Investments - SLP Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Investment Company, Nonconsolidated Subsidiary [Line Items]
Investments at fair value	$ 2,293,522	$ 2,289,105
Cash	32,343		$ 34,277
Deferred financing costs	3,702	2,178
Interest receivable on investments	27,875	19,269
Total Assets	2,521,383	2,571,193
Debt	1,359,639	1,414,982
Payable for investments purchased	17,664	7,594
Total Liabilities	1,425,269	1,471,187
Total Net Assets	1,096,114	1,100,006
Total Liabilities and Total Net assets	2,521,383	2,571,193
Investments, amortized cost	2,356,143	$ 2,311,384
Bain Capital Senior Loan Program, LLC
Investment Company, Nonconsolidated Subsidiary [Line Items]
Investments at fair value	570,584
Cash	28,366
Deferred financing costs	6,702
Interest receivable on investments	2,542
Other assets	1,516
Total Assets	609,710
Debt	393,700
Subordinated notes payable to members	102,000
Payable for investments purchased	79,688
Dividend payable	1,649
Other payables	6,322
Total Liabilities	583,359
Total Net Assets	26,351
Total Liabilities and Total Net assets	609,710
Investments, amortized cost	$ 575,658