GOODWILL AND OTHER INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
GOODWILL AND INTANGIBLE ASSETS
Goodwill	$ 59,042	$ 59,042	$ 69,802
Goodwill impairment	0
Intangible assets	1,326	$ 1,515
HarborOne Mortgage
GOODWILL AND INTANGIBLE ASSETS
Percentage of goodwill balance		100.00%
Goodwill impairment		$ 10,800
HarborOne Bank.
GOODWILL AND INTANGIBLE ASSETS
Goodwill	$ 59,000	$ 59,000