Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 18,448	$ 22,390
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	18,448	22,390
Derivative, Collateral, Obligation to Return Securities	65	272
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	18,383	22,118
Derivative Liability, Fair Value, Gross Liability	192,531	225,824
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	192,531	225,824
Derivative, Collateral, Right to Reclaim Securities	65	272
Derivative, Collateral, Right to Reclaim Cash	191,613	221,296
Derivative Liability, Fair Value, Amount Offset Against Collateral	853	4,256
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	0	0
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liability, Fair Value, Gross Liability	4,636	5,570
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	4,636	5,570
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	4,636	5,570
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	17,636	18,383
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	17,636	18,383
Derivative, Collateral, Obligation to Return Securities	65	272
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	17,571	18,111
Derivative Liability, Fair Value, Gross Liability	17,667	18,380
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	17,667	18,380
Derivative, Collateral, Right to Reclaim Securities	65	272
Derivative, Collateral, Right to Reclaim Cash	17,538	17,836
Derivative Liability, Fair Value, Amount Offset Against Collateral	65	272
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	812	4,007
Derivative Asset, Collateral, Obligation to Return Cash, Offset	0	0
Derivative Asset	812	4,007
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	812	4,007
Derivative Liability, Fair Value, Gross Liability	789	3,984
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	789	3,984
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral	789	3,984
Customer repurchase agreements and other short-term borrowings(c)
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	119,439	147,890
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	119,439	147,890
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	119,439	147,890
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Wholesale repurchase agreements
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability	50,000	50,000
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	0	0
Derivative Liability	50,000	50,000
Derivative, Collateral, Right to Reclaim Securities	0	0
Derivative, Collateral, Right to Reclaim Cash	50,000	50,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ 0	$ 0