NMI (NMIH) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document and Entity Information [Abstract]
Entity Registrant Name	NMI HOLDINGS, INC.
Entity Central Index Key	1547903
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		58,686,375

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Assets
Fixed maturities, available-for-sale, at fair value (amortized cost of $365,674 and $337,718 as of March 31, 2015 and December 31, 2014, respectively)	$367,947,000	$336,501,000
Cash and cash equivalents	66,420,000	103,021,000
Premiums receivable	1,663,000	1,048,000
Accrued investment income	1,732,000	1,707,000
Prepaid expenses	2,091,000	2,054,000
Deferred policy acquisition costs, net	5,283,000	2,985,000
Software and equipment, net	12,913,000	11,806,000
Goodwill and other indefinite lived intangible assets	3,634,000	3,634,000
Other assets	56,000	509,000
Total Assets	461,739,000	463,265,000
Liabilities
Unearned premiums	28,054,000	22,069,000
Reserve for insurance claims and claim expenses	187,000	83,000
Accounts payable and accrued expenses	6,845,000	10,646,000
Warrant liability, at fair value	2,124,000	3,372,000
Current tax payable	1,190,000	0
Deferred tax liability	137,000	137,000
Total Liabilities	38,537,000	36,307,000
Commitments and contingencies
Shareholders' Equity
Additional paid-in capital	564,915,000	562,911,000
Accumulated other comprehensive loss, net of tax	-1,548,000	-3,607,000
Accumulated deficit	-140,750,000	-132,930,000
Total Shareholders' Equity	423,202,000	426,958,000
Total Liabilities and Shareholders' Equity	461,739,000	463,265,000
Class A
Shareholders' Equity
Common stock - class A shares, $0.01 par value; 58,519,558 and 58,428,548 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively (250,000,000 shares authorized)	$585,000	$584,000

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Fixed maturity, amortized cost	$365,674	$337,718
Class A
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares issued	58,519,558	58,428,548
Common stock, shares outstanding	58,519,558	58,428,548
Common stock, shares authorized	250,000,000	250,000,000

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (UNAUDITED) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues
Net premiums written	$12,921	$5,178
Increase in unearned premiums	-5,985	-3,274
Net premiums earned	6,936	1,904
Net investment income	1,596	1,489
Net realized investment gains	613	0
Gain from change in fair value of warrant liability	1,248	817
Gain from settlement of warrants	0	37
Total revenues	10,393	4,247
Expenses
Insurance claims and claims expenses	104	0
Underwriting and operating expenses	18,350	19,302
Total expenses	18,454	19,302
Loss before income taxes	-8,061	-15,055
Income tax benefit	-241	0
Net loss	-7,820	-15,055
Other comprehensive income, net of tax:
Net unrealized holding gains for the period included in accumulated other comprehensive loss, net of tax expense of $1,431, and $0 for the three months ended March 31, 2015 and 2014, respectively	2,672	3,035
Reclassification adjustment for gains included in net loss, net of tax expense of $0, and $0 for the three months ended March 31, 2015 and 2014, respectively	-613	0
Other comprehensive income, net of tax	2,059	3,035
Total comprehensive loss	($5,761)	($12,020)
Loss per share
Basic and Diluted loss per share (in dollars per share)	($0.13)	($0.26)
Weighted average common shares outstanding (in shares)	58,485,899	58,061,299

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (UNAUDITED) (Parentheticals) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Change in unrealized investment gains (losses), tax amount	$1,431	$0
Reclassification adjustment from AOCI for sale of securities, tax amount	$0	$0

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) (USD $)		Total	Class A	Common Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
In Thousands, unless otherwise specified				Class A	Class B		Class A
Beginning balance at Dec. 31, 2013		$463,217		$581	$0	$553,707		($7,047)	($84,024)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock: class A shares issued under related to warrants	[1]		13				13
Common stock: class A shares issued under related to warrants			14	3			11
Share-based compensation expense		9,180				9,180
Change in unrealized investment gains/losses, net of tax		3,440						3,440
Net loss		-48,906							-48,906
Ending balance at Dec. 31, 2014		426,958		584	0	562,911		-3,607	-132,930
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock: class A shares issued under related to warrants			0	1			-1
Share-based compensation expense		2,005				2,005
Change in unrealized investment gains/losses, net of tax		2,059						2,059
Net loss		-7,820							-7,820
Ending balance at Mar. 31, 2015		$423,202		$585	$0	$564,915		($1,548)	($140,750)
[1]	During 2014, we issued 1,115 common shares with a par value of $0.01 related to the exercise of warrants, which is not identifiable in this schedule due to rounding.

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
Change in unrealized investment gains (losses), tax amount	$2,390
Class A
Common stock, par value (in dollars per share)	$0.01
Class A | Common Stock
Stock issued during period (in shares)	1,115
Common stock, par value (in dollars per share)	$0.01

CONDENSED_CONSOLIDATED_STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash Flows From Operating Activities
Net loss	($7,820)	($15,055)
Adjustments to reconcile net loss to net cash used in operating activities:
Net realized investment gains	-613	0
(Gain) loss from change in fair value of warrant liability	-1,248	-817
Gain from settlement of warrants	0	-37
Depreciation and other amortization	1,099	1,952
Share-based compensation expense	2,005	2,333
Benefit for taxes on current year unrealized gains	-241	0
Changes in operating assets and liabilities:
Accrued investment income	-25	210
Premiums receivable	-615	-110
Prepaid expenses	-37	-183
Deferred policy acquisition costs, net	-2,298	-887
Other assets	453	7
Unearned premiums	5,985	3,274
Reserve for insurance claims and claims expenses	104	0
Accounts payable and accrued expenses	-4,291	-2,678
Net Cash Used in Operating Activities	-7,542	-11,991
Cash Flows From Investing Activities
Purchase of fixed-maturity investments, available-for-sale	-61,676	-110
Proceeds from redemptions, maturities and sale of fixed-maturity investments, available-for-sale	33,935	718
Purchase of software and equipment	-1,317	-1,664
Net Cash Provided by (Used in) Investing Activities	-29,058	-1,056
Cash Flows From Financing Activities
Taxes paid related to net share settlement of equity awards	-334	-90
Issuance of common stock	333	0
Net Cash Provided by (Used in) Financing Activities	-1	-90
Net Increase (Decrease) in Cash and Cash Equivalents	-36,601	-13,137
Cash and Cash Equivalents, beginning of period	103,021	55,929
Cash and Cash Equivalents, end of period	$66,420	$42,792

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation
	NMI Holdings, Inc. (NMIH) is a Delaware corporation, incorporated in May 2011, to provide private mortgage guaranty insurance (which we refer to as mortgage insurance or MI) through its wholly owned insurance subsidiaries, National Mortgage Insurance Corporation (NMIC) and National Mortgage Reinsurance Inc One (Re One). In April 2013, NMIC, our primary insurance subsidiary, wrote our first mortgage insurance policy. As of March 31, 2015, we had $4.8 billion of primary insurance in force (IIF) and $4.6 billion of pool IIF, with $1.1 billion of primary risk-in-force (RIF) and $93.1 million of pool RIF.
	Freddie Mac and Fannie Mae each approved NMIC as an eligible mortgage insurer, on January 15, 2013 and January 16, 2013, respectively, which approvals are conditioned upon NMIC maintaining certain conditions (GSE Approval).
	Basis of Presentation
	The accompanying unaudited condensed consolidated financial statements, which include the results of NMIH and its wholly owned subsidiaries, have been prepared in accordance with the instructions to Form 10-Q as prescribed by the SEC for interim reporting and include other information and disclosures required by accounting principles generally accepted in the U.S. (GAAP). Our accounts are maintained in U.S. dollars. These statements should be read in conjunction with our consolidated financial statements and notes thereto for the year ended December 31, 2014 included in our Annual Report on Form 10-K. All intercompany transactions have been eliminated. The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, as well as disclosure of contingent assets and liabilities as of the balance sheet date. Estimates also affect the reported amounts of income and expenses for the reporting period. Actual results could differ from those estimates. The results of operations for the interim period may not be indicative of the results that may be expected for the full year ending December 31, 2015.
	Earnings per Share
	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 our net losses for the three months ended March 31, 2015 and 2014, 7,137,901 shares and 6,159,735 shares, respectively, of our common stock equivalents issued under stock-based compensation arrangements and warrants, respectively, were not included in the calculation of diluted net loss per share as of such dates because they were anti-dilutive.
	Deferred Policy Acquisition Costs
	Costs directly associated with the successful acquisition of mortgage insurance policies, consisting of certain selling expenses 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 expense in proportion to estimated gross profits over the estimated life of the policies. Total amortization of DAC for the three months ended March 31, 2015 and 2014 were $356 thousand and $19 thousand, respectively.
	Premium Deficiency Reserves
	We consider whether a premium deficiency exists at each fiscal quarter using best estimate assumptions as of the testing date. Per Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 944, a premium deficiency reserve shall be recognized if the sum of expected claim costs and claim adjustment expenses, expected dividends to policyholders, unamortized acquisition costs, and maintenance costs exceeds related unearned premiums and anticipated investment income. We have determined that no premium deficiency reserves were necessary for the three months ended March 31, 2015 or 2014.
	Recent Accounting Pronouncements
	In May 2014, the FASB issued Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers (Topic 606). This update is intended to provide a consistent approach in recognizing revenue. In accordance with the new standard, recognition of revenue occurs when a customer obtains control of promised goods or services in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, the new standard requires that reporting companies disclose the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The provisions of this update are effective for interim and annual periods beginning after December 15, 2016. The Company is currently evaluating the impact the adoption of this ASU will have on the consolidated financial statements.

Investments

Investments	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	Investments
	We have designated our investment portfolio as available-for-sale and report it at fair value. The related unrealized gains and losses are, after considering the related tax expense or benefit, recognized as a component of accumulated other comprehensive loss in shareholders' equity. Net realized investment gains and losses are reported in income based upon specific identification of securities sold.
	Fair Values and Gross Unrealized Gains and Losses on Investments
		Amortized				Gross Unrealized								Fair
		Cost				Gains				Losses				Value
	As of March 31, 2015	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	86,605			$	115			$	(127	)		$	86,593
	Municipal debt securities	12,008				21				(34		)		11,995
	Corporate debt securities	198,125				2,311				(308		)		200,128
	Asset-backed securities	68,936				397				(102		)		69,231
	Total investments	$	365,674			$	2,844			$	(571	)		$	367,947
		Amortized				Gross Unrealized								Fair
		Cost				Gains				Losses				Value
	As of December 31, 2014	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	68,911			$	7			$	(573	)		$	68,345
	Municipal debt securities	12,009				27				(73		)		11,963
	Corporate debt securities	200,358				883				(1,456		)		199,785
	Asset-backed securities	56,440				222				(254		)		56,408
	Total investments	$	337,718			$	1,139			$	(2,356	)		$	336,501
	Scheduled Maturities
	The amortized cost and fair values of available for sale securities at March 31, 2015 and December 31, 2014, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.
	As of March 31, 2015	Amortized				Fair
		Cost				Value
		(In Thousands)
	Due in one year or less	$	19,617			$	19,662
	Due after one through five years	180,613				181,103
	Due after five through ten years	79,706				81,044
	Due after ten years	16,802				16,907
	Asset-backed securities	68,936				69,231
	Total investments	$	365,674			$	367,947
	As of December 31, 2014	Amortized				Fair
		Cost				Value
		(In Thousands)
	Due in one year or less	$	6,110			$	6,125
	Due after one through five years	195,492				194,472
	Due after five through ten years	54,360				53,891
	Due after ten years	25,316				25,605
	Asset-backed securities	56,440				56,408
	Total investments	$	337,718			$	336,501
	Net Realized Investment Gains (Losses) on Investments
	Gross realized gains and losses were $0.8 million and $0.2 million, respectively, for the three months ended March 31, 2015. There were no realized investment gains or losses for the three months ended March 31, 2014.
	Aging of Unrealized Losses
	At March 31, 2015, the investment portfolio had gross unrealized losses of $0.6 million, $0.5 million of which has been in an unrealized loss position for a period of 12 months or greater. We did not consider these securities to be other-than-temporarily impaired as of March 31, 2015. We based our conclusion that these investments were not other-than-temporarily impaired at March 31, 2015 on the following facts: (i) the unrealized losses were primarily caused by interest rate movements since the purchase date; (ii) we do not intend to sell these investments; and (iii) we do not believe that it is more likely than not that we will be required to sell these investments before recovery of our amortized cost basis, which may not occur until maturity. For those securities in an unrealized loss position, the length of time the securities were in such a position is as follows:
		Less Than 12 Months									12 Months or Greater								Total
		# of Securities		Fair Value			Unrealized Losses				# of Securities		Fair Value			Unrealized Losses			# of Securities	Fair Value		Unrealized Losses
	As of March 31, 2015			(Dollars in Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	2		$	7,307		$	(17	)		6		$	22,448		$	(110	)	8	$	29,755	$	(127	)
	Municipal debt securities	1		3,240			(10		)		1		1,726			(24		)	2	4,966		(34		)
	Corporate debt securities	5		10,774			(38		)		7		21,276			(270		)	12	32,050		(308		)
	Assets-backed securities	5		13,452			(34		)		4		10,782			(68		)	9	24,234		(102		)
	Total investments	13		$	34,773		$	(99	)		18		$	56,232		$	(472	)	31	$	91,005	$	(571	)
		Less Than 12 Months									12 Months or Greater								Total
		# of Securities		Fair Value			Unrealized Losses				# of Securities		Fair Value			Unrealized Losses			# of Securities	Fair Value		Unrealized Losses
	As of December 31, 2014			(Dollars in Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	4		$	7,228		$	(33	)		10		$	49,884		$	(540	)	14	$	57,112	$	(573	)
	Municipal debt securities	1		3,232			(18		)		1		1,695			(55		)	2	4,927		(73		)
	Corporate debt securities	26		60,334			(559		)		22		65,806			(897		)	48	126,140		(1,456		)
	Assets-backed securities	3		10,614			(57		)		4		20,047			(197		)	7	30,661		(254		)
	Total investments	34		$	81,408		$	(667	)		37		$	137,432		$	(1,689	)	71	$	218,840	$	(2,356	)
	Net Investment Income
	For the three months ended March 31, 2015, net investment income was comprised of $1.7 million of investment income from fixed maturities and $0.1 million of investment expenses, compared to $1.6 million of investment income from fixed maturities and $0.1 million of investment expenses for the three months ended March 31, 2014.
	As of March 31, 2015 and December 31, 2014, there were approximately $7.0 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_Value_of_Financial_Instru

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The following is a list of those assets and liabilities that are measured at fair value by hierarchy level:
		Fair Value Measurements Using
		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 March 31, 2015	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	57,238		$	29,355		$	—	$	86,593
	Municipal debt securities	—			11,995			—		11,995
	Corporate debt securities	—			200,128			—		200,128
	Asset-backed securities	—			69,231			—		69,231
	Cash and cash equivalents	66,420			—			—		66,420
	Total assets	$	123,658		$	310,709		$	—	$	434,367
	Warrant liability	$	—		$	—		$	2,124	$	2,124
	Total liabilities	$	—		$	—		$	2,124	$	2,124
		Fair Value Measurements Using
		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, 2014	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	39,176		$	29,169		$	—	$	68,345
	Municipal debt securities	—			11,963			—		11,963
	Corporate debt securities	—			199,785			—		199,785
	Asset-backed securities	—			56,408			—		56,408
	Cash and cash equivalents	103,021			—			—		103,021
	Total assets	$	142,197		$	297,325		$	—	$	439,522
	Warrant liability	$	—		$	—		$	3,372	$	3,372
	Total liabilities	$	—		$	—		$	3,372	$	3,372
	The following is a roll-forward of Level 3 liabilities measured at fair value:
		For the three months ended March 31,
	Warrant Liability	2015			2014
		(In Thousands)
	Balance, January 1	$	3,372		$	6,371
	Change in fair value of warrant liability included in earnings	(1,248		)	(817		)
	Issuance of common stock on warrant exercise	—			(13		)
	Gain on settlement of warrants	—			(37		)
	Balance, March 31	$	2,124		$	5,504
	We revalue the warrant liability quarterly using a Black-Scholes option-pricing model, in combination with a binomial model, and we value the pricing protection features within the warrants using a Monte-Carlo simulation model. As of March 31, 2015, the assumptions used in the option pricing model were as follows: a common stock price as of March 31, 2015 of $7.49, risk free interest rate of 1.65%, expected life of 6.67 years, expected volatility of 34.4% and a dividend yield of 0%. The change in fair value is primarily attributable to a decline in the price of our common stock from December 31, 2014 to March 31, 2015.

Reserves_for_Insurance_Claims_

Reserves for Insurance Claims and Claim Expenses	3 Months Ended
	Mar. 31, 2015
Insurance [Abstract]
Reserves for Insurance Claims and Claim Expenses	Reserves for Insurance Claims and Claims Expenses
	We establish claim reserves to recognize the estimated liability for insurance claims and claim expenses related to defaults on insured mortgage loans. Our method, consistent with industry practice, is to establish claim reserves only for loans in default. Our claim reserves also include amounts for estimated claims incurred on loans that have been in default for at least 60 days that have not yet been reported to us by the servicers, often referred to as IBNR. We did not establish reserves for insurance claims within our primary insurance book until the second quarter of 2014. In 2013, we entered into a pool insurance agreement with Fannie Mae. We only establish claim or IBNR reserves for pool risk if we expect claims to exceed the deductible under the pool agreement, which represents the amount of claims absorbed by Fannie Mae before we are obligated to pay any claims. At March 31, 2015, thirty-five loans in the pool were past due by sixty days or more. These thirty-five loans represent approximately $1.9 million in RIF. Due to the deductible of $10.3 million, the level of notices of default (NODs) reported through March 31, 2015 and the expected severity (all loans in the pool have LTVs under 80%), we have not established any pool reserves for claims or IBNR for the three months ended March 31, 2015 and 2014. We have not paid any claims to date.
	The following table provides a reconciliation of the beginning and ending reserve balances for insurance claims and claims expenses:
		For the three months ended March 31,
		2015		2014
		(In Thousands)
	Reserve at beginning of period	$	83	$	—
	Claims incurred:
	Claims and claim expenses incurred:
	Current year	80		—
	Prior years	24		—
	Total claims incurred	104		—
	Claims paid:
	Claims and claim expenses paid:
	Current year	—		—
	Prior years	—		—
	Total claims paid	—		—
	Reserve at end of period	$	187	$	—
	There was a $24 thousand unfavorable prior year development during the three months ended March 31, 2015. Reserves remaining as of March 31, 2015 for prior years are $107 thousand as a result of re-estimation of unpaid claims and claim adjustment expenses. The increase in the period is generally the result of ongoing analysis of recent loss development trends. Original estimates are increased or decreased as additional information becomes known regarding individual claims.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Warrants	Warrants
	In April 2012, we issued 992,000 warrants with an aggregate fair value of $5.1 million upon the completion of a private placement of our securities and in conjunction with the acquisition of our insurance subsidiaries. Each warrant gives the holder thereof the right to purchase one share of common stock at an exercise price equal to $10.00.
	Upon exercise of these warrants, the amounts are reclassified from warrant liability to additional paid-in capital. During the first quarter of 2014, 7,790 warrants were exercised and we issued 1,115 Class A common shares via a cashless exercise. Upon exercise we recognized a gain of approximately $37 thousand. No warrants were exercised during the first quarter of 2015.
	We account for these warrants to purchase our common shares in accordance with ASC 470-20, Debt with Conversion and Other Options and ASC 815-40, Derivatives and Hedging - Contracts in Entity's Own Equity.

Share_Based_Compensation

Share Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share Based Compensation
	The following table provides a summary of option activity:
	For the three months ended March 31, 2015	Shares		Weighted Average Grant Date Fair Value per Share		Weighted Average Exercise Price
		(Shares in Thousands)
	Options outstanding at December 31, 2014	3,630		$	4.16	$	10.66
	Options granted	755		3.06		8.5
	Options forfeited	(12	)	4.34		11.07
	Options outstanding at March 31, 2015	4,373		$	3.97	$	10.29
	For the three months ended March 31, 2014	Shares		Weighted Average Grant Date Fair Value per Share		Weighted Average Exercise Price
		(Shares in Thousands)
	Options outstanding at December 31, 2013	3,063		$	3.98	$	10.31
	Options granted	693		4.97		12.32
	Options exercised	(2	)	3.84		10
	Options forfeited	(28	)	4.15		10.71
	Options outstanding at March 31, 2014	3,726		$	4.17	$	10.68
	At March 31, 2015, there were no options exercised and 2.1 million options were fully vested and exercisable. The weighted average exercise price for the fully vested and exercisable options was $10.53. The remaining weighted average contractual life of options fully vested and exercisable as of March 31, 2015 was 7.5 years. The aggregate intrinsic value for fully vested and exercisable options was $0 as of March 31, 2015. The fair value of option grants to employees is determined based on a Black-Scholes simulation model at the date of grant.
	The following table provides a summary of restricted stock unit (RSU) activity:
	For the three months ended March 31, 2015	Shares		Weighted Average Grant Date Fair Value per Share
		(Shares in Thousands)
	Non-vested restricted stock units at December 31, 2014	1,209		$	8.9
	Restricted stock units granted	677		7.57
	Restricted stock units vested and exercised	(91	)	12.21
	Restricted stock units forfeited	(15	)	10.82
	Non-vested restricted stock units at March 31, 2015	1,780		$	8.21
	For the three months ended March 31, 2014	Shares		Weighted Average Grant Date Fair Value per Share
		(Shares in Thousands)
	Non-vested restricted stock units at December 31, 2013	1,242		$	7.75
	Restricted stock units granted	239		12.32
	Restricted stock units vested and exercised	(19	)	11.31
	Restricted stock units forfeited	(14	)	6.98
	Non-vested restricted stock units at March 31, 2014	1,448		$	8.46
	At March 31, 2015, the 1.8 million shares of non-vested RSUs consisted of 0.5 million shares that are subject to both a market and service condition and 1.3 million shares that are subject only to service conditions. The non-vested RSUs subject to both a market and service condition vest in one-half increments upon the achievement of certain market price goals and continued service. Non-vested RSUs subject only to a service condition vest over a service period ranging from 1 to 3 years. The fair value of RSUs subject to market and service conditions is determined based on a Monte Carlo simulation model at the date of grant. The fair value of RSUs subject only to service conditions are valued at our stock price on the date of grant less the present value of anticipated dividends, which is $0.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	We are a U.S. taxpayer and are subject to a statutory U.S. federal corporate income tax rate of 35%. Our holding company files a consolidated U.S. federal and various state income tax returns on behalf of itself and its subsidiaries. Our effective income tax rate on our pre-tax loss was 3.0% for the three months ended March 31, 2015, compared to 0.0% for the comparable 2014 period.
	The income tax benefit of $0.2 million for the three months ended March 31, 2015 is related to the tax effects of unrealized gains credited to other comprehensive income (OCI). Generally, the amount of tax expense or benefit allocated to continuing operations is determined without regard to the tax effects of other categories of income or loss, such as OCI. However, an exception to the general rule is provided in ASC 740-20-45-7 when there is a pre-tax loss from continuing operations and there are items charged or credited to other categories, including OCI, in the current year. The intraperiod tax allocation rules related to items charged or credited directly to OCI can result in disproportionate tax effects that remain in OCI until certain events occur. As a result of net unrealized gains credited directly to OCI during the three months ended March 31, 2015, approximately $1.4 million of tax provision expense has been netted with current year unrealized gains in OCI, and $0.2 million of tax provision benefit was allocated to the income tax provision for continuing operations. Other benefits from income taxes were eliminated or reduced by the recognition of a full valuation allowance which was recorded to reflect the amount of the deferred taxes that may not be realized.

Statutory_Information

Statutory Information	3 Months Ended
	Mar. 31, 2015
Insurance [Abstract]
Statutory Information	Statutory Information
	Our insurance subsidiaries, NMIC and Re One, are domiciled in the state of Wisconsin and file financial statements in conformity with statutory basis accounting principles (SAP) prescribed or permitted by the Wisconsin Office of the Commissioner of Insurance (Wisconsin OCI). NMIC and Re One's principal regulator is the Wisconsin OCI. 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 Wisconsin OCI recognizes only SAP 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.
	Certain states limit the amount of risk a mortgage 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 cedes premiums, loss reserves and claims to Re One on an excess share basis for any primary or pool policy which offers coverage greater than 25% on any loan insured thereunder solely for purposes of compliance with these state statutory coverage limits. Currently, NMIC has no other reinsurance agreements.
	NMIC and Re One's combined statutory net loss, statutory surplus and contingency reserve were as follows:
	As of and for the three months ended March 31, 2015 and as of and for the year ended December 31, 2014	March 31, 2015			December 31, 2014
		(In Thousands)
	Statutory net loss	$	(12,131	)	$	(47,961	)
	Statutory surplus	224,604			236,738
	Contingency reserve	12,869			9,401
	NMIC is licensed in all 50 states and D.C. Under applicable Wisconsin law and 15 other states, a mortgage insurer must maintain a minimum amount of statutory capital relative to its risk-in-force (risk-to-capital ratio or RTC ratio) to continue to write new business. While formulas for minimum capital may vary among jurisdictions, the most common measure applied allows for a maximum permitted RTC ratio of 25 to 1. Our operation plan filed with the Wisconsin OCI and other state insurance departments in connection with NMIC's applications for licensure includes the expectation that NMIH will downstream additional capital if needed so that NMIC does not exceed RTC ratios agreed to with those states. In addition, under the terms of our conditional approvals from the GSEs, we are required to operate at a risk-to-capital ratio not to exceed 15 to 1 for our first three years of operations.
	As of March 31, 2015, NMIC had $1.1 billion in total RIF with a RTC ratio of 5:1, significantly below the GSE and state imposed financial requirements. As of March 31, 2014, NMIC had $175.2 million of RIF, resulting in a RTC ratio of 0.9:1. The risk-to-capital calculation for each of our insurance subsidiaries, as well as our combined risk-to-capital calculation, is presented below.
	As of March 31, 2015	NMIC			Re One			Combined
		(In Thousands)
	Primary risk-in-force (1)
	Direct	$	1,145,252		$	—		$	1,145,252
	Assumed	—			98,680			98,680
	Ceded	(98,680		)	—			(98,680		)
	Total primary risk-in-force	1,046,572			98,680			1,145,252
	Pool risk-in-force (2)
	Direct	93,090			—			93,090
	Assumed	—			24,705			24,705
	Ceded	(24,705		)	—			(24,705		)
	Total pool risk-in-force	68,385			24,705			93,090
	Total risk-in-force	1,114,957			123,385			1,238,342
	Statutory policyholders' surplus	211,130			13,474			224,604
	Statutory contingency reserve	11,216			1,653			12,869
	Total statutory policyholders' position	$	222,346		$	15,127		$	237,473
	Risk-to-Capital (3)	5:01			8.2:1			5.2:1
	(1)	Primary RIF excludes risk on policies that are currently in default and for which loss reserves have been established.
	(2)	Pool RIF as shown in the table above is equal to the aggregate stop loss less a deductible.
	(3)	Represents total RIF divided by statutory policyholders' position which is the metric by which the majority of state insurance regulators will assess our capital adequacy.
	NMIH 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 NMIH. 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, 2014, NMIH's shareholders' equity was approximately $427 million. NMIH's total assets, excluding its investment in NMIC and Re One, were approximately $179 million at December 31, 2014, and were unencumbered by any debt or other subsidiary commitments or obligations. The insurance subsidiaries are both mono-line mortgage insurance companies and the assets of each are dedicated only to the support of direct risk and obligations of each mortgage insurance entity. NMIC only writes direct mortgage insurance business and assumes no business from any other entity. Re One only assumes business from NMIC to allow NMIC to comply with state statutory risk requirements. Neither NMIC nor Re One have subsidiaries, and therefore do not have subsidiary risks and obligations that compete for its resources.
	The GSEs and state insurance regulators may restrict our insurance subsidiaries' ability to pay dividends to NMIH. In addition to the restrictions imposed during the GSE Approval and state licensing processes, the ability of our insurance subsidiaries to pay dividends to NMIH 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 Wisconsin OCI (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 policyholders' surplus as of the prior December 31 or (b) its net income (excluding realized capital gains) for the 12 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 Wisconsin OCI. As of December 31, 2014, the amount of restricted net assets held by our consolidated insurance subsidiaries totaled approximately $252 million of NMIH's consolidated net assets of $427 million. The amount of restricted assets used to determine any dividend to NMIH, once all restrictions expire, would be computed under SAP which may differ from the amount of restricted assets computed under GAAP. Since inception, NMIC has not paid any dividends to NMIH. As NMIC had a statutory net loss for the year ended December 31, 2014, NMIC cannot pay any dividends to NMIH through December 31, 2015, without the prior approval of the Wisconsin OCI. Additionally, NMIC will not be permitted to pay dividends to NMIH until after December 31, 2015 as a condition of GSE Approval or until January 2016 under agreements with various state insurance regulators.

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2015
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 March 31, 2015	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	86,605			$	115			$	(127	)		$	86,593
	Municipal debt securities	12,008				21				(34		)		11,995
	Corporate debt securities	198,125				2,311				(308		)		200,128
	Asset-backed securities	68,936				397				(102		)		69,231
	Total investments	$	365,674			$	2,844			$	(571	)		$	367,947
		Amortized				Gross Unrealized								Fair
		Cost				Gains				Losses				Value
	As of December 31, 2014	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	68,911			$	7			$	(573	)		$	68,345
	Municipal debt securities	12,009				27				(73		)		11,963
	Corporate debt securities	200,358				883				(1,456		)		199,785
	Asset-backed securities	56,440				222				(254		)		56,408
	Total investments	$	337,718			$	1,139			$	(2,356	)		$	336,501
Schedule of Investments by Maturity	The amortized cost and fair values of available for sale securities at March 31, 2015 and December 31, 2014, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in separate categories.
	As of March 31, 2015	Amortized				Fair
		Cost				Value
		(In Thousands)
	Due in one year or less	$	19,617			$	19,662
	Due after one through five years	180,613				181,103
	Due after five through ten years	79,706				81,044
	Due after ten years	16,802				16,907
	Asset-backed securities	68,936				69,231
	Total investments	$	365,674			$	367,947
	As of December 31, 2014	Amortized				Fair
		Cost				Value
		(In Thousands)
	Due in one year or less	$	6,110			$	6,125
	Due after one through five years	195,492				194,472
	Due after five through ten years	54,360				53,891
	Due after ten years	25,316				25,605
	Asset-backed securities	56,440				56,408
	Total investments	$	337,718			$	336,501
Schedule of Aging Unrealized Losses	For those securities in an unrealized loss position, the length of time the securities were in such a position is as follows:
		Less Than 12 Months									12 Months or Greater								Total
		# of Securities		Fair Value			Unrealized Losses				# of Securities		Fair Value			Unrealized Losses			# of Securities	Fair Value		Unrealized Losses
	As of March 31, 2015			(Dollars in Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	2		$	7,307		$	(17	)		6		$	22,448		$	(110	)	8	$	29,755	$	(127	)
	Municipal debt securities	1		3,240			(10		)		1		1,726			(24		)	2	4,966		(34		)
	Corporate debt securities	5		10,774			(38		)		7		21,276			(270		)	12	32,050		(308		)
	Assets-backed securities	5		13,452			(34		)		4		10,782			(68		)	9	24,234		(102		)
	Total investments	13		$	34,773		$	(99	)		18		$	56,232		$	(472	)	31	$	91,005	$	(571	)
		Less Than 12 Months									12 Months or Greater								Total
		# of Securities		Fair Value			Unrealized Losses				# of Securities		Fair Value			Unrealized Losses			# of Securities	Fair Value		Unrealized Losses
	As of December 31, 2014			(Dollars in Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	4		$	7,228		$	(33	)		10		$	49,884		$	(540	)	14	$	57,112	$	(573	)
	Municipal debt securities	1		3,232			(18		)		1		1,695			(55		)	2	4,927		(73		)
	Corporate debt securities	26		60,334			(559		)		22		65,806			(897		)	48	126,140		(1,456		)
	Assets-backed securities	3		10,614			(57		)		4		20,047			(197		)	7	30,661		(254		)
	Total investments	34		$	81,408		$	(667	)		37		$	137,432		$	(1,689	)	71	$	218,840	$	(2,356	)

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
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:
		Fair Value Measurements Using
		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 March 31, 2015	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	57,238		$	29,355		$	—	$	86,593
	Municipal debt securities	—			11,995			—		11,995
	Corporate debt securities	—			200,128			—		200,128
	Asset-backed securities	—			69,231			—		69,231
	Cash and cash equivalents	66,420			—			—		66,420
	Total assets	$	123,658		$	310,709		$	—	$	434,367
	Warrant liability	$	—		$	—		$	2,124	$	2,124
	Total liabilities	$	—		$	—		$	2,124	$	2,124
		Fair Value Measurements Using
		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, 2014	(In Thousands)
	U.S. Treasury securities and obligations of U.S. government agencies	$	39,176		$	29,169		$	—	$	68,345
	Municipal debt securities	—			11,963			—		11,963
	Corporate debt securities	—			199,785			—		199,785
	Asset-backed securities	—			56,408			—		56,408
	Cash and cash equivalents	103,021			—			—		103,021
	Total assets	$	142,197		$	297,325		$	—	$	439,522
	Warrant liability	$	—		$	—		$	3,372	$	3,372
	Total liabilities	$	—		$	—		$	3,372	$	3,372
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 three months ended March 31,
	Warrant Liability	2015			2014
		(In Thousands)
	Balance, January 1	$	3,372		$	6,371
	Change in fair value of warrant liability included in earnings	(1,248		)	(817		)
	Issuance of common stock on warrant exercise	—			(13		)
	Gain on settlement of warrants	—			(37		)
	Balance, March 31	$	2,124		$	5,504

Reserves_for_Insurance_Claims_1

Reserves for Insurance Claims and Claim Expenses (Tables)	3 Months Ended
	Mar. 31, 2015
Insurance [Abstract]
Reconciliation of Liability for Insurance Claims and Claims Expenses	The following table provides a reconciliation of the beginning and ending reserve balances for insurance claims and claims expenses:
		For the three months ended March 31,
		2015		2014
		(In Thousands)
	Reserve at beginning of period	$	83	$	—
	Claims incurred:
	Claims and claim expenses incurred:
	Current year	80		—
	Prior years	24		—
	Total claims incurred	104		—
	Claims paid:
	Claims and claim expenses paid:
	Current year	—		—
	Prior years	—		—
	Total claims paid	—		—
	Reserve at end of period	$	187	$	—

Share_Based_Compensation_Table

Share Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Option Activity	The following table provides a summary of option activity:
	For the three months ended March 31, 2015	Shares		Weighted Average Grant Date Fair Value per Share		Weighted Average Exercise Price
		(Shares in Thousands)
	Options outstanding at December 31, 2014	3,630		$	4.16	$	10.66
	Options granted	755		3.06		8.5
	Options forfeited	(12	)	4.34		11.07
	Options outstanding at March 31, 2015	4,373		$	3.97	$	10.29
	For the three months ended March 31, 2014	Shares		Weighted Average Grant Date Fair Value per Share		Weighted Average Exercise Price
		(Shares in Thousands)
	Options outstanding at December 31, 2013	3,063		$	3.98	$	10.31
	Options granted	693		4.97		12.32
	Options exercised	(2	)	3.84		10
	Options forfeited	(28	)	4.15		10.71
	Options outstanding at March 31, 2014	3,726		$	4.17	$	10.68
Schedule of Restricted Stock Units Activity	The following table provides a summary of restricted stock unit (RSU) activity:
	For the three months ended March 31, 2015	Shares		Weighted Average Grant Date Fair Value per Share
		(Shares in Thousands)
	Non-vested restricted stock units at December 31, 2014	1,209		$	8.9
	Restricted stock units granted	677		7.57
	Restricted stock units vested and exercised	(91	)	12.21
	Restricted stock units forfeited	(15	)	10.82
	Non-vested restricted stock units at March 31, 2015	1,780		$	8.21
	For the three months ended March 31, 2014	Shares		Weighted Average Grant Date Fair Value per Share
		(Shares in Thousands)
	Non-vested restricted stock units at December 31, 2013	1,242		$	7.75
	Restricted stock units granted	239		12.32
	Restricted stock units vested and exercised	(19	)	11.31
	Restricted stock units forfeited	(14	)	6.98
	Non-vested restricted stock units at March 31, 2014	1,448		$	8.46

Statutory_Information_Tables

Statutory Information (Tables)	3 Months Ended
	Mar. 31, 2015
Insurance [Abstract]
Schedule of Risk to Capital	The risk-to-capital calculation for each of our insurance subsidiaries, as well as our combined risk-to-capital calculation, is presented below.
	As of March 31, 2015	NMIC			Re One			Combined
		(In Thousands)
	Primary risk-in-force (1)
	Direct	$	1,145,252		$	—		$	1,145,252
	Assumed	—			98,680			98,680
	Ceded	(98,680		)	—			(98,680		)
	Total primary risk-in-force	1,046,572			98,680			1,145,252
	Pool risk-in-force (2)
	Direct	93,090			—			93,090
	Assumed	—			24,705			24,705
	Ceded	(24,705		)	—			(24,705		)
	Total pool risk-in-force	68,385			24,705			93,090
	Total risk-in-force	1,114,957			123,385			1,238,342
	Statutory policyholders' surplus	211,130			13,474			224,604
	Statutory contingency reserve	11,216			1,653			12,869
	Total statutory policyholders' position	$	222,346		$	15,127		$	237,473
	Risk-to-Capital (3)	5:01			8.2:1			5.2:1
	(1)	Primary RIF excludes risk on policies that are currently in default and for which loss reserves have been established.
	(2)	Pool RIF as shown in the table above is equal to the aggregate stop loss less a deductible.
	(3)	Represents total RIF divided by statutory policyholders' position which is the metric by which the majority of state insurance regulators will assess our capital adequacy.
	NMIC and Re One's combined statutory net loss, statutory surplus and contingency reserve were as follows:
	As of and for the three months ended March 31, 2015 and as of and for the year ended December 31, 2014	March 31, 2015			December 31, 2014
		(In Thousands)
	Statutory net loss	$	(12,131	)	$	(47,961	)
	Statutory surplus	224,604			236,738
	Contingency reserve	12,869			9,401

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Business Acquisition [Line Items]
Primary insurance in force	$4,800,000,000
Pool insurance in force	4,600,000,000
Antidilutive securities excluded from computation of earnings per share (in shares)	7,137,901	6,159,735
Deferred policy acquisition cost, amortization expense	356,000	19,000
Combined
Business Acquisition [Line Items]
Primary insurance risk in force	1,100,000,000
Pool risk in force	$93,090,000

Investments_Fair_Values_and_Gr

Investments - Fair Values and Gross Unrealized Gains and Losses on Investments (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$365,674	$337,718
Gross Unrealized Gains	2,844	1,139
Gross Unrealized (Losses)	-571	-2,356
Fair Value	367,947	336,501
U.S. Treasury securities and obligations of U.S. government agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	86,605	68,911
Gross Unrealized Gains	115	7
Gross Unrealized (Losses)	-127	-573
Fair Value	86,593	68,345
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,008	12,009
Gross Unrealized Gains	21	27
Gross Unrealized (Losses)	-34	-73
Fair Value	11,995	11,963
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	198,125	200,358
Gross Unrealized Gains	2,311	883
Gross Unrealized (Losses)	-308	-1,456
Fair Value	200,128	199,785
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68,936	56,440
Gross Unrealized Gains	397	222
Gross Unrealized (Losses)	-102	-254
Fair Value	$69,231	$56,408

Investments_Scheduled_Maturiti

Investments - Scheduled Maturities (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Amortized Cost, Due in one year or less	$19,617	$6,110
Amortized Cost, Due after one through five years	180,613	195,492
Amortized Cost, Due after five through ten years	79,706	54,360
Amortized Cost, Due after ten years	16,802	25,316
Amortized Cost, Total Investments	365,674	337,718
Available-for-sale Securities, Debt Maturities, Single Maturity Date [Abstract]
Fair Value, Due in one year or less	19,662	6,125
Fair Value, Due after one through five years	181,103	194,472
Fair Value, Due after five through ten years	81,044	53,891
Fair Value Due after ten years	16,907	25,605
Fair Value, Total Investments	367,947	336,501
Asset-backed securities
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Amortized Cost, Total Investments	68,936	56,440
Available-for-sale Securities, Debt Maturities, Single Maturity Date [Abstract]
Fair Value, Total Investments	$69,231	$56,408

Investments_Unrealized_Losses_

Investments - Unrealized Losses (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	security	security
Schedule of Available-for-sale Securities [Line Items]
Number of securities, less than 12 months	13	34
Fair value, less than 12 months	$34,773	$81,408
Unrealized losses, less than 12 months	-99	-667
Number of securities,12 months or greater	18	37
Fair value, 12 months or greater	56,232	137,432
Unrealized losses, 12 months or greater	-472	-1,689
Number of securities, total	31	71
Fair value	91,005	218,840
Unrealized Losses	-571	-2,356
U.S. Treasury securities and obligations of U.S. government agencies
Schedule of Available-for-sale Securities [Line Items]
Number of securities, less than 12 months	2	4
Fair value, less than 12 months	7,307	7,228
Unrealized losses, less than 12 months	-17	-33
Number of securities,12 months or greater	6	10
Fair value, 12 months or greater	22,448	49,884
Unrealized losses, 12 months or greater	-110	-540
Number of securities, total	8	14
Fair value	29,755	57,112
Unrealized Losses	-127	-573
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Number of securities, less than 12 months	1	1
Fair value, less than 12 months	3,240	3,232
Unrealized losses, less than 12 months	-10	-18
Number of securities,12 months or greater	1	1
Fair value, 12 months or greater	1,726	1,695
Unrealized losses, 12 months or greater	-24	-55
Number of securities, total	2	2
Fair value	4,966	4,927
Unrealized Losses	-34	-73
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities, less than 12 months	5	26
Fair value, less than 12 months	10,774	60,334
Unrealized losses, less than 12 months	-38	-559
Number of securities,12 months or greater	7	22
Fair value, 12 months or greater	21,276	65,806
Unrealized losses, 12 months or greater	-270	-897
Number of securities, total	12	48
Fair value	32,050	126,140
Unrealized Losses	-308	-1,456
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities, less than 12 months	5	3
Fair value, less than 12 months	13,452	10,614
Unrealized losses, less than 12 months	-34	-57
Number of securities,12 months or greater	4	4
Fair value, 12 months or greater	10,782	20,047
Unrealized losses, 12 months or greater	-68	-197
Number of securities, total	9	7
Fair value	24,234	30,661
Unrealized Losses	($102)	($254)

Investments_Narrative_Details

Investments - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, gross realized gains	$800,000	$0
Realized losses, excluding other than temporary impairments	-200,000	0
Unrealized loss position, accumulated loss	571,000		2,356,000
Unrealized losses, 12 months or greater	472,000		1,689,000
Investment income, investment expense	-100,000	-100,000
U.S. Treasury securities and obligations of U.S. government agencies
Schedule of Available-for-sale Securities [Line Items]
Unrealized loss position, accumulated loss	127,000		573,000
Unrealized losses, 12 months or greater	110,000		540,000
Cash and investments held with various state insurance departments	7,000,000		7,000,000
Fixed Maturities
Schedule of Available-for-sale Securities [Line Items]
Investment Income, gross	$1,700,000	$1,600,000

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Assets and Liabilities at Fair Value (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$367,947	$336,501
Warrant liability	2,124	3,372
U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	86,593	68,345
Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	11,995	11,963
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	200,128	199,785
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	69,231	56,408
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	66,420	103,021
Total assets	434,367	439,522
Warrant liability	2,124	3,372
Total liabilities	2,124	3,372
Fair Value, Measurements, Recurring | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	86,593	68,345
Fair Value, Measurements, Recurring | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	11,995	11,963
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	200,128	199,785
Fair Value, Measurements, Recurring | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	69,231	56,408
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	66,420	103,021
Total assets	123,658	142,197
Warrant liability	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	57,238	39,176
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total assets	310,709	297,325
Warrant liability	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	29,355	29,169
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	11,995	11,963
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	200,128	199,785
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	69,231	56,408
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
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	2,124	3,372
Total liabilities	2,124	3,372
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | U.S. Treasury securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$0	$0

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Rollforward of Level 3 (Details) (Significant Unobservable Inputs (Level 3), Warrant Liability, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Significant Unobservable Inputs (Level 3) | Warrant Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$3,372	$6,371
Change in fair value of warrant liability included in earnings	-1,248	-817
Issuance of common stock on warrant exercise	0	-13
Gain on settlement of warrants	0	-37
Ending balance	$2,124	$5,504

Fair_Value_of_Financial_Instru4

Fair Value of Financial Instruments - Narrative (Details) (Significant Unobservable Inputs (Level 3), USD $)	3 Months Ended
	Mar. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Volatility assumption	34.40%
Warrant Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Share Price (in dollars per share)	7.49
Risk free rate	1.65%
Expected term	6 years 7 months 30 days
Expected dividend rate	0.00%

Reconciliation_of_Reserve_Bala

Reconciliation of Reserve Balances for Insurance Claims Expenses (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Reserve at beginning of period	$83	$0
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Current year	80	0
Prior years	24	0
Total claims incurred	104	0
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Current year	0	0
Prior years	0	0
Total claims paid	0	0
Reserve at end of period	$187	$0

Reconciliation_of_Reserve_Bala1

Reconciliation of Reserve Balances for Insurance Claims Expenses - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Insurance Agreement [Line Items]
Claim and claim adjustment expense reserve	$187,000	$0	$83,000	$0
Prior years	24,000	0
Reserve for prior year insurance claims and claim expenses	107,000
Fannie Mae
Insurance Agreement [Line Items]
Number of loans in pool past due 60 days or more	35
Risk in Force of loans in pool past due 60 days or more	1,900,000
Deductible on policy	10,300,000
Loan-to-value ratio (less than)	0.8
Claim and claim adjustment expense reserve	$0	$0

Warrants_Details

Warrants (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Apr. 30, 2012
Line of Credit Facility [Line Items]
Warrants issued (in shares)				992,000
Warrants value				$5,100,000
Right to purchase, number of shares per warrant				1
Exercise price of warrants (in dollars per warrant)				$10
Number of warrants exercised during period	0	7,790
Gain from settlement of warrants	$0	$37,000	$37,000
Class A | Common Stock
Line of Credit Facility [Line Items]
Issuance of Class A shares of common stock as part of cashless exercise of warrants, shares			1,115

Share_Based_Compensation_Stock

Share Based Compensation - Stock Option Activity (Details) (The 2012 Stock Incentive Plan, USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
The 2012 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options beginning balance (in shares)	3,630,000	3,063,000
Options granted (in shares)	755,000	693,000
Options exercised (in shares)	0	-2,000
Options forfeited (in shares)	-12,000	-28,000
Options ending balance (in shares)	4,373,000	3,726,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Options beginning balance (in dollars per share)	$4.16	$3.98
Options granted (in dollars per share)	$3.06	$4.97
Options exercised (in dollars per shares)		$3.84
Options forfeited (in dollars per share)	$4.34	$4.15
Options ending balance (in dollars per share)	$3.97	$4.17
Weighted Average Exercise Price
Options beginning balance (in dollars per share)	$10.66	$10.31
Options granted (in dollars per share)	$8.50	$12.32
Options exercised (in dollars per share)		$10
Options forfeited (in dollars per share)	$11.07	$10.71
Options ending balance (in dollars per share)	$10.29	$10.68

Share_Based_Compensation_Narra

Share Based Compensation - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
The 2012 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised (in shares)	0	2,000
Number of options vested (in shares)	2,100,000
Weighted average exercise price for options vested (in dollars per share)	$10.53
Weighted average remaining contractual term	7 years 5 months 20 days
Options vested aggregate value	$0
Present value of anticipated dividends	$0
The 2012 Stock Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (in shares)	1,780,000	1,448,000	1,209,000	1,242,000
Subject to Market and Service Conditions | The 2012 Stock Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (in shares)	500,000
Subject to Service Conditions | The 2012 Stock Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (in shares)	1,300,000
Subject to Service Conditions | Minimum | The 2012 Stock Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	1 year
Subject to Service Conditions | Maximum | The 2012 Stock Incentive Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	3 years
First Increment | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	50.00%
Second Increment | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage	50.00%

Share_Based_Compensation_Restr

Share Based Compensation - Restricted Stock Units Activity (Details) (The 2012 Stock Incentive Plan, Restricted Stock Units, USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
The 2012 Stock Incentive Plan | Restricted Stock Units
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)	1,209	1,242
Restricted stock units granted (in shares)	677	239
Restricted stock units vested (in shares)	-91	-19
Restricted stock units forfeited (in shares)	-15	-14
Restricted Stock ending balance (in shares)	1,780	1,448
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Stock beginning balance (in dollars per share)	$8.90	$7.75
Restricted Stock Units Granted (in dollars per share)	$7.57	$12.32
Restricted stock units vested (in dollars per share)	$12.21	$11.31
Restricted stock units forfeited (in dollars per share)	$10.82	$6.98
Restricted Stock ending balance (in dollars per share)	$8.21	$8.46

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	35.00%
Effective income tax rate on pre-tax loss	3.00%	0.00%
Income tax benefit	$241,000	$0
Tax provision expense netted against unrealized gains in OCI	1,400,000
Deferred tax liabilities, net	$137,000		$137,000

Statutory_Information_Statutor

Statutory Information - Statutory Income (Details) (Combined, USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Combined
Statutory Accounting Practices [Line Items]
Statutory net loss	($12,131)	($47,961)
Statutory surplus	224,604	236,738
Contingency reserve	$12,869	$9,401

Statutory_Information_Narrativ

Statutory Information - Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
	state
Statutory Accounting Practices [Line Items]
Mortgage insurance, percentage of indebtedness on single loan	25.00%
Number of states entity is licensed to write mortgage insurance	50
Number of states which require minimum amount of statutory capital relative to risk in force	15
Risk-to-capital	25
Required risk-to-capital ratio on agreements per GSE approval, maximum	15
Required maximum risk-to-capital ratio on agreements per GSE approval, time period	3 years
Shareholders' equity	$423,202,000	$426,958,000	$463,217,000
Investment in subsidiaries, at equity in net assets		179,000,000
Ordinary dividends, restriction with regards to capital surplus		10.00%
Combined
Statutory Accounting Practices [Line Items]
Mortgage Insurance risk in force	1,238,342,000
Risk to capital ratio	5.2
NMIC
Statutory Accounting Practices [Line Items]
Mortgage Insurance risk in force	1,100,000,000			175,200,000
Risk to capital ratio	5			0.9
Subsidiaries
Statutory Accounting Practices [Line Items]
Shareholders' equity		$252,000,000

Statutory_Information_Risk_to_

Statutory Information - Risk to Capital (Details) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
In Thousands, unless otherwise specified
NMIC
Primary risk-in-force
Direct	$1,145,252
Assumed	0
Ceded	-98,680
Total primary risk-in-force	1,046,572
Pool risk-in-force
Direct	93,090
Assumed	0
Ceded	-24,705
Total pool risk-in-force	68,385
Total risk-in-force	1,100,000	175,200
Statutory policyholders' surplus	211,130
Statutory contingency reserve	11,216
Total statutory policyholders' position	222,346
Risk to capital ratio	5	0.9
Re One
Primary risk-in-force
Direct	0
Assumed	98,680
Ceded	0
Total primary risk-in-force	98,680
Pool risk-in-force
Direct	0
Assumed	24,705
Ceded	0
Total pool risk-in-force	24,705
Total risk-in-force	123,385
Statutory policyholders' surplus	13,474
Statutory contingency reserve	1,653
Total statutory policyholders' position	15,127
Risk to capital ratio	8.2
Combined
Primary risk-in-force
Direct	1,145,252
Assumed	98,680
Ceded	-98,680
Total primary risk-in-force	1,145,252
Pool risk-in-force
Direct	93,090
Assumed	24,705
Ceded	-24,705
Total pool risk-in-force	93,090
Total risk-in-force	1,238,342
Statutory policyholders' surplus	224,604		236,738
Statutory contingency reserve	12,869
Total statutory policyholders' position	$237,473
Risk to capital ratio	5.2