Disclosures About Offsetting Assets and Liabilities (Financial Assets and Derivative Assets that are Subject to Offset) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Offsetting [Abstract]
Gross amounts of recognized assets, Securities borrowing	$ 356,551	$ 313,131
Net amounts presented in the Statement of Financial Condition, Securities borrowing	356,551	313,131
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Securities borrowing	(68,274)	(46,183)
Gross amounts not offset in the Statement of Financial Position, Collateral received, Securities borrowing	(282,564)	(244,578)
Securities borrowed, Net amount	5,713	22,370
Gross amounts of recognized assets, Reverse repurchase agreements	622,930	217,930
Net amounts presented in the Statement of Financial Condition, Securities purchased under agreements to resell	622,930	217,930
Gross amounts not offset in the Statement of Financial Position, Financial instruments, Securities purchased under agreements to resell	(15,416)	(17,992)
Gross amounts not offset in the Statement of Financial Position, Collateral received, Securities purchased under agreements to resell	(600,682)	(199,110)
Securities purchased under agreements to resell, Net amount	6,832	828
Gross amounts of recognized assets	979,481	531,061
Net amounts presented in the Statements of Financial Condition	979,481	531,061
Gross amounts not offset in the Statement of Financial Position	(83,690)	(64,175)
Gross amounts not offset in the Statement of Financial Position, Collateral received	(883,246)	(443,688)
Net amount	$ 12,545	$ 23,198