CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
NET INCOME	$ 38,836	$ 30,337	$ 33,608
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	137,838	128,391	115,877
Non-cash lease expense	60,552	61,102	68,847
Equity in earnings of joint ventures, net of dividend	(9,926)	9,176	(5,952)
Amortization of deferred financing costs and loan discount	3,093	2,987	2,693
Loss on sale and disposal of equipment	2,276	2,187	2,529
Loss on extinguishment of debt	3,903	0	0
Gain on contribution of imaging centers into joint venture	0	(16,808)	0
Lease abandonment charges	2,478	5,146	0
Amortization of cash flow hedge	9,352	3,576	3,687
Non-cash change in fair value of interest rate swaps	8,006	8,185	(39,621)
Stock-based compensation	29,833	26,785	23,770
Loss on impairment	1,275	3,949	0
Change in fair value of contingent consideration	1,995	(3,880)	(325)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	(21,767)	2,650	(30,078)
Other current assets	(32,790)	(8,441)	(3,327)
Other assets	10,723	(1,484)	(12,166)
Deferred taxes	6,454	6,056	13,356
Operating lease liability	(54,866)	(54,763)	(68,943)
Deferred revenue	(1,359)	626	(7,316)
Accounts payable, accrued expenses and other	37,117	15,086	49,778
Net cash provided by operating activities	233,023	220,863	146,417
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging facilities and other acquisitions	(43,661)	(10,918)	(129,961)
Purchase of property and equipment	(188,070)	(176,600)	(119,451)
Proceeds from sale of equipment	157	83	3,904
Equity contributions in existing and purchase of interest in joint ventures	(1,496)	(14,035)	(1,441)
Net cash used in investing activities	(233,070)	(201,470)	(246,949)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(5,989)	(2,930)	0
Payments on term loan debt	(692,437)	(41,063)	(53,750)
Proceeds from issuance of debt, net of issuance costs	863,757	0	147,996
Sale of noncontrolling interests	22,357	5,121	0
Payments of contingent consideration and holdbacks	(4,268)	(5,495)	0
Distributions paid to noncontrolling interests	(4,522)	(5,972)	(893)
Proceeds from issuance of common stock	218,385	245,832	0
Proceeds from issuance of common stock upon exercise of options	667	142	294
Net cash provided by financing activities	397,950	195,635	93,647
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(453)	(292)	113
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	397,450	214,736	(6,772)
CASH AND CASH EQUIVALENTS, beginning of period	342,570	127,834	134,606
CASH AND CASH EQUIVALENTS, end of period	740,020	342,570	127,834
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	84,601	64,695	39,151
Cash paid during the period for income taxes	$ 4,170	$ 1,587	$ 587