Distributions - Declared on GAAP Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Amount	$ 4,928	$ 3,290
% of Distributions Declared	100.00%	100.00%
Amount of expense support received	$ 0	$ 2,650
Net Investment Income
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Amount	$ 4,046	$ 2,421
% of Distributions Declared	82.10%	73.60%
Amount of expense support received	$ (1,630)	$ 2,650
Distributions in excess of net investment income
Distribution Made to Limited Liability Company (LLC) Member [Line Items]
Amount	$ 882	$ 869
% of Distributions Declared	17.90%	26.40%