SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information
Number of reportable segments | segment	2
Net interest and dividend income	$ 30,582	$ 34,398
Provision (benefit) for credit losses	(168)	1,866
Net interest and dividend income, after provision for credit losses	30,750	32,532
Mortgage banking income:
Gain on sale of mortgage loans	2,013	2,224
Changes in mortgage servicing rights fair value	54	(1,692)
Other	2,276	2,216
Total mortgage banking income	4,343	2,748
Other noninterest income	6,398	5,942
Total noninterest income	10,741	8,690
Noninterest expense	31,750	31,509
Income (loss) before income taxes	9,741	9,713
Provision(benefit) for income taxes	2,441	2,416
Net income	7,300	7,297
Total assets at period end	5,862,222	5,572,858	$ 5,667,896
Goodwill at period end	59,042	69,802	$ 59,042
Operating Segments | HarborOne Bank
Segment Reporting Information
Net interest and dividend income	30,485	34,562
Provision (benefit) for credit losses	(168)	1,866
Net interest and dividend income, after provision for credit losses	30,653	32,696
Mortgage banking income:
Intersegment gain (loss)	(236)	(348)
Changes in mortgage servicing rights fair value	(32)	(136)
Other	180	201
Total mortgage banking income	(88)	(283)
Other noninterest income	6,391	5,942
Total noninterest income	6,303	5,659
Noninterest expense	27,407	26,190
Income (loss) before income taxes	9,549	12,165
Provision(benefit) for income taxes	2,386	3,115
Net income	7,163	9,050
Total assets at period end	5,867,715	5,583,453
Goodwill at period end	59,042	59,042
Operating Segments | HarborOne Mortgage.
Segment Reporting Information
Net interest and dividend income	80	327
Net interest and dividend income, after provision for credit losses	80	327
Mortgage banking income:
Gain on sale of mortgage loans	2,013	2,224
Intersegment gain (loss)	308	454
Changes in mortgage servicing rights fair value	86	(1,556)
Other	2,097	2,015
Total mortgage banking income	4,504	3,137
Other noninterest income	10
Total noninterest income	4,514	3,137
Noninterest expense	4,311	5,322
Income (loss) before income taxes	283	(1,858)
Provision(benefit) for income taxes	60	(565)
Net income	223	(1,293)
Total assets at period end	$ 92,719	109,090
Goodwill at period end		$ 10,760