Loans (Recorded Investment By Loan Grade) (Details) - USD ($) $ in Thousands		Sep. 30, 2018		Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		$ 5,625,323		$ 5,372,483
Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		151,757		125,389
Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		403,147		393,094
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	[1]	1,302,630		1,167,607
Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		2,632		2,993
5 Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		4,910		23,088
5 Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		1,588		278
5 Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		195		216
5 Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		980	[2]	17,272	[3]
5 Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		2,147	[2]	5,322	[3]
5 Rated [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		0		0
6 Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		495		611
6 Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment				0
6 Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		44		1
6 Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		451	[2]	153	[3]
6 Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment	[3]			457
6 Rated [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		0		0
Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		46,835		56,589
Impaired [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		2,016		1,324
Impaired [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		2,913		19,059
Impaired [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		16,101	[2]	18,064	[3]
Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		25,805	[2]	18,142	[3]
Impaired [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		0		0
Purchased credit impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		4,494
Purchased credit impaired [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		499
Purchased credit impaired [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		44
Purchased credit impaired [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment	[2]	405
Purchased credit impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment	[2]	3,546
Purchased credit impaired [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		0		0
Pass Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		2,847,377		2,672,410
Pass Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		148,128		125,790
Pass Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		401,107		394,123
Pass Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		1,019,169	[2]	1,057,866	[3]
Pass Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		1,276,301	[2]	1,171,890	[3]
Pass Rated [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Total ending loan balance, recorded investment		2,672		3,029
Recorded Investment [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		2,904,111		2,752,698
Recorded Investment [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		152,231		124,188
Recorded Investment [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		404,303		374,847
Recorded Investment [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		1,037,106	[2]	1,022,377	[3]
Recorded Investment [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		1,307,799	[2]	1,147,969	[3]
Recorded Investment [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment		$ 2,672		$ 3,029

[1] Included within each of commercial, financial and agricultural loans and commercial real estate loans is an immaterial amount of consumer loans that are not broken out by class.

[2] * Included within each of commercial, financial and agricultural loans and commercial real estate loans is an immaterial amount of consumer loans that are not broken out by class.

[3] * Included within each of commercial, financial and agricultural loans and commercial real estate loans is an immaterial amount of consumer loans that are not broken out by class.