Loans and Allowance for Credit Losses - Class of loan, an aging analysis and the recorded investments in loans past due (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	$ 7,206,141	$ 7,595,544
Loans Past Due	3,938	103,725
Non-Accrual	49,479	60,943
Loans	7,259,558	7,760,212
Construction - C&I (owner occupied)
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	160,335
Loans	161,187
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	1,341,971	1,394,244
Loans Past Due	2,312	27,837
Non-Accrual	14,874	15,352
Loans	1,359,157	1,437,433
PPP loans
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	238,041	454,771
Loans	238,041	454,771
Income producing - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	3,512,671	3,616,207
Loans Past Due		51,913
Non-Accrual	21,386	18,880
Loans	3,534,057	3,687,000
Owner occupied - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	984,448	960,364
Loans Past Due	430	14,172
Non-Accrual	7,058	23,158
Loans	991,936	997,694
Real estate mortgage - residential
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	75,193	72,231
Loans Past Due		1,430
Non-Accrual	1,938	2,931
Loans	77,131	76,592
Construction - commercial and residential
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	832,074	869,723
Loans Past Due		3,332
Non-Accrual	3,659	206
Loans	835,733	873,261
Construction - commercial and residential | Construction - C&I (owner occupied)
Loans and Leases Receivable Disclosure [Line Items]
Loans	161,187	158,905
Construction and Industrial, Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	852
Construction and Industrial, Owner Occupied | Construction - C&I (owner occupied)
Loans and Leases Receivable Disclosure [Line Items]
Current Loans		158,905
Loans		158,905
Home equity
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	59,715	67,732
Loans Past Due	280	5,019
Non-Accrual	564	416
Loans	60,559	73,167
Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Current Loans	1,693	1,367
Loans Past Due	64	22
Loans	1,757	1,389
30 to 59 days past due
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	2,607	21,951
30 to 59 days past due | Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	1,477	6,411
30 to 59 days past due | Owner occupied - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		10,630
30 to 59 days past due | Real estate mortgage - residential
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		1,430
30 to 59 days past due | Construction - commercial and residential
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		2,992
30 to 59 days past due | Construction and Industrial, Owner Occupied
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	852
30 to 59 days past due | Home equity
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	214	467
30 to 59 days past due | Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	64	21
60-89 days past due
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	1,331	81,774
60-89 days past due | Commercial
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	835	21,426
60-89 days past due | Income producing - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		51,913
60-89 days past due | Owner occupied - commercial real estate
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	430	3,542
60-89 days past due | Construction - commercial and residential
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		340
60-89 days past due | Home equity
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	66	4,552
60-89 days past due | Other consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due		1
90 Days or More Past Due
Loans and Leases Receivable Disclosure [Line Items]
Loans Past Due	$ 0	$ 0