Quarterly Statements of Operations - Schedule of Quarterly Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Expenses:
Sponsor's Fee, related party	$ 778	$ 1,158	$ 1,860	$ 1,561	$ 2,093	$ 1,466	$ 389	$ 91	$ 5,357	$ 4,039	$ 17
Net investment loss	(778)	(1,158)	(1,860)	(1,561)	(2,093)	(1,466)	(389)	(91)	(5,357)	(4,039)	(17)
Net realized and unrealized gain (loss) from:
Net realized gain (loss) on investment in LTC	(123)	260	937	639	1,238	800	104	(2)	1,713	2,140	(12)
Net change in unrealized appreciation (depreciation) on investment in LTC	(112,716)	(31,291)	(12,344)	15,700	(79,418)	89,044	69,491	(2,422)	(140,651)	76,695	(742)
Net realized and unrealized (loss) gain on investment	(112,839)	(31,031)	(11,407)	16,339	(78,180)	89,844	69,595	(2,424)	(138,938)	78,835	(753)
Net increase (decrease) in net assets resulting from operations	$ (113,617)	$ (32,189)	$ (13,267)	$ 14,778	$ (80,273)	$ 88,378	$ 69,206	$ (2,515)	$ (144,295)	$ 74,796	$ (770)