CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ (22,958)	$ 5,668
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	43,289	39,703
Amortization of operating lease right-of-use assets	34,094	32,937
Equity in earnings of joint ventures	(2,900)	(4,117)
Distributions from joint ventures	0	3,438
Amortization of deferred financing costs and loan discount	2,163	2,021
(Gain) loss on sale and disposal of equipment and other	202	1,073
Amortization of cash flow hedge	892	0
Non-cash change in fair value of interest rate hedge	3,843	0
Stock-based compensation	8,078	5,582
Other non-cash items included in cost of operations	0	(559)
Change in fair value of contingent consideration	(97)	(1,953)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	29,018	(12,042)
Other current assets	9,884	4,331
Other assets	(4,257)	2,069
Deferred taxes	(11,678)	(3,542)
Operating lease liability	(30,182)	(32,268)
Deferred revenue	44,384	(666)
Accounts payable, accrued expenses and other	27,690	2,860
Net cash provided by operating activities	131,465	44,535
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging facilities and other acquisitions	(4,188)	(27,149)
Equity investments at fair value	0	(143)
Purchase of property and equipment	(64,193)	(50,342)
Proceeds from sale of equipment	779	760
Proceeds from the sale of equity interests in a joint venture	0	132
Equity contributions in existing and purchase of interest in joint ventures	0	(103)
Net cash used in investing activities	(67,602)	(76,845)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(1,814)	(3,320)
Payments on term loan debt	(21,648)	(19,469)
Proceeds from debt issuance, net of issuing costs	0	97,144
Proceeds from Payment Protection Program	4,023	0
Proceeds from sale of noncontrolling interest	0	5,275
Contribution from noncontrolling partner	0	750
Proceeds from revolving credit facility	250,900	236,200
Payments on revolving credit facility	(250,900)	(264,200)
Proceeds from issuance of common stock upon exercise of options	0	50
Net cash (used in) provided by financing activities	(19,439)	52,430
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(6)	(5)
NET INCREASE IN CASH AND CASH EQUIVALENTS	44,418	20,115
CASH AND CASH EQUIVALENTS, beginning of period	40,165	10,389
CASH AND CASH EQUIVALENTS, end of period	84,583	30,504
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	22,826	23,292
Equipment acquired and leasehold improvements	$ 31,800	14,000
Distribution to noncontrolling interests		$ 1,818