Loans - Risk Categories of Loans by Class of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 1,132,273
2019	971,727
2018	853,987
2017	661,944
2016	635,981
Prior	997,119
Revolving	604,998
Total	5,858,029	$ 5,198,404
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	1,131,047
2019	961,149
2018	805,200
2017	629,293
2016	600,175
Prior	954,165
Revolving	593,089
Total	5,674,118	5,091,691
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	594
2019	2,506
2018	30,619
2017	20,799
2016	18,883
Prior	7,272
Revolving	2,551
Total	83,224	51,560
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	153
2019	145
2018	13,204
2017	4,967
2016	10,718
Prior	14,643
Revolving	5,393
Total	49,223	53,958
Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	479
2019	7,927
2018	4,964
2017	6,885
2016	5,884
Prior	21,012
Revolving	3,965
Total	51,116
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	321
Prior	27
Revolving	0
Total	348	1,195
Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
2020	48,418
2019	79,240
2018	61,130
2017	30,141
2016	10,160
Prior	19,888
Revolving	31,633
Total	280,610	325,113
Construction and land development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	48,020
2019	78,737
2018	59,752
2017	17,830
2016	9,586
Prior	18,206
Revolving	31,633
Total	263,764	317,765
Construction and land development | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	398
2019	503
2018	1,378
2017	12,311
2016	0
Prior	1,478
Revolving	0
Total	16,068	2,235
Construction and land development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	55
Revolving	0
Total	55	5,113
Construction and land development | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	574
Prior	149
Revolving	0
Total	723
Construction and land development | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	0	0
Commercial real estate - owner-occupied
Financing Receivable, Credit Quality Indicator [Line Items]
2020	93,603
2019	204,112
2018	166,093
2017	158,701
2016	163,195
Prior	324,964
Revolving	14,792
Total	1,125,460	1,000,000
Commercial real estate - owner-occupied | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	93,407
2019	202,179
2018	164,622
2017	151,893
2016	156,433
Prior	313,205
Revolving	14,792
Total	1,096,531
Commercial real estate - owner-occupied | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	196
2019	1,596
2018	389
2017	1,010
2016	4,471
Prior	3,338
Revolving	0
Total	11,000
Commercial real estate - owner-occupied | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	204
2017	4,742
2016	1,970
Prior	5,531
Revolving	0
Total	12,447
Commercial real estate - owner-occupied | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	337
2018	878
2017	1,056
2016	0
Prior	2,890
Revolving	0
Total	5,161
Commercial real estate - owner-occupied | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	321
Prior	0
Revolving	0
Total	321
Commercial real estate - non owner-occupied
Financing Receivable, Credit Quality Indicator [Line Items]
2020	98,658
2019	324,569
2018	239,217
2017	133,264
2016	208,774
Prior	383,315
Revolving	6,667
Total	1,394,464
Commercial real estate - non owner-occupied | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	98,658
2019	322,048
2018	200,813
2017	131,590
2016	186,063
Prior	372,215
Revolving	5,317
Total	1,316,704
Commercial real estate - non owner-occupied | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	103
2018	28,710
2017	1,674
2016	14,266
Prior	114
Revolving	0
Total	44,867
Commercial real estate - non owner-occupied | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	9,694
2017	0
2016	8,319
Prior	5,072
Revolving	1,350
Total	24,435
Commercial real estate - non owner-occupied | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	2,418
2018	0
2017	0
2016	126
Prior	5,914
Revolving	0
Total	8,458
Commercial real estate - non owner-occupied | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	0
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,378,971
Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total		2,331,725
Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total		26,827
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total		20,098
Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total		321
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2020	53,283
2019	151,788
2018	235,092
2017	239,281
2016	181,516
Prior	193,212
Revolving	339,224
Total	1,393,396	1,507,863
Residential real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	53,171
2019	151,107
2018	233,660
2017	235,119
2016	178,988
Prior	180,156
Revolving	334,622
Total	1,366,823	1,482,278
Residential real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	98
2017	0
2016	0
Prior	562
Revolving	391
Total	1,051	7,364
Residential real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	1,677
Revolving	1,443
Total	3,120	18,221
Residential real estate | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	112
2019	681
2018	1,334
2017	4,162
2016	2,528
Prior	10,790
Revolving	2,768
Total	22,375
Residential real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	27
Revolving	0
Total	27	0
Commercial and financial
Financing Receivable, Credit Quality Indicator [Line Items]
2020	163,168
2019	163,287
2018	117,874
2017	78,465
2016	47,674
Prior	64,509
Revolving	198,106
Total	833,083	778,252
Commercial and financial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	162,696
2019	158,468
2018	111,812
2017	70,868
2016	44,846
Prior	59,387
Revolving	194,344
Total	802,421	755,957
Commercial and financial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	234
2018	14
2017	5,732
2016	81
Prior	1,773
Revolving	304
Total	8,138	11,925
Commercial and financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	153
2019	145
2018	3,306
2017	198
2016	407
Prior	2,270
Revolving	2,261
Total	8,740	9,496
Commercial and financial | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	319
2019	4,440
2018	2,742
2017	1,667
2016	2,340
Prior	1,079
Revolving	1,197
Total	13,784
Commercial and financial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	0	874
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2020	36,343
2019	48,731
2018	34,581
2017	22,092
2016	24,662
Prior	11,231
Revolving	14,576
Total	192,216	208,205
Consumer | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	36,295
2019	48,610
2018	34,541
2017	21,993
2016	24,259
Prior	10,996
Revolving	12,381
Total	189,075	203,966
Consumer | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	70
2018	30
2017	72
2016	65
Prior	7
Revolving	1,856
Total	2,100	3,209
Consumer | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	27
2016	22
Prior	38
Revolving	339
Total	426	1,030
Consumer | Substandard Impaired
Financing Receivable, Credit Quality Indicator [Line Items]
2020	48
2019	51
2018	10
2017	0
2016	316
Prior	190
Revolving	0
Total	615
Consumer | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2020	0
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	0	$ 0
Paycheck Protection Program
Financing Receivable, Credit Quality Indicator [Line Items]
2020	638,800
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	638,800
Paycheck Protection Program | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2020	638,800
2019	0
2018	0
2017	0
2016	0
Prior	0
Revolving	0
Total	$ 638,800