Significant Agreements and Related Party Transactions - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) Component	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Related Party Transaction [Line Items]
Management fee percentage per quarter			0.001875
Annual management fee percentage			0.75%
Management fees	$ 1,490,000	$ 611,000	$ 3,628,000	$ 1,651,000
Management fees payable	1,490,000		$ 1,490,000		$ 771,000
Number of components included in incentive fees \| Component			2
Hurdle rate for incentive fee purpose			1.75%
Incentive fee if no excess income amount			$ 0
Incentive fees based on income	2,343,000	0	5,888,000	0
Incentive Fee Payable	2,343,000		2,343,000
Unrealized accrued incentive fees on capital gain (loss)	(138,000)	0	163,000	0
Incurred expenses for services provided by administrator and custodian fees	190,000	96,000	408,000	280,000
Administration and custodian fees payable	128,000		$ 128,000
Percentage of transfer agent fees			0.15%
Incurred expenses for services provided by transfer agent	163,000	$ 75,000	$ 388,000	$ 206,000
Transfer agent fees payable	163,000		$ 163,000
Ordinary Income Exceeds Hurdle Amount
Related Party Transaction [Line Items]
Percentage of ordinary income considered for incentive If that exceeds hurdle amount			100.00%
Catch-up Amount Multiplied by NAV
Related Party Transaction [Line Items]
Percentage of ordinary income considered for incentive If that exceeds hurdle amount			2.0588%
Catch-up Amount Multiplied by NAV Event of Listing
Related Party Transaction [Line Items]
Percentage of ordinary income considered for incentive If that exceeds hurdle amount			2.1875%
Ordinary Income Exceeds Catch-up Amount
Related Party Transaction [Line Items]
Percentage of ordinary income considered for incentive If that exceeds hurdle amount			15.00%
Incentive Fee Cap Equal to Cumulative Net Return
Related Party Transaction [Line Items]
Hurdle rate for incentive fee purpose			15.00%
If Positive of Sum of Realized Capital Gains
Related Party Transaction [Line Items]
Management and service fees, incentive rate			15.00%
Hurdle rate for incentive fee purpose			15.00%
Affiliated Entity [Member] \| Accrued Expenses And Other Liabilities
Related Party Transaction [Line Items]
Other liabilities	14,000		$ 14,000		161,000
Affiliated Entity [Member] \| Interest and Other Debt Expenses
Related Party Transaction [Line Items]
Other liabilities	$ 14,000		$ 14,000		$ 161,000
Maximum \| Ordinary Income Exceeds Catch-up Amount
Related Party Transaction [Line Items]
Percentage of ordinary income considered for incentive If that exceeds hurdle amount			20.00%
Maximum \| Incentive Fee Cap Equal to Cumulative Net Return
Related Party Transaction [Line Items]
Hurdle rate for incentive fee purpose			20.00%
Maximum \| If Positive of Sum of Realized Capital Gains
Related Party Transaction [Line Items]
Management and service fees, incentive rate			20.00%
Hurdle rate for incentive fee purpose			20.00%
Average end of such quarter
Related Party Transaction [Line Items]
Management fee percentage per quarter			0.001875
Annual management fee percentage			0.75%
Average end of two recently completed quarters
Related Party Transaction [Line Items]
Management fee percentage per quarter			0.0025
Annual management fee percentage			1.00%

Goldman Sachs Middle Market Lending Corp. II 10-Q