Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands		12 Months Ended
	May 12, 2021 USD ($)	Dec. 31, 2024 USD ($) investment company segment shares	Dec. 31, 2023 USD ($) investment company shares
Subsidiary, Sale of Stock [Line Items]
Stock aggregate price	$ 450,000
Cost	$ 602,400	$ 3,117,330	$ 2,467,727
Maximum percent of purchasable stock outstanding		5.00%
Early repurchase deduction period		12 months
Percent of early repurchase deduction		2.00%
Stockholders minimum account balance		$ 5
Total investments at fair value		$ 3,094,065	$ 2,458,929
Number of non-accrual portfolio companies | company		6	2
Number of portfolio company on PIK non-accrual | company		1
Number of reportable segments | segment		1
Number of operating segments | segment		1
Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		$ 2,888,065	$ 2,361,224
Investment Denominated In Australian Dollars
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		15	17
Investment Denominated In Canadian Dollars
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		1	2
Investment Denominated In Danish Kroner
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		1	1
Investment Denominated In Euros
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		76	72
Investment Denominated In Swiss Francs
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		2	2
Investment Denominated In Swedish Krona
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		2	2
Investment Denominated In New Zealand Dollars
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		2	2
Investment Denominated In Norwegian Krone
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		1	1
Investment Denominated In British Pounds Sterling
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		25	26
Equity shares
Subsidiary, Sale of Stock [Line Items]
Cost		$ 298,038	$ 254,999
Total investments at fair value		337,684	297,213
Equity shares | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		$ 337,684	$ 297,138
Equity shares | Yield Analysis | Market Approach
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		2	1
Total investments at fair value		$ 20,400	$ 2,600
Senior debt and 1st lien notes
Subsidiary, Sale of Stock [Line Items]
Cost		2,552,342	1,981,715
Total investments at fair value		2,503,156	1,958,306
Senior debt and 1st lien notes | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		$ 2,402,177	1,915,633
Senior debt and 1st lien notes | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value			$ 28,299
Senior debt and 1st lien notes | Yield Analysis | Market Approach
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		1	6
Total investments at fair value		$ 4,200	$ 16,400
Senior debt and 1st lien notes | Discounted Cash Flow Analysis | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes | Discount Rate
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		3	1
Total investments at fair value		$ 23,200	$ 16,500
Structured Product
Subsidiary, Sale of Stock [Line Items]
Cost		79,722	27,146
Total investments at fair value		80,401	23,947
Structured Product | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		19,899	15,705
Structured Product | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		15,937	$ 15,705
Structured Product | Discounted Cash Flow Analysis | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment			1
Total investments at fair value			$ 6,500
Subordinated debt and 2nd lien notes
Subsidiary, Sale of Stock [Line Items]
Cost		125,971	158,720
Total investments at fair value		122,748	148,450
Subordinated debt and 2nd lien notes | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value		$ 110,909	130,273
Subordinated debt and 2nd lien notes | Valuation, Unadjusted Prices From Independent Pricing Services And Independent Indicative Broker Quotes | Level 3
Subsidiary, Sale of Stock [Line Items]
Total investments at fair value			$ 1,339
Subordinated debt and 2nd lien notes | Expected Recovery | Transaction Price | Level 3
Subsidiary, Sale of Stock [Line Items]
Number of investments | investment		1
Total investments at fair value		$ 5,700
Single Portfolio Company | Fair Value | Portfolio Company Investment Risk
Subsidiary, Sale of Stock [Line Items]
Concentration risk, percentage		4.00%	4.70%
Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares repurchased (in shares) | shares		2,683,648	1,850,649
Value of shares repurchased		$ 56,100	$ 38,500