Consolidated Statements of Financial Condition (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Treasury stock (in shares)	2,410,964	1,583,380
Voting
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	446,863,844	446,863,844
Common stock, shares issued (in shares)	52,161,922	51,997,061
Common stock, shares outstanding (in shares)	49,750,958	50,413,681
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	3,136,156	3,136,156
Common stock, shares issued (in shares)	477,321	477,321
Common stock, shares outstanding (in shares)	477,321	477,321