SUMMARY OF ACCOUNTING POLICIES (Details Narrative)						1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 01, 2019 USD ($)	Jan. 01, 2019 USD ($)	Apr. 12, 2018 USD ($)	Mar. 01, 2018 USD ($)	Feb. 01, 2018 USD ($) shares	Sep. 30, 2019 USD ($) shares	Nov. 06, 2014 USD ($)	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) joint_venture	Jun. 30, 2019 USD ($)	Apr. 01, 2017	Mar. 24, 2017 USD ($)	Oct. 06, 2014
Property, Plant and Equipment [Line Items]
Contracts receivable, factored amount										$ 9,000,000
Contracts receivable, factoring receivable						$ 24,300,000		$ 24,300,000		24,300,000
Deferred financing costs, net of accumulated amortization						1,700,000		1,700,000		1,700,000		$ 1,400,000
Deferred financing costs, net, period increase										683,000
Goodwill						439,867,000		439,867,000		439,867,000		418,093,000
Indefinite-lived intangible assets						11,900,000		11,900,000		11,900,000
Impairment of intangible assets												3,900,000
Goodwill, impairment loss												3,800,000
Indefinite-lived trade names												100,000
Income tax expense								$ 1,816,000	$ 2,827,000	$ 3,556,000	$ 2,835,000
Effective tax rate								26.30%	32.90%	24.80%	29.50%
Total credit facilities outstanding						0		$ 0		$ 0
Investment at cost						30,421,000		30,421,000		30,421,000		30,030,000
Aggregate cost						65,469,000		65,469,000		65,469,000		$ 65,031,000
Number of unconsolidated joint ventures | joint_venture												12
Loss on economic interest transaction										(134,000)
Management service fees								2,500,000	$ 3,500,000	$ 7,800,000	$ 10,600,000
Minimum
Property, Plant and Equipment [Line Items]
Share-based payment award, award vesting period										3 years
Share-based payment award, expiration period										5 years
Maximum
Property, Plant and Equipment [Line Items]
Share-based payment award, award vesting period										5 years
Share-based payment award, expiration period										10 years
Medic Vision
Property, Plant and Equipment [Line Items]
Ownership percentage				14.21%											12.50%
Investment at cost				$ 200,000											$ 1,000,000
Option to purchase additional equity method investment															$ 1,400,000
Additional equity interest acquired				1.96%
Initial qwnership percentage after dilution				12.25%
Aggregate cost						$ 1,200,000		$ 1,200,000		$ 1,200,000
Turner Imaging
Property, Plant and Equipment [Line Items]
Number of shares purchased (in shares) | shares					2,100,000.0
Number of shares purchased, value					$ 2,000,000
Restated Plan
Property, Plant and Equipment [Line Items]
Shares authorized (in shares) | shares						14,000,000		14,000,000		14,000,000
Restated Plan | Minimum
Property, Plant and Equipment [Line Items]
Share-based payment award, award vesting period										3 years
Share-based payment award, expiration period										5 years
Restated Plan | Maximum
Property, Plant and Equipment [Line Items]
Share-based payment award, award vesting period										5 years
Share-based payment award, expiration period										10 years
2016 Caps
Property, Plant and Equipment [Line Items]
Premium liability for 2016 Caps						$ 5,300,000		$ 5,300,000		$ 5,300,000
2016 Caps | September 2020
Property, Plant and Equipment [Line Items]
Notional amounts						150,000,000		150,000,000		150,000,000
2016 Caps | October 2020
Property, Plant and Equipment [Line Items]
Notional amounts						$ 350,000,000		$ 350,000,000		$ 350,000,000
2019 SWAPS
Property, Plant and Equipment [Line Items]
Notional amounts													$ 500,000,000
2019 SWAPS | October 2023
Property, Plant and Equipment [Line Items]
Notional amounts													50,000,000
2019 SWAPS | October 2025
Property, Plant and Equipment [Line Items]
Notional amounts													200,000,000
Property and equipment, net | Minimum
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										3 years
Property and equipment, net | Maximum
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										15 years
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										3 years
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										15 years
2016 Caps | London Interbank Offered Rate (LIBOR)
Property, Plant and Equipment [Line Items]
Basis spread on variable rate						2.00%		2.00%		2.00%
2019 SWAPS - Interest Rate Contracts | 2019 SWAPS
Property, Plant and Equipment [Line Items]
Notional amounts													100,000,000
2019 SWAPS - Interest Rate Contracts | 2019 SWAPS1
Property, Plant and Equipment [Line Items]
Notional amounts													$ 400,000,000
2019 SWAPS - Interest Rate Contracts | London Interbank Offered Rate (LIBOR) | 2019 SWAPS
Property, Plant and Equipment [Line Items]
Basis spread on variable rate													1.96%
2019 SWAPS - Interest Rate Contracts | London Interbank Offered Rate (LIBOR) | 2019 SWAPS1
Property, Plant and Equipment [Line Items]
Basis spread on variable rate													2.05%
Revolving Credit Facility
Property, Plant and Equipment [Line Items]
Deferred financing costs, net of accumulated amortization						$ 1,700,000		$ 1,700,000		$ 1,700,000
Total credit facilities outstanding						0		0		0		$ 28,000,000
RadNet | Santa Monica Imaging Group
Property, Plant and Equipment [Line Items]
Ownership percentage		35.00%												40.00%
Loss on economic interest transaction		$ 2,000
Cedars Sinai Medical Center | Santa Monica Imaging Group
Property, Plant and Equipment [Line Items]
Ownership percentage														60.00%
Additional equity interest acquired		5.00%
Investment owned, value		$ 134,000
Dignity Health | Glendale Advanced Imaging | Joint Venture | Minimum
Property, Plant and Equipment [Line Items]
Variable interest entity, ownership percentage												35.00%
Dignity Health | Glendale Advanced Imaging | Joint Venture | Maximum
Property, Plant and Equipment [Line Items]
Variable interest entity, ownership percentage												55.00%
Promissory Note
Property, Plant and Equipment [Line Items]
Convertible promissory note						0		$ 0		$ 0		$ 199,000
Promissory Note | Turner Imaging
Property, Plant and Equipment [Line Items]
Convertible promissory note		$ 143,000
US Attorney's Office For The Western District of New York
Property, Plant and Equipment [Line Items]
Loss contingency accrual liability													$ 2,300,000
Settled Litigation | US Attorney's Office For The Western District of New York
Property, Plant and Equipment [Line Items]
Loss contingency, settlement amount						$ 2,200,000
Garden State Radiology Network, LLC.
Property, Plant and Equipment [Line Items]
Goodwill	$ 888,000
Ownership percentage																49.00%
Loss on economic interest transaction	114,000
Payments to acquire equity method investments							$ 2,200,000
Nulogix, Inc.
Property, Plant and Equipment [Line Items]
Goodwill	$ 1,400,000
Ownership percentage	75.00%		25.00%
Loss on economic interest transaction	$ 504,000
Payments to acquire equity method investments	$ 1,500,000		$ 2,000,000
Jefferson Health
Property, Plant and Equipment [Line Items]
Ownership percentage																51.00%