Quarterly Statements of Operations - Schedule of Quarterly Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Expenses:
Sponsor's Fee, related party	$ 829	$ 827	$ 611	$ 549	$ 778	$ 1,158	$ 1,860	$ 1,561	$ 2,816	$ 5,357	$ 4,039
Net investment loss	(829)	(827)	(611)	(549)	(778)	(1,158)	(1,860)	(1,561)	(2,816)	(5,357)	(4,039)
Net realized and unrealized gain (loss) from:
Net realized gain (loss) on investment in LTC	(51)	(48)	(290)	(357)	(123)	260	937	639	(746)	1,713	2,140
Net change in unrealized appreciation (depreciation) on investment in LTC	23,568	29,624	25,520	4,120	(112,716)	(31,291)	(12,344)	15,700	82,832	(140,651)	76,695
Net realized and unrealized gain (loss) on investment	23,517	29,576	25,230	3,763	(112,839)	(31,031)	(11,407)	16,339	82,086	(138,938)	$ 78,835
Net increase (decrease) in net assets resulting from operations	$ 22,688	$ 28,749	$ 24,619	$ 3,214	$ (113,617)	$ (32,189)	$ (13,267)	$ 14,778	$ 79,270	$ (144,295)