v3.21.1
Loans Receivable and the Allowance for Credit Losses - Activity in Allowance for Credit Losses (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance $ 55,500 $ 29,079    
Charge-offs (1,003) (1,497)    
Recoveries 687 299    
Credit loss expense (4,534) 19,322    
Ending balance 50,650 $ 51,187 $ 29,079  
Accounting standards update   us-gaap:AccountingStandardsUpdate201613Member us-gaap:AccountingStandardsUpdate201613Member  
Credit loss expense, off balance sheet credit exposure (200) $ 2,400    
Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   3,984    
Ending balance     $ 3,984  
Loans receivable        
Financing Receivable, Allowance for Credit Loss [Line Items]        
Accrued interest receivable 11,700     $ 14,200
Agricultural        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance 1,346 3,748    
Charge-offs (41) (84)    
Recoveries 27 25    
Credit loss expense (222) 14    
Ending balance 1,110 1,146 3,748  
Agricultural | Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   (2,557)    
Ending balance     (2,557)  
Commercial and industrial        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance 15,689 8,394    
Charge-offs (666) (471)    
Recoveries 292 213    
Credit loss expense (1,671) 8,445    
Ending balance 13,644 19,309 8,394  
Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   2,728    
Ending balance     2,728  
Commercial real estate        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance 32,640 13,804    
Charge-offs (66) (720)    
Recoveries 306 8    
Credit loss expense (2,455) 8,746    
Ending balance 30,425 23,138 13,804  
Commercial real estate | Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   1,300    
Ending balance     1,300  
Residential real estate        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance 4,882 2,685    
Charge-offs (35) 0    
Recoveries 9 7    
Credit loss expense (201) 1,683    
Ending balance 4,655 6,425 2,685  
Residential real estate | Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   2,050    
Ending balance     2,050  
Consumer        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance 943 448    
Charge-offs (195) (222)    
Recoveries 53 46    
Credit loss expense 15 434    
Ending balance $ 816 1,169 448  
Consumer | Cumulative Effect, Period of Adoption, Adjustment        
Financing Receivable, Allowance for Credit Loss [Roll Forward]        
Beginning balance   $ 463    
Ending balance     $ 463