Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 76,238	$ (175,656)	$ (24,295)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, accretion, and amortization	638,189	660,021	627,072
Non-cash interest expense	2,203	1,505	27,112
Deferred income tax expense (benefit)	1,409	(5)	530
Non-cash asset impairment and decommission costs	25,693	89,406	18,384
Non-cash compensation expense	32,915	28,747	22,671
Amortization of deferred financing fees	21,136	19,154	17,572
(Gain) loss on remeasurement of U.S. denominated intercompany loan	(90,030)	178,854	22,965
Gain on sale of cost method investments	0	(38,326)	(12,461)
Loss from extinguishment of debt, net	52,701	783	26,204
Gain on foreign currency swap contract			(17,891)
Provision for doubtful accounts	22,516	896	365
Other non-cash items reflected in the Statements of Operations	(4,837)	(6,755)	(7,754)
Changes in operating assets and liabilities, net of acquisitions:
AR and costs and est. earnings in excess of billings on uncompleted contracts, net	(7,270)	15,975	(36,245)
Prepaid expenses and other assets	(40,289)	(62,934)	(62,185)
Accounts payable and accrued expenses	(10,516)	7,366	5,475
Other liabilities	22,467	3,999	66,821
Net cash provided by operating activities	742,525	723,030	674,340
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions	(276,835)	(609,530)	(1,585,222)
Capital expenditures	(139,982)	(208,707)	(211,251)
Proceeds from sale of investments	712	89,728	20,889
Other investing activities	(12,130)	(8,556)	11,457
Net cash used in investing activities	(428,235)	(737,065)	(1,764,127)
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under Revolving Credit Facility	580,000	770,000	700,000
Repayments under Revolving Credit Facility	(190,000)	(895,000)	(790,000)
Repayment of Term Loans	(20,000)	(190,000)	(310,500)
Proceeds from Term Loans, net of fees		489,884	1,483,337
Payments on settlement of convertible debt			(499,721)
Payments for settlement of common stock warrants		(150,874)	(884,985)
Proceeds from issuance of Tower Securities, net of fees	690,475	489,100	1,518,229
Repayment of Tower Securities	(550,000)		(680,000)
Repurchase and retirement of common stock, inclusive of fees	(545,689)	(450,073)
Other financing activities	8,394	12,714	(19,582)
Net cash (used in) provided by financing activities	(288,557)	75,751	995,298
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	13,618	(12,993)	13,977
NET CHANGE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	39,351	48,723	(80,512)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH:
Beginning of year	146,619	97,896	178,408
End of year	185,970	146,619	97,896
Cash paid during the period for:
Interest	338,409	322,396	278,359
Income taxes	9,655	9,431	7,525
SUPPLEMENTAL CASH FLOW INFORMATION OF NON-CASH ACTIVITIES:
Assets acquired through capital leases	1,386	$ 2,627	1,290
Issuance of stock for settlement of convertible debt and warrants, net			229
8.25% Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment for the redemption of Senior Notes			(253,805)
5.625% Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment for the redemption of Senior Notes	(514,065)
5.75% Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment for the redemption of Senior Notes	(825,795)
2014 Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Senior Notes, net of fees			$ 732,325
2016 Senior Notes [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Senior Notes, net of fees	$ 1,078,123