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Summary of Significant Accounting Policies - Summary of Properties (Details) - New Mountain Net Lease Corporation ft² in Thousands, $ in Thousands	Dec. 31, 2024 USD ($) ft²
Property, Plant and Equipment [Line Items]
Fair Value	$ 114,794
NM NL Holdings LP / NM GP Holdco LLC
Property, Plant and Equipment [Line Items]
Fair Value	$ 104,834
NM YI, LLC
Property, Plant and Equipment [Line Items]
Total Square Feet | ft²	212
Fair Value	$ 9,960

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Area of a real estate property.

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- Definition

Fair value portion of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
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-Name Accounting Standards Codification
-Section 50
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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