Loans and Leases Held for Investment and Credit Quality - Age Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	$ 101,080	$ 78,712
Current	2,538,760	1,771,768
Total loans and leases receivable	2,639,840	1,850,480
Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	30,669	12,320
30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	24,773	21,022
30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,563	4,484
Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	39,075	40,886
Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	31,564	25,690
Current	863,433	593,058
Total loans and leases receivable	894,997	618,748
Commercial & Industrial | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	3,022	4,109
Commercial & Industrial | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	8,677	1,454
Commercial & Industrial | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	3,878	1,585
Commercial & Industrial | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	15,987	18,542
Commercial & Industrial | Agriculture
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	269
Current	9,075	6,400
Total loans and leases receivable	9,344	6,400
Commercial & Industrial | Agriculture | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	269
Commercial & Industrial | Funeral Home & Cemetery
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	26,388	17,378
Total loans and leases receivable	26,388	17,378
Commercial & Industrial | Healthcare
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,484	8,554
Current	39,097	42,528
Total loans and leases receivable	45,581	51,082
Commercial & Industrial | Healthcare | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	28	41
Commercial & Industrial | Healthcare | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		1,027
Commercial & Industrial | Healthcare | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,725	665
Commercial & Industrial | Healthcare | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	4,731	6,821
Commercial & Industrial | Independent Pharmacies
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,045	8,998
Current	100,051	99,785
Total loans and leases receivable	106,096	108,783
Commercial & Industrial | Independent Pharmacies | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,725	1,399
Commercial & Industrial | Independent Pharmacies | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	59	29
Commercial & Industrial | Independent Pharmacies | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	3,261	7,570
Commercial & Industrial | Registered Investment Advisors
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,527	3,293
Current	97,664	91,045
Total loans and leases receivable	99,191	94,338
Commercial & Industrial | Registered Investment Advisors | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	252	232
Commercial & Industrial | Registered Investment Advisors | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,132	320
Commercial & Industrial | Registered Investment Advisors | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	143	2,741
Commercial & Industrial | Veterinary Industry
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,961	1,506
Current	49,290	44,098
Total loans and leases receivable	51,251	45,604
Commercial & Industrial | Veterinary Industry | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	504	600
Commercial & Industrial | Veterinary Industry | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,457	906
Commercial & Industrial | Other Industries
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	15,278	3,339
Current	541,868	291,824
Total loans and leases receivable	557,146	295,163
Commercial & Industrial | Other Industries | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		2,669
Commercial & Industrial | Other Industries | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	8,366	166
Commercial & Industrial | Other Industries | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	517
Commercial & Industrial | Other Industries | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,395	504
Construction & Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	347,318	248,904
Total loans and leases receivable	347,318	248,904
Construction & Development | Agriculture
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	44,571	43,454
Total loans and leases receivable	44,571	43,454
Construction & Development | Funeral Home & Cemetery
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	9,033	9,874
Total loans and leases receivable	9,033	9,874
Construction & Development | Healthcare
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	94,742	81,619
Total loans and leases receivable	94,742	81,619
Construction & Development | Independent Pharmacies
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	443	2,149
Total loans and leases receivable	443	2,149
Construction & Development | Registered Investment Advisors
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,404	1,232
Total loans and leases receivable	2,404	1,232
Construction & Development | Veterinary Industry
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	22,132	14,094
Total loans and leases receivable	22,132	14,094
Construction & Development | Other Industries
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	173,993	96,482
Total loans and leases receivable	173,993	96,482
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	43,981	41,964
Current	1,008,812	697,066
Total loans and leases receivable	1,052,793	739,030
Commercial Real Estate | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	3,077	1,934
Commercial Real Estate | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	15,131	19,568
Commercial Real Estate | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,685	2,899
Commercial Real Estate | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	23,088	17,563
Commercial Real Estate | Agriculture
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,085
Current	48,280	53,085
Total loans and leases receivable	50,365	53,085
Commercial Real Estate | Agriculture | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,085
Commercial Real Estate | Funeral Home & Cemetery
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	4,319	3,010
Current	109,198	68,334
Total loans and leases receivable	113,517	71,344
Commercial Real Estate | Funeral Home & Cemetery | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	127	248
Commercial Real Estate | Funeral Home & Cemetery | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,542
Commercial Real Estate | Funeral Home & Cemetery | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,650	2,762
Commercial Real Estate | Healthcare
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	17,770	9,127
Current	229,855	179,404
Total loans and leases receivable	247,625	188,531
Commercial Real Estate | Healthcare | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		42
Commercial Real Estate | Healthcare | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	4,976	1,668
Commercial Real Estate | Healthcare | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	28
Commercial Real Estate | Healthcare | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	12,766	7,417
Commercial Real Estate | Independent Pharmacies
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,638	5,593
Current	19,741	15,004
Total loans and leases receivable	26,379	20,597
Commercial Real Estate | Independent Pharmacies | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		3,400
Commercial Real Estate | Independent Pharmacies | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	930
Commercial Real Estate | Independent Pharmacies | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	5,708	2,193
Commercial Real Estate | Registered Investment Advisors
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	7,431	7,905
Total loans and leases receivable	7,431	7,905
Commercial Real Estate | Veterinary Industry
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	6,142	13,491
Current	140,177	123,230
Total loans and leases receivable	146,319	136,721
Commercial Real Estate | Veterinary Industry | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	865	1,644
Commercial Real Estate | Veterinary Industry | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	586	3,757
Commercial Real Estate | Veterinary Industry | 30-89 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	1,727	2,899
Commercial Real Estate | Veterinary Industry | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	2,964	5,191
Commercial Real Estate | Other Industries
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	7,027	10,743
Current	454,130	250,104
Total loans and leases receivable	461,157	260,847
Commercial Real Estate | Other Industries | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	7,027	10,743
Commercial Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	25,535	11,058
Current	319,197	232,740
Total loans and leases receivable	344,732	243,798
Commercial Land | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	24,570	6,277
Commercial Land | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	965
Commercial Land | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		4,781
Commercial Land | Agriculture
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	25,535	11,058
Current	319,197	232,740
Total loans and leases receivable	344,732	243,798
Commercial Land | Agriculture | Less Than 30 Days Past Due & Not Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	24,570	6,277
Commercial Land | Agriculture | 30-89 Days Past Due & Accruing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due	$ 965
Commercial Land | Agriculture | Greater Than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Not Accruing & Past Due		$ 4,781