CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ 21,862	$ (22,958)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	46,667	43,289
Amortization of operating lease right-of-use assets	36,834	34,094
Equity in earnings of joint ventures, net of dividends	(5,406)	(2,900)
Amortization of deferred financing costs and loan discount	1,959	2,163
(Gain) loss on sale and disposal of equipment and other	(2,874)	202
Loss on extinguishment of debt	1,496	0
Amortization of cash flow hedge, net of taxes	1,845	892
Non-cash change in fair value of interest rate hedge	(11,280)	3,843
Stock-based compensation	17,145	8,078
Change in fair value of contingent consideration	1,292	(97)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in purchase transactions:
Accounts receivable	(28,156)	29,018
Other current assets	2,963	9,884
Other assets	(4,997)	(4,257)
Deferred taxes	5,297	(11,678)
Operating lease liability	(36,564)	(30,182)
Deferred revenue	(7,147)	44,384
Accounts payable, accrued expenses and other	17,765	27,690
Net cash provided by operating activities	58,701	131,465
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of imaging facilities and other acquisitions	(64,918)	(4,188)
Purchase of property and equipment	(53,799)	(64,193)
Proceeds from sale of equipment	500	779
Equity contributions in existing and purchase of interest in joint ventures	(1,441)	0
Net cash used in investing activities	(119,658)	(67,602)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on notes and leases payable	(3,304)	(1,814)
Payments on term loan debt	(613,279)	(21,648)
Proceeds from debt refinancing, net of issuing costs	716,369	0
Proceeds from paycheck protection program loans	0	4,023
Proceeds from revolving credit facility	128,300	250,900
Payments on revolving credit facility	(128,300)	(250,900)
Proceeds from issuance of common stock upon exercise of options	26	0
Net cash provided by (used in) financing activities	99,812	(19,439)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	(21)	(6)
NET INCREASE IN CASH AND CASH EQUIVALENTS	38,834	44,418
CASH AND CASH EQUIVALENTS, beginning of period	102,018	40,165
CASH AND CASH EQUIVALENTS, end of period	140,852	84,583
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	13,774	22,826
Equipment acquired and leasehold improvements	42,100	$ 31,800
Investment in joint ventures	$ 41,375