Derivative Financial Instruments - Balance Sheet Offsetting, Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative Assets
Gross Amounts of Recognized Assets	$ 108,901	$ 108,389
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	108,901	108,389
Financial Instruments (Collateral)	(47,242)	(26,754)
Cash Collateral Received	(11,998)	(3,730)
Net Amount	49,661	77,905
Reverse repurchase, securities borrowing, and similar arrangements
Gross Amounts of Recognized Assets	123,611	247,876
Gross Amounts offset in the Statement of Financial Position	0	0
Securities purchased under agreements to resell	123,611	247,876
Financial Instruments (Collateral)	(123,611)	(247,876)
Cash Collateral Received	0	0
Net Amount	0	0
Total
Gross Amounts of Recognized Assets	232,512	356,265
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	232,512	356,265
Financial Instruments (Collateral)	(170,853)	(274,630)
Cash Collateral Received	(11,998)	(3,730)
Net Amount	49,661	77,905
Foreign exchange forwards
Derivative Assets
Gross Amounts of Recognized Assets	98,643	95,449
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	98,643	95,449
Financial Instruments (Collateral)	(38,213)	(14,570)
Cash Collateral Received	(11,825)	(3,616)
Net Amount	48,605	77,263
Client foreign currency options
Derivative Assets
Gross Amounts of Recognized Assets	1,759	1,187
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	1,759	1,187
Financial Instruments (Collateral)	(613)	(557)
Cash Collateral Received	(90)	0
Net Amount	1,056	630
Client interest rate derivatives
Derivative Assets
Gross Amounts of Recognized Assets	8,499	11,753
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	8,499	11,753
Financial Instruments (Collateral)	(8,416)	(11,627)
Cash Collateral Received	(83)	(114)
Net Amount	$ 0	$ 12