Allowance for Loan and Lease Losses (Troubled Debt Restructuring) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($) loans	Sep. 30, 2017 USD ($) loans	Sep. 30, 2018 USD ($) loans	Sep. 30, 2017 USD ($) loans	Dec. 31, 2017 USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	104	115	385	426
Financing Receivable, Modifications, Recorded Investment	$ 161,971		$ 161,971		$ 164,561
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 11,807	$ 13,180	$ 37,155	$ 33,174
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	50	67	162	155
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 3,766	$ 4,271	$ 11,472	$ 10,493
PCI Loans
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	18,369		18,369		18,400
Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	81,451		81,451		95,392
Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,350		2,350		4,572
Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	67,664		67,664		78,221
Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	929		929		1,800
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,319		9,319		8,508
Commercial | Lease financing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	947		947		1,770
Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	242		242		521
Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	80,520		80,520		69,169
Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,824		2,824		0
Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	46,892		46,892		43,542
Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	27,917		27,917		22,853
Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,887		2,887		2,774
Accruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	130,611		130,611		130,391
Accruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	66,790		66,790		76,300
Accruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,020		2,020		4,089
Accruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	55,362		55,362		62,358
Accruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	899		899		1,012
Accruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,762		7,762		7,598
Accruing | Commercial | Lease financing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	628		628		722
Accruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	119		119		521
Accruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	63,821		63,821		54,091
Accruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,673		2,673		0
Accruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	38,169		38,169		34,067
Accruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,577		20,577		17,673
Accruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,402		2,402		2,351
Nonaccruing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	31,360		31,360		34,170
Nonaccruing | Commercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	14,661		14,661		19,092
Nonaccruing | Commercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	330		330		483
Nonaccruing | Commercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	12,302		12,302		15,863
Nonaccruing | Commercial | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	30		30		788
Nonaccruing | Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,557		1,557		910
Nonaccruing | Commercial | Lease financing
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	319		319		1,048
Nonaccruing | Commercial | Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	123		123		0
Nonaccruing | Noncommercial
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	16,699		16,699		15,078
Nonaccruing | Noncommercial | Construction and land development
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	151		151		0
Nonaccruing | Noncommercial | Mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	8,723		8,723		9,475
Nonaccruing | Noncommercial | Revolving mortgage
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,340		7,340		5,180
Nonaccruing | Noncommercial | Consumer and Other
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 485		$ 485		$ 423
Interest only period provided
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	1	3	3	6
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 300	$ 696	$ 1,136	$ 1,180
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	0	0	2	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 0	$ 0	$ 836	$ 328
Loan term extension
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	9	6	32	31
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 2,565	$ 156	$ 4,414	$ 2,787
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	2	0	9	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 327	$ 0	$ 943	$ 31
Below market interest rate
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	56	63	211	238
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 7,109	$ 6,859	$ 24,245	$ 19,526
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	32	27	82	75
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 2,832	$ 1,956	$ 6,098	$ 5,332
Discharged from bankruptcy
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | loans	38	43	139	151
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 1,833	$ 5,469	$ 7,360	$ 9,681
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loans	16	40	69	78
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 607	$ 2,315	$ 3,595	$ 4,802