Basis of Presentation (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) class bank office segment	Dec. 31, 2018 USD ($)
Basis of Presentation
Number of full-service banking offices | bank	31
Number of lending offices | office	2
Impairment of restricted securities	$ 0	$ 0
Number of days past due, non-accrual status (in days)	90 days
Period after which a non-accrual loan is restructured (in months)	6 months
Total loans and leases	$ 6,737,816,000	6,303,516,000
BOLI, as percentage of capital plus reserves, maximum, individual carrier (as a percent)	10.00%
BOLI, as percentage of capital plus reserves, maximum, aggregate (as a percent)	25.00%
Number of reportable segments | segment	1
Minimum
Basis of Presentation
Term of operating lease	3 years
Maximum
Basis of Presentation
Term of operating lease	25 years
Taxi Medallion Portfolio
Basis of Presentation
Total loans and leases	$ 10,300,000	13,700,000
Commercial real estate
Basis of Presentation
Number of loan classes within specific portfolio | class	3
Commercial loans
Basis of Presentation
Number of loan classes within specific portfolio | class	3
Total loans and leases	$ 1,838,748,000	$ 1,768,958,000
Consumer Loan
Basis of Presentation
Number of loan classes within specific portfolio | class	3
BankRI
Basis of Presentation
Number of full-service banking offices | bank	20