Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 104,450	$ 26,113
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		104,450	26,113
Derivative, Collateral, Obligation to Return Securities	[1]	29,677	6,556
Derivative, Collateral, Obligation to Return Cash		0	(8,528)
Derivative Asset, Fair Value, Amount Offset Against Collateral		74,773	11,029
Derivative Liability, Fair Value, Gross Liability		75,093	17,523
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		75,093	17,523
Derivative, Collateral, Right to Reclaim Securities	[1]	29,677	6,556
Derivative, Collateral, Right to Reclaim Cash		41,436	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		3,980	10,794
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		29,551	8,955
Derivative, Collateral, Obligation to Return Securities	[1]	29,551	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		244	391
Derivative, Collateral, Right to Reclaim Securities	[1]	0	391
Derivative, Collateral, Right to Reclaim Cash		244	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		71,554	15,580
Derivative, Collateral, Obligation to Return Securities	[1]	126	6,165
Derivative, Collateral, Obligation to Return Cash		0	3,001
Derivative Asset, Fair Value, Amount Offset Against Collateral		71,428	6,414
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		71,544	15,584
Derivative, Collateral, Right to Reclaim Securities	[1]	29,677	6,165
Derivative, Collateral, Right to Reclaim Cash		41,192	173
Derivative Liability, Fair Value, Amount Offset Against Collateral		675	9,246
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		3,345	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		3,345	1,578
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		3,305	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		3,305	1,548
Other Assets [Member]
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		106,601	26,310
Other Assets [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		71,554	15,580
Other Assets [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		3,345	1,578
Other Liabilities [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		75,134	17,523
Other Liabilities [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		71,544	15,584
Other Liabilities [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		3,305	1,548
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Assets, at Fair Value		29,551	8,955
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Liabilities, at Fair Value		$ 244	$ 391

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