Consolidated Statements of Cash Flows - USD ($) shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 79,727	$ (9,702)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, accretion, and amortization	517,590	502,659
Non-cash asset impairment and decommission costs	22,816	22,146
Non-cash compensation expense	60,633	32,140
Deferred income tax expense (benefit)	5,988	(27,925)
Loss on remeasurement of U.S. dollar denominated intercompany loans	25,880	113,138
Other non-cash items reflected in the Statements of Operations	14,839	31,374
Changes in operating assets and liabilities, net of acquisitions:
AR and costs and est. earnings in excess of billings on uncompleted contracts, net	(13,909)	(4,655)
Prepaid expenses and other assets	669	(28,061)
Operating lease right-of-use assets, net	68,518
Accounts payable and accrued expenses	(2,521)	(2,496)
Accrued interest	(14,228)	(14,813)
Long-term lease liabilities	(64,057)
Other liabilities	3,039	10,338
Net cash provided by operating activities	704,984	624,143
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(283,701)	(403,835)
Capital expenditures	(111,381)	(104,966)
Purchase of investments	(528,915)	(99,823)
Proceeds from sale of investments	515,557	95,890
Other investing activities	(6,626)	(7,583)
Net cash used in investing activities	(415,066)	(520,317)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under Revolving Credit Facility	265,000	805,000
Repayments under Revolving Credit Facility	(590,000)	(725,000)
Repayment of Tower Securities	(920,000)	(755,000)
Proceeds from issuance of Tower Securities, net of fees	1,153,036	631,479
Repurchase and retirement of common stock	(267,534)	(453,539)
Proceeds from employee stock purchase/stock option plans	112,909	33,678
Repayment of Term Loans	(18,000)	(1,941,000)
Proceeds from Term Loans, net of fees		2,377,264
Payment of dividends on common stock	(41,873)
Other financing activities	(1,119)	(4,071)
Net cash used in financing activities	(307,581)	(31,189)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(1,957)	(13,608)
NET CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(19,620)	59,029
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH:
Beginning of period	178,300	104,295
End of period	158,680	163,324
Cash paid during the period for:
Interest	306,810	293,372
Income taxes	14,860	16,525
SUPPLEMENTAL DISCLOSURE OF NON-CASH ACTIVITIES:
Right-of-use assets obtained in exchange for new operating lease liabilities	37,913
Operating lease modifications and reassessments	67,794
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 1,706	$ 1,142
Common stock issued in connection with acquisitions	1,680
Consolidation of an equity method investment	$ 71,990