Basis of Presentation (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2020
USD ($)
bank
office
Jan. 01, 2020
USD ($)
Dec. 31, 2019
USD ($)
Basis of Presentation      
Number of full-service banking offices | bank 31    
Number of lending offices | office 2    
Allowance for loan and lease losses     $ 61,082
Reserve for unfunded commitments $ 17,222   $ 1,880
BankRI      
Basis of Presentation      
Number of full-service banking offices | bank 20    
Accounting Standards Update 2016-13      
Basis of Presentation      
Allowance for loan and lease losses   $ 6,600  
Reserve for unfunded commitments   8,900  
Retained earnings   $ 11,500