Repurchase Agreements - Borrowings Under Financing Arrangements and Associated Assets Pledged as Collateral (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Mar. 31, 2023	Jun. 30, 2022	Dec. 31, 2022
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Outstanding Repurchase Agreements	$ 226,778		$ 50,077
Fair Value of Loans Pledged	3,374,856		3,525,080
Repurchase agreements
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Outstanding Repurchase Agreements	226,778		50,077
Carrying Value of Repurchase Agreements	787,902		737,023
Fair Value of Loans Pledged	$ 368,876		$ 170,551
Weighted Average Months to Maturity	55 days		9 days
Residential loans
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Maximum Aggregate Uncommitted Principal Amount	$ 1,975,000		$ 2,030,879
Outstanding Repurchase Agreements	562,371		688,487
Net Deferred Finance Costs	(1,247)		(1,541)
Fair Value of Loans Pledged	$ 695,701		$ 867,033
Weighted Average Rate	7.34%		6.65%
Weighted Average Months to Maturity	17 years 2 months 15 days	16 years 8 months 8 days
Residential loans \| Repurchase agreements
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Carrying Value of Repurchase Agreements	$ 561,124		$ 686,946
Residential loans \| Repurchase Agreement, Non Mark-to Market
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Outstanding Repurchase Agreements	$ 317,300		$ 446,800
Weighted Average Rate	7.45%		6.77%
Weighted Average Months to Maturity	23 years 18 days	23 years 11 months 15 days

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

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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(i))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(ii)(A)(i))
-URI https://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

+ Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types: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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(ii)(A)(ii))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(i))
-URI https://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

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 https://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

+ Details

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

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

- Details

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