Marketable Securities - Details of Marketable Securities (Details) - IronNet [Member] - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Fair Value	$ 19,178	$ 16,167
Basis	44,444	38,993
Cumulative Unrealized (Loss) Gain	(25,266)	(22,826)
Put Options [Member]
Marketable Securities [Line Items]
Fair Value		1,245
Basis		489
Cumulative Unrealized (Loss) Gain		756
IronNet Securities [Member]
Marketable Securities [Line Items]
Fair Value	2,848	6,351
Basis	27,636	29,185
Cumulative Unrealized (Loss) Gain	(24,788)	(22,834)
Equity Funds and Other Securities [Member]
Marketable Securities [Line Items]
Fair Value	16,330	9,816
Basis	16,808	9,808
Cumulative Unrealized (Loss) Gain	(478)	8
Shares of Common Stock [Member]
Marketable Securities [Line Items]
Fair Value	2,848	5,106
Basis	27,636	28,696
Cumulative Unrealized (Loss) Gain	$ (24,788)	$ (23,590)