Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 130,512	$ 87,867
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	513,248	392,617
Stock-based compensation	92,261	83,948
Amortization of intangible assets	101,651	79,175
Amortization of debt issuance costs and debt discounts and premiums	7,461	15,710
Provision for allowance for doubtful accounts	3,606	7,989
Loss on debt extinguishment	40,706	19,947
Other items	7,998	3,773
Changes in operating assets and liabilities:
Accounts receivable	(38,441)	(151,900)
Income taxes, net	(22,866)	(33,927)
Other assets	3,536	20,285
Accounts payable and accrued expenses	(24,325)	16,171
Other liabilities	24,288	12,189
Net cash provided by operating activities	839,635	553,844
Cash flows from investing activities:
Purchases of investments	(54,421)	(26,257)
Sales and maturities of investments	67,164	29,456
Business acquisitions, net of cash and restricted cash acquired	(830,993)	(3,629,654)
Purchases of real estate	(41,782)	(48,580)
Purchases of other property, plant and equipment	(869,968)	(625,814)
Proceeds from sale of assets, net of cash transferred	0	47,767
Net cash used in investing activities	(1,730,000)	(4,253,082)
Cash flows from financing activities:
Proceeds from employee equity awards	25,860	20,119
Payment of dividends and special distribution	(368,759)	(304,373)
Proceeds from public offering of common stock, net of issuance costs	7,622	2,126,341
Proceeds from senior notes	929,850	1,250,000
Proceeds from loans payable	0	1,059,800
Repayments of capital lease and other financing obligations	(69,856)	(44,460)
Repayments of mortgage and loans payable	(25,415)	(42,305)
Debt extinguishment costs	(20,556)	(11,254)
Debt issuance costs	(11,583)	(40,619)
Other financing activities	580	(900)
Net cash provided by financing activities	467,743	4,012,349
Effect of foreign currency exchange rates on cash, cash equivalents and restricted cash	(25,840)	16,868
Net increase in cash, cash equivalents and restricted cash	(448,462)	329,979
Cash, cash equivalents and restricted cash at beginning of period	1,450,701	773,247
Cash, cash equivalents and restricted cash at end of period	1,002,239	1,103,226
Cash and cash equivalents	966,308	1,063,777
Current portion of restricted cash included in other current assets	25,277	28,965
Non-current portion of restricted cash included in other assets	$ 10,654	$ 10,484