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ACCOUNTING POLICIES (Details Textual) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Accounting Policies [Line Items]
Advertising expense	$ 144,000	$ 113,000	$ 140,000
Interest costs capitalized	110,000	115,000	138,000
Original cost of operating lease contracts	92,135,000	94,031,000
Accumulated depreciation	55,148,000	53,716,000
Insurance coverage receivable	0	1,137,000
Revenue recognized, including assessed tax	19,396,000
Revenue recognized, excluding assessed tax	$ 20,605,000	$ 19,714,000	$ 19,556,000
Percentage of tax benefit realized upon settlement	50.00%
Asset retirement obligation liability	$ 0
Antidilutive securities excluded from computation of earnings per share (in shares)	387	519	14
Operating lease, liability	$ 1,106,000
Operating lease, right-of-use asset	1,106,000
Mevion Medical Systems Inc
Accounting Policies [Line Items]
Gain on business interruption insurance recovery	$ 185,000
Medical Services Revenues
Accounting Policies [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
Customer One \| Medical Services Revenues
Accounting Policies [Line Items]
Concentration risk, percentage	30.00%	26.00%	21.00%
Restricted Stock Units (RSUs)
Accounting Policies [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	3	4	4
Accounting Standards Update 2014-09
Accounting Policies [Line Items]
Revenue recognized, excluding assessed tax	$ 1,209,000
Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Operating lease, liability				$ 1,362,000
Operating lease, right-of-use asset				$ 1,362,000
PBRT
Accounting Policies [Line Items]
Property equipment, useful life	20 years
Mevion Medical Systems Inc
Accounting Policies [Line Items]
Cost of repairs	$ 977,000
Mevion Medical Systems Inc \| Insurance Settlement Receivable Current
Accounting Policies [Line Items]
Cost of repairs	$ 977,000
Maximum
Accounting Policies [Line Items]
Stock options exercise price (in dollars per share)	$ 3.90	$ 3.90
Maximum \| Medical and Office equipment
Accounting Policies [Line Items]
Property equipment, useful life	10 years
Minimum
Accounting Policies [Line Items]
Stock options exercise price (in dollars per share)	$ 2.68	$ 2.82	$ 3.90
Minimum \| Customer Three \| Accounts Receivable
Accounting Policies [Line Items]
Concentration risk, percentage	10.00%	10.00%
Minimum \| Medical and Office equipment
Accounting Policies [Line Items]
Property equipment, useful life	3 years