Derivative Financial Instruments - Balance Sheet Offsetting, Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Liabilities
Gross Amounts of Recognized Liabilities	$ 98,050	$ 108,581
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	98,050	108,581
Financial Instruments (Collateral)	(25,832)	(11,498)
Cash Collateral Pledged	(29,939)	(81,164)
Net Amount	42,279	15,919
Repurchase, securities lending, and similar arrangements
Securities Sold under Agreements to Repurchase, Gross	319,414	0
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase	319,414	0
Financial Instruments (Collateral)	0	0
Cash Collateral Pledged	0	0
Net Amount	319,414	0
Total
Gross Amounts of Recognized Liabilities	417,464	108,581
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	417,464	108,581
Financial Instruments (Collateral)	(25,832)	(11,498)
Cash Collateral Pledged	(29,939)	(81,164)
Net Amount	361,693	15,919
Foreign exchange forwards
Derivative Liabilities
Gross Amounts of Recognized Liabilities	86,800	95,454
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	86,800	95,454
Financial Instruments (Collateral)	(24,778)	(10,997)
Cash Collateral Pledged	(20,732)	(69,110)
Net Amount	41,290	15,347
Client foreign currency options
Derivative Liabilities
Gross Amounts of Recognized Liabilities	1,759	1,187
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	1,759	1,187
Financial Instruments (Collateral)	(1,054)	(501)
Cash Collateral Pledged	0	(130)
Net Amount	705	556
Client interest rate derivatives
Derivative Liabilities
Gross Amounts of Recognized Liabilities	9,491	11,940
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	9,491	11,940
Financial Instruments (Collateral)	0	0
Cash Collateral Pledged	(9,207)	(11,924)
Net Amount	$ 284	$ 16