Derivative Financial Instruments - Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative Assets	$ 224,861	$ 167,341
Derivative Liabilities	137,781	137,984
Derivative Assets, Total	427,045	332,814
Derivative Liabilities, Total	137,781	137,984
Reduction in derivative liabilities due to rules of clearing houses	59,200	17,400
Interest rate swaps
Derivative [Line Items]
Derivative Assets	0	22,676
Derivative Liabilities	0	25,623
Foreign exchange forwards
Derivative [Line Items]
Derivative Assets	142,605	114,546
Derivative Liabilities	109,237	96,899
Client foreign currency options
Derivative [Line Items]
Derivative Assets	2,986	1,308
Derivative Liabilities	2,986	1,308
Client interest rate derivatives
Derivative [Line Items]
Derivative Assets	79,270	28,811
Derivative Liabilities	25,558	14,154
Derivatives designated as hedging instruments | Interest rate swaps | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	0	1,915,000
Derivative Assets	0	22,676
Derivatives designated as hedging instruments | Interest rate swaps | Other liabilities
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	0	3,085,000
Derivative Liabilities	0	25,623
Derivatives not designated as hedging instruments
Derivative [Line Items]
Derivative Assets	427,045	310,138
Derivative Liabilities	137,781	112,361
Derivatives not designated as hedging instruments | Foreign exchange forwards | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	462,765
Derivative Liabilities	4,083
Derivatives not designated as hedging instruments | Foreign exchange forwards | Other liabilities
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	59,992	300,250
Derivative Liabilities	278	2,154
Derivatives not designated as hedging instruments | Equity warrant assets | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	256,774	225,893
Derivative Assets	202,184	165,473
Derivatives not designated as hedging instruments | Client foreign exchange forwards | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	6,955,487	4,661,517
Derivative Assets	138,522	114,546
Derivatives not designated as hedging instruments | Client foreign exchange forwards | Other liabilities
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	5,754,213	4,326,059
Derivative Liabilities	108,959	94,745
Derivatives not designated as hedging instruments | Client foreign currency options | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	111,107	154,985
Derivative Assets	2,986	1,308
Derivatives not designated as hedging instruments | Client foreign currency options | Other liabilities
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	111,107	154,985
Derivative Liabilities	2,986	1,308
Derivatives not designated as hedging instruments | Client interest rate derivatives | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	916,573	1,275,190
Derivative Assets	79,270	28,811
Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liabilities
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	1,048,715	1,372,914
Derivative Liabilities	$ 25,558	$ 14,154