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Related Parties (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 01, 2024	Mar. 30, 2020	Sep. 30, 2024	Oct. 31, 2023	Oct. 30, 2023	May 04, 2020	May 03, 2020
Credit Facility | Revolving Credit Facility | Affiliates | Unsecured Management Company Revolver
Related Party Transaction [Line Items]
Maximum borrowing capacity		$ 30,000	$ 100,000	$ 100,000	$ 50,000	$ 50,000	$ 30,000
Investments in Majority-owned Subsidiaries
Related Party Transaction [Line Items]
Shares redeemed for a promissory note (in shares)		105,030
Redemption of shares paid-in-kind		$ 11,315
Interest rate		7.00%
Common Stock | New Mountain Net Lease Corporation
Related Party Transaction [Line Items]
Sale of stock, number of shares issued (in shares)		105,030
Sale of stock, price per share (in dollars per share)		$ 107.73
Sale of stock, consideration received		$ 11,315
Common Stock | New Mountain Net Lease Corporation | Investments in Majority-owned Subsidiaries
Related Party Transaction [Line Items]
Sale of stock, price per share (in dollars per share)	$ 73.39
Sale of stock, consideration received	$ 4,666
Shares sold (in shares)	63,575
Common Stock | Affiliate Of Investment Adviser | New Mountain Net Lease Corporation
Related Party Transaction [Line Items]
Sale of stock, number of shares issued (in shares)	63,575
Sale of stock, price per share (in dollars per share)	$ 73.39
Sale of stock, consideration received	$ 4,666

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