Derivatives - Gains/(Losses) on Derivatives Associated with Interest Rate Risk Management Activities (Details) - Hedging Instruments And Hedged Items - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Customer Interest Rate Contracts Hedging | Customer Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) related to interest rate derivatives	$ 92,497	$ 1,779	$ (10,703)
Customer Interest Rate Contracts Hedging | Offsetting Upstream Interest Rate Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) related to interest rate derivatives	(92,497)	(1,779)	10,699
Debt Hedging | Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) related to interest rate derivatives	13,240	(1,648)	(7,766)
Debt Hedging | Term Borrowings
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(Losses) related to term borrowings	$ (13,234)	$ 1,622	$ 7,582