Investments - Summary of Unobservable Inputs Used in Fair Value Measurements of Level 3 Investments (Detail) - Level 3 $ in Thousands		Jun. 30, 2024 USD ($)		Dec. 31, 2023 USD ($)
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 2,434,652		$ 2,332,982
First Lien Secured Debt | Recent Transaction | Recent Transaction
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		132,181		59,746
First Lien Secured Debt | Recovery Analysis | Recoverable Amount
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		124,227		111,468
First Lien Secured Debt | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 1,913,912		$ 1,903,817
First Lien Secured Debt | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		6.8		0.066
First Lien Secured Debt | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		22.4		0.251
First Lien Secured Debt | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	12.1		0.122
First Lien Secured Debt | Market Comparable Technique | Comparable Multiple
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 32,493
First Lien Secured Debt | Market Comparable Technique | Minimum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		3.3
First Lien Secured Debt | Market Comparable Technique | Maximum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		25.2
First Lien Secured Debt | Market Comparable Technique | Weighted Average | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[2]	13.7
Second Lien Secured Debt | Recovery Analysis | Recoverable Amount
Schedule of Investments [Line Items]
Assets Fair Value Disclosure				$ 238
Second Lien Secured Debt | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure				$ 29,442
Second Lien Secured Debt | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input				0.137
Second Lien Secured Debt | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input				0.258
Second Lien Secured Debt | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]			0.173
Second Lien Secured Debt | Market Comparable Technique | Comparable Multiple
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 5,446		$ 2,207
Second Lien Secured Debt | Market Comparable Technique | Minimum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		5.8		8.5
Second Lien Secured Debt | Market Comparable Technique | Maximum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		5.8		8.5
Second Lien Secured Debt | Market Comparable Technique | Weighted Average | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	5.8		8.5
Structured Products And Other | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 34,705		$ 41,333
Structured Products And Other | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.113		0.13
Structured Products And Other | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.124		0.156
Structured Products And Other | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	0.116		0.149
Preferred Equity | Residual Value | Residual Value
Schedule of Investments [Line Items]
Assets Fair Value Disclosure				$ 78
Preferred Equity | Recent Transaction | Recent Transaction
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 19		268
Preferred Equity | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 241		$ 109
Preferred Equity | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.133		0.135
Preferred Equity | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.133		0.135
Preferred Equity | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	0.133		0.135
Preferred Equity | Market Comparable Technique | Comparable Multiple
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 32,350		$ 31,950
Preferred Equity | Market Comparable Technique | Minimum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.5		2.8
Preferred Equity | Market Comparable Technique | Maximum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		16.9		12.5
Preferred Equity | Market Comparable Technique | Weighted Average | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		11.7	[2]	11.1	[1]
Common Equity/Interests | Recent Transaction | Recent Transaction
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 77		$ 125
Common Equity/Interests | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 120,315		$ 117,454
Common Equity/Interests | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		10.5		0.135
Common Equity/Interests | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		13.3		0.143
Common Equity/Interests | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	10.5		0.143
Common Equity/Interests | Estimated Proceeds | Estimated Proceeds
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 21,034		$ 21,369
Common Equity/Interests | Market Comparable Technique | Comparable Multiple
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 16,946		$ 12,898
Common Equity/Interests | Market Comparable Technique | Minimum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.028
Quantitative Information on Unobservable input				3.6
Common Equity/Interests | Market Comparable Technique | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.235
Common Equity/Interests | Market Comparable Technique | Maximum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input				26
Common Equity/Interests | Market Comparable Technique | Weighted Average | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	0.114
Quantitative Information on Unobservable input	[1]			11.8
Common Equity/Interests | Option Pricing Model | Expected Volatility
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 211		$ 281
Common Equity/Interests | Option Pricing Model | Minimum | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.30		0.30
Common Equity/Interests | Option Pricing Model | Maximum | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		1.05		1.15
Common Equity/Interests | Option Pricing Model | Weighted Average | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	0.641		0.591
Warrants - Warrants | Market Comparable Technique | Comparable Multiple
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 22
Warrants - Warrants | Market Comparable Technique | Minimum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.065
Warrants - Warrants | Market Comparable Technique | Maximum | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.065
Warrants - Warrants | Market Comparable Technique | Weighted Average | Comparable Multiple
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[2]	0.065
Warrants - Warrants | Option Pricing Model | Expected Volatility
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 148		$ 199
Warrants - Warrants | Option Pricing Model | Minimum | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.50		0.50
Warrants - Warrants | Option Pricing Model | Maximum | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.50		0.50
Warrants - Warrants | Option Pricing Model | Weighted Average | Expected Volatility
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[1]	0.50		0.50
Unsecured Debt | Yield Analysis | Discount Rate
Schedule of Investments [Line Items]
Assets Fair Value Disclosure		$ 325
Unsecured Debt | Yield Analysis | Minimum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.118
Unsecured Debt | Yield Analysis | Maximum | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input		0.118
Unsecured Debt | Yield Analysis | Weighted Average | Discount Rate
Schedule of Investments [Line Items]
Quantitative Information on Unobservable input	[2]	0.118

[1] The weighted average information is generally derived by assigning each disclosed unobservable input a proportionate weight based on the fair value of the related investment. For the commodity price unobservable input, the weighted average price is an undiscounted price based upon the estimated production level from the underlying reserves.

[2] The weighted average information is generally derived by assigning each disclosed unobservable input a proportionate weight based on the fair value of the related investment. For the commodity price unobservable input, the weighted average price is an undiscounted price based upon the estimated production level from the underlying reserves.