Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income (loss)	$ 136,209	$ 92,580
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	196,443	163,680
Amortization of financing costs and discounts	21,295	21,393
Non-cash operating lease costs	8,366	15,686
Share-based compensation	19,119	18,643
Provision for doubtful accounts	7,934	9,508
Deferred income taxes, net	2,537	7,815
Loss (gain) on sale of businesses	21,798	(17,122)
Lease asset impairments	9,410	9,786
Goodwill impairment on business	32,629	0
Changes in fair value of contingent consideration	(567)	(243)
Foreign currency remeasurement gain	181	(15,919)
(Income) loss from equity method investments	(16,596)	10,799
Loss on equity and debt investments	16,677	20,826
Decrease (increase) in:
Accounts receivable	49,888	57,560
Prepaid expenses and other current assets	(10,610)	(3,279)
Other assets	(2,378)	543
Increase (decrease) in:
Accounts payable and accrued expenses	(1,409)	(26,430)
Income taxes payable	(37,863)	(496)
Deferred revenue	4,774	(10,494)
Operating lease liabilities	(19,346)	(12,857)
Liability for uncertain tax positions	(2,903)	7,746
Other long-term liabilities	(5,336)	6,284
Net cash provided by operating activities	430,252	356,009
Cash flows from investing activities:
Proceeds on sale of available-for-sale investments	663	0
Distribution from equity method investment	15,327	0
Purchases of equity method investment	(22,249)	(29,979)
Purchases of equity investments	(999)	(843)
Purchases of property and equipment	(87,495)	(71,266)
Proceeds from sale of assets	0	507
Acquisition of businesses, net of cash received	(112,444)	(27,156)
Proceeds from sale of businesses, net of cash divested	48,876	24,353
Purchases of intangible assets	(1,255)	(2,902)
Net cash used in investing activities	(159,576)	(107,286)
Cash flows from financing activities:
Payment of debt	(402,414)	0
Payment of note payable	0	(400)
Proceeds from bridge loan	485,000	0
Repurchase of common stock	(29,855)	(238,905)
Issuance of common stock under employee stock purchase plan	4,232	3,303
Exercise of stock options	2,880	952
Deferred payments for acquisitions	(13,387)	(20,427)
Other	(6,619)	(1,377)
Net cash provided by (used in) financing activities	39,837	(256,854)
Effect of exchange rate changes on cash and cash equivalents	(6,698)	446
Net change in cash and cash equivalents	303,815	(7,685)
Cash and cash equivalents at beginning of period	242,652	575,615
Cash and cash equivalents at end of period	$ 546,467	$ 567,930