Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income (loss)	$ (3,256)	$ 246,792
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Depreciation and amortization	131,465	135,911
Loss (gain) on sale of subsidiary and disposal of property and equipment	1,927	(243,261)
(Gain) loss on derivative instruments	(39,386)	7,883
Loss on debt extinguishment	8,430	1,681
Payment of redemption and call premiums and fees on debt modification	(65,225)	0
Non-cash interest expense	22,359	28,312
Non-cash share-based compensation expense	35,337	20,909
Bad debt expense	51,439	56,114
Deferred income taxes	(3,196)	(12,535)
Unrealized foreign currency exchange loss (gain)	11,756	(58,656)
Non-cash loss from non-income tax contingencies	3,813	7,758
Other, net	(1,052)	(1,090)
Changes in operating assets and liabilities:
Restricted cash	318	(6,089)
Receivables	(162,375)	(148,198)
Prepaid expenses and other assets	(99,019)	(68,340)
Accounts payable and accrued expenses	(86,368)	6,766
Income tax receivable/payable, net	(21,868)	7
Deferred revenue and other liabilities	9,231	(37,377)
Net cash used in operating activities	(205,670)	(63,413)
Cash flows from investing activities
Purchase of property and equipment	(86,793)	(86,224)
Expenditures for deferred costs	(8,248)	(8,753)
Receipts from sale of subsidiary and property and equipment	1,001	340,096
Property insurance recoveries	370	1,431
Settlement of derivatives related to sale of subsidiaries	0	(10,297)
Business acquisitions, net of cash acquired	(835)	0
Proceeds from affiliates	85	0
Payments (to) from related parties	(593)	1,045
Change in restricted cash and investments	(639)	(9,629)
Net cash (used in) provided by investing activities	(95,652)	227,669
Cash flows from financing activities
Proceeds from issuance of long-term debt, net of original issue discount	2,110,859	262,696
Payments on long-term debt	(2,415,530)	(477,008)
Payments of deferred purchase price for acquisitions	(6,329)	(7,746)
Payments to purchase noncontrolling interests	0	(25,665)
Proceeds from issuance of convertible redeemable preferred stock, net of issuance costs	55,290	0
Payment of dividends to noncontrolling interest holders	0	(89)
Proceeds from initial public offering, net of issuance costs	456,561	0
Proceeds from exercise of stock options	0	245
Withholding of shares to satisfy tax withholding for vested stock awards and exercised stock options	(1,277)	(1,308)
Payments of debt issuance costs	(11,244)	(1,443)
Noncontrolling interest holder's loan to subsidiaries	943	492
Distributions to noncontrolling interest holders	(847)	(1,447)
Net cash provided by (used in) financing activities	188,426	(251,273)
Effects of exchange rate changes on cash	15,094	14,449
Change in cash included in current assets held for sale	0	(1,337)
Net change in cash and cash equivalents	(97,802)	(73,905)
Cash and cash equivalents at beginning of period	464,965	458,673
Cash and cash equivalents at end of period	$ 367,163	$ 384,768