SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)										3 Months Ended		9 Months Ended		24 Months Ended	40 Months Ended	42 Months Ended
	Sep. 01, 2023 USD ($) center location	Jul. 07, 2023 USD ($) shares	Apr. 30, 2023 shares	Nov. 01, 2022 USD ($)	Jan. 20, 2022 USD ($) loan shares	Nov. 05, 2019 USD ($)	Jan. 01, 2019 USD ($)	Feb. 01, 2018 USD ($) shares	Apr. 01, 2017	Sep. 30, 2023 USD ($) security incentivePlan jointVenture	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) security incentivePlan jointVenture	Sep. 30, 2022 USD ($)	Oct. 31, 2025 USD ($)	Oct. 31, 2023 USD ($)	Sep. 30, 2023 USD ($) security incentivePlan jointVenture	Sep. 20, 2023 USD ($) shares	Jun. 30, 2023 USD ($)	Jun. 07, 2023 shares	Apr. 27, 2023 shares	Dec. 31, 2022 USD ($)	Oct. 01, 2022 USD ($)	Jul. 01, 2020 USD ($)	Dec. 21, 2019 shares	Jun. 30, 2019 USD ($) agreement
Property, Plant and Equipment [Line Items]
Contracts receivable, factoring receivable										$ 14,700,000		$ 14,700,000				$ 14,700,000					$ 15,400,000
Deferred financing costs, net of accumulated amortization										1,800,000		1,800,000				1,800,000					2,300,000
Goodwill										676,376,000		676,376,000				$ 676,376,000					677,665,000
Intangible asset amortization expense												8,900,000	$ 7,500,000
Income tax expense (benefit)										$ (7,220,000)	$ (2,188,000)	$ (7,741,000)	$ (7,087,000)
Effective tax rate										23.10%	25.30%	24.10%	19.80%
Number of plans | incentivePlan										1		1				1
Number of shares authorized (in shares) | shares																			20,100,000
Amount of loss recognized in income on derivative (current period ineffective portion)										$ 618,901,000		$ 618,901,000				$ 618,901,000					332,995,000
Number of securities without readily determinable fair value | security										3		3				3
Number of unconsolidated joint ventures | jointVenture										13		13				13
Management service fees										$ 3,900,000	$ 6,100,000	$ 12,200,000	$ 17,200,000
Investment in joint ventures										94,472,000		94,472,000				$ 94,472,000					57,893,000
Gain on disposal of equipment and other										(527,000)	$ 247,000	(1,183,000)	$ (962,000)
Los Angeles Imaging Group, LLC
Property, Plant and Equipment [Line Items]
Ownership interest	65.00%
Santa Monica Imaging Group, LLC
Property, Plant and Equipment [Line Items]
Ownership interest	49.00%						35.00%		40.00%
Limited partners' contributed capital	$ 5,200,000
Investment in joint ventures	8,500,000
Gain on disposal of equipment and other	$ 16,800,000
Beverly Hills Imaging Center
Property, Plant and Equipment [Line Items]
Ownership interest	6.00%
Limited partners' contributed capital	$ 27,200,000
Cedars-Sinai Medical Center | Los Angeles Imaging Group, LLC
Property, Plant and Equipment [Line Items]
Number of location offering multi-modality services | location	3
Number of centers contributed | center	3
Ownership interest	35.00%
Limited partners' contributed capital	$ 5,900,000
Cedars-Sinai Medical Center | Santa Monica Imaging Group, LLC
Property, Plant and Equipment [Line Items]
Ownership interest									60.00%
Limited liability company (LLC) or limited partnership (LP), managing member or general partner, ownership lnterest disposed							5.00%
Medic Vision
Property, Plant and Equipment [Line Items]
Total net assets										$ 1,200,000		$ 1,200,000				$ 1,200,000
Ownership percentage										14.21%		14.21%				14.21%
Turner Imaging Systems
Property, Plant and Equipment [Line Items]
Number of shares purchased (in shares) | shares								2,100,000
Payments to acquire equity method investments								$ 2,000,000
Preferred stock issued upon conversion (in shares) | shares																								80,000
Turner Imaging Systems | Promissory Note
Property, Plant and Equipment [Line Items]
Short-term debt							$ 100,000
WhiteRabbit.ai Inc.
Property, Plant and Equipment [Line Items]
Payments to acquire equity method investments						$ 1,000,000
Payments to fund loan to related parties						$ 2,500,000
Aidence
Property, Plant and Equipment [Line Items]
Impairment of intangible assets (excluding goodwill)												$ 3,900,000
Range of outcomes (upto)					$ 10,000,000
Number of identified milestones | loan					2,000
Milestone contingent consideration										$ 0		0				$ 0		$ 7,191,000			11,158,000
Aidence | Contingent Milestone Consideration
Property, Plant and Equipment [Line Items]
Milestone contingent consideration																		7,200,000
Aidence | General Holdback
Property, Plant and Equipment [Line Items]
Milestone contingent consideration										4,000,000		4,000,000				4,000,000
Quantib
Property, Plant and Equipment [Line Items]
Milestone contingent consideration										0		0				0		5,271,000			3,709,000
Shares issued (in shares) | shares					965,058
Contingent consideration, liability, period					18 months
Additional number of shares issued (in shares) | shares					113,303
Fair value of additional shares issued after execution					$ 3,000,000
Quantib | General Holdback
Property, Plant and Equipment [Line Items]
Milestone contingent consideration										1,600,000		1,600,000				1,600,000
Contingent consideration settlement																	$ 1,600,000
Quantib | Stock Holdback
Property, Plant and Equipment [Line Items]
Milestone contingent consideration		$ 3,500,000
Shares issued (in shares) | shares		113,303
Additional number of shares issued (in shares) | shares		113,303
Montclair
Property, Plant and Equipment [Line Items]
Milestone contingent consideration										0		0				0					1,200,000	$ 1,200,000
Contingent consideration settlement										1,200,000		1,200,000				1,200,000
Heart and Lung Limited
Property, Plant and Equipment [Line Items]
Milestone contingent consideration										11,099,000		11,099,000				11,099,000		$ 14,358,000			$ 11,656,000
Contingent consideration, liability, period				24 months
Business acquisition, percentage of voting interests acquired				75.00%
Heart and Lung Limited | Contingent Milestone Consideration
Property, Plant and Equipment [Line Items]
Milestone contingent consideration				$ 10,200,000						$ 11,100,000		$ 11,100,000				$ 11,100,000	$ 1,600,000
Additional number of shares issued (in shares) | shares																	56,600
Contingent consideration settlement																	$ 1,800,000
Heart and Lung Limited | Cash Holdback
Property, Plant and Equipment [Line Items]
Milestone contingent consideration				$ 600,000
Aidence
Property, Plant and Equipment [Line Items]
Shares issued (in shares) | shares					1,141,234
Aidence | General Holdback
Property, Plant and Equipment [Line Items]
Shares issued (in shares) | shares			144,227
Forecast
Property, Plant and Equipment [Line Items]
Monthly amortization of deferred hedge gains														$ 300,000	$ 400,000
Accumulated Other Comprehensive Loss, net of taxes
Property, Plant and Equipment [Line Items]
Amount of loss recognized in income on derivative (current period ineffective portion)																							$ 24,400,000
2019 SWAPS
Property, Plant and Equipment [Line Items]
Number of forward interest rate cap agreements | agreement																									4
Notional amounts																									$ 500,000,000
2019 SWAPS | 2019 Swaps - Interest Rate Contracts
Property, Plant and Equipment [Line Items]
Notional amounts																									$ 100,000,000
2019 SWAPS | 2019 Swaps - Interest Rate Contracts | SOFR
Property, Plant and Equipment [Line Items]
Basis spread on variable rate																									1.89%
2019 SWAPS | October 2023
Property, Plant and Equipment [Line Items]
Number of forward interest rate cap agreements | agreement																									2
Notional amounts																									$ 50,000,000
2019 SWAPS | October 2025
Property, Plant and Equipment [Line Items]
Number of forward interest rate cap agreements | agreement																									2
Notional amounts																									$ 200,000,000
2019 SWAPS-1 | 2019 Swaps - Interest Rate Contracts
Property, Plant and Equipment [Line Items]
Notional amounts																									$ 400,000,000
2019 SWAPS-1 | 2019 Swaps - Interest Rate Contracts | SOFR
Property, Plant and Equipment [Line Items]
Basis spread on variable rate																									1.98%
Restated Plan
Property, Plant and Equipment [Line Items]
Number of shares authorized (in shares) | shares																				20,100,000
Management Service Contracts
Property, Plant and Equipment [Line Items]
Useful life										25 years		25 years				25 years
Minimum
Property, Plant and Equipment [Line Items]
Share-based payment award, award vesting period												3 years
Share-based payment award, expiration period												5 years
Minimum | Dignity Health | Joint Venture | Glendale Advanced Imaging
Property, Plant and Equipment [Line Items]
Variable interest entity, ownership percentage												35.00%
Minimum | Amounts Returned to Property and Equipment
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										3 years		3 years				3 years
Minimum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										3 years		3 years				3 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
Maximum | Dignity Health | Joint Venture | Glendale Advanced Imaging
Property, Plant and Equipment [Line Items]
Variable interest entity, ownership percentage												55.00%
Maximum | Amounts Returned to Property and Equipment
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										15 years		15 years				15 years
Maximum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
PPE estimated useful lives										15 years		15 years				15 years
COVID-19 Pandemic
Property, Plant and Equipment [Line Items]
Advance medicare payments																$ 39,600,000
Repayment of advance medicare payments												$ 38,600,000