GOODWILL AND OTHER INTANGIBLE ASSETS - Other intangible assets - (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Other intangible assets:
Cost	$ 11,229,000	$ 11,225,000
Accumulated amortization	6,419,000	5,899,000
Net book value	4,810,000	5,326,000
Customer relationships
Other intangible assets:
Cost	6,923,000	6,921,000
Accumulated amortization	4,532,000	4,099,000
Net book value	$ 2,391,000	$ 2,822,000
Acquired finite-lived intangible assets, weighted average useful life	5 years 4 months 24 days	5 years 10 months 24 days
Trademarks and trade names
Other intangible assets:
Cost	$ 2,167,000	$ 2,166,000
Accumulated amortization	0	0
Net book value	$ 2,167,000	$ 2,166,000
Acquired finite-lived intangible assets, weighted average useful life	7 years 9 months 18 days	8 years 6 months
Trademarks and trade names
Other intangible assets:
Cost	$ 200,000	$ 200,000
Accumulated amortization	96,000	86,000
Net book value	104,000	114,000
Engineering drawings
Other intangible assets:
Cost	330,000	330,000
Accumulated amortization	279,000	268,000
Net book value	$ 51,000	$ 62,000
Acquired finite-lived intangible assets, weighted average useful life	3 years 4 months 24 days	4 years 1 month 6 days
Non-compete agreements
Other intangible assets:
Cost	$ 323,000	$ 322,000
Accumulated amortization	321,000	303,000
Net book value	$ 2,000	$ 19,000
Acquired finite-lived intangible assets, weighted average useful life	3 months 18 days	1 year
Patents
Other intangible assets:
Cost	$ 1,286,000	$ 1,286,000
Accumulated amortization	1,191,000	1,143,000
Net book value	$ 95,000	$ 143,000
Acquired finite-lived intangible assets, weighted average useful life	4 years 4 months 24 days	4 years 1 month 6 days