Investments, at Fair Value - Schedule of Investments at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	$ 74,866	$ 37,622
Total Liabilities	(14)	(2)
Total	74,852	37,620
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	57,197	32,868
Total Liabilities	(14)	(2)
Total	57,183	32,866
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	17,669	4,754
Total	17,669	4,754
Texas Pacific Land Corporation
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	51,046	30,084
Texas Pacific Land Corporation | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	51,046	30,084
Kinetics Market Opportunities Fund
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	6,676
Kinetics Market Opportunities Fund | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	6,676
Kinetics Mutual Funds and ETFs
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	6,160	224
Kinetics Mutual Funds and ETFs | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	6,160	224
Kinetics Spin-Off and Corporate Restructuring Fund-Institutional Class
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	3,203	2,015
Kinetics Spin-Off and Corporate Restructuring Fund-Institutional Class | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	3,203	2,015
All Other Market Traded Equity Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	2,518	1,679
All Other Market Traded Equity Securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	2,518	1,679
CBOE Global Markets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	2,016
CBOE Global Markets | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	2,016
FRMO Corporation
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	1,630	1,259
FRMO Corporation | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	1,630	1,259
Grayscale Bitcoin Trust
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	1,617	1,105
Grayscale Bitcoin Trust | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments	1,617	1,105
Horizon Kinetics SPAC Active ETF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments		1,256
Horizon Kinetics SPAC Active ETF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments		1,256
Market Traded Equity Securities - Sold Short
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Liabilities	(14)	(2)
Market Traded Equity Securities - Sold Short | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Liabilities	$ (14)	$ (2)