Loans (Recorded Investment By Loan Grade) (Details) - USD ($)		Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment		$ 7,226,312,000	$ 6,520,625,000
Recorded Investment		7,204,445,000	6,501,404,000
Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment		246,131,000	234,463,000
Recorded Investment		245,339,000	233,637,000
Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment		500,008,000	480,420,000
Recorded Investment		498,697,000	479,081,000
Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment	[1]	1,639,455,000	1,614,984,000
Recorded Investment	[1]	1,632,625,000	1,609,413,000
Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment		28,845,000	30,101,000
Recorded Investment		28,832,000	30,081,000
5 Rated [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		75,429,000	27,473,000
5 Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment			4,857,000
5 Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		542,000	3,839,000
5 Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		11,216,000	11,981,000
5 Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		63,235,000	6,796,000
5 Rated [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		436,000	0
6 Rated [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		138,000	979,000
6 Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment			1,000
6 Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		25,000	30,000
6 Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment			3,000
6 Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		113,000	945,000
6 Rated [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		0	0
Impaired [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		91,794,000	77,528,000
Impaired [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		631,000	453,000
Impaired [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		5,257,000	2,025,000
Impaired [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		30,194,000	33,125,000
Impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		54,071,000	41,791,000
Impaired [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		1,641,000	134,000
Purchased credit impaired [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		11,718,000	13,469,000
Purchased credit impaired [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		1,022,000	1,044,000
Purchased credit impaired [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		1,556,000	1,754,000
Purchased credit impaired [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		140,000	523,000
Purchased credit impaired [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		453,000	966,000
Purchased credit impaired [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		8,547,000	9,182,000
Pass Rated [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		3,977,369,000	3,430,022,000
Pass Rated [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		244,478,000	228,108,000
Pass Rated [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		492,628,000	472,772,000
Pass Rated [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		1,700,146,000	1,143,428,000
Pass Rated [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		1,513,489,000	1,556,270,000
Pass Rated [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total ending loan balance, recorded investment		26,628,000	29,444,000
Recorded Investment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		4,156,448,000	3,549,471,000
Recorded Investment [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		246,131,000	234,463,000
Recorded Investment [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		500,008,000	480,420,000
Recorded Investment [Member] | Commercial, Financial, and Agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		1,742,009,000	1,189,503,000
Recorded Investment [Member] | Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		1,639,455,000	1,614,984,000
Recorded Investment [Member] | Finance Leases Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Recorded Investment		$ 28,845,000	30,101,000
Financial Asset Acquired with Credit Deterioration [Member] | Nonperforming Financial Instruments [Member] | Purchased credit impaired [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Recorded Investment			6,000
Total ending loan balance, recorded investment			$ 5,000

[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.