Investments - Schedule of Investments at Fair Value and Net Assets (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Schedule of Investments [Line Items]
Investment owned, percent of net assets	161.30%	150.30%
Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	100.00%	100.00%
Software
Schedule of Investments [Line Items]
Investment owned, percent of net assets	24.50%	19.80%
Software \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	15.20%	13.30%
Commercial Services & Supplies
Schedule of Investments [Line Items]
Investment owned, percent of net assets	14.90%	12.10%
Commercial Services & Supplies \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	9.30%	8.00%
Diversified Consumer Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	14.70%	13.70%
Diversified Consumer Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	9.10%	9.10%
Financial Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	13.70%	11.60%
Financial Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	8.50%	7.70%
IT Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	12.40%	11.10%
IT Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	7.70%	7.40%
Trading Companies & Distributors
Schedule of Investments [Line Items]
Investment owned, percent of net assets	11.90%	11.10%
Trading Companies & Distributors \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	7.40%	7.40%
Wireless Telecommunication Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	9.60%	9.90%
Wireless Telecommunication Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	6.00%	6.60%
Construction & Engineering
Schedule of Investments [Line Items]
Investment owned, percent of net assets	9.30%	8.70%
Construction & Engineering \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	5.80%	5.80%
Machinery
Schedule of Investments [Line Items]
Investment owned, percent of net assets	6.50%	7.00%
Machinery \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	4.00%	4.60%
Food Products
Schedule of Investments [Line Items]
Investment owned, percent of net assets	6.00%	6.30%
Food Products \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	3.70%	4.20%
Hotels, Restaurants & Leisure
Schedule of Investments [Line Items]
Investment owned, percent of net assets	4.70%	4.90%
Hotels, Restaurants & Leisure \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	2.90%	3.20%
Containers & Packaging
Schedule of Investments [Line Items]
Investment owned, percent of net assets	4.70%	4.90%
Containers & Packaging \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	2.90%	3.20%
Insurance
Schedule of Investments [Line Items]
Investment owned, percent of net assets	4.00%	4.10%
Insurance \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	2.50%	2.70%
Health Care Equipment & Supplies
Schedule of Investments [Line Items]
Investment owned, percent of net assets	3.90%	3.90%
Health Care Equipment & Supplies \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	2.40%	2.60%
Health Care Technology
Schedule of Investments [Line Items]
Investment owned, percent of net assets	3.50%	3.60%
Health Care Technology \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	2.20%	2.40%
Professional Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	2.60%	2.80%
Professional Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	1.60%	1.90%
Specialty Retail
Schedule of Investments [Line Items]
Investment owned, percent of net assets	2.60%	2.50%
Specialty Retail \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	1.60%	1.70%
Health Care Providers & Services
Schedule of Investments [Line Items]
Investment owned, percent of net assets	2.00%	2.10%
Health Care Providers & Services \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	1.20%	1.40%
Leisure Products
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.80%	1.90%
Leisure Products \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	1.10%	1.20%
Media
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.60%	1.60%
Media \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	1.00%	1.10%
Electrical Equipment
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.50%	1.60%
Electrical Equipment \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.90%	1.10%
Chemicals
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.20%	1.20%
Chemicals \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.70%	0.80%
Distributors
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.20%	1.20%
Distributors \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.70%	0.80%
Consumer Staples Distribution & Retail
Schedule of Investments [Line Items]
Investment owned, percent of net assets	1.00%	1.10%
Consumer Staples Distribution & Retail \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.70%	0.70%
Aerospace & Defense
Schedule of Investments [Line Items]
Investment owned, percent of net assets	0.80%	0.90%
Aerospace & Defense \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.50%	0.60%
Textiles, Apparel & Luxury Goods
Schedule of Investments [Line Items]
Investment owned, percent of net assets	0.70%	0.70%
Textiles, Apparel & Luxury Goods \| Investments at Fair Value \| Industry Concentration Risk
Schedule of Investments [Line Items]
Composition of investments, percentage	0.40%	0.50%

Phillip Street Middle Market Lending Fund LLC 10-Q