Plan are Non-Qualified Stock Options and may be granted to employees, directors and other key persons of the Company. The exercise price per share for the common stock covered by this Plan shall be determined by the Board at the time of grant, but shall not be less than the fair market value on the date of the grant. The term of the stock option grants will be established by the Board, but no stock option shall be exercisable more than 10 years after the date the stock option is granted. The vesting period of the stock option grants will also be established by the Board at the time of grant and generally is for a three year period.
	A summary of option activity in the plan during the period ending September 30, 2013 is as follows:
		Shares		Weighted Average Grant Date Fair Value per Share
	Options balance at December 31, 2012	2,546,750		$	3.86
	Options granted	531,829		4.57
	Less: Options forfeited	(14,701	)	3.84
	Options balance outstanding at September 30, 2013	3,063,878		$	3.98
	As of September 30, 2013 there were no exercises and 659,723 options were exercisable.
	The remaining weighted average contractual life of options outstanding as of September 30, 2013 was 8.8 years. As of September 30, 2013, there was approximately $4.6 million of total unrecognized compensation cost related to non-vested stock options. The weighted-average period over which total compensation related to non-vested stock options will be recognized is 0.96 years.
	The Company accounts for stock options under ASC No. 718, Compensation - Stock Compensation ("ASC 718"), which requires all share-based payments to be recognized in the financial statements at their fair values. To measure the fair value of stock options granted, the Company utilizes the Black-Scholes options pricing model. Expense is recognized over the required service period, which is generally the three-year vesting period of the options (vesting in one-third increments per year).
	The estimated grant date fair values of the stock options granted during 2013 were calculated using the Black-Scholes valuation model based on the following assumptions:
	Expected life	6.00 years
	Risk free interest rate	0.85%
	Dividend yield	0	%
	Expected stock price volatility	39	%
	Projected forfeiture rates	1	%
	Expected Price Volatility - is a measure of the amount by which a price has fluctuated or is expected to fluctuate. At the time of grant, the Company's common shares trading history was less than six months which was not sufficient to calculate an expected volatility representative of the volatility over the expected lives of the options. As a substitute for such estimate, the Company used historical volatilities of a set of comparable companies in the industry in which the Company operates.
	Risk-Free Interest Rate - is the U.S. Treasury rate for the date of the grant having a term approximating the expected life of the option.
	Expected Lives - is the period of time over which the options granted are expected to remain outstanding giving consideration to vesting schedules, historical exercise and forfeiture patterns. The Company uses the simplified method outlined in SEC Staff Accounting Bulletin No. 107 to estimate expected lives for options granted during the period as historical exercise data is not available and the options meet the requirements set out in the Bulletin. Options granted have a maximum term of ten years.
	Forfeiture Rate - is the estimated percentage of options granted that are expected to be forfeited or canceled before becoming fully vested. An increase in the forfeiture rate will decrease compensation expense.
	Dividend Yield - is calculated by dividing the expected annual dividend by the stock price of the Company at the valuation date.
	A summary of restricted stock unit activity in the plan during the period ending September 30, 2013 is as follows:
		Shares		Weighted Average Grant Date Fair Value per Share
	Restricted Stock Units balance at December 31, 2012	1,429,260		$	7.35
	Restricted Stock Units Granted	82,000		11.75
	Less: Restricted Stock Units Vested	(262,610	)	6.79
	Less: Restricted Stock Units Forfeited	—		—
	Restricted Stock Units balance outstanding at September 30, 2013	1,248,650		$	7.76
	In February 2013, the Board of Directors approved a modification to the vesting terms of approximately 400,000 outstanding and unvested restricted stock units held by employees of the Company. The modification to the vesting terms removed the market condition leaving the restricted stock units subject to a service condition only. The modification resulted in a change in the period over which compensation costs are recognized and prospective recognition of incremental compensation cost, measured as the excess of the fair value of the modified award over the fair value of the original award immediately before its terms are modified, measured based on the share price and relevant valuation inputs at the modification date.
	At September 30, 2013, the 1.2 million shares of restricted stock units outstanding consisted of 0.5 million shares that are subject to both a market and service condition and 0.7 million shares that are subject only to service conditions. The restricted stock units subject to both a market and service condition vest in one-third increments upon the achievement of certain market price goals and continued service. Restricted stock units subject only to a service condition vest over a service period ranging from 1 to 3 years. The fair value of restricted stock units subject to market and service conditions is determined based on a Monte Carlo simulation model at the date of grant. The fair value of restricted stock units subject only to service conditions are valued at the Company's stock price on the date of grant less the present value of anticipated dividends.
	The estimated grant date fair values of the restricted stock units granted in 2012 that are subject to both a market and service condition were calculated using a Monte Carlo simulation model based on the average outcome of 150,000 simulations using the following assumption:
	Expected life	5.00 years
	Risk free interest rate	0.86	%
	Dividend yield	0	%
	Expected stock price volatility	39	%
	Projected forfeiture rates	1	%
	The remaining weighted average contractual life of RSUs outstanding as of September 30, 2013 was 4.3 years. As of September 30, 2013, there was approximately $4.8 million of total unrecognized compensation cost related to non-vested restricted stock units. The weighted-average period over which total compensation related to non-vested RSUs will be recognized is 0.93 years.
	On April 5, 2013 approximately 263,000 restricted stock units containing a market condition vested resulting in an acceleration of compensation expense of approximately $1.1 million in the second quarter of 2013.

Software_and_Equipment

Software and Equipment	9 Months Ended
	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'
Software and Equipment	'
	Software and Equipment
	Software and equipment consist largely of capitalized software purchased in connection with the MAC Acquisition which had a fair value of $5.0 million at the date of acquisition. Software and equipment, net of accumulated amortization and depreciation, as of September 30, 2013 and December 31, 2012, consist of the following:
	As of September 30, 2013
	Software	$	12,526,481
	Equipment	387,446
	Leasehold Improvements	35,039
	Less accumulated amortization and depreciation	(3,894,971		)
	Software and equipment, net	$	9,053,995
	As of December 31, 2012
	Software	$	7,268,439
	Equipment	284,573
	Less accumulated amortization and depreciation	(2,917		)
	Software and equipment, net	$	7,550,095
	Amortization and depreciation expense for the three and nine months ended September 30, 2013 was $2.0 million and $3.9 million, respectively. During the second quarter of 2013, the Company conducted an analysis on the existing Insurance Management System ("IMS") which was acquired in connection with the MAC Acquisition. Based on that analysis, the Company made the business decision during the second quarter of 2013 to pursue the development of new modules to support policy servicing, billing and delinquency and claims management business functions. As a result of the change in approach, during the second quarter the Company reduced the useful life of the modules of IMS that support these business functions and shortened the amortization period to a range of 7 and 18 months. There was no amortization and depreciation expense for the three and nine months ended September 30, 2012.

Intangible_Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Intangible Assets	'
	Intangible Assets
	Intangible assets consist of identifiable intangible assets purchased in connection with the MAC Acquisition. Intangible assets, net, as of September 30, 2013 and December 31, 2012, consist of the following:
	As of September 30, 2013 and December 31, 2012			Expected Lives
	State licenses	$	260,000	Indefinite
	GSE Approvals	130,000		Indefinite
	Total Intangible Assets	$	390,000
	The Company tests goodwill and intangibles for impairment in the third and fourth quarter, respectively, of every year, or more frequently if the Company believes indicators of impairment exist. At the time of the MAC Acquisition, the Company, as part of the acquisition, acquired operational manuals that were a key deliverable in the Company's GSE application and were expected to be placed in service following GSE Approval. Subsequently, the processes and procedures underlying the operational manuals were reengineered to be substantially different as defined by the Company's current management. Therefore, at December 31, 2012 the Company determined the carrying value of operational manuals would not be recovered and the manuals could not be sold and would be disposed, and as a result, assessed the fair value at zero and recognized a loss on impairment of $1.2 million. No impairments of indefinite-lived intangibles were identified as of September 30, 2013.

Line_of_Credit_and_Related_War

Line of Credit and Related Warrants	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Line of Credit and Related Warrants	'
	Line of Credit and Related Warrants
	As of December 31, 2011, in connection with the funding of the Company and prior to the offering, FBR granted an uncommitted line of credit up to an aggregate principal amount of $1.5 million to support legal, accounting and others costs associated with the formation and the capitalization of the Company.
	As part of the consideration for granting the line of credit, upon successful completion of the common stock offering on April 24, 2012, the Company issued warrants to FBR having an aggregate value equal to three times the amount of the outstanding line of credit balance. Each warrant gave the holder thereof the right to purchase one share of common stock at an exercise price equal to $10.00. Accordingly, FBR was issued approximately 314,000 warrants with an aggregate fair value of approximately $1.6 million. These warrants were measured at fair value and recorded as a finance fee with an offsetting charge to liabilities. As the line of credit was paid off on April 24, 2012, the debt discount was fully amortized as of April 24, 2012.
	Upon exercise of these warrants, the amounts will be reclassified from warrant liability to additional paid-in capital.
	The Company is required to revalue the warrants at the end of each reporting period and any change in fair value is reported in the statements of operations as "Gain (Loss) from change in fair value of warrant liability" in the period in which the change occurred. The fair value of the warrants is calculated using a Black-Scholes option-pricing model in combination with a binomial model and a Monte-Carlo simulation model used to value the pricing protection features within the warrant. The loss from the change in fair value for the nine months ended September 30, 2013 was $0.6 million.

Litigation

Litigation	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Litigation	'
	Litigation
	On August 8, 2012, Germaine Marks, as Receiver, and Truitte Todd, as Special Deputy Receiver, of PMI Mortgage Insurance Co. (“PMI”), an Arizona insurance company in receivership, filed a complaint (the “PMI Complaint”) against the Company, NMIC and certain named individuals, in California Superior Court, Alameda County. The PMI Complaint, as amended, alleges breach of fiduciary duty, breach of loyalty, aiding and abetting breach of fiduciary duty and loyalty, misappropriation of trade secrets, conversion, breach of proprietary information agreement, breach of separation agreement and intentional interference with contractual relations and unfair competition. The lawsuit seeks injunctive relief as well as unspecified monetary damages. The litigation is at an early stage of review and evaluation and the Company has filed an answer to PMI's complaint denying all allegations and believes the claims are without merit.
	The parties are now engaged in discovery and the court has set a trial date for May 27, 2014. Because the litigation and related discovery are still at an early stage, the Company does not have sufficient information to determine or predict the ultimate outcome or estimate the range of possible losses, if any. Accordingly, no provision for litigation losses has been included in the financial statements.

Statutory_Information

Statutory Information	9 Months Ended
	Sep. 30, 2013
Insurance [Abstract]	'
Statutory Information	'
	Statutory Information
	The Company's insurance subsidiaries, NMIC, NMI Re One and NMI Re Two, file financial statements in conformity with statutory basis accounting principles ("SAP") prescribed or permitted by the Wisconsin Office of the Commission of Insurance ("WOCI"). Prescribed SAP includes state laws, regulations and general administrative rules, as well as a variety of publications of the National Association of Insurance Commissioners ("NAIC"). The WOCI 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. As of September 30, 2013, NMI Re Two was merged into NMIC, with NMIC surviving the merger. See Note 1. Organization.
	Prescribed and permitted practices generally vary in some respects from accounting principles generally accepted in the United States of America ("GAAP"). The principal differences between these accounting practices and GAAP are as follows: (1) acquisition expenses incurred in connection with acquiring new business are charged to expense under SAP but under GAAP are deferred and amortized as the related premiums are earned; (2) under SAP there are limitations on the net deferred tax assets created by the tax effects of temporary differences; (3) under SAP unpaid losses and loss adjustment expense ceded to reinsurers are reported as a deduction of the related reserve rather than as an asset as would be required under GAAP; (4) under SAP, fixed maturity investments are generally valued at amortized cost while under GAAP, those investments are considered to be available-for-sale and are recorded at fair value, with the unrealized gain or loss recognized, net of tax, as an increase or decrease to shareholders' equity.
	NMIC's principal regulator is the Wisconsin OCI. Under applicable Wisconsin law, as well as that of 15 other states, a mortgage guaranty insurer must maintain a minimum amount of statutory capital relative to the risk-in-force (Risk to Capital ratio or “RTC ratio”) in order for the mortgage guaranty insurer to continue to write new business. The Company refers to these requirements as the “RTC requirement.” While formulations of minimum capital may vary in each jurisdiction that has such a requirement, the most common measure applied allows for a maximum permitted RTC ratio of 25 to 1. Wisconsin and certain other states, including California and Illinois, apply a substantially similar requirement referred to as minimum policyholders position. The Company's operation plan filed with the WOCI and other state insurance departments in connection with NMIC's applications for licensure includes the expectation that the Company will downstream additional capital if needed so that NMIC does not exceed an 18 to 1 risk-to-capital ratio. NMIC may in the future seek state insurance department approvals, as needed, of an amendment to the Company's business plan to increase this ratio to the Wisconsin regulatory minimum of 25 to 1.
	Additionally, as a condition of GSE Approval, NMIC has agreed with Fannie Mae and Freddie Mac to limit NMIC's RTC ratio to no greater than 15 to 1 and to maintain total statutory capital of at least $150 million for a three year period ending on December 31, 2015. After that date, NMIC agreed to comply with the risk-to-capital ratios that are imposed in the GSEs' then existing eligibility requirements. As part of the state licensing process, NMIC entered into risk-to-capital agreements with the California Insurance Department, the Missouri Department of Insurance, the New York State Department of Financial Services, the Ohio Department of Insurance and the Texas Commissioner of Insurance. These agreements require NMIC to maintain a risk-to-capital ratio not to exceed 20 to 1 until January 15, 2016.
	Certain states limit the amount of risk a mortgage guaranty insurer may retain on a single loan to 25% of the indebtedness to the insured and as a result the portion of such insurance in excess of 25% must be reinsured. NMIC has entered into a primary excess share reinsurance agreement with NMI Re One effective August 1, 2012. NMIC cedes premiums and losses to NMI Re One on an excess share basis for any primary or pool policy which offers coverage greater than 25%. The Company will use reinsurance provided by NMI Re One solely for purposes of compliance with statutory coverage limits. During April 2013, NMIC began writing its first mortgage insurance policies and began ceding premium and risk to NMI Re One the following month.
	As of December 31, 2012, none of the Company's insurance subsidiaries had written any business, had no risk-in-force and therefore had no ratios. As of September 30, 2013 NMIC's RTC ratio is less than 1:1, significantly below the limits established with the GSEs and state insurance departments.
	The risk-to-capital calculation for the Company's combined insurance subsidiaries is:
		30-Sep-13
		(In Thousands)
	Pool risk-in-force (1)	$	93,090
	Primary risk-in-force	1,196
	Total risk-in-force	$	94,286
	Statutory policyholders' surplus	$	198,981
	Statutory contingency reserve	2,149
	Statutory policyholders' position	$	201,130
	Risk-to-capital (2)	0.5:1
	(1) Pool risk-in-force as shown in the table above is equal to the aggregate stop loss less a deductible.
	(2) Represents total risk-in-force divided by statutory policyholders' position which is the metric by which the majority of state insurance regulators will assess our capital adequacy. Additionally, Fannie Mae requires us to maintain the greater of (a) the risk-to-capital requirements outlined in the January 2013 approval letter, or (b) a risk-to-capital ratio of 18:1 on primary business plus statutory capital equal to the amount of net risk-in-force of the pool.
	NMI Holdings, Inc. is not subject to any limitations on its ability to pay dividends except those generally applicable to corporations that are incorporated in Delaware, such as NMI Holdings, Inc. Delaware corporation law provides that dividends are only payable out of a corporation's capital surplus or (subject to certain limitations) recent net profits. As of December 31, 2012 NMI Holdings, Inc.'s capital surplus was approximately $489 million.
	The GSEs and state insurance regulators may restrict the Company's insurance subsidiaries ability to pay dividends to the Company. Please see Note 9. Commitments and Contingencies for a discussion of the dividend restrictions imposed by the GSEs as part of NMIC's approval as well as restrictions imposed by various states in conjunction with the approval of NMIC in those states. In addition to the restrictions imposed during the approval and licensing process, the ability of the Company's insurance subsidiaries to pay dividends to the Company is limited by insurance laws of the State of Wisconsin and certain other states. Wisconsin law provides that an insurance company may pay out dividends without the prior approval of the WOCI (“ordinary dividends”) in an amount, when added to other shareholder distributions made in the prior 12 months, not to exceed the lesser of (a) 10% of the insurer's surplus as regards to policyholders as of the prior December 31, or (b) its net income (excluding realized capital gains) for the twelve month period ending December 31 of the immediately preceding calendar year. In determining net income, an insurer may carry forward net income from the previous calendar years that has not already been paid out as a dividend. Dividends that exceed this amount are “extraordinary dividends”, which require prior approval of the WOCI. As of September 30, 2013, the amount of restricted net assets held by the Company's consolidated insurance subsidiaries totaled approximately $203 million of the Company's consolidated net assets of $447 million. The amount of restricted assets used to determine any dividend to the Company, once all restrictions expire, would be computed under SAP which may differ from the amount of restricted assets computed under GAAP.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	In October 2013, the Company amended its facility’s lease to (1) add approximately 23,000 square feet of furnished office space, and (2) extend the facility’s lease period through October 31, 2017.
	On November 8, 2013, the Company filed a final prospectus announcing the sale of approximately 2.1 million shares of common stock through an initial public offering. The underwriters of the offering were granted a 30-day option to purchase up to an additional 315,000 shares of common stock from the Company at an initial public offering price, less underwriting discounts and commissions, to cover over-allotments. The principal reason for conducting the public offering was to expedite an increase in the number of holders of the Company's common stock to permit a listing of its common stock on the NASDAQ Global Market. Obtaining a listing on the NASDAQ Global Market satisfies certain contractual obligations the Company has to its stockholders under a Registration Rights Agreement.
	On November 12, 2013, the underwriters exercised their option in full to purchase an additional 315,000 shares of common stock at a price of $13.00 per share, before underwriting discounts. The offering closed on November 14, 2013. Gross proceeds to the Company were $31.4 million. Net proceeds from the offering were approximately $29 million, after an approximate 6% underwriting fee and other offering expenses and reimbursements pursuant to the underwriting agreement.
	The Company has performed subsequent events procedures through November 18, 2013 which was the date the financial statements were available for issuance.

Summary_of_Accounting_Policies1

Summary of Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company considers items such as certificates of deposit and money market funds with original maturities of 90 days or less to be cash equivalents.
	The Company had restricted cash as of December 31, 2012. The restricted cash balance was comprised of two escrow accounts that were initially funded on April 24, 2012 with an agreement that the funds would be released upon GSE Approval. The restricted cash was payable to FBR and MAC Financial Ltd. and was released from escrow on January 23, 2013. There was no restricted cash as of September 30, 2013.
Investments	'
	Investments
	The Company has designated its investment portfolio as available-for-sale and is reported at fair value. The related unrealized gains and losses are, after considering the related tax expense or benefit, recognized as a component of accumulated other comprehensive income (loss) in shareholders' equity. Net realized investment gains and losses are reported in income based upon specific identification of securities sold.
	Purchases and sales of investments are recorded on a trade date basis. Net investment income is recognized when earned and includes interest and dividend income together with amortization of market premiums and discounts using the effective yield method and is net of investment management fees and other investment related expenses. For asset-backed securities and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Any adjustments required due to the change in effective yields and maturities are recognized on a prospective basis through yield adjustments.
	Each quarter the Company evaluates the investments in order to determine whether declines in fair value below amortized cost were considered other-than-temporary in accordance with applicable guidance. In evaluating whether a decline in fair value is other-than-temporary, the Company considers several factors including, but not limited to:
	•	the Company's intent to sell the security or whether it is more likely than not that the Company will be required to sell the security before recovery;
	•	severity and duration of the decline in fair value;
	•	the financial condition of the issuer;
	•	failure of the issuer to make scheduled interest or principal payments;
	•	recent credit downgrades of the applicable security or the issuer below investment grade; and
	•	adverse conditions specifically related to the security, an industry, or a geographic area.
	Under the current guidance, a debt security impairment is deemed other than temporary if (1) the Company either intends to sell the security, or it is more likely than not that the Company will be required to sell the security before recovery or (2) the Company does not expect to collect cash flows sufficient to recover the amortized cost basis of the security. In the event of the decline in fair value of a debt security, a holder of that security that does not intend to sell the debt security and for whom it is more likely than not that such holder will be required to sell the debt security before recovery of its amortized cost basis is required to separate the decline in fair value into (a) the amount representing the credit loss and (b) the amount related to other factors. The amount of total decline in fair value related to the credit loss shall be recognized in earnings as other-than-temporary impairment ("OTTI") with the amount related to other factors recognized in accumulated other comprehensive income or loss, net of tax. In periods after recognition of an OTTI on debt securities, the Company accounts for such securities as if they had been purchased on the measurement date of the OTTI at an amortized cost basis equal to the previous amortized cost basis less the OTTI recognized in earnings. For debt securities for which OTTI were recognized in earnings, the difference between the new amortized cost basis and the cash flows expected to be collected will be accreted into net investment income. The determination of OTTI is a subjective process, and different judgments and assumptions could affect the timing of the loss realization.
Revenue Recognition	'
	Revenue Recognition
	In the mortgage guaranty insurance industry, a “book” is a group of loans that an MI ("Mortgage Insurance") company insures in a particular period, normally a calendar year. The Company sets premiums at the time a policy is issued based on the Company's expectations regarding likely performance over the term of coverage. The policies the Company writes are guaranteed renewable contracts at the policyholder's option on a single, annual or monthly premium basis. The Company generally has no ability to reunderwrite or reprice these contracts.  Premiums written on a single premium basis and an annual premium basis are initially deferred as unearned premium reserve and earned over the policy term.  Premiums written on policies covering more than one year are amortized over the policy life in accordance with the expiration of risk which is the anticipated claim payment pattern based on industry experience.  Premiums written on annual policies are earned on a monthly pro rata basis.  Premiums written on monthly policies are earned as coverage is provided. Premiums written on pool transactions are earned over the period that coverage is provided.  Upon cancellation of a policy, all premium that is non-refundable is immediately earned. Any refundable premium is returned to the policyholder. The actual return of premium for all periods affects premiums written and earned in those periods.
Deferred Policy Acquisition Costs	'
	Deferred Policy Acquisition Costs
	Costs directly associated with the successful acquisition of mortgage guaranty insurance business, consisting of certain employee compensation and other policy issuance and underwriting expenses, are initially deferred and reported as deferred policy acquisition costs ("DAC"). For each book year of business, these costs are amortized to income in proportion to estimated gross profits over the estimated life of the policies.
Business Combinations, Goodwill and Intangible Assets	'
	Business Combinations, Goodwill and Intangible Assets
	Goodwill represents the excess of the purchase price over the estimated fair value of net assets acquired from a business combination. In accordance with Accounting Standards Codification ("ASC") 350, Intangibles - Goodwill and Other, the Company will test goodwill for impairment during the third quarter each year or more frequently if the Company believes indicators of impairment exist. The Company has not identified any impairments of goodwill through September 30, 2013.
	The Company's intangible assets consist of state licenses and GSE applications which have indefinite lives. The Company tests indefinite-lived intangible assets for impairment during the fourth quarter of each year or more frequently if the Company believes indicators of impairment exist. The Company does not believe that the indefinite-lived intangible assets were impaired as of September 30, 2013.
Software and Equipment	'
	Software and Equipment
	Software and equipment are stated at cost, less accumulated amortization and depreciation. Amortization and depreciation are calculated using the straight-line method over the estimated useful lives of the respective assets ranging typically from 3 to 7 years, unless factors indicate a shorter useful life. During the second quarter of 2013, the Company conducted an analysis on the existing Insurance Management System ("IMS"), which was acquired in connection with the MAC Acquisition, and evaluated development efforts in pursuit of designing a system that would meet the Company's business requirements. Based on that analysis, the Company made the business decision during the second quarter of 2013 to pursue the development of new modules to support policy servicing, billing and delinquency and claims management business functions. As a result of the change in approach, the Company reduced the useful life of the modules of IMS that support these business functions and shortened the amortization period of the modules to 7 and 18 months. Amortization of software and depreciation of equipment commences at the beginning of the month following the placement of the assets into use by the Company.
Warrants	'
	Warrants
	The Company accounts for warrants to purchase common shares of the Company that were issued to FBR and MAC Financial Ltd. in conjunction with the line of credit and stock purchase agreement, respectively, in accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 470-20 Debt with Conversion and Other Options and ASC 815-40 Derivatives and Hedging - Contracts in Entity's Own Equity. These warrants may be settled by the Company using the physical settlement method or through cashless exercises in which shares subject to the warrants are reduced in lieu of cash payment of the exercise price. The exercise price and the number of warrants are subject to anti-dilution provisions whereby the existing exercise price is adjusted downward and the number of warrants increased for events that may not be dilutive and the adjustment may be in excess of any dilution suffered. As a result, the warrants are classified as a liability. The Company revalues the warrants at the end of each reporting period and any change in fair value is reported in the statements of operations in the period in which the change occurred. The fair value of the warrants is calculated using a Black-Scholes option-pricing model in combination with a binomial model and a Monte Carlo simulation model used to value the pricing protection features within the warrant.
Share-based Compensation	'
	Stock-Based Compensation
	The Company adopted ASC 718, Compensation - Stock Compensation ("ASC 718"). ASC 718 addresses accounting for share-based awards and recognition of compensation expense, measured using grant date fair value, over the requisite service or performance period of the award. Share-based payments include restricted stock units and stock option grants under the 2012 Stock Incentive Plan. The fair value of stock option grants issued are determined based on an option pricing model which takes into account various assumptions that are subjective. Key assumptions used in the stock option valuation include the expected term of the equity award taking into account the contractual term of the award, the effects of expected exercise and post-vesting termination behavior, expected volatility, expected dividends and the risk-free interest rate for the expected term of the award. Restricted stock unit grants to employees contain a market condition and/or service condition. The fair value of restricted stock unit grants to employees with a market condition is determined based on a Monte Carlo simulation model at the date of grant. Restricted stock unit grants to employees with a service condition and restricted stock unit grants to non-employee directors are valued at the Company's stock price on the date of grant less the present value of anticipated dividends.
Offering and Incorporation Expenses	'
	Offering and Incorporation Expenses
	Offering expenses incurred in connection with the capitalization of the Company were recorded as a reduction of paid-in-capital at closing. These costs include certain investment banking fees, legal fees, printer fees and audit fees. Any incorporation and organizational expenses not related to the raising of capital are expensed as incurred and are included in the statement of operations.
Income Taxes	'
	Income Taxes
	The Company accounts for income taxes using the liability method in accordance with FASB ASC Topic 740 - Income Taxes. The liability method measures the expected future tax effects of temporary differences at the enacted tax rates applicable for the period in which the deferred asset or liability is expected to be realized or settled. Temporary differences are differences between the tax basis of an asset or liability and its reported amount in the consolidated financial statements that will result in future increases or decreases in taxes owed on a cash basis compared to amounts already recognized as tax expense in the consolidated statement of operations.
	The Company evaluates the need for a valuation allowance against its deferred tax assets on a quarterly basis. In the course of its review, the Company assesses all available evidence, both positive and negative, including future sources of income, tax planning strategies, future contractual cash flows and reversing temporary differences. Additional valuation allowance benefits or charges could be recognized in the future due to changes in management's expectations regarding the realization of tax benefits. Uncertain tax positions taken or expected to be taken in a tax return by the Company are recognized in the financial statements when it is more likely than not that the position would be sustained upon examination by tax authorities. There are no tax uncertainties that are expected to result in significant increases or decreases to unrecognized tax benefits within the next twelve month period.
	In assessing the valuation of deferred tax assets, the Company considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible.
Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income	'
	Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the FASB issued an Accounting Standards Update addressing the reporting of reclassifications out of accumulated other comprehensive income. The Update requires an entity to report the effect of significant reclassifications out of accumulated other comprehensive income on the respective line items in the statement of operations if the amount being reclassified is required under U.S. GAAP to be reclassified in its entirety to net income. For other amounts that are not required under U.S. GAAP to be reclassified in their entirety to net income in the same reporting period, an entity is required to cross-reference other disclosures required under U.S. GAAP that provide additional detail about those amounts. For public entities, the amendments are effective for reporting periods beginning after December 15, 2012. For nonpublic entities, the amendments are effective for reporting periods beginning after December 15, 2013. Early adoption is permitted. The Company expects this guidance to affect financial statement disclosures but not to have an impact on the Company's results of operations, financial position or liquidity.
Nonpublic Entity Disclosure about Financial Instruments	'
	Nonpublic Entity Disclosures about Financial Instruments
	In February 2013, the FASB issued an Accounting Standards Update clarifying the intended scope of the disclosures required by Update 2011-04, Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs. The amendments clarify that the requirement to disclose "the level of the fair value hierarchy within which the fair value measurements are categorized in their entirety (Level 1, 2, or 3)" does not apply to nonpublic entities for items that are not measured at fair value in the statement of financial position but for which fair value is disclosed. The amendments were effective upon issuance. The adoption of this guidance in February 2013 did not have any effect on the Company's results of operations, financial position or liquidity.
Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities	'
	Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities
	In January 2013, the FASB issued an Accounting Standards Update clarifying that the scope of Update 2011-11, Balance Sheet (Topic 210): Disclosures about Offsetting Assets and Liabilities, applies to derivatives accounted for in accordance with Topic 815, Derivatives and Hedging, including bifurcated embedded derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing and securities lending transactions that are either offset in accordance with Section 210-20-45 or Section 815-10-45 or subject to an enforceable master netting arrangement or similar agreement. The amendments are effective for fiscal years beginning on or after January 1, 2013, and interim periods within those annual periods. The adoption of this guidance in January 2013 did not have any effect on the Company's results of operations, financial position or liquidity.
Reclassifications	'
	Reclassifications
	Certain items in the financial statements as of December 31, 2012 and for the periods ending September 30, 2012 and for the period from May 19, 2011 (inception) to September 30, 2013 have been reclassified to conform to the current period's presentation. There was no effect on net income or shareholders' equity previously reported.

Acquisition_of_MAC_Tables

Acquisition of MAC (Tables)	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Schedule of Assets Acquired and Liabilities Assumed	'
	The consideration (net of expenses paid on MAC's behalf) was held in an escrow account until the Company received GSE Approval, upon which time it was released to MAC Financial Ltd. The total purchase consideration was allocated to the acquired assets and liabilities as follows:
	April 24, 2012
	Current assets	$	52,159
	Intangibles	1,590,000
	Capitalized software	5,000,000
	Goodwill	3,244,197
	Subtotal	9,886,356
	Current liabilities and deferred tax liabilities	(1,386,356		)
	Estimated fair value of net assets acquired	$	8,500,000

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
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
		Cost				Gains				(Losses)				Value
	As of September 30, 2013
	U.S. Treasury securities and obligations of U.S. government agencies	$	108,067,508			$	—			$	(1,178,688	)		$	106,888,820
	Municipal bonds	12,019,214				—				(103,372		)		11,915,842
	Corporate debt securities	224,245,377				150,482				(4,818,660		)		219,577,199
	Asset-backed securities	74,689,572				81,955				(1,170,372		)		73,601,155
	Total Investments	$	419,021,671			$	232,437			$	(7,271,092	)		$	411,983,016
		Amortized				Gross Unrealized								Fair
		Cost				Gains				(Losses)				Value
	As of December 31, 2012
	Short-term investments	$	4,863,647			$	559			$	—			$	4,864,206
	Total Investments	$	4,863,647			$	559			$	—			$	4,864,206
Schedule of Investments by Maturity	'
	The amortized cost and fair values of available for sale securities at September 30, 2013, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.
		Amortized				Fair
		Cost				Value
	Due in one year or less	$	—			$	—
	Due after one through five years	253,500,682				250,727,716
	Due after five through ten years	75,369,556				72,704,193
	Due after ten years	15,461,861				14,949,952
	Asset-backed securities	74,689,572				73,601,155
	Total Investments	$	419,021,671			$	411,983,016
Schedule of Realized Investment (Losses) Gains on Investments	'
	Net Realized Investment (Losses) Gains on Investments
		Three Months Ended September 30, 2013				Nine months ended September 30, 2013				For the Period from May 19, 2011 (inception) to September 30, 2013
	Corporate Bond	$	(206,875	)		$	309,234			$	309,234
	U.S. Treasury securities and obligations of U.S. government agencies	(71,700		)		(87,359		)		(87,359		)
	Mortgage-backed security	(29,843		)		(49,584		)		(49,584		)
	Total Net Realized Investment (Losses) Gains	$	(308,418	)		$	172,291			$	172,291
Schedule of Aging Unrealized Losses	'
	At September 30, 2013, the investment portfolio had gross unrealized losses of approximately $7 million. For those securities in an unrealized loss position, the length of time the securities were in such a position, as measured by their month-end fair values, is as follows:
		Less Than 12 Months							12 Months or Greater							Total
		Fair Value			Unrealized Losses				Fair Value			Unrealized Losses				Fair Value		Unrealized Losses
	As of September 30, 2013
	U.S. Treasury Securities and Obligations of U.S. government agencies	$	106,888,820		$	(1,178,688	)		$	—		$	—			$	106,888,820	$	(1,178,688	)
	Municipal bonds	11,915,842			(103,372		)		—			—				11,915,842		(103,372		)
	Corporate debt securities	197,641,652			(4,818,660		)		—			—				197,641,652		(4,818,660		)
	Assets-backed securities	66,012,200			(1,170,372		)		—			—				66,012,200		(1,170,372		)
	Total Investments	$	382,458,514		$	(7,271,092	)		$	—		$	—			$	382,458,514	$	(7,271,092	)
Schedule of Net Investment Income	'
	Net investment income is comprised of the following:
		Nine months ended September 30, 2013				For the Nine months ended September 30, 2012				For the Year Ended December 31, 2012				For the Period From May 19, 2011 (inception) to September 30, 2013
	Fixed maturities	$	3,663,254			$	874			$	2,019			$	3,665,273
	Cash equivalents	—				—				3,806				3,806
	Other	1,517				—				—				1,517
	Investment income	3,664,771				874				5,825				3,670,596
	Investment expenses	(328,621		)		—				—				(328,621		)
	Net Investment Income	$	3,336,150			$	874			$	5,825			$	3,341,975

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements, Recurring and Nonrecurring	'
	The following is a list of those assets and liabilities that are measured at fair value by hierarchy level as of September 30, 2013 and December 31, 2012:
		Fair Value Measurements Using
	Assets and Liabilities at Fair Value	Quoted Prices in		Significant Other		Significant		Fair Value
		Active Markets for		Observable Inputs		Unobservable
		Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	As of September 30, 2013
	U.S. Treasury securities and obligations of U.S. government agencies	$	106,888,820	$	—	$	—	$	106,888,820
	Municipal bonds	—		11,915,842		—		11,915,842
	Corporate debt securities	—		219,577,199		—		219,577,199
	Asset-backed securities	—		73,601,155		—		73,601,155
	Cash and cash equivalents	34,097,356		—		—		34,097,356
	Total Assets	$	140,986,176	$	305,094,196	$	—	$	446,080,372
	Warrant liability	—		—		$	5,452,428	$	5,452,428
	Total Liabilities	$	—	$	—	$	5,452,428	$	5,452,428
		Fair Value Measurements Using
	Assets and Liabilities at Fair Value	Quoted Prices in		Significant Other		Significant		Fair Value
		Active Markets for		Observable Inputs		Unobservable
		Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	As of December 31, 2012
	U.S. Treasury securities and obligations of U.S. government agencies	$	4,864,206	$	—	$	—	$	4,864,206
	Cash and cash equivalents	526,193,573		—		—		526,193,573
	Total Assets	$	531,057,779	$	—	$	—	$	531,057,779
	Warrant liability	—		—		$	4,841,765	$	4,841,765
	Total Liabilities	$	—	$	—	$	4,841,765	$	4,841,765
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	'
	The following is a roll-forward of Level 3 liabilities measured at fair value for the nine months ended September 30, 2013:
		Total Fair Value Measurements
	Nine months ended September 30, 2013
	Level 3 Instruments Only	Warrant Liability
	Balance, January 1, 2013	$	4,841,765
	Change in fair value of warrant liability included in earnings	610,663
	Balance, September 30, 2013	$	5,452,428
		Total Fair Value Measurements
	Period from May 19, 2011 (inception) to September 30, 2013
	Level 3 Instruments Only	Warrant Liability
	Balance, May 19, 2011	$	—
	Initial fair value of warrant liability	5,119,569
	Change in fair value of warrant liability included in earnings	332,859
	Balance, September 30, 2013	$	5,452,428

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Deferred Tax Assets and Liabilities	'
	Following is a reconciliation of the Company's net deferred income tax asset as of September 30, 2013 and December 31, 2012:
		September 30, 2013
		Gross			Tax Effected
	Deferred tax asset:
	Capitalized start-up costs	$	40,318,967		$	13,708,449
	Stock compensation	13,159,292			4,474,159
	Unrealized loss on investments	7,038,655			2,393,143
	Net operating loss carry forwards	14,825,590			5,040,701
	Other	5,647,019			1,919,986
	Total gross deferred tax assets	80,989,523			27,536,438
	Less: valuation allowance	78,544,235			26,705,040
	Total deferred tax assets	2,445,288			831,398
	Deferred tax liability:
	Capitalized Software	(2,439,542		)	(829,444		)
	Intangible Assets	(390,000		)	(132,600		)
	Other	(5,746		)	(1,954		)
	Total deferred tax liabilities	(2,835,288		)	(963,998		)
	Net deferred income tax liability	$	(390,000	)	$	(132,600	)
		December 31, 2012
		Gross			Tax Effected
	Deferred tax asset:
	Capitalized start-up costs	$	21,796,012		$	7,410,644
	Net operating loss carry forwards	7,307,344			2,484,497
	Total gross deferred tax assets	29,103,356			9,895,141
	Less: valuation allowance	24,103,356			8,195,141
	Total deferred tax assets	5,000,000			1,700,000
	Deferred tax liability:
	Capitalized Software	(5,000,000		)	(1,700,000		)
	Intangible Assets	(390,000		)	(132,600		)
	Total deferred tax liabilities	(5,390,000		)	(1,832,600		)
	Net deferred income tax liability	$	(390,000	)	$	(132,600	)

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of Future Minimum Lease Payments	'
	Management expects that, in the normal course of business, as of September 30, 2013, future minimum lease payments under this lease will be as follows:
	Years ending December 31,
	2013	$	205,884
	2014	416,176
	Totals	$	622,060

Stock_Compensation_Tables

Stock Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Stock Option Activity	'
	A summary of option activity in the plan during the period ending September 30, 2013 is as follows:
		Shares		Weighted Average Grant Date Fair Value per Share
	Options balance at December 31, 2012	2,546,750		$	3.86
	Options granted	531,829		4.57
	Less: Options forfeited	(14,701	)	3.84
	Options balance outstanding at September 30, 2013	3,063,878		$	3.98
Schedule of Grant Date Fair Values of Stock Options, Valuation Assumptions	'
	The estimated grant date fair values of the stock options granted during 2013 were calculated using the Black-Scholes valuation model based on the following assumptions:
	Expected life	6.00 years
	Risk free interest rate	0.85%
	Dividend yield	0	%
	Expected stock price volatility	39	%
	Projected forfeiture rates	1	%
Schedule of Restricted Stock Units Activity	'
	A summary of restricted stock unit activity in the plan during the period ending September 30, 2013 is as follows:
		Shares		Weighted Average Grant Date Fair Value per Share
	Restricted Stock Units balance at December 31, 2012	1,429,260		$	7.35
	Restricted Stock Units Granted	82,000		11.75
	Less: Restricted Stock Units Vested	(262,610	)	6.79
	Less: Restricted Stock Units Forfeited	—		—
	Restricted Stock Units balance outstanding at September 30, 2013	1,248,650		$	7.76
Schedule of Grant Date Fair Value of Restricted Stock Units, Valuation Assumptions	'
	The estimated grant date fair values of the restricted stock units granted in 2012 that are subject to both a market and service condition were calculated using a Monte Carlo simulation model based on the average outcome of 150,000 simulations using the following assumption:
	Expected life	5.00 years
	Risk free interest rate	0.86	%
	Dividend yield	0	%
	Expected stock price volatility	39	%
	Projected forfeiture rates	1	%

Software_and_Equipment_Tables

Software and Equipment (Tables)	9 Months Ended
	Sep. 30, 2013
Property, Plant and Equipment [Abstract]	'
Schedule of Equipment and Software	'
	Software and equipment, net of accumulated amortization and depreciation, as of September 30, 2013 and December 31, 2012, consist of the following:
	As of September 30, 2013
	Software	$	12,526,481
	Equipment	387,446
	Leasehold Improvements	35,039
	Less accumulated amortization and depreciation	(3,894,971		)
	Software and equipment, net	$	9,053,995
	As of December 31, 2012
	Software	$	7,268,439
	Equipment	284,573
	Less accumulated amortization and depreciation	(2,917		)
	Software and equipment, net	$	7,550,095

Intangible_Assets_Tables

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Indefinite-Lived Intangible Assets	'
	Intangible assets consist of identifiable intangible assets purchased in connection with the MAC Acquisition. Intangible assets, net, as of September 30, 2013 and December 31, 2012, consist of the following:
	As of September 30, 2013 and December 31, 2012			Expected Lives
	State licenses	$	260,000	Indefinite
	GSE Approvals	130,000		Indefinite
	Total Intangible Assets	$	390,000

Statutory_Information_Tables

Statutory Information (Tables)	9 Months Ended
	Sep. 30, 2013
Insurance [Abstract]	'
Schedule of Risk to Capital	'
	The risk-to-capital calculation for the Company's combined insurance subsidiaries is:
		30-Sep-13
		(In Thousands)
	Pool risk-in-force (1)	$	93,090
	Primary risk-in-force	1,196
	Total risk-in-force	$	94,286
	Statutory policyholders' surplus	$	198,981
	Statutory contingency reserve	2,149
	Statutory policyholders' position	$	201,130
	Risk-to-capital (2)	0.5:1

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Details) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended		28 Months Ended	1 Months Ended
	Jan. 31, 2013	Apr. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Nov. 30, 2011	Apr. 30, 2012
								MAC Financial Holding Corporation and Subsidiaries [Member]	Common Class A [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'	'
Cash, common stock and warrants issued for acquisition	'	'	'	'	'	'	'	$8,500,000	'
Liabilities assumed in acquisition	'	'	'	'	'	'	'	1,300,000	'
Tax liabilities assumed in acquisition	'	'	'	'	'	'	'	100,000	'
Common stock offered and sold, (in shares)	'	'	'	'	'	'	'	'	55,000,000
Common stock issue price (usd per share)	'	'	'	'	'	'	'	'	$10
Issuance of common stock	'	'	'	'	0	510,465,124	510,465,125	'	550,000,000
Underwriting fee and other offering expense (percent)	'	7.00%	'	'	'	'	'	'	'
Underwriting fee and other offering expense	'	510,000,000	'	'	'	'	'	'	'
Payments of stock issuance costs	$1,500,000	'	'	'	'	'	'	'	'
Antidilutive securities excluded from computation of earnings per share (shares)	'	'	5,304,693	4,414,165	5,304,693	4,414,165	'	'	'

Summary_of_Accounting_Policies2

Summary of Accounting Policies (Details)	Apr. 24, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	escrow_account	Minimum [Member]	Minimum [Member]	Minimum [Member]	Maximum [Member]	Maximum [Member]	Maximum [Member]
		Software [Member]	Equipment [Member]	Insurance Management System [Member]	Software [Member]	Equipment [Member]	Insurance Management System [Member]
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'
Number of escrow accounts, funds released upon GSE approval	2	'	'	'	'	'	'
Estimated useful life	'	'3 years	'3 years	'7 months	'7 years	'7 years	'18 months

Common_Stock_Offering_Details

Common Stock Offering (Details) (USD $)	1 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 30, 2012	Sep. 30, 2013	Oct. 24, 2012
Class of Stock [Line Items]	'	'	'
Underwriting fee and other offering expense	$510	'	'
Net stock issuance proceeds (percent)	93.00%	'	'
Proceeds from issuance of common stock, net of stock issuance costs	476	'	'
Cash placed in operating account through time of GSE Approval	'	32	'
Purchaser discounts and placement fees	'	38.3	'
Purchase discount and placement fees paid in common stock	'	19.5	'
Purchase discount and placement fees paid in cash	'	18.8	'
Proceeds from sale of common stock placed in escrow	'	'	19.5
Common Class A [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Common stock offered and sold, (in shares)	55,000,000	'	'
MAC Financial Holding Corporation and Subsidiaries [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Repayments of long-term debt	'	$35	'

Acquisition_of_MAC_Details

Acquisition of MAC (Details) (MAC Financial Holding Corporation and Subsidiaries [Member], USD $)	Apr. 24, 2012
MAC Financial Holding Corporation and Subsidiaries [Member]	'
Business Acquisition [Line Items]	'
Current assets	$52,159
Intangibles	1,590,000
Capitalized software	5,000,000
Goodwill	3,244,197
Subtotal	9,886,356
Current liabilities and deferred tax liabilities	-1,386,356
Estimated fair value of net assets acquired	$8,500,000

Acquisition_of_MAC_Narrative_D

Acquisition of MAC - Narrative (Details) (USD $)

3 Months Ended

9 Months Ended

28 Months Ended

1 Months Ended

1 Months Ended

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Nov. 30, 2011

Sep. 30, 2013

Dec. 31, 2012

Apr. 24, 2012

Apr. 24, 2012

Nov. 30, 2011

Nov. 30, 2011

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

MAC Financial Holding Corporation and Subsidiaries [Member]

Operational Manuals [Member]

Warrant [Member]

Common Stock [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Consideration paid

'

'

'

'

'

'

$8,500,000

'

'

'

'

'

'

Cash paid in acquisition

'

'

'

'

'

'

2,500,000

'

'

'

'

'

'

Common stock issued in connection with acquisition of subsidiaries (in shares)

'

'

'

'

'

'

'

'

'

'

'

2,500,000

3,500,000

Liabilities assumed in acquisition

'

'

'

'

'

'

1,300,000

'

'

'

'

'

'

Tax liabilities assumed in acquisition

'

'

'

'

'

'

100,000

'

'

'

'

'

'

Cash deposited in escrow

'

'

'

'

'

'

'

0

2,000,000

'

'

'

'

Intangibles

'

'

'

'

'

'

'

'

'

1,590,000

'

'

'

Operating manuals acquired

'

'

'

'

'

'

'

'

'

'

1,200,000

'

'

Loss on impairment

$0

$1,200,000

$0

$0

$0

$1,200,000

'

'

'

'

'

'

'

Investments_Narrative_Details

Investments - Narrative (Details) (USD $)	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]	'
Cash and investments	$7,000,000
Unrealized losses	($7,271,092)

Investments_Fair_Values_and_Gr

Investments - Fair Values and Gross Unrealized Gains and Losses on Investments (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$419,021,671	$4,863,647
Gross Unrealized Gains	232,437	559
Gross Unrealized (Losses)	-7,271,092	0
Fair Value	411,983,016	4,864,206
U.S. Treasury securities and obligations of U.S. government agencies [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	108,067,508	'
Gross Unrealized Gains	0	'
Gross Unrealized (Losses)	-1,178,688	'
Fair Value	106,888,820	'
Municipal bonds [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	12,019,214	'
Gross Unrealized Gains	0	'
Gross Unrealized (Losses)	-103,372	'
Fair Value	11,915,842	'
Corporate debt securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	224,245,377	'
Gross Unrealized Gains	150,482	'
Gross Unrealized (Losses)	-4,818,660	'
Fair Value	219,577,199	'
Asset-backed securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	74,689,572	'
Gross Unrealized Gains	81,955	'
Gross Unrealized (Losses)	-1,170,372	'
Fair Value	73,601,155	'
Short-term investments [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	'	4,863,647
Gross Unrealized Gains	'	559
Gross Unrealized (Losses)	'	0
Fair Value	'	$4,864,206

Investments_Scheduled_Maturiti

Investments - Scheduled Maturities (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]	'	'
Amortized Cost, Due in one year or less	$0	'
Amortized Cost, Due after one through five years	253,500,682	'
Amortized Cost, Due after five through ten years	75,369,556	'
Amortized Cost, Due after ten years	15,461,861	'
Amortized Cost, Total Investments	419,021,671	4,863,647
Available-for-sale Securities, Debt Maturities, Single Maturity Date [Abstract]	'	'
Fair Value, Due in one year or less	0	'
Fair Value, Due after one through five years	250,727,716	'
Fair Value, Due after five through ten years	72,704,193	'
Fair Value Due after ten years	14,949,952	'
Fair Value, Total Investments	411,983,016	4,864,206
Asset-backed securities [Member]	'	'
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]	'	'
Amortized Cost, Total Investments	74,689,572	'
Available-for-sale Securities, Debt Maturities, Single Maturity Date [Abstract]	'	'
Fair Value, Total Investments	$73,601,155	'

Investments_Net_Realized_Inves

Investments - Net Realized Investment (Losses) Gains on Investments (Details) (USD $)	3 Months Ended		9 Months Ended		28 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Net realized investment gains (losses)	($308,418)	$0	$172,291	$0	$172,291
Corporate debt securities [Member]	'	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Net realized investment gains (losses)	-206,875	'	309,234	'	309,234
U.S. Treasury securities and obligations of U.S. government agencies [Member]	'	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Net realized investment gains (losses)	-71,700	'	-87,359	'	-87,359
Asset-backed securities [Member]	'	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'
Net realized investment gains (losses)	($29,843)	'	($49,584)	'	($49,584)

Investments_Unrealized_Losses_

Investments - Unrealized Losses (Details) (USD $)	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value, Less than 12 Months	$382,458,514
Unrealized Losses, Less than 12 Months	-7,271,092
Fair Value, 12 Months or Greater	0
Unrealized Losses, 12 Months or Greater	0
Fair Value, Total	382,458,514
Unrealized Losses	-7,271,092
U.S. Treasury securities and obligations of U.S. government agencies [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value, Less than 12 Months	106,888,820
Unrealized Losses, Less than 12 Months	-1,178,688
Fair Value, 12 Months or Greater	0
Unrealized Losses, 12 Months or Greater	0
Fair Value, Total	106,888,820
Unrealized Losses	-1,178,688
Municipal bonds [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value, Less than 12 Months	11,915,842
Unrealized Losses, Less than 12 Months	-103,372
Fair Value, 12 Months or Greater	0
Unrealized Losses, 12 Months or Greater	0
Fair Value, Total	11,915,842
Unrealized Losses	-103,372
Corporate debt securities [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value, Less than 12 Months	197,641,652
Unrealized Losses, Less than 12 Months	-4,818,660
Fair Value, 12 Months or Greater	0
Unrealized Losses, 12 Months or Greater	0
Fair Value, Total	197,641,652
Unrealized Losses	-4,818,660
Asset-backed securities [Member]	'
Schedule of Available-for-sale Securities [Line Items]	'
Fair Value, Less than 12 Months	66,012,200
Unrealized Losses, Less than 12 Months	-1,170,372
Fair Value, 12 Months or Greater	0
Unrealized Losses, 12 Months or Greater	0
Fair Value, Total	66,012,200
Unrealized Losses	($1,170,372)

Investments_Net_Investment_Inc

Investments - Net Investment Income (Details) (USD $)	9 Months Ended		12 Months Ended	28 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Investment income	$3,664,771	$874	$5,825	$3,670,596
Investment expenses	-328,621	0	0	-328,621
Net Investment Income	3,336,150	874	5,825	3,341,975
Fixed maturities [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Investment income	3,663,254	874	2,019	3,665,273
Cash equivalents [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Investment income	0	0	3,806	3,806
Other [Member]	'	'	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Investment income	$1,517	$0	$0	$1,517

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Narrative (Details) (Significant Unobservable Inputs (Level 3) [Member], USD $)	9 Months Ended
	Sep. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Volatility Assumption	39.00%
Warrant Liability [Member]	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'
Share Price (in dollars per share)	11.4
Risk free rate	2.03%
Expected term	'7 years 0 months 22 days
Expected dividend rate	0.00%

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Assets and Liabilities at Fair Value (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	$411,983,016	$4,864,206
Warrant liability	5,452,428	4,841,765
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	34,097,356	526,193,573
Total Assets	446,080,372	531,057,779
Warrant liability	5,452,428	4,841,765
Financial and Nonfinancial Liabilities, Fair Value Disclosure	5,452,428	4,841,765
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	34,097,356	526,193,573
Total Assets	140,986,176	531,057,779
Warrant liability	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	0	0
Total Assets	305,094,196	0
Warrant liability	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash and cash equivalents	0	0
Total Assets	0	0
Warrant liability	5,452,428	4,841,765
Financial and Nonfinancial Liabilities, Fair Value Disclosure	5,452,428	4,841,765
U.S. Treasury securities and obligations of U.S. government agencies [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	106,888,820	'
U.S. Treasury securities and obligations of U.S. government agencies [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	106,888,820	4,864,206
U.S. Treasury securities and obligations of U.S. government agencies [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	106,888,820	4,864,206
U.S. Treasury securities and obligations of U.S. government agencies [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	0
U.S. Treasury securities and obligations of U.S. government agencies [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	0
Municipal bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	11,915,842	'
Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	11,915,842	'
Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	'
Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	11,915,842	'
Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	'
Corporate debt securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	219,577,199	'
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	219,577,199	'
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	'
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	219,577,199	'
Corporate debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	'
Asset-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	73,601,155	'
Asset-backed securities [Member] | Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	73,601,155	'
Asset-backed securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	0	'
Asset-backed securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	73,601,155	'
Asset-backed securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities	$0	'

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Rollforward of Level 3 (Details) (Significant Unobservable Inputs (Level 3) [Member], USD $)	Sep. 30, 2013	Dec. 31, 2012	18-May-11	Sep. 30, 2013	Sep. 30, 2013
				Warrant Liability [Member]	Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'	'	'
Beginning balance	$5,452,428	$4,841,765	$0	'	'
Initial fair value of warrant liability	'	'	'	'	5,119,569
Change in fair value of warrant liability included in earnings	'	'	'	610,663	332,859
Ending balance	$5,452,428	$4,841,765	$0	'	'

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Asset (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Deferred Tax Asset, Gross [Abstract]	'	'
Capitalized start-up costs	$40,318,967	$21,796,012
Stock compensation	13,159,292	'
Unrealized loss on investments	7,038,655	'
Net operating loss carry forwards	14,825,590	7,307,344
Other	5,647,019	'
Total gross deferred tax assets	80,989,523	29,103,356
Less: valuation allowance	78,544,235	24,103,356
Total deferred tax assets	2,445,288	5,000,000
Deferred tax asset:	'	'
Capitalized start-up costs	13,708,449	7,410,644
Stock compensation	4,474,159	'
Unrealized loss on investments	2,393,143	'
Net operating loss carry forwards	5,040,701	2,484,497
Other	1,919,986	'
Total gross deferred tax assets	27,536,438	9,895,141
Less: valuation allowance	26,705,040	8,195,141
Total deferred tax assets	831,398	1,700,000
Deferred Tax Liability, Gross [Abstract]	'	'
Capitalized Software	-2,439,542	-5,000,000
Intangible Assets	-390,000	-390,000
Other	-5,746	'
Total deferred tax liabilities	-2,835,288	-5,390,000
Net deferred income tax liability	-390,000	-390,000
Deferred tax liability:	'	'
Capitalized Software	-829,444	-1,700,000
Intangible Assets	-132,600	-132,600
Other	-1,954	'
Total deferred tax liabilities	-963,998	-1,832,600
Net deferred income tax liability	($132,600)	($132,600)

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]	'	'
Deferred tax liabilities, gross	($132,600)	($132,600)
Taxes paid related to net share settlement of equity awards	1,500,000	'
Loss carry forwards subject to expiration	7,300,000	'
Less: valuation allowance	26,705,040	8,195,141
Annual Limitation Through Year Three [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Loss carry forwards subject to expiration	800,000	'
Annual Limitations After Year Three [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Loss carry forwards subject to expiration	300,000	'
MAC Financial Holding Corporation and Subsidiaries [Member]	'	'
Income Tax Contingency [Line Items]	'	'
Deferred tax liabilities, gross	($100,000)	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Future Minimum Lease Payments (Details) (USD $)	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
2013	$205,884
2014	416,176
Totals	$622,060

Commitments_and_Contingencies_2

Commitments and Contingencies - Narrative (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Minimum capitalization requirement period	'		'	'3 years		'
Shareholder percent provision regarding underwriting policies	5.00%		'	5.00%		'
Pool risk-in-force	$93,090,000		'	$93,090,000		'
Office facility lease, term of contract	'		'	'2 years		'
Rent expense	200,000		100,000	400,000		100,000
Fannie Mae and Freddie Mac [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Capital required to be capitalized	200,000,000		'	200,000,000		'
Minimum capital required	150,000,000		'	150,000,000		'
Risk-to-capital	20		'	20		'
Statutory capital and surplus required, period	'		'	'3 years		'
Statutory capital and surplus required, no declaration or dividend payment period	'		'	'3 years		'
Statutory capital and surplus required, requirement to not enter in capital support agreement period	'		'	'3 years		'
Statutory capital and surplus required, agreement to not enter in to reinsurance risk period	'		'	'3 years		'
Fannie Mae and Freddie Mac [Member] | NMI Re One [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Capital required to be capitalized	10,000,000		'	10,000,000		'
Fannie Mae and Freddie Mac [Member] | NMI Re Two [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Capital required to be capitalized	10,000,000		'	10,000,000		'
Fannie Mae [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Risk-to-capital	18		'	18		'
Mortgage insurance pool agreement, number of loans	22,000		'	'		'
Mortgage insurance pool agreement, aggregate unpaid principal balance	5,200,000,000		'	5,200,000,000		'
Mortgage insurance pool agreement, expected term	'		'	'10 years		'
Pool risk-in-force	$93,100,000	[1]	'	$93,100,000	[1]	'
Maximum [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Risk-to-capital	25		'	25		'
Maximum [Member] | Fannie Mae and Freddie Mac [Member]	'		'	'		'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'		'	'		'
Risk-to-capital	15		'	15		'
[1]	Pool risk-in-force as shown in the table above is equal to the aggregate stop loss less a deductible.

Stock_Compensation_Stock_Optio

Stock Compensation - Stock Option Activity (Details) (The 2012 Stock Incentive Plan [Member], USD $)	9 Months Ended
	Sep. 30, 2013
The 2012 Stock Incentive Plan [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'
Options begninning balance (in shares)	2,546,750
Options granted (in shares)	531,829
Less: Options forfeited (in shares)	-14,701
Options ending balance (in shares)	3,063,878
Weighted Average Grant Date Fair Value per Share	'
Options beginning balance (in dollars per share)	$3.86
Options granted (in dollars per share)	$4.57
Less: Options forfeited (in dollars per share)	$3.84
Options beginning balance (in dollars per share)	$3.98

Stock_Compensation_Stock_Optio1

Stock Compensation - Stock Options, Valuation Assumptions (Details) (The 2012 Stock Incentive Plan [Member], Stock Options [Member])	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Expected life	'6 years
Dividend yield	0.00%
Expected stock price volatility	39.00%
Projected forfeiture rates	1.00%
Minimum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk free interest rate	0.85%
Maximum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk free interest rate	1.10%

Stock_Compensation_Restricted_

Stock Compensation - Restricted Stock Units Activity (Details) (The 2012 Stock Incentive Plan [Member], Restricted Stock Units [Member], USD $)	9 Months Ended
	Sep. 30, 2013
The 2012 Stock Incentive Plan [Member] | Restricted Stock Units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'
Restricted Stock beginning balance (in shares)	1,429,260
Restricted Stock Units Granted (in shares)	82,000
Less: Restricted Stock Units Vested (in shares)	-262,610
Less: Restricted Stock Units Forfeited (in shares)	0
Restricted Stock beginning balance (in shares)	1,248,650
Weighted Average Grant Date Fair Value per Share	'
Restricted Stock beginning balance (in dollars per share)	$7.35
Restricted Stock Units Granted (in dollars per share)	$11.75
Less: Restricted Stock Units Vested (in dollars per share)	$6.79
Less: Restricted Stock Units Forfeited (in dollars per share)	$0
Restricted Stock ending balance (in dollars per share)	$7.76

Stock_Compensation_Restricted_1

Stock Compensation - Restricted Stock Units, Valuation Assumptions (Details) (The 2012 Stock Incentive Plan [Member], Restricted Stock Units [Member])	9 Months Ended
	Sep. 30, 2013
The 2012 Stock Incentive Plan [Member] | Restricted Stock Units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Expected life	'5 years
Risk free interest rate	0.86%
Dividend yield	0.00%
Expected stock price volatility	39.00%
Projected forfeiture rates	1.00%

Stock_Compensation_Narrative_D

Stock Compensation - Narrative (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 05, 2013	Feb. 28, 2013	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Apr. 16, 2012
				simulation
Stock Options [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Restricted stock vesting period	'	'	'	'3 years	'	'
Expiration period	'	'	'	'10 years	'	'
The 2012 Stock Incentive Plan [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Number of shares authorized to be reserved for issuance (in shares)	'	'	'	'	'	5,500,000
Stock options, number of shares exercisable (in shares)	'	'	'	659,723	'	'
Weighted average remaining contractual life of options outstanding	'	'	'	'8 years 9 months 18 days	'	'
Total unrecognized compensation cost related to non-vested stock options	'	'	'	$4.60	'	'
Compensation related to non-vested awards, weighted-average period for recognition	'	'	'	'11 months 16 days	'	'
The 2012 Stock Incentive Plan [Member] | Stock Options [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Number of shares authorized to be reserved for issuance (in shares)	'	'	'	'	'	3,850,000
The 2012 Stock Incentive Plan [Member] | Restricted Stock Units [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Number of shares authorized to be reserved for issuance (in shares)	'	'	'	'	'	1,650,000
Compensation related to non-vested awards, weighted-average period for recognition	'	'	'	'11 months 5 days	'	'
Expiration period	'	'	'	'10 years	'	'
Modification to vesting terms, number of restricted stock units affected (in shares)	'	400,000	'	'	'	'
Restricted stock units outstanding (in shares)	'	'	'	1,248,650	1,429,260	'
Vesting percentage subject to both market and service conditions, annual vesting percentage	'	'	'	33.00%	'	'
Number of simulations	'	'	'	150,000	'	'
Restricted stock units outstanding, number of shares subject to both market and service conditions (in shares)	'	'	'	500,000	'	'
Restricted stock units outstanding, number of shares subject to only service conditions (in shares)	'	'	'	700,000	'	'
Weighted average remaining contractual life of RSUs outstanding	'	'	'	'4 years 3 months 18 days	'	'
Total unrecognized compensation cost related to non-vested restricted stock units	'	'	'	4.8	'	'
Restricted stock units, number of shares containing a market condition vested (in shares)	263,000	'	'	'	'	'
Acceleration of compensation expense	'	'	$1.10	'	'	'
Minimum [Member] | The 2012 Stock Incentive Plan [Member] | Restricted Stock Units [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Restricted stock vesting period	'	'	'	'1 year	'	'
Maximum [Member] | The 2012 Stock Incentive Plan [Member] | Restricted Stock Units [Member]	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Restricted stock vesting period	'	'	'	'3 years	'	'

Software_and_Equipment_Details

Software and Equipment (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]	'	'
Less accumulated amortization and depreciation	($3,894,971)	($2,917)
Software and equipment, net	9,053,995	7,550,095
Software [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	12,526,481	7,268,439
Equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	387,446	284,573
Leasehold Improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property plant and equipment	$35,039	'

Software_and_Equipment_Narrati

Software and Equipment - Narrative (Details) (USD $)	3 Months Ended		9 Months Ended		28 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Apr. 24, 2012
						Insurance Management System [Member]	Insurance Management System [Member]	MAC Financial Holding Corporation and Subsidiaries [Member]
						Minimum [Member]	Maximum [Member]
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'	'	'
Capitalized software	'	'	'	'	'	'	'	$5,000,000
Depreciation and amortization	$2,045,306	$0	$3,892,054	$0	$3,894,971	'	'	'
Estimated useful life	'	'	'	'	'	'7 months	'18 months	'

Intangible_Assets_Details

Intangible Assets (Details) (USD $)	3 Months Ended			9 Months Ended		28 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Indefinite-lived Intangible Assets [Line Items]	'	'	'	'	'	'
Intangible assets	$390,000	$390,000	'	$390,000	'	$390,000
Loss on impairment	0	1,200,000	0	0	0	1,200,000
State licenses [Member]	'	'	'	'	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'	'	'	'	'
Intangible assets	260,000	260,000	'	260,000	'	260,000
GSE Approvals [Member]	'	'	'	'	'	'
Indefinite-lived Intangible Assets [Line Items]	'	'	'	'	'	'
Intangible assets	$130,000	$130,000	'	$130,000	'	$130,000

Line_of_Credit_and_Related_War1

Line of Credit and Related Warrants (Details) (USD $)	3 Months Ended		9 Months Ended		28 Months Ended
Share data in Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Apr. 24, 2012	Dec. 31, 2011
							FBR Capital Markets and Co. [Member]
							Line of Credit [Member]
Line of Credit Facility [Line Items]	'	'	'	'	'	'	'
Line of credit facility, borrowing capacity	'	'	'	'	'	'	$1,500,000
Exercise price of warrants	'	'	'	'	'	10	'
Warrants issued	'	'	'	'	'	314	'
Warrants value	'	'	'	'	'	1,600,000	'
Gain (Loss) from change in fair value of warrant liability	($468,848)	$0	$610,663	$0	$332,859	'	'

Statutory_Information_Narrativ

Statutory Information - Narrative (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011	18-May-11	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	state				Subsidiaries [Member]	Maximum [Member]	WISCONSIN [Member]	Fannie Mae and Freddie Mac [Member]	Fannie Mae and Freddie Mac [Member]	Fannie Mae [Member]
							Maximum [Member]		Maximum [Member]
Statutory Accounting Practices [Line Items]	'	'	'	'	'	'	'	'	'	'
Number of states which require minimum amount of statutory capital relative to risk in force	15	'	'	'	'	'	'	'	'	'
Risk-to-capital	'	'	'	'	'	25	18	20	15	18
Potential risk In force to capital, ratio	'	'	'	'	'	'	25	'	'	'
Statutory capital and surplus required	'	'	'	'	'	'	'	$150,000,000	'	'
Statutory capital and surplus required, period	'	'	'	'	'	'	'	'3 years	'	'
Mortgage insurance, percentage of indebtedness on single loan	25.00%	'	'	'	'	'	'	'	'	'
Shareholders' equity	$446,858,105	$488,747,641	($1,348,824)	$0	$203,000,000	'	'	'	'	'
Ordinary dividends, restriction with regards to capital surplus	10.00%	'	'	'	'	'	'	'	'	'

Statutory_Information_Risk_to_

Statutory Information - Risk to Capital (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Insurance [Abstract]	'
Pool risk-in-force	$93,090
Primary risk-in-force	1,196
Total risk-in-force	94,286
Statutory policyholders' position	198,981
Statutory contingency reserve	2,149
Statutory Accounting Practices Statutory Policyholders Surplus Plus Contingency Reserves	$201,130
Risk to capital ratio	0.5	[1]
[1]	Represents total risk-in-force divided by statutory policyholders' position which is the metric by which the majority of state insurance regulators will assess our capital adequacy. Additionally, Fannie Mae requires us to maintain the greater of (a) the risk-to-capital requirements outlined in the January 2013 approval letter, or (b) a risk-to-capital ratio of 18:1 on primary business plus statutory capital equal to the amount of net risk-in-force of the pool.

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	1 Months Ended		0 Months Ended
In Millions, except Share data, unless otherwise specified	Apr. 30, 2012	Oct. 31, 2013	Nov. 14, 2013	Nov. 12, 2013	Nov. 08, 2013
		Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
		sqft	IPO [Member]	IPO [Member]	IPO [Member]
Subsequent Event [Line Items]	'	'	'	'	'
Additional square feet of furnished office space under amended lease terms	'	23,000	'	'	'
Common stock offered and sold, (in shares)	'	'	'	'	2,100,000
Underwriting offering period	'	'	'	'	'30 years
Maximum number of additional common stock shares granted to Underwriters of IPO	'	'	'	'	315,000
Maximum number of common stock shares granted to underwriters of IPO, exercise price	'	'	'	$13	'
Gross proceeds from issuance of initial public offering	'	'	$31.40	'	'
Underwriting fee and other offering expense	$510	'	$29	'	'
Underwriting fee and other offering expense (percent)	7.00%	'	6.00%	'	'