Loans and Leases (Purchases Loans and Leases) (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Contractually required payments	$ 1,078,854
Loans acquired	850,352
Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Contractually required payments	175,465
Loans acquired	162,845
PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Contractually required payments	19,720
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contractual Cash Flows Expected To Be Collected	16,815
Loans acquired	13,032
PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Contractually required payments	23,389
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contractual Cash Flows Expected To Be Collected	21,392
Loans acquired	16,398
Commercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	345,494
Commercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	131,093
Commercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	9,249
Commercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	11,790
Noncommercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	504,858
Noncommercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	31,752
Noncommercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	3,783
Noncommercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	4,608
Construction and land development | Commercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	15,647
Construction and land development | Commercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	8,663
Construction and land development | Commercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	0
Construction and land development | Commercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	1,233
Construction and land development | Noncommercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	31,668
Construction and land development | Noncommercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	3,552
Construction and land development | Noncommercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	0
Construction and land development | Noncommercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	17
Mortgage | Commercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	203,605
Mortgage | Commercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	74,713
Mortgage | Commercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	7,589
Mortgage | Commercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	9,355
Mortgage | Noncommercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	405,419
Mortgage | Noncommercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	24,641
Mortgage | Noncommercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	3,783
Mortgage | Noncommercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	4,591
Other commercial real estate | Commercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	98,107
Other commercial real estate | Commercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	7,509
Commercial and industrial | Commercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	28,135
Commercial and industrial | Commercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	40,208
Commercial and industrial | Commercial | PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	1,660
Commercial and industrial | Commercial | PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	1,202
Revolving mortgage | Noncommercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	54,081
Revolving mortgage | Noncommercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	2,162
Consumer | Noncommercial | Non-PCI Loans | Biscayne Bancshares
Business Acquisition [Line Items]
Loans acquired	13,690
Consumer | Noncommercial | Non-PCI Loans | First South Bancorp
Business Acquisition [Line Items]
Loans acquired	$ 1,397