Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended			12 Months Ended
		Sep. 30, 2017		Sep. 30, 2016	Sep. 30, 2018		Dec. 31, 2016
Cash flows from operating activities:
Net loss		$ (13,955)		$ (28,870)	$ (15,087)		$ (52,364)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation		56,473		58,025	75,296		79,255
Amortization of intangible assets		92,863		98,671	104,943		131,562
Amortization of financing costs and original issue discount		7,701		7,198	10,351		9,640
Loss on debt extinguishment	[1]				25,109
Deferred taxes		(34,831)		(26,611)	(63,360)		(42,762)
Equity-based compensation		3,839	[2]	3,718	28,795	[2]	2,772	[2]
Hedge ineffectiveness and realized loss		7,809		(7,153)	9,809		333
Provision for doubtful accounts		117		3,420	896		6,005
Other non-cash activities, net		(1,304)		(389)	573		87
Change in operating assets and liabilities:
Accounts receivable		(24,238)		(22,231)	25,153		(23,723)
Unbilled and deferred revenue		(42,309)		(46,209)	2,636		(17,997)
Inventories		6,162		218	1,746		720
Other operating assets		3,791		(20,104)	(16,576)		(28,037)
Accounts payable and other operating liabilities		16,781		46,948	(9,901)		46,456
Net cash provided by operating activities		78,899		66,631	180,383		111,947
Cash flows from investing activities:
Purchase of property and equipment		(50,633)		(65,357)	(86,425)		(75,609)
Proceeds from sale of property and equipment		6,336		5,252	11,984		5,964
Business acquisitions, net of cash acquired		(53,822)			(104,377)
Other investing activities, net		657		(1,834)	(452)		110
Net cash used in investing activities		(97,462)		(61,939)	(179,270)		(69,535)
Cash flows from financing activities:
Repayments of capital lease obligations		(3,900)		(2,752)	(6,262)		(3,533)
Repayments of debt		(181,617)		(11,700)	(1,662,625)		(14,600)
Proceeds from term loan, net of financing costs					1,016,870
Proceeds from receivables financing agreement		150,000			115,000
Proceeds from revolving credit facility					60,000
Proceeds from issuance of common stock, net of share issuance costs		125		1,916	501,271		1,916
Repurchase of common stock and distributions		(1,229)		(28,456)	(2,922)		(30,229)
Net cash provided by (used in) financing activities		(36,621)		(40,992)	21,332		(46,446)
Net change in cash and cash equivalents		(55,184)		(36,300)	22,445		(4,034)
Cash and cash equivalents, beginning of period		67,963		71,997	12,779		71,997
Cash and cash equivalents, end of period		12,779		35,697	35,224		67,963
Supplemental Cash Flow Information:
Cash paid for income taxes, net		4,231		14,100	16,227		18,667
Cash paid for interest		$ 65,669		$ 59,644	$ 84,258		$ 86,370

[1] Represents losses on the extinguishment of debt.

[2] Represents equity-based compensation expense recognized for equity incentive plans outstanding, including $19,590 related to the IPO in the fiscal year ended September 30, 2018.