Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 32,936	$ 26,113
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		32,936	26,113
Derivative, Collateral, Obligation to Return Securities	[1]	13,186	6,556
Derivative, Collateral, Obligation to Return Cash		(1,190)	(8,528)
Derivative Asset, Fair Value, Amount Offset Against Collateral		18,560	11,029
Derivative Liability, Fair Value, Gross Liability		19,762	17,523
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		19,762	17,523
Derivative, Collateral, Right to Reclaim Securities	[1]	13,186	6,556
Derivative, Collateral, Right to Reclaim Cash		505	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		6,071	10,794
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		13,136	8,955
Derivative, Collateral, Obligation to Return Securities	[1]	9,988	391
Derivative, Collateral, Obligation to Return Cash		(928)	5,527
Derivative Asset, Fair Value, Amount Offset Against Collateral		2,220	3,037
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		0	391
Derivative, Collateral, Right to Reclaim Securities	[1]	0	391
Derivative, Collateral, Right to Reclaim Cash		0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral		0	0
Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		17,660	15,580
Derivative, Collateral, Obligation to Return Securities	[1]	3,198	6,165
Derivative, Collateral, Obligation to Return Cash		(262)	3,001
Derivative Asset, Fair Value, Amount Offset Against Collateral		14,200	6,414
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		17,660	15,584
Derivative, Collateral, Right to Reclaim Securities	[1]	13,186	6,165
Derivative, Collateral, Right to Reclaim Cash		505	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		3,969	9,246
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		2,140	1,578
Derivative, Collateral, Obligation to Return Securities	[1]	0	0
Derivative, Collateral, Obligation to Return Cash		0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		2,140	1,578
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		2,102	1,548
Derivative, Collateral, Right to Reclaim Securities	[1]	0	0
Derivative, Collateral, Right to Reclaim Cash		0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral		2,102	1,548
Other Assets [Member]
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		33,192	26,310
Other Assets [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		17,660	15,580
Other Assets [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		2,140	1,578
Other Liabilities [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		19,762	17,523
Other Liabilities [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		17,660	15,584
Other Liabilities [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		2,102	1,548
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Assets, at Fair Value		13,136	8,955
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Liabilities, at Fair Value		$ 0	$ 391

[1] Reflects offsetting derivative positions with the same counterparty.