Adoption of New Accounting Pronouncements and Issued Not Yet Effective Accounting Standards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	$ 52
Financing Receivable, before Allowance for Credit Loss	6,871,122	$ 7,177,785
Financing Receivable, Allowance for Credit Loss	83,197	85,675	$ 56,679	$ 51,512
Off-Balance Sheet, Credit Loss, Liability	4,282	116
Net deferred tax liability	450	2,892
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,110,759	1,040,256
Commercial Financial Agricultural [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		25,608
Commercial Real Estate Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		23,480
Construction Real Estate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		7,288
Residential real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		11,363
Consumer Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		17,418
Finance Leases Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		518
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	52
Financing Receivable, before Allowance for Credit Loss		(119)
Financing Receivable, Allowance for Credit Loss		6,090
Off-Balance Sheet, Credit Loss, Liability		3,866
Net deferred tax liability		(2,115)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		(7,956)
Cumulative Effect, Period of Adoption, Adjustment | Commercial Financial Agricultural [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		(8,257)
Cumulative Effect, Period of Adoption, Adjustment | Commercial Real Estate Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		2,119
Cumulative Effect, Period of Adoption, Adjustment | Construction Real Estate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		(1,898)
Cumulative Effect, Period of Adoption, Adjustment | Residential real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		3,121
Cumulative Effect, Period of Adoption, Adjustment | Consumer Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		10,925
Cumulative Effect, Period of Adoption, Adjustment | Finance Leases Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		80
Cumulative Effect, Period of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, before Allowance for Credit Loss		7,177,666
Financing Receivable, Allowance for Credit Loss		91,765
Off-Balance Sheet, Credit Loss, Liability		3,982
Net deferred tax liability		777
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		1,032,300
Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial Financial Agricultural [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		17,351
Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial Real Estate Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		25,599
Cumulative Effect, Period of Adoption, Adjusted Balance | Construction Real Estate [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		5,390
Cumulative Effect, Period of Adoption, Adjusted Balance | Residential real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		14,484
Cumulative Effect, Period of Adoption, Adjusted Balance | Consumer Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		28,343
Cumulative Effect, Period of Adoption, Adjusted Balance | Finance Leases Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable, Allowance for Credit Loss		598
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 776,294	704,764	$ 646,847	614,069
Accounting Standards Update 2016-13 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest				$ 613,926
Accounting Standards Update 2016-13 | Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest		8,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		(7,956)
Accounting Standards Update 2016-13 | Retained Earnings | Cumulative Effect, Period of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest		$ 696,808