CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY - Schedule of CONDENSED BALANCE SHEETS (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash due from Berkshire Bank	$ 148,148	$ 145,342
Other assets	341,757	348,935
Total assets	12,430,821	11,662,864
Liabilities and Shareholders’ Equity
Subordinated notes	121,363	121,064
Shareholders’ equity	1,012,221	954,062	$ 1,182,435	$ 1,187,773
Total liabilities and shareholders’ equity	12,430,821	11,662,864
Reportable legal entity | Berkshire Hills Bancorp
Assets
Cash due from Berkshire Bank	98,452	90,022
Investment in subsidiaries	1,038,039	986,805
Other assets	399	1,445
Total assets	1,136,890	1,078,272
Liabilities and Shareholders’ Equity
Subordinated notes	121,363	121,064
Accrued expenses	3,306	3,146
Shareholders’ equity	1,012,221	954,062
Total liabilities and shareholders’ equity	$ 1,136,890	$ 1,078,272