GOODWILL AND OTHER INTANGIBLE ASSETS - Other intangible assets - (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Other intangible assets:
Cost	$ 11,249,000	$ 11,225,000
Accumulated amortization	6,258,000	5,899,000
Net book value	4,991,000	5,326,000
Customer relationships
Other intangible assets:
Cost	6,932,000	6,921,000
Accumulated amortization	4,395,000	4,099,000
Net book value	$ 2,537,000	$ 2,822,000
Acquired finite-lived intangible assets, weighted average useful life	5 years 7 months 6 days	5 years 10 months 24 days
Trademarks and trade names
Other intangible assets:
Cost	$ 2,174,000	$ 2,166,000
Accumulated amortization	0	0
Net book value	$ 2,174,000	$ 2,166,000
Acquired finite-lived intangible assets, weighted average useful life	8 years	8 years 6 months
Trademarks and trade names
Other intangible assets:
Cost	$ 200,000	$ 200,000
Accumulated amortization	93,000	86,000
Net book value	107,000	114,000
Engineering drawings
Other intangible assets:
Cost	330,000	330,000
Accumulated amortization	276,000	268,000
Net book value	$ 54,000	$ 62,000
Acquired finite-lived intangible assets, weighted average useful life	3 years 7 months 6 days	4 years 1 month 6 days
Non-compete agreements
Other intangible assets:
Cost	$ 327,000	$ 322,000
Accumulated amortization	319,000	303,000
Net book value	$ 8,000	$ 19,000
Acquired finite-lived intangible assets, weighted average useful life	6 months	1 year
Patents
Other intangible assets:
Cost	$ 1,286,000	$ 1,286,000
Accumulated amortization	1,175,000	1,143,000
Net book value	$ 111,000	$ 143,000
Acquired finite-lived intangible assets, weighted average useful life	4 years 2 months 12 days	4 years 1 month 6 days