Debt - Summary of Commitments, Borrowings Outstanding and Fair Value of Notes (Details) - Unsecured Notes - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Commitments	$ 145,933	$ 145,933
Total Amount Outstanding	145,933	145,933
Fair Value	142,277	147,266
GECCM Notes
Debt Instrument [Line Items]
Commitments	45,610	45,610
Total Amount Outstanding	45,610	45,610
Fair Value	45,081	45,701
GECCN Notes
Debt Instrument [Line Items]
Commitments	42,823	42,823
Total Amount Outstanding	42,823	42,823
Fair Value	42,686	42,823
GECCO Notes
Debt Instrument [Line Items]
Commitments	57,500	57,500
Total Amount Outstanding	57,500	57,500
Fair Value	$ 54,510	$ 58,742