Investment Securities Available For Sale, at Fair Value - Weighted Average Life (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
0 to 5 years	$ 283,554	$ 39,655
Over 5 to 10 years	1,727,269	46,558
10+ years	2,994	13,346
Total	$ 2,013,817	$ 99,559

Debt Securities, Trading, Available-For-Sale, Maturity, Allocated And Single Maturity Date, After Five Through Ten Years, Fair Value

No definition available.

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