Derivative Instruments and Hedging Activities - Offsetting Derivatives (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets
Gross amounts recognized	$ 177,790	$ 62,436
Less: amounts offset in the Consolidated Statements of Financial Condition	0	0
Net amount presented in the Consolidated Statements of Financial Condition	177,790	62,436
Offsetting derivative positions	(6,356)	(2,674)
Cash collateral pledged	0	0
Net credit exposure	171,434	59,762
Liabilities
Gross amounts recognized	51,516	18,535
Less: amounts offset in the Consolidated Statements of Financial Condition	0	0
Net amount presented in the Consolidated Statements of Financial Condition	51,516	18,535
Offsetting derivative positions	(6,356)	(2,674)
Cash collateral pledged	(46,250)	(15,861)
Net credit exposure	$ (1,090)	$ 0