Related Party Transactions - Transactions with Other Related Parties (Details) - $ / shares			1 Months Ended						3 Months Ended				6 Months Ended
	May 19, 2025	May 16, 2025	Jun. 30, 2025	May 31, 2025	Apr. 30, 2025	Jun. 30, 2024	May 31, 2024	Apr. 30, 2024	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)			12,000	16,115,000	1,097,000	4,102,000	5,031,000	1,555,000	17,224,000	3,184,000	10,688,000	11,250,000	20,408,000	21,938,000
Class A Common Stock
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)									16,127,307		9,431,127		18,572,136	19,251,407
Stock repurchased, weighted average price (in dollars per share)									$ 9.21		$ 8.32		$ 9.23	$ 7.70
Mr. Howard W. Lutnick | Related Party | Class A Common Stock
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)	16,115,102	16,452,850
Stock repurchased, weighted average price (in dollars per share)		$ 9.2082
Mr. Howard W. Lutnick | Related Party | Common Class A, Shares Held Directly By Howard W. Lutnick
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)		5,616,612
Mr. Howard W. Lutnick | Related Party | Common Class A, Shares Held in the Personal Asset Trust
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)		10,489,582
Mr. Howard W. Lutnick | Related Party | Common Class A, Shares Held by the Family Trust
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)		8,908
Mr. Howard W. Lutnick | Related Party | Common Class A, Shares Held in A Retirement Account
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)		337,748