Represents the advance rate of the Company's outstanding balance of repurchase agreements.

No definition available.

Name:	nymt_AdvanceRate
Namespace Prefix:	nymt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Period within which FHLBI advances mature.

+ References

No definition available.

+ Details

Name:	nymt_AdvancesFromFederalHomeLoanBanksContractualMaturity
Namespace Prefix:	nymt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Average haircut percentage.

+ References

No definition available.

+ Details

Name:	nymt_AverageHaircut
Namespace Prefix:	nymt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of counterparties the entity has repurchase agreements with.

+ References

No definition available.

+ Details

Name:	nymt_RepurchaseAgreementsNumberOfCounterparties
Namespace Prefix:	nymt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of unencumbered investment securities available to meet additional haircut or market valuation requirements.

+ References

No definition available.

+ Details

Name:	nymt_UnencumberedInvestmentSecurities
Namespace Prefix:	nymt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

+ References

+ Details

Name:	us-gaap_AdvancesFromFederalHomeLoanBanks
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(A)(ii))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseRepurchaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_Cash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22 (b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

States the weighted average interest rate applicable to the advances from the Federal Home Loan Bank outstanding as of the Balance Sheet date.

+ References

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Indicates, if estimable, (as a percentage) the approximate extent to which the proceeds from liquidation of any assets held either as collateral or by third parties would be expected to cover the maximum potential amount of future payments under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsLiquidationProceedsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest payable on debt, including, but not limited to, trade payables.

+ References

+ Details

Name:	us-gaap_InterestPayableCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=29638263&loc=d3e39828-111592

+ Details

Name:	us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average maturity (weighted by amount of the agreement) of repurchase agreements with the counterparty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(B)(iii))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_RepurchaseAgreementCounterpartyWeightedAverageMaturityOfAgreements1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_InterestOnlyStripMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=nymt_CMBSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis=nymt_HeldInAgencyIOPortfolioForTradingPurposesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseAxis=us-gaap_LoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_StockholdersEquityTotalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_LenderConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=nymt_GLIHMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=nymt_ReceivablesAndOtherAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financing Arrangements, Portfolio Investments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) counterparty	Dec. 31, 2014 USD ($) counterparty	Sep. 30, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase agreement, outstanding balance	$ 456.4	$ 652.0
Repurchase agreement, average days to maturity	27 days	26 days
Accrued interest payable	$ 0.3	$ 0.3
Advance rate (as a percent)	92.10%
Average haircut (as a percent)	7.90%
Repurchase agreement, number of counterparties \| counterparty	6	10
Cash	$ 62.0
Unencumbered investment securities	$ 147.2
Liquidation proceeds (as a percent)	38.20%
Agency RMBS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average haircut (as a percent)	5.00%	5.00%
Unencumbered investment securities	$ 82.5
Interest-Only-Strip
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average haircut (as a percent)	25.00%
Residential Mortgage Backed Securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unencumbered investment securities	$ 84.0
CMBS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unencumbered investment securities	62.1
Held in Agency IO Portfolio for Trading Purposes
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unencumbered investment securities	$ 11.6
Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average interest rate (as a percent)	0.77%	0.43%
Stockholders' Equity, Total \| Lender Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repurchase agreement, number of counterparties \| counterparty	0	0
GLIH
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding secured advances from FHLBI	$ 121.0		$ 121.0
FHLBI, weighted-average borrowing rate (as a percent)	0.47%
FHLBI, additional available uncommitted capacity for borrowings	$ 79.0
FHLBI, carrying value of investment securities available-for-sale	$ 129.1
Advances from FHLBI, contractual maturity	30 days
Receivables And Other Assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in FHLBI stock, fair value	$ 5.4