CONSOLIDATED SCHEDULE OF INVESTMENTS (unaudited) - Composition of the Company's Portfolio at Cost by Investment Type and Industry - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investment cost	$ 5,303,265	$ 4,427,510
Investment cost		4,427,510
Investments at fair value	$ 5,287,232	$ 4,308,892
% of Net Assets	163.20%	200.00%
Aerospace & Defense
Investment cost	$ 4,984
Investment cost		$ 11,620
Investments at fair value	$ 4,996	$ 11,474
% of Net Assets	0.20%	0.50%
Asset Backed Securities
Investment cost	$ 27,468
Investment cost		$ 27,721
Investments at fair value	$ 27,130	$ 27,204
% of Net Assets	0.80%	1.30%
Auto Components
Investment cost		$ 55,682
Investments at fair value		$ 51,033
% of Net Assets		2.40%
Automobile Components
Investment cost	$ 31,191
Investments at fair value	$ 31,244
% of Net Assets	1.00%
Biotechnology
Investment cost	$ 58,830
Investment cost		$ 37,036
Investments at fair value	$ 58,230	$ 36,546
% of Net Assets	1.80%	1.70%
Building Products
Investment cost	$ 24,207
Investment cost		$ 114,407
Investments at fair value	$ 23,791	$ 106,570
% of Net Assets	0.70%	4.90%
Capital Markets
Investment cost	$ 91,266
Investment cost		$ 43,661
Investments at fair value	$ 88,271	$ 41,197
% of Net Assets	2.70%	1.90%
Chemicals
Investment cost	$ 101,680
Investment cost		$ 65,513
Investments at fair value	$ 96,997	$ 62,324
% of Net Assets	3.00%	2.90%
Commercial Services & Supplies
Investment cost	$ 585,889
Investment cost		$ 446,989
Investments at fair value	$ 586,286	$ 437,275
% of Net Assets	18.10%	20.30%
Communications Equipment
Investment cost	$ 56,094
Investment cost		$ 66,668
Investments at fair value	$ 47,190	$ 59,907
% of Net Assets	1.50%	2.80%
Construction & Engineering
Investment cost	$ 80,074
Investment cost		$ 45,770
Investments at fair value	$ 79,827	$ 45,736
% of Net Assets	2.50%	2.10%
Construction Materials
Investment cost	$ 3,744
Investments at fair value	$ 3,742
% of Net Assets	0.10%
Consumer Finance
Investment cost	$ 31,055
Investment cost		$ 25,231
Investments at fair value	$ 31,078	$ 24,906
% of Net Assets	1.00%	1.20%
Consumer Staples Distribution & Retail
Investment cost	$ 78,053
Investments at fair value	$ 78,365
% of Net Assets	2.40%
Containers & Packaging
Investment cost	$ 43,065
Investment cost		$ 78,041
Investments at fair value	$ 42,957	$ 75,423
% of Net Assets	1.30%	3.50%
Diversified Consumer Services
Investment cost	$ 201,922
Investment cost		$ 71,812
Investments at fair value	$ 201,613	$ 72,077
% of Net Assets	6.20%	3.30%
Diversified Financial Services
Investment cost		$ 72,109
Investments at fair value		$ 72,267
% of Net Assets		3.40%
Diversified Telecommunication Services
Investment cost	$ 3,983
Investment cost		$ 4,015
Investments at fair value	$ 3,568	$ 3,441
% of Net Assets	0.10%	0.20%
Electric Utilities
Investment cost	$ 28,992
Investment cost		$ 29,152
Investments at fair value	$ 29,033	$ 29,178
% of Net Assets	0.90%	1.40%
Electrical Equipment
Investment cost	$ 91,683
Investment cost		$ 33,342
Investments at fair value	$ 90,216	$ 32,895
% of Net Assets	2.80%	1.50%
Entertainment
Investment cost	$ 97,545
Investment cost		$ 90,636
Investments at fair value	$ 97,719	$ 91,439
% of Net Assets	3.00%	4.20%
Equity Real Estate Investment Trusts (REITs)
Investment cost		$ 7,444
Investments at fair value		$ 7,332
% of Net Assets		0.30%
Financial Services
Investment cost	$ 86,121
Investments at fair value	$ 86,613
% of Net Assets	2.70%
Financing
Investment cost		$ 7,443
Investments at fair value		$ 7,369
% of Net Assets		0.30%
Food & Staples Retailing
Investment cost		$ 8,288
Investments at fair value		$ 8,251
% of Net Assets		0.40%
Food Products
Investment cost		$ 11,018
Investments at fair value		$ 10,853
% of Net Assets		0.50%
Ground Transportation
Investment cost	$ 52,906
Investments at fair value	$ 52,926
% of Net Assets	1.60%
Health Care Equipment & Supplies
Investment cost	$ 60,595
Investment cost		$ 14,319
Investments at fair value	$ 59,040	$ 13,525
% of Net Assets	1.80%	0.60%
Health Care Providers & Services
Investment cost	$ 602,299
Investment cost		$ 559,058
Investments at fair value	$ 602,526	$ 548,769
% of Net Assets	18.60%	25.50%
Health Care Technology
Investment cost	$ 78,576
Investment cost		$ 80,954
Investments at fair value	$ 79,898	$ 77,607
% of Net Assets	2.50%	3.60%
Hotels, Restaurants & Leisure
Investment cost	$ 127,528
Investment cost		$ 27,149
Investments at fair value	$ 129,062	$ 26,211
% of Net Assets	4.00%	1.20%
Household Durables
Investment cost	$ 9,736
Investment cost		$ 9,789
Investments at fair value	$ 9,756	$ 9,781
% of Net Assets	0.30%	0.50%
Household Products
Investment cost	$ 7,377
Investment cost		$ 31,638
Investments at fair value	$ 7,076	$ 28,225
% of Net Assets	0.20%	1.30%
Independent Power & Renewable Electricity Producers
Investment cost	$ 53,447
Investments at fair value	$ 50,510
% of Net Assets	1.60%
Insurance
Investment cost	$ 401,890
Investment cost		$ 139,715
Investments at fair value	$ 402,537	$ 136,745
% of Net Assets	12.40%	6.30%
IT Services
Investment cost	$ 263,879
Investment cost		$ 234,946
Investments at fair value	$ 267,775	$ 232,210
% of Net Assets	8.30%	10.80%
Leisure Products
Investment cost	$ 5,916
Investments at fair value	$ 5,970
% of Net Assets	0.20%
Internet & Direct Marketing Retail
Investment cost		$ 131,145
Investments at fair value		$ 131,996
% of Net Assets		6.10%
Machinery
Investment cost	$ 42,531
Investment cost		$ 70,160
Investments at fair value	$ 42,213	$ 67,986
% of Net Assets	1.30%	3.20%
Media
Investment cost	$ 248,114
Investment cost		$ 279,580
Investments at fair value	$ 246,296	$ 271,647
% of Net Assets	7.60%	12.60%
Paper & Forest Products
Investment cost		$ 22,448
Investments at fair value		$ 21,561
% of Net Assets		1.00%
Personal Products
Investment cost		$ 257,069
Investments at fair value		$ 258,349
% of Net Assets		12.00%
Personal Care Products
Investment cost	$ 210,504
Investments at fair value	$ 214,894
% of Net Assets	6.60%
Pharmaceuticals
Investment cost	$ 78,588
Investment cost		$ 93,331
Investments at fair value	$ 72,527	$ 85,327
% of Net Assets	2.20%	4.00%
Professional Services
Investment cost	$ 30,452
Investment cost		$ 27,323
Investments at fair value	$ 29,931	$ 25,549
% of Net Assets	0.90%	1.20%
Real Estate Management & Development
Investment cost	$ 9,849
Investment cost		$ 109,479
Investments at fair value	$ 9,711	$ 109,264
% of Net Assets	0.30%	5.10%
Road & Rail
Investment cost		$ 10,606
Investments at fair value		$ 10,027
% of Net Assets		0.50%
Semiconductors & Semiconductor Equipment
Investment cost	$ 115,322
Investments at fair value	$ 115,584
% of Net Assets	3.60%
Software
Investment cost	$ 914,942
Investment cost		$ 721,217
Investments at fair value	$ 923,740	$ 703,317
% of Net Assets	28.50%	32.60%
Special Purpose Entity
Investment cost	$ 7,406
Investment cost		$ 7,463
Investments at fair value	$ 7,258	$ 7,351
% of Net Assets	0.20%	0.30%
Specialty Retail
Investment cost	$ 64,334
Investment cost		$ 76,229
Investments at fair value	$ 51,670	$ 49,938
% of Net Assets	1.60%	2.30%
Technology Hardware, Storage & Peripherals
Investment cost	$ 20,531
Investment cost		$ 19,348
Investments at fair value	$ 21,373	$ 20,062
% of Net Assets	0.70%	0.90%
Textiles, Apparel & Luxury Goods
Investment cost	$ 71,030
Investment cost		$ 53,623
Investments at fair value	$ 70,987	$ 52,814
% of Net Assets	2.20%	2.50%
Transportation Infrastructure
Investment cost	$ 97,667
Investment cost		$ 97,323
Investments at fair value	$ 105,106	$ 105,934
% of Net Assets	3.20%	4.90%
Preferred Equity
Investment cost	$ 100
Investment cost		$ 100
Investments at fair value	$ 35	$ 56
% of Net Assets	0.00%	0.00%
Preferred Equity | Commercial Services & Supplies
Investment cost		$ 100
Investments at fair value		56
Preferred Equity | Health Care Providers & Services
Investment cost	$ 100
Investments at fair value	35
Common Equity
Investment cost	390
Investment cost		200
Investments at fair value	$ 480	$ 205
% of Net Assets	0.00%	0.00%
Common Equity | Chemicals
Investment cost	$ 100
Investments at fair value	100
Common Equity | Commercial Services & Supplies
Investment cost	140
Investment cost		$ 50
Investments at fair value	150	50
Common Equity | Construction & Engineering
Investment cost	50
Investment cost		50
Investments at fair value	46	51
Common Equity | Household Durables
Investment cost	50
Investment cost		50
Investments at fair value	53	54
Common Equity | Personal Products
Investment cost		50
Investments at fair value		50
Common Equity | Personal Care Products
Investment cost	50
Investments at fair value	131
Unsecured Debt
Investment cost	15,460
Investment cost		69,276
Investments at fair value	$ 14,206	$ 41,665
% of Net Assets	0.40%	1.90%
Unsecured Debt | Machinery
Investment cost	$ 5,994
Investment cost		$ 5,973
Investments at fair value	5,799	4,941
Unsecured Debt | Media
Investment cost	9,466
Investment cost		9,396
Investments at fair value	8,407	8,536
Unsecured Debt | Specialty Retail
Investment cost		53,907
Investments at fair value		28,188
First Lien Secured Debt
Investment cost	5,247,771
Investment cost		4,357,934
Investments at fair value	$ 5,241,795	$ 4,266,966
% of Net Assets	161.90%	198.00%
First Lien Secured Debt | Aerospace & Defense
Investment cost	$ 4,984
Investment cost		$ 11,620
Investments at fair value	4,996	11,474
First Lien Secured Debt | Asset Backed Securities
Investment cost	27,468
Investment cost		27,721
Investments at fair value	27,130	27,204
First Lien Secured Debt | Auto Components
Investment cost		55,682
Investments at fair value		51,033
First Lien Secured Debt | Automobile Components
Investment cost	31,191
Investments at fair value	31,244
First Lien Secured Debt | Biotechnology
Investment cost	58,830
Investment cost		37,036
Investments at fair value	58,230	36,546
First Lien Secured Debt | Building Products
Investment cost	24,207
Investment cost		114,407
Investments at fair value	23,791	106,570
First Lien Secured Debt | Capital Markets
Investment cost	91,266
Investment cost		43,661
Investments at fair value	88,271	41,197
First Lien Secured Debt | Chemicals
Investment cost	101,580
Investment cost		65,513
Investments at fair value	96,897	62,324
First Lien Secured Debt | Commercial Services & Supplies
Investment cost	585,749
Investment cost		446,839
Investments at fair value	586,136	437,169
First Lien Secured Debt | Communications Equipment
Investment cost	16,550
Investment cost		66,668
Investments at fair value	16,474	59,907
First Lien Secured Debt | Construction & Engineering
Investment cost	80,024
Investment cost		45,720
Investments at fair value	79,781	45,685
First Lien Secured Debt | Construction Materials
Investment cost	3,744
Investments at fair value	3,742
First Lien Secured Debt | Consumer Finance
Investment cost	31,055
Investment cost		25,231
Investments at fair value	31,078	24,906
First Lien Secured Debt | Consumer Staples Distribution & Retail
Investment cost	78,053
Investments at fair value	78,365
First Lien Secured Debt | Containers & Packaging
Investment cost	43,065
Investment cost		78,041
Investments at fair value	42,957	75,423
First Lien Secured Debt | Diversified Consumer Services
Investment cost	201,922
Investment cost		71,812
Investments at fair value	201,613	72,077
First Lien Secured Debt | Diversified Financial Services
Investment cost		72,109
Investments at fair value		72,267
First Lien Secured Debt | Diversified Telecommunication Services
Investment cost	3,983
Investment cost		4,015
Investments at fair value	3,568	3,441
First Lien Secured Debt | Electric Utilities
Investment cost	28,992
Investment cost		29,152
Investments at fair value	29,033	29,178
First Lien Secured Debt | Electrical Equipment
Investment cost	91,683
Investment cost		33,342
Investments at fair value	90,216	32,895
First Lien Secured Debt | Entertainment
Investment cost	97,545
Investment cost		90,636
Investments at fair value	97,719	91,439
First Lien Secured Debt | Equity Real Estate Investment Trusts (REITs)
Investment cost		7,444
Investments at fair value		7,332
First Lien Secured Debt | Financial Services
Investment cost	86,121
Investments at fair value	86,613
First Lien Secured Debt | Financing
Investment cost		7,443
Investments at fair value		7,369
First Lien Secured Debt | Food & Staples Retailing
Investment cost		8,288
Investments at fair value		8,251
First Lien Secured Debt | Food Products
Investment cost		11,018
Investments at fair value		10,853
First Lien Secured Debt | Ground Transportation
Investment cost	52,906
Investments at fair value	52,926
First Lien Secured Debt | Health Care Equipment & Supplies
Investment cost	60,595
Investment cost		14,319
Investments at fair value	59,040	13,525
First Lien Secured Debt | Health Care Providers & Services
Investment cost	602,199
Investment cost		559,058
Investments at fair value	602,491	548,769
First Lien Secured Debt | Health Care Technology
Investment cost	78,576
Investment cost		80,954
Investments at fair value	79,898	77,607
First Lien Secured Debt | Hotels, Restaurants & Leisure
Investment cost	127,528
Investment cost		27,149
Investments at fair value	129,062	26,211
First Lien Secured Debt | Household Durables
Investment cost	9,686
Investment cost		9,739
Investments at fair value	9,703	9,727
First Lien Secured Debt | Household Products
Investment cost	7,377
Investment cost		31,638
Investments at fair value	7,076	28,225
First Lien Secured Debt | Independent Power & Renewable Electricity Producers
Investment cost	53,447
Investments at fair value	50,510
First Lien Secured Debt | Insurance
Investment cost	401,890
Investment cost		139,715
Investments at fair value	402,537	136,745
First Lien Secured Debt | IT Services
Investment cost	263,879
Investment cost		234,946
Investments at fair value	267,775	232,210
First Lien Secured Debt | Leisure Products
Investment cost	5,916
Investments at fair value	5,970
First Lien Secured Debt | Internet & Direct Marketing Retail
Investment cost		131,145
Investments at fair value		131,996
First Lien Secured Debt | Machinery
Investment cost	36,537
Investment cost		64,187
Investments at fair value	36,414	63,045
First Lien Secured Debt | Media
Investment cost	238,648
Investment cost		270,184
Investments at fair value	237,889	263,111
First Lien Secured Debt | Paper & Forest Products
Investment cost		22,448
Investments at fair value		21,561
First Lien Secured Debt | Personal Products
Investment cost		257,019
Investments at fair value		258,299
First Lien Secured Debt | Personal Care Products
Investment cost	210,454
Investments at fair value	214,763
First Lien Secured Debt | Pharmaceuticals
Investment cost	78,588
Investment cost		93,331
Investments at fair value	72,527	85,327
First Lien Secured Debt | Professional Services
Investment cost	30,452
Investment cost		27,323
Investments at fair value	29,931	25,549
First Lien Secured Debt | Real Estate Management & Development
Investment cost	9,849
Investment cost		109,479
Investments at fair value	9,711	109,264
First Lien Secured Debt | Road & Rail
Investment cost		10,606
Investments at fair value		10,027
First Lien Secured Debt | Semiconductors & Semiconductor Equipment
Investment cost	115,322
Investments at fair value	115,584
First Lien Secured Debt | Software
Investment cost	914,942
Investment cost		721,217
Investments at fair value	923,740	703,317
First Lien Secured Debt | Special Purpose Entity
Investment cost	7,406
Investment cost		7,463
Investments at fair value	7,258	7,351
First Lien Secured Debt | Specialty Retail
Investment cost	64,334
Investment cost		22,322
Investments at fair value	51,670	21,750
First Lien Secured Debt | Technology Hardware, Storage & Peripherals
Investment cost	20,531
Investment cost		19,348
Investments at fair value	21,373	20,062
First Lien Secured Debt | Textiles, Apparel & Luxury Goods
Investment cost	71,030
Investment cost		53,623
Investments at fair value	70,987	52,814
First Lien Secured Debt | Transportation Infrastructure
Investment cost	97,667
Investment cost		97,323
Investments at fair value	105,106	$ 105,934
Second Lien Secured Debt
Investment cost	39,544
Investments at fair value	$ 30,716
% of Net Assets	0.90%
Second Lien Secured Debt | Communications Equipment
Investment cost	$ 39,544
Investments at fair value	$ 30,716