Annual report pursuant to Section 13 and 15(d)

Allowance for Loan and Lease Losses - Additional Information (Details)

v3.20.4
Allowance for Loan and Lease Losses - Additional Information (Details)
3 Months Ended 12 Months Ended
Feb. 28, 2020
USD ($)
Nov. 15, 2019
USD ($)
Apr. 02, 2019
USD ($)
Dec. 31, 2020
USD ($)
Loan
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Loan
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Sep. 30, 2018
USD ($)
Dec. 31, 2020
USD ($)
Loan
Dec. 31, 2019
USD ($)
Loan
Dec. 31, 2018
USD ($)
Loan
Financing Receivable Recorded Investment Past Due [Line Items]                            
Provision for loan losses       $ 4,417,000 $ 2,831,000 $ 2,838,000 $ 1,171,000 $ 775,000 $ 332,000 $ 849,000 $ 900,000 $ 11,257,000 $ 2,856,000 $ 2,160,000
Recorded investment, 90 days past due and still accruing               2,000         2,000  
Non-accrual loans, Past due       8,597,000       $ 6,459,000       $ 8,597,000 $ 6,459,000  
Number of restructured loans, defaulted | Loan                       1 3 0
Charge-offs due to restructure                       $ 85,000 $ 181,000  
Covid-19                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Description of Loan modifications                       Loan modifications made between March 1, 2020 and the earlier of i) 60 days after the end of the national emergency proclamation or ii) December 31, 2020. Section 541 of the Consolidated Appropriations Act of 2021, amended Section 4013 of the CARES Act to extend this relief to the earlier of i) 60 days after the end of the national emergency proclamation or ii) January 1, 2022.    
Loans, payment deferrals days                       90 days    
Loans, interest only payment period                       90 days    
Payments remaining in deferral       $ 86,900,000               $ 86,900,000    
Financing Receivables, Past Due Greater Than 90 Days or More and Still Accruing                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Recorded investment, 90 days past due and still accruing number of loans | Loan       0       1       0 1  
Non-accrual loans, Past due       $ 2,200,000       $ 2,600,000       $ 2,200,000 $ 2,600,000  
Financing Receivables, 30 to 59 Days Past Due                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Non-accrual loans, Past due       930,000       308,000       930,000 308,000  
Financing Receivables, 60 to 89 Days Past Due                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Non-accrual loans, Past due       545,000       $ 1,200,000       545,000 $ 1,200,000  
Second 90 Day Deferral Period | Covid-19                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Payments requested for deferral periods       52,700,000               52,700,000    
Third 90 Day Deferral Period | Covid-19                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Payments requested for deferral periods       12,800,000               12,800,000    
Paycheck Protection Loans                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Provision for loan losses                       $ 0    
Percentage Reserve                       0.00%    
Purchased Credit Impaired Loans                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Impaired loans       610,000               $ 610,000    
Beeville                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Business combination loan in acquiree, amount     $ 298,900,000                      
Business combination loan In acquiree, fair value     296,400,000                      
Business combination loan in acquiree, discount     $ 2,500,000                      
Citizens                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Business combination loan in acquiree, amount   $ 253,100,000                        
Business combination loan In acquiree, fair value   250,300,000                        
Business combination loan in acquiree, discount   $ 2,800,000                        
Citizens | Purchased Credit Impaired Loans                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Impaired loans       3,200,000               3,200,000    
Simmons Bank                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Business combination loan in acquiree, amount $ 260,300,000                          
Business combination loan In acquiree, fair value 255,500,000                          
Business combination loan in acquiree, discount $ 4,800,000                          
Beeville or Simmons | Purchased Credit Impaired Loans                            
Financing Receivable Recorded Investment Past Due [Line Items]                            
Impaired loans       $ 0               $ 0