Allowance for Loan and Lease Losses (Note Restructurings During Period) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) loans	Dec. 31, 2017 USD ($) loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 156,130	$ 164,561
Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	74,560	95,392
Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,298	4,572
Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	61,065	78,221
Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	860	1,800
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,046	10,278
Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	291	521
Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	81,570	69,169
Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,337	0
Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	47,524	43,542
Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	28,688	22,853
Non-PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 137,910	$ 146,126
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	164	204
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 13,318	$ 11,990
Financing Receivable, Modifications, Number of Contracts | loans	491	632
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 43,553	$ 49,000
PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 18,220	$ 18,435
Principal Forgiveness [Member] | Non-PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 634
Financing Receivable, Modifications, Number of Contracts | loans	3	6
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,003	$ 1,206
Principal Forgiveness [Member] | Non-PCI Loans | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 634
Financing Receivable, Modifications, Number of Contracts | loans	3	5
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,003	$ 1,124
Principal Forgiveness [Member] | Non-PCI Loans | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0
Financing Receivable, Modifications, Number of Contracts | loans	0	1
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 82
Extended Maturity [Member] | Non-PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	8	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 865	$ 273
Financing Receivable, Modifications, Number of Contracts | loans	42	47
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 5,486	$ 6,517
Extended Maturity [Member] | Non-PCI Loans | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	4	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 675	$ 0
Financing Receivable, Modifications, Number of Contracts | loans	21	13
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 3,933	$ 3,007
Extended Maturity [Member] | Non-PCI Loans | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	4	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 190	$ 273
Financing Receivable, Modifications, Number of Contracts | loans	21	34
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,554	$ 3,510
Interest Rate Below Market Reduction [Member] | Non-PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	92	110
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 8,459	$ 7,983
Financing Receivable, Modifications, Number of Contracts | loans	269	363
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 28,404	$ 30,412
Interest Rate Below Market Reduction [Member] | Non-PCI Loans | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	24	32
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 2,998	$ 3,392
Financing Receivable, Modifications, Number of Contracts | loans	85	92
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 12,859	$ 14,811
Interest Rate Below Market Reduction [Member] | Non-PCI Loans | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	68	78
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 5,461	$ 4,591
Financing Receivable, Modifications, Number of Contracts | loans	184	271
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 15,545	$ 15,601
Discharge of Debt [Member] | Non-PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	64	91
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 3,994	$ 3,100
Financing Receivable, Modifications, Number of Contracts | loans	177	216
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 8,660	$ 10,865
Discharge of Debt [Member] | Non-PCI Loans | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	8	26
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 825	$ 708
Financing Receivable, Modifications, Number of Contracts | loans	26	39
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 2,043	$ 3,012
Discharge of Debt [Member] | Non-PCI Loans | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	56	65
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 3,169	$ 2,392
Financing Receivable, Modifications, Number of Contracts | loans	151	177
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 6,617	$ 7,853