Investment Securities Available For Sale, at Fair Value - Weighted Average Lives for Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
0 to 5 years	$ 374,823	$ 283,554
Over 5 to 10 years	1,863,538	1,727,269
10+ years	2,979	2,994
Total	$ 2,241,340	$ 2,013,817

Debt Securities, Trading, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value

No definition available.

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