Assets Sold under Agreements to Repurchase, Deferred Finance Costs, Net

No definition available.

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

- Definition

The total amount of repossession that is available under the repurchase agreement.

+ References

No definition available.

+ Details

Name:	nymt_AssetsSoldUnderAgreementsToRepurchaseMaximumRepurchaseAmount
Namespace Prefix:	nymt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

Carrying amount of assets sold under agreements to repurchase when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under repurchase agreements exceeds 10 percent of total assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(A)(i))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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

- Definition

Interest rate on the 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://fasb.org/us-gaap/role/ref/legacyRef
-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=120395691&loc=d3e23780-122690

+ Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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://fasb.org/us-gaap/role/ref/legacyRef
-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=120395691&loc=d3e23780-122690

+ Details

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

- Definition

Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5086-111524

+ Details

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

- Definition

Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G))
-URI http://asc.fasb.org/extlink&oid=120402547&loc=d3e617274-123014

+ Details

Name:	us-gaap_MortgageLoansOnRealEstate
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://fasb.org/us-gaap/role/ref/legacyRef
-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=120395691&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_AssetsSoldUnderAgreementsToRepurchaseAxis=nymt_ResidentialMortgageLoansAtFairValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_RepurchaseAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=nymt_ResidentialMortgageLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Repurchase Agreements - Schedule of Borrowings Under Repurchase Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average months to maturity		73 days
Fair Value	$ 3,049,166	$ 20,780,548	$ 12,707,625	$ 10,157,126
Residential loans, at fair value
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	575,400	881,200
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum Aggregate Uncommitted Principal Amount	1,301,389	1,200,000
Outstanding Repurchase Agreements	407,213	754,132
Net Deferred Finance Costs	(1,682)	(818)
Carrying Value of Loans Pledged	$ 575,380	$ 961,749
Weighted Average Rate	2.92%	3.67%
Weighted average months to maturity	11 years 11 months 1 day	11 years 2 months 12 days
Residential Mortgage Loans \| Repurchase agreements
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying Value of Loans Pledged	$ 405,531	$ 753,314
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	$ 1,090,930	1,429,754
Loans pledged as collateral		$ 80,600