XML 46 R22.htm IDEA: XBRL DOCUMENT v3.20.1

Investments (Tables)

3 Months Ended

Mar. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Schedule of Fair Values and Gross Unrealized Gains and Losses

Fair Values and Gross Unrealized Gains and Losses on Investments

			Amortized Cost						Gross Unrealized																		Fair Value
												Gains						Losses
As of March 31, 2020			(In Thousands)
U.S. Treasury securities and obligations of U.S. government agencies			$	48,207					$	3,519					$	—					$	51,726
Municipal debt securities			196,750						3,853						(668)						199,935
Corporate debt securities			628,834						18,272						(6,658)						640,448
Asset-backed securities			180,514						404						(7,811)						173,107
Total bonds			1,054,305						26,048						(15,137)						1,065,216
Short-term investments			4,838						18						—						4,856
Total investments			$	1,059,143					$	26,066					$	(15,137)					$	1,070,072

			Amortized Cost						Gross Unrealized																		Fair Value
												Gains						Losses
As of December 31, 2019			(In Thousands)
U.S. Treasury securities and obligations of U.S. government agencies			$	48,203					$	784					$	(58)					$	48,929
Municipal debt securities			189,530						1,721						(1,035)						190,216
Corporate debt securities			661,719						23,373						(211)						684,881
Asset-backed securities			170,153						2,603						(114)						172,642
Total bonds			1,069,605						28,481						(1,418)						1,096,668
Short-term investments			44,174						98						—						44,272
Total investments			$	1,113,779					$	28,579					$	(1,418)					$	1,140,940

Schedule of Investments by Industry Group

The following table presents a breakdown of the fair value of our corporate debt securities by issuer industry group as of March 31, 2020 and December 31, 2019:

			March 31, 2020						December 31, 2019
Financial			40		%				38		%
Consumer			23						26
Communications			11						10
Utilities			10						9
Industrial			9						8
Technology			7						7
Energy			—						2
Total			100		%				100		%

Schedule of Investments by Maturity

The amortized cost and fair values of available-for-sale securities as of March 31, 2020 and December 31, 2019, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most asset-backed securities provide for periodic payments throughout their lives, they are listed below in a separate category.

As of March 31, 2020			Amortized Cost						Fair Value
			(In Thousands)
Due in one year or less			$	83,740					$	83,736
Due after one through five years			408,063						415,419
Due after five through ten years			373,220						383,838
Due after ten years			13,606						13,972
Asset-backed securities			180,514						173,107
Total investments			$	1,059,143					$	1,070,072

As of December 31, 2019			Amortized Cost						Fair Value
			(In Thousands)
Due in one year or less			$	138,776					$	139,113
Due after one through five years			406,986						417,208
Due after five through ten years			380,737						394,180
Due after ten years			17,127						17,797
Asset-backed securities			170,153						172,642
Total investments			$	1,113,779					$	1,140,940

Schedule of Aging Unrealized Losses

The following table summarizes the investment portfolio in an unrealized loss position for which an allowance is not recorded, aggregated by major security type and length of time in a continuous unrealized loss position:

			Less Than 12 Months																		12 Months or Greater																		Total
			# of Securities			Fair Value			Unrealized Losses						# of Securities			Fair Value			Unrealized Losses						# of Securities			Fair Value			Unrealized Losses
As of March 31, 2020						(Dollars in Thousands)
U.S. Treasury securities and obligations of U.S. government agencies			—			$	—		$	—					—			$	—		$	—					—			$	—		$	—
Municipal debt securities			14			46,936			(668)						—			—			—						14			46,936			(668)
Corporate debt securities			87			178,776			(6,630)						5			3,294			(28)						92			182,070			(6,658)
Asset-backed securities			60			133,997			(7,745)						1			2,934			(66)						61			136,931			(7,811)
Total			161			$	359,709		$	(15,043)					6			$	6,228		$	(94)					167			$	365,937		$	(15,137)

			Less Than 12 Months																		12 Months or Greater																		Total
			# of Securities			Fair Value			Unrealized Losses						# of Securities			Fair Value			Unrealized Losses						# of Securities			Fair Value			Unrealized Losses
As of December 31, 2019						(Dollars in Thousands)
U.S. Treasury securities and obligations of U.S. government agencies			4			$	12,001		$	(58)					—			$	—		$	—					4			$	12,001		$	(58)
Municipal debt securities			26			92,844			(1,034)						1			999			(1)						27			93,843			(1,035)
Corporate debt securities			10			30,481			(140)						14			23,976			(71)						24			54,457			(211)
Asset-backed securities			9			19,236			(102)						1			2,988			(12)						10			22,224			(114)
Total			49			$	154,562		$	(1,334)					16			$	27,963		$	(84)					65			$	182,525		$	(1,418)

Schedule of Components of Net Investment Income

The following table presents the components of net investment income:

			For the three months ended March 31,
			2020						2019
			(In Thousands)
Investment income			$	8,349					$	7,496
Investment expenses			(245)						(113)
Net investment income			$	8,104					$	7,383

Schedule of Net Realized Investment Gains (Losses)

The following table presents the components of net realized investment gains (losses):

			For the three months ended March 31,
			2020						2019
			(In Thousands)
Gross realized investment gains			$	540					$	195
Gross realized investment losses			(612)						(382)
Net realized investment (losses)			$	(72)					$	(187)

X

- Definition

Investments Classified By Issuer Industry Group [Table Text Block]

+ References

No definition available.

+ Details

Name:	nmih_InvestmentsClassifiedByIssuerIndustryGroupTableTextBlock
Namespace Prefix:	nmih_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-URI http://asc.fasb.org/topic&trid=2196928

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of investment income, including, but not limited to, interest and dividend income and amortization of discount (premium) derived from debt and equity securities. Excludes realized and unrealized gain (loss) on investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.9)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.2)
-URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(a),(b))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

Name:	us-gaap_InvestmentIncomeTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments.

+ References

No definition available.

+ Details

Name:	us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of realized gains and losses on investments reported in the statement of income.

+ References

No definition available.

+ Details

Name:	us-gaap_RealizedGainLossOnInvestmentsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

For all investments in an unrealized loss position, including those for which other-than-temporary impairments have not been recognized in earnings (including investments for which a portion of an other-than-temporary impairment has been recognized in other comprehensive income), a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of unrealized losses (that is, the amount by which amortized cost basis exceeds fair value).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563

+ Details

Name:	us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration