Quarterly report pursuant to Section 13 or 15(d)

Investments - Schedule of Fair Value Portfolio By Industry Sector (Details)

v3.23.3
Investments - Schedule of Fair Value Portfolio By Industry Sector (Details) - USD ($)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2023
Dec. 31, 2022
Schedule Of Investments [Line Items]    
Investments at Fair Value $ 3,261,391 $ 2,963,955
Industry Sector Concentration Risk | Drug Discovery & Development    
Schedule Of Investments [Line Items]    
Investments at Fair Value 1,191,061 1,150,707
Industry Sector Concentration Risk | Software    
Schedule Of Investments [Line Items]    
Investments at Fair Value 828,849 798,264
Industry Sector Concentration Risk | Consumer & Business Services    
Schedule Of Investments [Line Items]    
Investments at Fair Value 497,664 439,384
Industry Sector Concentration Risk | Healthcare Services, Other    
Schedule Of Investments [Line Items]    
Investments at Fair Value 278,221 198,763
Industry Sector Concentration Risk | Communications & Networking    
Schedule Of Investments [Line Items]    
Investments at Fair Value 106,032 101,833
Industry Sector Concentration Risk | Diversified Financial Services    
Schedule Of Investments [Line Items]    
Investments at Fair Value 107,554 68,569
Industry Sector Concentration Risk | Information Services    
Schedule Of Investments [Line Items]    
Investments at Fair Value 122,485 60,759
Industry Sector Concentration Risk | Manufacturing Technology    
Schedule Of Investments [Line Items]    
Investments at Fair Value 25,879 46,109
Industry Sector Concentration Risk | Biotechnology Tools    
Schedule Of Investments [Line Items]    
Investments at Fair Value 33,763 32,825
Industry Sector Concentration Risk | Electronics & Computer Hardware    
Schedule Of Investments [Line Items]    
Investments at Fair Value 20,285 21,517
Industry Sector Concentration Risk | Media/Content/Info    
Schedule Of Investments [Line Items]    
Investments at Fair Value 13,117 35
Industry Sector Concentration Risk | Sustainable and Renewable Technology    
Schedule Of Investments [Line Items]    
Investments at Fair Value 10,514 15,486
Industry Sector Concentration Risk | Consumer & Business Products    
Schedule Of Investments [Line Items]    
Investments at Fair Value 2,159 2,821
Industry Sector Concentration Risk | Semiconductors    
Schedule Of Investments [Line Items]    
Investments at Fair Value 1,179 21,921
Industry Sector Concentration Risk | Medical Devices & Equipment    
Schedule Of Investments [Line Items]    
Investments at Fair Value 22,191 1,834
Industry Sector Concentration Risk | Surgical Devices    
Schedule Of Investments [Line Items]    
Investments at Fair Value 418 3,038
Industry Sector Concentration Risk | Drug Delivery    
Schedule Of Investments [Line Items]    
Investments at Fair Value 20 90
Industry Sector Concentration Risk | Total Industry Sectors    
Schedule Of Investments [Line Items]    
Investments at Fair Value $ 3,261,391 $ 2,963,955
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Drug Discovery & Development    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 36.50% 38.80%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Software    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 25.40% 26.90%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Consumer & Business Services    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 15.30% 14.80%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Healthcare Services, Other    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 8.50% 6.70%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Communications & Networking    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 3.30% 3.40%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Diversified Financial Services    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 3.30% 2.30%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Information Services    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 3.80% 2.00%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Manufacturing Technology    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.80% 1.60%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Biotechnology Tools    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 1.00% 1.10%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Electronics & Computer Hardware    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.60% 0.70%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Media/Content/Info    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.40% 0.00%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Sustainable and Renewable Technology    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.30% 0.50%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Consumer & Business Products    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.10% 0.10%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Semiconductors    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.70%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Medical Devices & Equipment    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.70% 0.10%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Surgical Devices    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.10%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Drug Delivery    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 0.00% 0.00%
Industry Sector Concentration Risk | Industry Sub Sector Investments Benchmark | Total Industry Sectors    
Schedule Of Investments [Line Items]    
Percentage of Total Portfolio 100.00% 100.00%