Investment Securities Available for Sale, at Fair Value - Weighted Average Lives for Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
0 to 5 years	$ 68,455	$ 144,266
Over 5 to 10 years	58,419	39,306
10+ years	13,632	17,272
Total	$ 140,506	$ 200,844

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