Loans and Leases Held for Investment and Credit Quality - Impaired Loans and Leases With Associated Reserves and No Associated Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	$ 147,799	$ 100,321
Recorded Investment, With No Recorded Allowance	3,848	2,093
Recorded Investment, Total	151,647	102,414
Loans, Unpaid Principal Balance	155,580	106,658
Loans, Related Allowance Recorded	16,937	9,091
Loans, Average Balance	138,781	102,624	$ 40,338
Loans, Interest Income Recognized	3,217	1,573	894
Commercial & Industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	33,970	27,639
Recorded Investment, With No Recorded Allowance	464	1,020
Recorded Investment, Total	34,434	28,659
Loans, Unpaid Principal Balance	37,239	31,537
Loans, Related Allowance Recorded	7,676	2,598
Loans, Average Balance	35,108	27,992	15,409
Loans, Interest Income Recognized	390	290	248
Commercial & Industrial | Agriculture
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	449
Recorded Investment, With No Recorded Allowance	6	7
Recorded Investment, Total	455	7
Loans, Unpaid Principal Balance	465	6
Loans, Related Allowance Recorded	99
Loans, Average Balance	405	6
Loans, Interest Income Recognized	2
Commercial & Industrial | Healthcare
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	8,023	9,604
Recorded Investment, With No Recorded Allowance		64
Recorded Investment, Total	8,023	9,668
Loans, Unpaid Principal Balance	8,729	10,432
Loans, Related Allowance Recorded	1,422	827
Loans, Average Balance	8,446	9,825	6,101
Loans, Interest Income Recognized	113	95	53
Commercial & Industrial | Independent Pharmacies
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	6,047	9,032
Recorded Investment, With No Recorded Allowance	101	324
Recorded Investment, Total	6,148	9,356
Loans, Unpaid Principal Balance	7,195	10,564
Loans, Related Allowance Recorded	327	478
Loans, Average Balance	6,452	8,510	6,018
Loans, Interest Income Recognized	19	40	100
Commercial & Industrial | Registered Investment Advisors
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	1,506	3,347
Recorded Investment, Total	1,506	3,347
Loans, Unpaid Principal Balance	1,512	3,839
Loans, Related Allowance Recorded	381	811
Loans, Average Balance	1,733	3,197	759
Loans, Interest Income Recognized	18	38	50
Commercial & Industrial | Veterinary Industry
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	2,486	2,160
Recorded Investment, With No Recorded Allowance	159	166
Recorded Investment, Total	2,645	2,326
Loans, Unpaid Principal Balance	2,935	2,593
Loans, Related Allowance Recorded	140	65
Loans, Average Balance	2,682	2,451	2,523
Loans, Interest Income Recognized	49	69	45
Commercial & Industrial | Other Industries
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	15,459	3,496
Recorded Investment, With No Recorded Allowance	198	453
Recorded Investment, Total	15,657	3,949
Loans, Unpaid Principal Balance	16,403	4,097
Loans, Related Allowance Recorded	5,307	417
Loans, Average Balance	15,390	3,997
Loans, Interest Income Recognized	189	48
Commercial & Industrial | Funeral Home & Cemetery
Financing Receivable, Impaired [Line Items]
Recorded Investment, With No Recorded Allowance		6
Recorded Investment, Total		6
Loans, Unpaid Principal Balance		6
Loans, Average Balance		6	8
Construction & Development
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	719	5,027
Recorded Investment, Total	719	5,027
Loans, Unpaid Principal Balance	706	4,939
Loans, Related Allowance Recorded	17	118
Loans, Average Balance	722	4,951	1,240
Loans, Interest Income Recognized	22	20	11
Construction & Development | Agriculture
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance		5,027
Recorded Investment, Total		5,027
Loans, Unpaid Principal Balance		4,939
Loans, Related Allowance Recorded		118
Loans, Average Balance		4,951
Loans, Interest Income Recognized		20
Construction & Development | Healthcare
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	719
Recorded Investment, Total	719
Loans, Unpaid Principal Balance	706
Loans, Related Allowance Recorded	17
Loans, Average Balance	722		1,240
Loans, Interest Income Recognized	22		11
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	67,489	45,658
Recorded Investment, With No Recorded Allowance	3,384	1,073
Recorded Investment, Total	70,873	46,731
Loans, Unpaid Principal Balance	71,939	48,035
Loans, Related Allowance Recorded	4,818	2,424
Loans, Average Balance	65,734	47,543	23,576
Loans, Interest Income Recognized	1,851	1,075	635
Commercial Real Estate | Agriculture
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	2,085	1,798
Recorded Investment, Total	2,085	1,798
Loans, Unpaid Principal Balance	2,085	1,732
Loans, Related Allowance Recorded	45	93
Loans, Average Balance	1,773	1,738
Loans, Interest Income Recognized		10
Commercial Real Estate | Healthcare
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	27,834	20,211
Recorded Investment, With No Recorded Allowance	1,842	231
Recorded Investment, Total	29,676	20,442
Loans, Unpaid Principal Balance	29,581	20,461
Loans, Related Allowance Recorded	2,765	1,145
Loans, Average Balance	27,980	19,845	4,381
Loans, Interest Income Recognized	955	515	49
Commercial Real Estate | Independent Pharmacies
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	7,964	5,184
Recorded Investment, With No Recorded Allowance		449
Recorded Investment, Total	7,964	5,633
Loans, Unpaid Principal Balance	8,248	5,884
Loans, Related Allowance Recorded	352	220
Loans, Average Balance	7,276	6,021	1,708
Loans, Interest Income Recognized	111	22
Commercial Real Estate | Veterinary Industry
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	11,952	15,606
Recorded Investment, With No Recorded Allowance	696	109
Recorded Investment, Total	12,648	15,715
Loans, Unpaid Principal Balance	13,816	16,677
Loans, Related Allowance Recorded	1,207	936
Loans, Average Balance	13,126
Loans, Interest Income Recognized	406
Commercial Real Estate | Other Industries
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	16,001
Recorded Investment, With No Recorded Allowance	719
Recorded Investment, Total	16,720
Loans, Unpaid Principal Balance	16,358
Loans, Related Allowance Recorded	256
Loans, Average Balance	13,681	16,735	14,605
Loans, Interest Income Recognized	377	437	536
Commercial Real Estate | Funeral Home & Cemetery
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	1,653	2,859
Recorded Investment, With No Recorded Allowance	127	284
Recorded Investment, Total	1,780	3,143
Loans, Unpaid Principal Balance	1,851	3,281
Loans, Related Allowance Recorded	193	30
Loans, Average Balance	1,898	3,204	2,882
Loans, Interest Income Recognized	2	91	50
Commercial Land
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	45,621	21,997
Recorded Investment, Total	45,621	21,997
Loans, Unpaid Principal Balance	45,696	22,147
Loans, Related Allowance Recorded	4,426	3,951
Loans, Average Balance	37,217	22,138	113
Loans, Interest Income Recognized	954	188
Commercial Land | Agriculture
Financing Receivable, Impaired [Line Items]
Recorded Investment, With a Recorded Allowance	45,621	21,997
Recorded Investment, Total	45,621	21,997
Loans, Unpaid Principal Balance	45,696	22,147
Loans, Related Allowance Recorded	4,426	3,951
Loans, Average Balance	37,217	22,138	$ 113
Loans, Interest Income Recognized	$ 954	$ 188