Condensed Consolidated Statements of Financial Condition (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Class A Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	363,848,000	358,440,000
Common stock, shares outstanding	313,323,000	307,915,000
Treasury stock, at cost	50,525,000	50,525,000
Class B Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	45,884,000	45,884,000
Common stock, shares outstanding	45,884,380	45,884,380