CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ (14,283)	$ 8,363
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	31,315	27,118
Amortization of operating lease right-of-use assets	15,699	16,802
Equity in earnings of joint ventures, net of dividends	(1,835)	(2,517)
Amortization of deferred financing costs and loan discount	746	648
Loss on sale and disposal of equipment and other	579	1,128
Amortization of cash flow hedge, net of taxes	922	923
Non-cash change in fair value of interest rate hedge	4,093	(20,819)
Stock-based compensation	12,185	11,102
Change in fair value of contingent consideration	2,335	(501)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	(9,997)	(23,904)
Other current assets	(1,691)	(4,065)
Other assets	(2,726)	(1,417)
Deferred taxes	942	1,387
Operating lease liability	(15,080)	(15,859)
Deferred revenue	335	(4,519)
Accounts payable, accrued expenses and other	9,077	7,031
Net cash provided by operating activities	32,616	901
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging centers and other acquisitions	(9,644)	(25,123)
Purchase of property and equipment	(55,915)	(36,558)
Proceeds from sale of equipment	3	117
Net cash used in investing activities	(65,556)	(61,564)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(184)	0
Payments on term loan debt	(3,688)	(3,313)
Proceeds from issuance of common stock upon exercise of options	51	0
Net cash used in financing activities	(3,821)	(3,313)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(229)	83
NET DECREASE IN CASH AND CASH EQUIVALENTS	(36,990)	(63,893)
CASH AND CASH EQUIVALENTS, beginning of period	127,834	134,606
CASH AND CASH EQUIVALENTS, end of period	90,844	70,713
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	21,471	7,448
Cash paid during the period for income taxes	$ 40	$ 34