Loans - Risk Category, Class of Loans by Class of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	$ 5,198,404	$ 4,825,214
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	5,091,691	4,694,297
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	51,560	67,296
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	53,958	63,596
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	1,195	25
Real Estate | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	325,113	443,568
Real Estate | Construction and land development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	317,765	428,044
Real Estate | Construction and land development | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	2,235	10,429
Real Estate | Construction and land development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	5,113	5,095
Real Estate | Construction and land development | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	0	0
Real Estate | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	2,378,971	2,132,066
Real Estate | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	2,331,725	2,063,589
Real Estate | Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	26,827	41,429
Real Estate | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	20,098	27,048
Real Estate | Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	321	0
Real Estate | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	1,507,863	1,324,377
Real Estate | Residential real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	1,482,278	1,296,634
Real Estate | Residential real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	7,364	3,654
Real Estate | Residential real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	18,221	24,089
Real Estate | Residential real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	0	0
Commercial and financial | Commercial and financial
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	778,252	722,322
Commercial and financial | Commercial and financial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	755,957	707,663
Commercial and financial | Commercial and financial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	11,925	8,387
Commercial and financial | Commercial and financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	9,496	6,247
Commercial and financial | Commercial and financial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	874	25
Consumer | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	208,205	202,881
Consumer | Consumer | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	203,966	198,367
Consumer | Consumer | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	3,209	3,397
Consumer | Consumer | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	1,030	1,117
Consumer | Consumer | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Net Loans	$ 0	$ 0