Master Netting and Similar Agreements—Repurchase, Reverse Repurchase, and Securities Borrowing Transactions - Securities Sold Under Agreements To Repurchase And Collateral Pledged By Company (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Securities Sold under Agreements to Repurchase [Abstract]
Gross amounts of recognized liabilities	$ 1,482,585	$ 716,925
Gross amounts offset in the Statements of Condition	0	0
Net amounts of liabilities presented in the Statements of Condition	1,482,585	716,925
Offsetting securities purchased under agreements to resell	(23,207)	(21,004)
Securities/ government guaranteed loans collateral	(1,459,297)	(695,879)
Net amount	$ 81	$ 42