Fair Value Measurement (Fair Value Assets And Liabilities Measured On Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	$ 3,613,657	$ 3,423,919
Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	64,320	61,393
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	3,425,075	3,186,744
Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	124,262	175,782
Fair Value, Nonrecurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	27,390	106,228
Fair Value, Nonrecurring | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	27,390	106,228
Fair Value, Nonrecurring | Loans and leases
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	25,000	98,696
Fair Value, Nonrecurring | Loans and leases | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Loans and leases | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Loans and leases | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	25,000	98,696
Fair Value, Nonrecurring | Other real estate owned
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	2,390	7,532
Fair Value, Nonrecurring | Other real estate owned | Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Other real estate owned | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	0	0
Fair Value, Nonrecurring | Other real estate owned | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets measured at fair value	$ 2,390	$ 7,532