Fair Value Measurements (Valuation Techniques and Unobservable Inputs Used in the Valuation of Financial Instruments Falling within Level 3 of the Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Fair Value Inputs Assets Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 8,025,867	$ 8,196,018
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.08032
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.25936
Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.162391943001682
Fair Value, Inputs, Level 3
Fair Value Inputs Assets Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 33,414	$ 49,055
Fair Value, Inputs, Level 3 | Private label residential mortgage-backed securities and CMO's - Investment grade
Fair Value Inputs Assets Quantitative Information [Line Items]
Assets, Fair Value Disclosure	12,244
Fair Value, Inputs, Level 3 | Private label residential mortgage-backed securities and CMO's - Non-investment grade
Fair Value Inputs Assets Quantitative Information [Line Items]
Assets, Fair Value Disclosure	8,068
Fair Value, Inputs, Level 3 | Commercial Servicing Rights [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 8,631
Measurement Input, Prepayment Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.04
Measurement Input, Prepayment Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.35182
Measurement Input, Prepayment Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.153668231845843
Measurement Input, Prepayment Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0315545275807381
Measurement Input, Prepayment Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.221289992332459
Measurement Input, Prepayment Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.147995924071946
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.001
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.1
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0200890622499698
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.002
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.06
Measurement Input, Default Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0215
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.15
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	1
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.419282995900416
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.15
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	1
Measurement Input, Loss Severity [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.253756282425065
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.020712
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.058374
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0308314333199526
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0225
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.1345
Measurement Input, Discount Rate [Member] | Private label residential mortgage-backed securities and CMO's - Non-investment grade | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.051
Measurement Input, Discount Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.0524177029728889
Measurement Input, Discount Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.259857028722763
Measurement Input, Discount Rate [Member] | Commercial Servicing Rights [Member] | Discounted cash flow | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value, Option, Relation to Measurement Inputs	0.130923663601062