Non-performing Loans and Impaired Loans - Payment Status by Class of Loan (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Current	$ 3,948,336	$ 3,609,036
Total Past Due	3,976	7,875
Total	$ 3,952,312	$ 3,616,911
Current,Percentage of total loans	99.90%	99.78%
Total Past Due, Percentage of Total Loans	0.10%	0.22%
Percentage of total loans	100.00%	100.00%
Carrying Amount	$ 3,923,292
Commercial
Financing Receivable, Past Due [Line Items]
Current	2,298,252	$ 2,039,953
Total Past Due	216	1,830
Total	2,298,468	2,041,783
Commercial | Owner occupied real estate
Financing Receivable, Past Due [Line Items]
Current	491,811	515,604
Total Past Due	116	920
Total	491,927	516,524
Commercial | Non-owner occupied real estate
Financing Receivable, Past Due [Line Items]
Current	1,007,524	972,195
Total Past Due	0	80
Total	1,007,524	972,275
Commercial | Residential spec homes
Financing Receivable, Past Due [Line Items]
Current	12,036	12,925
Total Past Due	0	0
Total	12,036	12,925
Commercial | Development & spec land
Financing Receivable, Past Due [Line Items]
Current	28,917	35,881
Total Past Due	0	0
Total	28,917	35,881
Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Current	757,964	503,348
Total Past Due	100	830
Total	758,064	504,178
Real estate
Financing Receivable, Past Due [Line Items]
Current	994,830	910,691
Total Past Due	1,558	1,985
Total	996,388	912,676
Real estate | Residential mortgage
Financing Receivable, Past Due [Line Items]
Current	672,729	740,712
Total Past Due	1,558	1,985
Total	674,287	742,697
Real estate | Residential construction
Financing Receivable, Past Due [Line Items]
Current	21,715	19,686
Total Past Due	0	0
Total	21,715	19,686
Real estate | Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Current	300,386	150,293
Total Past Due	0	0
Total	300,386	150,293
Consumer
Financing Receivable, Past Due [Line Items]
Current	655,254	658,392
Total Past Due	2,202	4,060
Total	657,456	662,452
Consumer | Direct installment
Financing Receivable, Past Due [Line Items]
Current	39,413	40,864
Total Past Due	75	185
Total	39,488	41,049
Consumer | Indirect installment
Financing Receivable, Past Due [Line Items]
Current	355,305	344,478
Total Past Due	1,439	2,946
Total	356,744	347,424
Consumer | Home equity
Financing Receivable, Past Due [Line Items]
Current	260,536	273,050
Total Past Due	688	929
Total	261,224	273,979
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 3,072	$ 7,289
Total Past Due, Percentage of Total Loans	0.08%	0.20%
30-59 Days Past Due | Commercial
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 216	$ 1,819
30-59 Days Past Due | Commercial | Owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	116	920
30-59 Days Past Due | Commercial | Non-owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	80
30-59 Days Past Due | Commercial | Residential spec homes
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
30-59 Days Past Due | Commercial | Development & spec land
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
30-59 Days Past Due | Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	100	819
30-59 Days Past Due | Real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	1,295	1,984
30-59 Days Past Due | Real estate | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	1,295	1,984
30-59 Days Past Due | Real estate | Residential construction
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
30-59 Days Past Due | Real estate | Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
30-59 Days Past Due | Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	1,561	3,486
30-59 Days Past Due | Consumer | Direct installment
Financing Receivable, Past Due [Line Items]
Total Past Due	30	175
30-59 Days Past Due | Consumer | Indirect installment
Financing Receivable, Past Due [Line Items]
Total Past Due	1,097	2,407
30-59 Days Past Due | Consumer | Home equity
Financing Receivable, Past Due [Line Items]
Total Past Due	434	904
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 781	$ 440
Total Past Due, Percentage of Total Loans	0.02%	0.01%
60-89 Days Past Due | Commercial
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 11
60-89 Days Past Due | Commercial | Owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Commercial | Non-owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Commercial | Residential spec homes
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Commercial | Development & spec land
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	0	11
60-89 Days Past Due | Real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	263	0
60-89 Days Past Due | Real estate | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	263	0
60-89 Days Past Due | Real estate | Residential construction
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Real estate | Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
60-89 Days Past Due | Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	518	429
60-89 Days Past Due | Consumer | Direct installment
Financing Receivable, Past Due [Line Items]
Total Past Due	5	5
60-89 Days Past Due | Consumer | Indirect installment
Financing Receivable, Past Due [Line Items]
Total Past Due	259	404
60-89 Days Past Due | Consumer | Home equity
Financing Receivable, Past Due [Line Items]
Total Past Due	254	20
90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 123	$ 146
Total Past Due, Percentage of Total Loans	0.00%	0.01%
90 Days or Greater Past Due | Commercial
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 0
90 Days or Greater Past Due | Commercial | Owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Commercial | Non-owner occupied real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Commercial | Residential spec homes
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Commercial | Development & spec land
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	0	1
90 Days or Greater Past Due | Real estate | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total Past Due	0	1
90 Days or Greater Past Due | Real estate | Residential construction
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Real estate | Mortgage warehouse
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
90 Days or Greater Past Due | Consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	123	145
90 Days or Greater Past Due | Consumer | Direct installment
Financing Receivable, Past Due [Line Items]
Total Past Due	40	5
90 Days or Greater Past Due | Consumer | Indirect installment
Financing Receivable, Past Due [Line Items]
Total Past Due	83	135
90 Days or Greater Past Due | Consumer | Home equity
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 5