Related Party Transactions - Transactions with Other Related Parties (Details) - USD ($)				1 Months Ended						3 Months Ended						12 Months Ended
	Oct. 06, 2025	May 19, 2025	May 16, 2025	Dec. 31, 2025	Nov. 30, 2025	Oct. 31, 2025	Dec. 31, 2024	Nov. 30, 2024	Oct. 31, 2024	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)				0	1,191,000	6,200,000	0	0	6,369,000	4,239,000	17,224,000	3,184,000	7,893,000	10,688,000	11,250,000	32,038,000	36,200,000
Class A Common Stock
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)																30,197,095	31,573,031	23,250,551
Stock repurchased, weighted average price (in dollars per share)																$ 9.31	$ 8.30
Mr. Howard W. Lutnick | Related Party | Class A Common Stock
Related Party Transaction [Line Items]
Repurchase of class A common stock (in shares)	337,765	16,115,102	16,452,850
Stock repurchased, weighted average price (in dollars per share)			$ 9.2082
Shares issued, price per share, after tax (in dollars per share)			$ 0.04
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
Cantor | Class B Common Stock | Former Chief Executive Officer And Former Chairman
Related Party Transaction [Line Items]
Shares held by related party, number of shares sold (in shares)	8,973,721
Shares held by related party, shares sold, price per share (in dollars per share)	$ 9.2082
Shares issued, price per share, after tax (in dollars per share)	$ 0.032
Certain Other Trusts Controlled By Mr. Brandon G. Lutnick | Former Chief Executive Officer And Former Chairman
Related Party Transaction [Line Items]
Shares held by related party, value of shares sold	$ 13,096,795.7
Purchaser Trusts | Former Chief Executive Officer And Former Chairman
Related Party Transaction [Line Items]
Shares held by related party, value of shares sold	$ 200,000