Acquisitions and Mergers
3 Months Ended
Mar. 31, 2020
Business Combinations [Abstract]  
Acquisitions and Mergers Acquisitions and Mergers
First Ipswich Bank
On February 15, 2020, the merger of First Ipswich Bank with and into Brookline Bank was completed. First Ipswich was already a wholly-owned subsidiary of the Company, therefore the merger qualified as a tax-free reorganization for federal income tax purposes and there was minimal impact to customers. All of First Ipswich Bank's six branch locations were retained and converted to Brookline Bank branches.