Derivative Financial Instruments - Master Netting Arrangements (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	$ 169,435	$ 142,975
Gross Amounts offset in the Statement of Financial Position	0	0
Gross Amounts of Recognized Liabilities	100,916	64,438
Net Amounts of Assets Presented in the Statement of Financial Position	169,435	142,975
Gross Assets Subject To Master Netting Arrangement Not Offset	(95,957)	(106,384)
Cash Collateral Received Subject to Master Netting Arrangements	(4,840)	(12,668)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	68,638	23,923
Gross Amounts offset in the Statement of Financial Position	0	0
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Securities Sold under Agreements to Repurchase, Asset	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	100,916	64,438
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(81,547)	(29,319)
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	19,369	35,119
Securities Sold under Agreements to Repurchase, Gross	0	0
Securities Purchased under Agreements to Resell, Gross	62,664	64,028
Securities Purchased under Agreements to Resell, Liability	0	0
Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Securities	62,664	64,028
Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Cash	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	0	0
Collateral	4,840	12,668
Interest rate swaps
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset		810
Derivative Asset, Fair Value, Gross Liability		0
Derivative, Collateral, Obligation to Return Securities		721
Derivative, Collateral, Obligation to Return Cash		89
Foreign exchange forwards
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	93,857	57,644
Derivative Asset, Fair Value, Gross Liability	0	0
Fair value, Liabilities	(87,871)	(44,285)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative, Collateral, Obligation to Return Securities	21,154	22,738
Derivative, Collateral, Obligation to Return Cash	4,840	12,579
Derivative, Collateral, Right to Reclaim Securities	68,852	17,964
Derivative, Collateral, Right to Reclaim Cash	0	0
Client foreign currency options
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,090	10,383
Derivative Asset, Fair Value, Gross Liability	0	0
Fair value, Liabilities	(1,090)	(10,383)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative, Collateral, Obligation to Return Securities	331	8,806
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative, Collateral, Right to Reclaim Securities	759	1,585
Derivative, Collateral, Right to Reclaim Cash	0	0
Client interest rate derivatives
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,824	10,110
Derivative Asset, Fair Value, Gross Liability	0	0
Fair value, Liabilities	(11,955)	(9,770)
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative, Collateral, Obligation to Return Securities	11,808	10,091
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative, Collateral, Right to Reclaim Securities	11,936	9,770
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Gross Amounts of Recognized Assets	106,771	78,947
Gross Amounts offset in the Statement of Financial Position	0	0
Gross Amounts of Recognized Liabilities	100,916	64,438
Net Amounts of Assets Presented in the Statement of Financial Position	106,771	78,947
Gross Assets Subject To Master Netting Arrangement Not Offset	(33,293)	(42,356)
Cash Collateral Received Subject to Master Netting Arrangements	(4,840)	(12,668)
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	68,638	23,923
Gross Amounts offset in the Statement of Financial Position	0	0
Cash Collateral Pledged Subject to Master Netting Arrangements	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	100,916	64,438
Gross Liabilities Subject To Master Netting Arrangement Not Offset	(81,547)	(29,319)
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	19,369	35,119
Derivative | Interest rate swaps
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Net Amounts of Assets Presented in the Statement of Financial Position		810
Net Assets After Deducting Amounts Subject to Master Netting Arrangements		0
Derivative | Foreign exchange forwards
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Net Amounts of Assets Presented in the Statement of Financial Position	93,857	57,644
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	67,863	22,327
Net Amounts of Liabilities Presented in the Statement of Financial Position	87,871	44,285
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	19,019	26,321
Derivative | Client foreign currency options
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Net Amounts of Assets Presented in the Statement of Financial Position	1,090	10,383
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	759	1,577
Net Amounts of Liabilities Presented in the Statement of Financial Position	1,090	10,383
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	331	8,798
Derivative | Client interest rate derivatives
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Net Amounts of Assets Presented in the Statement of Financial Position	11,824	10,110
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	16	19
Net Amounts of Liabilities Presented in the Statement of Financial Position	11,955	9,770
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	19	0
Reverse Repurchase Securities Borrowing And Similar Arrangements
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Net Amounts of Assets Presented in the Statement of Financial Position	62,664	64,028
Net Assets After Deducting Amounts Subject to Master Netting Arrangements	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	0	0
Net Liabilities After Deducting Amounts Subject to Master Netting Arrangements	0	0
Other assets | Derivatives not designated as hedging instruments | Equity warrant assets | Other derivative instruments
Assets and Liabilities Subject to Master Netting Arrangements [Line Items]
Derivative, Notional Amount	211,018	211,434
Derivative Asset, Fair Value, Gross Asset	141,785	131,123
Collateral	$ 0	$ 0