Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 188,720	$ (82,139)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, accretion, and amortization	530,266	541,587
Loss on remeasurement of U.S. dollar denominated intercompany loans	42,582	299,913
Non-cash compensation expense	59,175	51,915
Non-cash asset impairment and decommission costs	17,935	28,675
Loss from extinguishment of debt	12,672	19,463
Deferred income tax benefit	(2,711)	(93,104)
Other non-cash items reflected in the Statements of Operations	58,725	28,700
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable and costs and estimated earnings in excess of billings on uncompleted contracts, net	(6,371)	48,272
Prepaid expenses and other assets	(25,589)	(2,571)
Operating lease right-of-use assets, net	86,717	88,470
Accounts payable and accrued expenses	8,465	5,672
Accrued interest	(27,873)	(17,010)
Long-term lease liabilities	(83,885)	(75,199)
Other liabilities	32,502	40,264
Net cash provided by operating activities	891,330	882,908
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(1,187,754)	(199,899)
Capital expenditures	(90,407)	(95,371)
Purchase of investments	(755,530)	(1,288,267)
Proceeds from sale of investments	755,280	1,235,000
Other investing activities	589	(4,841)
Net cash used in investing activities	(1,277,822)	(353,378)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under Revolving Credit Facility	810,000	515,000
Repayments under Revolving Credit Facility	(1,190,000)	(1,005,000)
Proceeds from issuance of Senior Notes, net of fees	1,485,512	1,479,522
Repayment of Senior Notes	(757,500)	(759,143)
Proceeds from issuance of Tower Securities, net of fees	1,152,437	1,336,003
Repayment of Tower Securities	(760,000)	(1,200,000)
Repurchase and retirement of common stock	(284,343)	(378,988)
Payment of dividends on common stock	(190,456)	(156,199)
Proceeds from employee stock purchase/stock option plans, net of taxes	64,127	50,283
Termination of interest rate swap		(176,200)
Other financing activities	(21,165)	(19,528)
Net cash provided by (used in) financing activities	308,612	(314,250)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(10,529)	(20,427)
NET CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(88,409)	194,853
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH:
Beginning of period	342,808	141,120
End of period	254,399	335,973
Cash paid during the period for:
Interest	298,589	298,140
Income taxes	20,153	14,061
SUPPLEMENTAL CASH FLOW INFORMATION OF NON-CASH ACTIVITIES:
Right-of-use assets obtained in exchange for new operating lease liabilities	27,691	21,785
Operating lease modifications and reassessments	21,829	23,811
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 1,765	$ 893