Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) bank
Basis of Presentation
Number of full-service banking offices	25
FDIC insurance limit per depositor | $	$ 250,000
Number of banks on whose deposits insurance coverage was offered	3
Percentage of insurance offered	100.00%
Eastern Funding LLC
Basis of Presentation
Percentage of ownership in subsidiary	84.40%
BankRI
Basis of Presentation
Number of full-service banking offices	19
First Ipswich Bancorp:
Basis of Presentation
Number of full-service banking offices	5