Condensed Consolidated Statement Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 31,697	$ 65,038
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	104,068	106,212
Amortization of financing costs and discounts	14,102	5,995
Non-cash operating lease costs	11,453	9,038
Share-based compensation	12,843	11,948
Provision for doubtful accounts	6,793	5,686
Deferred income taxes, net	2,752	3,908
Changes in fair value of contingent consideration	(232)	8,475
Foreign currency remeasurement gain	(704)	0
Loss (income) on equity method investments	(10,090)	4,765
Debt and Equity Securities, Gain (Loss)	(20,826)	0
Decrease (increase) in:
Accounts receivable	63,675	42,930
Prepaid expenses and other current assets	(4,185)	(3,277)
Other assets	(300)	(1,233)
(Decrease) increase in:
Accounts payable and accrued expenses	(34,682)	(12,452)
Income taxes payable	7,376	(3,810)
Deferred revenue	(2,698)	(3,292)
Increase Decrease in Operating Lease Liabilities	(8,780)	(8,833)
Liability for uncertain tax positions	5,114	(10,811)
Other long-term liabilities	2,419	1,454
Net cash provided by operating activities	241,627	212,211
Cash flows from investing activities:
Payments to Acquire Equity Method Investments	(26,523)	(14,668)
Payments to Acquire Other Investments	843	0
Purchases of property and equipment	(50,537)	(30,791)
Acquisition of businesses, net of cash received	(19,349)	(266,000)
Proceeds from sale of assets	407	0
Purchases of intangible assets	(23)	0
Net cash used in investing activities	(96,868)	(311,459)
Cash flows from financing activities:
Proceeds from line of credit	0	100,000
Repurchase of common stock	(88,469)	(3,807)
Issuance of common stock under employee stock purchase plan	3,303	1,995
Exercise of stock options	952	5,274
Dividends paid	0	(43,965)
Deferred payments for acquisitions	(16,296)	(14,269)
Other	(1,032)	(429)
Net cash (used in) provided by financing activities	(101,542)	44,799
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	(2,012)	451
Net change in cash and cash equivalents	41,205	(53,998)
Cash and cash equivalents at beginning of period	575,615	209,474
Cash and cash equivalents at end of period	$ 616,820	$ 155,476