Derivative Financial Instruments - Total Notional or Contractual Amounts, Fair Value, Collateral and Net Exposure of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Maximum length of time over which forecasted transactions are hedged	6 years
Derivative [Line Items]
Fair Value, Derivative Assets	$ 188,864	$ 108,901
Fair Value, Derivative Liabilities	148,540	98,050
Derivative Assets, Total	337,977	258,139
Derivative Liabilities, Total	148,540	98,050
Interest rate swaps
Derivative [Line Items]
Fair Value, Derivative Assets	40,976
Fair Value, Derivative Liabilities	9,286
Foreign exchange forwards
Derivative [Line Items]
Fair Value, Derivative Assets	120,795	98,643
Fair Value, Derivative Liabilities	100,244	86,800
Client foreign currency options
Derivative [Line Items]
Fair Value, Derivative Assets	1,485	1,759
Fair Value, Derivative Liabilities	1,485	1,759
Client interest rate derivatives
Derivative [Line Items]
Fair Value, Derivative Assets	25,608	8,499
Fair Value, Derivative Liabilities	37,525	9,491
Derivatives designated as hedging instruments | Interest rate swaps | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	2,000,000	0
Fair Value, Derivative Assets	40,976	0
Derivatives designated as hedging instruments | Interest rate swaps | Other liability
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	2,000,000	0
Fair Value, Derivative Liabilities	9,286	0
Derivatives not designated as hedging instruments
Derivative [Line Items]
Fair Value, Derivative Assets	297,001	258,139
Fair Value, Derivative Liabilities	139,254	98,050
Derivatives not designated as hedging instruments | Foreign exchange forwards | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	255,228	263,733
Fair Value, Derivative Assets	4,303	4,767
Derivatives not designated as hedging instruments | Foreign exchange forwards | Other liability
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	0	178,310
Fair Value, Derivative Liabilities	0	1,094
Derivatives not designated as hedging instruments | Equity warrant assets | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	223,383	223,532
Fair Value, Derivative Assets	149,113	149,238
Derivatives not designated as hedging instruments | Client foreign exchange forwards | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	3,921,970	2,759,878
Fair Value, Derivative Assets	116,492	93,876
Derivatives not designated as hedging instruments | Client foreign exchange forwards | Other liability
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	3,876,021	2,568,085
Fair Value, Derivative Liabilities	100,244	85,706
Derivatives not designated as hedging instruments | Client foreign currency options | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	125,531	93,556
Fair Value, Derivative Assets	1,485	1,759
Derivatives not designated as hedging instruments | Client foreign currency options | Other liability
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	125,531	93,579
Fair Value, Derivative Liabilities	1,485	1,759
Derivatives not designated as hedging instruments | Client interest rate derivatives | Other assets
Derivative [Line Items]
Derivative Asset, Notional or Contractual Amount	1,230,782	1,020,416
Fair Value, Derivative Assets	25,608	8,499
Reduction in derivative assets due to rules of clearing houses		(400)
Derivatives not designated as hedging instruments | Client interest rate derivatives | Other liability
Derivative [Line Items]
Derivative Liabilities, Notional or Contractual Amount	1,310,689	1,337,328
Fair Value, Derivative Liabilities	37,525	$ 9,491
Reduction in derivative liabilities due to rules of clearing houses	$ (7,800)