Consolidated Entities (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Mar. 30, 2022	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	May 31, 2021	Dec. 31, 2020
CONSOLIDATED ENTITIES
Initial contribution				$ 190,000
Total assets		$ 1,267,612		1,243,507
Net investment-related income (expense) earned (incurred)		$ 200
ISP Fund LP
CONSOLIDATED ENTITIES
Distribution from partnership					$ 110,000
Economic interest of the Partnership (in percent)		100.00%
Total assets		$ 287,200		311,800
Total liabilities		1,800		$ 100
Changes in fair values of equity and long-term investments, net		$ 26,200	$ 4,100
Net investment-related income (expense) earned (incurred)			$ 500
Capital contribution	$ 110,000					$ 300,000
Lock-up period	36 months