Allowance for Loan and Lease Losses (Troubled Debt Restructuring) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) loans	Sep. 30, 2018 USD ($) loans	Sep. 30, 2019 USD ($) loans	Sep. 30, 2018 USD ($) loans	Dec. 31, 2018 USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	142	104	381	385
Financing Receivable, Modifications, Recorded Investment	$ 161,312		$ 161,312		$ 156,130
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 14,251	$ 11,807	$ 35,546	$ 37,155
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	59	50	164	162
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 4,036	$ 3,766	$ 13,976	$ 11,472
PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	17,400		17,400		18,200
Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	71,972		71,972		74,560
Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,627		1,627		2,298
Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	57,270		57,270		61,065
Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	474		474		860
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	12,341		12,341		10,046
Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	260		260		291
Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	89,340		89,340		81,570
Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3,088		3,088		2,337
Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	54,237		54,237		47,524
Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	28,807		28,807		28,688
Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3,208		3,208		3,021
Accruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	124,414		124,414		127,093
Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	61,512		61,512		64,171
Accruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	518		518		1,946
Accruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	50,206		50,206		53,270
Accruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	474		474		851
Accruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,161		10,161		7,986
Accruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	153		153		118
Accruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	62,902		62,902		62,922
Accruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,570		1,570		2,227
Accruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	37,798		37,798		37,903
Accruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,968		20,968		20,492
Accruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,566		2,566		2,300
Nonaccruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	36,898		36,898		29,037
Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,460		10,460		10,389
Nonaccruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,109		1,109		352
Nonaccruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,064		7,064		7,795
Nonaccruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0		0		9
Nonaccruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,180		2,180		2,060
Nonaccruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	107		107		173
Nonaccruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	26,438		26,438		18,648
Nonaccruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,518		1,518		110
Nonaccruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	16,439		16,439		9,621
Nonaccruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,839		7,839		8,196
Nonaccruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 642		$ 642		$ 721
Interest only period provided
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	2	1	6	3
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,221	$ 300	$ 3,209	$ 1,136
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	0	2	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0	$ 2,064	$ 836
Loan term extension
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	5	9	13	32
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 2,473	$ 2,565	$ 3,870	$ 4,414
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	2	4	9
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 327	$ 514	$ 943
Below market interest rate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	80	56	205	211
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 4,460	$ 7,109	$ 14,968	$ 24,245
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	34	32	86	82
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 2,034	$ 2,832	$ 5,977	$ 6,098
Discharged from bankruptcy
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	55	38	157	139
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 6,097	$ 1,833	$ 13,499	$ 7,360
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	25	16	72	69
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 2,002	$ 607	$ 5,421	$ 3,595