Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 40,702	$ 23,072
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	40,702	23,072
Derivative, Collateral, Obligation to Return Securities	0	2
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	40,702	23,070
Derivative Liability, Fair Value, Gross Liability	178,188	160,270
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	178,188	160,270
Derivative, Collateral, Right to Reclaim Securities	0	2
Derivative, Collateral, Right to Reclaim Cash	176,312	159,692
Derivative Liability, Fair Value, Amount Offset Against Collateral	1,876	576
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	3,007	3,273
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	3,007	3,273
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	3,007	3,273
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	38,787	22,470
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	38,787	22,470
Derivative, Collateral, Obligation to Return Securities	0	2
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	38,787	22,468
Derivative Liability, Fair Value, Gross Liability	38,737	22,465
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	38,737	22,465
Derivative, Collateral, Right to Reclaim Securities	0	2
Derivative, Collateral, Right to Reclaim Cash	38,737	22,461
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	2
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,915	602
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	1,915	602
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	1,915	602
Derivative Liability, Fair Value, Gross Liability	1,876	574
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	1,876	574
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	1,876	574
Customer repurchase agreements and other short-term borrowings(c)
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	134,568	133,958
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	134,568	133,958
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	134,568	133,958
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ 0	$ 0