Derivative Financial Instruments - Balance Sheet Offsetting, Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Liabilities
Gross Amounts of Recognized Liabilities	$ 91,612	$ 98,050
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	91,612	98,050
Financial Instruments (Collateral)	(10,887)	(25,832)
Cash Collateral Pledged	(41,711)	(29,939)
Net Amount	39,014	42,279
Repurchase, securities lending, and similar arrangements
Securities Sold under Agreements to Repurchase, Gross	0	319,414
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase	0	319,414
Financial Instruments (Collateral)	0	0
Cash Collateral Pledged	0	0
Net Amount	0	319,414
Total
Gross Amounts of Recognized Liabilities	91,612	417,464
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	91,612	417,464
Financial Instruments (Collateral)	(10,887)	(25,832)
Cash Collateral Pledged	(41,711)	(29,939)
Net Amount	39,014	361,693
Interest rate swaps
Derivative Liabilities
Gross Amounts of Recognized Liabilities	303
Gross Amounts offset in the Statement of Financial Position	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	303
Financial Instruments (Collateral)	(303)
Cash Collateral Pledged	0
Net Amount	0
Foreign exchange forwards
Derivative Liabilities
Gross Amounts of Recognized Liabilities	81,132	86,800
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	81,132	86,800
Financial Instruments (Collateral)	(10,238)	(24,778)
Cash Collateral Pledged	(32,690)	(20,732)
Net Amount	38,204	41,290
Client foreign currency options
Derivative Liabilities
Gross Amounts of Recognized Liabilities	1,336	1,759
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	1,336	1,759
Financial Instruments (Collateral)	(346)	(1,054)
Cash Collateral Pledged	(341)	0
Net Amount	649	705
Client interest rate derivatives
Derivative Liabilities
Gross Amounts of Recognized Liabilities	8,841	9,491
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	8,841	9,491
Financial Instruments (Collateral)	0	0
Cash Collateral Pledged	(8,680)	(9,207)
Net Amount	$ 161	$ 284