CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ 17,047,000	$ 38,836,000	$ 30,337,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	152,127,000	137,838,000	128,391,000
Non-cash lease expense	59,867,000	60,552,000	61,102,000
Equity in earnings of joint ventures, net of dividend	(5,803,000)	(9,926,000)	9,176,000
Amortization of deferred financing costs and loan discount	3,014,000	3,093,000	2,987,000
Loss on sale and disposal of equipment	9,658,000	2,276,000	2,187,000
Loss on extinguishment of debt	0	3,903,000	0
Gain on contribution of imaging centers into joint venture	0	0	(16,808,000)
Lease abandonment charges	8,563,000	2,478,000	5,146,000
Amortization of cash flow hedge	2,273,000	9,352,000	3,576,000
Non-cash change in fair value of interest rate swaps	7,112,000	8,006,000	8,185,000
Stock-based compensation	54,601,000	29,833,000	26,785,000
Loss on impairment	0	1,275,000	3,949,000
Change in fair value of contingent consideration	111,000	1,995,000	(3,880,000)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	(9,560,000)	(21,767,000)	2,650,000
Other current assets	2,279,000	(32,790,000)	(8,441,000)
Other assets	(5,710,000)	10,723,000	(1,484,000)
Deferred taxes	10,828,000	6,454,000	6,056,000
Operating lease liability	(62,816,000)	(54,866,000)	(54,763,000)
Deferred revenue	2,813,000	(1,359,000)	626,000
Accounts payable, accrued expenses and other	52,416,000	37,117,000	15,086,000
Net cash provided by operating activities	298,820,000	233,023,000	220,863,000
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging facilities and other acquisitions, net of cash acquired	(133,422,000)	(43,661,000)	(10,918,000)
Purchase of property and equipment	(213,251,000)	(188,070,000)	(176,600,000)
Proceeds from sale of equipment	1,288,000	157,000	83,000
Equity Contributions In Joint Ventures	(4,147,000)	(1,496,000)	(14,035,000)
Collection of notes receivable	5,667,000	0	0
Net cash used in investing activities	(343,865,000)	(233,070,000)	(201,470,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(7,025,000)	(5,989,000)	(2,930,000)
Payments on term loan debt	(20,756,000)	(692,437,000)	(41,063,000)
Proceeds from issuance of debt, net of issuance costs	99,001,000	863,757,000	0
Sale of noncontrolling interests	2,389,000	22,357,000	5,121,000
Payments of contingent consideration and holdbacks	(2,249,000)	(4,268,000)	(5,495,000)
Distributions paid to noncontrolling interests	(4,602,000)	(4,522,000)	(5,972,000)
Proceeds from issuance of common stock	0	218,385,000	245,832,000
Proceeds from issuance of common stock upon exercise of options	5,449,000	667,000	142,000
Net cash provided by financing activities	72,207,000	397,950,000	195,635,000
EFFECT OF EXCHANGE RATE CHANGES ON CASH	33,000	(453,000)	(292,000)
NET INCREASE IN CASH AND CASH EQUIVALENTS	27,195,000	397,450,000	214,736,000
CASH AND CASH EQUIVALENTS, beginning of period	740,020,000	342,570,000	127,834,000
CASH AND CASH EQUIVALENTS, end of period	767,215,000	740,020,000	342,570,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	$ 72,266,000	$ 84,601,000	$ 64,695,000