Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 78,176	$ 26,113
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		78,176	26,113
Derivative, Collateral, Obligation to Return Securities	[1]	26,195	6,556
Derivative, Collateral, Obligation to Return Cash		0	(8,528)
Derivative Asset, Fair Value, Amount Offset Against Collateral		51,981	11,029
Derivative Liability, Fair Value, Gross Liability		53,043	17,523
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		53,043	17,523
Derivative, Collateral, Right to Reclaim Securities	[1]	26,195	6,556
Derivative, Collateral, Right to Reclaim Cash		23,834	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		3,014	10,794
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		25,216	8,955
Derivative, Collateral, Obligation to Return Securities	[1]	25,216	391
Derivative, Collateral, Obligation to Return Cash		0	5,527
Derivative Asset, Fair Value, Amount Offset Against Collateral		0	3,037
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		125	391
Derivative, Collateral, Right to Reclaim Securities	[1]	0	391
Derivative, Collateral, Right to Reclaim Cash		125	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		51,417	15,580
Derivative, Collateral, Obligation to Return Securities	[1]	979	6,165
Derivative, Collateral, Obligation to Return Cash		0	3,001
Derivative Asset, Fair Value, Amount Offset Against Collateral		50,438	6,414
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		51,411	15,584
Derivative, Collateral, Right to Reclaim Securities	[1]	26,195	6,165
Derivative, Collateral, Right to Reclaim Cash		23,709	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		1,507	9,246
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		1,543	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		1,543	1,578
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		1,507	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		1,507	1,548
Other Assets [Member]
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		80,556	26,310
Other Assets [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		51,417	15,580
Other Assets [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		1,543	1,578
Other Liabilities [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		53,679	17,523
Other Liabilities [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		51,411	15,584
Other Liabilities [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		1,507	1,548
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Assets, at Fair Value		25,216	8,955
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Liabilities, at Fair Value		$ 125	$ 391

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