Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income (loss)	$ 38,436	$ (104,028)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	203,081	168,651
Stock-based compensation expense	56,018	67,930
Deferred taxes	(4,746)	(99,450)
Gain from divested operations	(38,500)	0
Amortization and write-off of deferred financing fees	12,205	13,236
Changes in assets and liabilities, net of acquisitions and divestitures:
Fees receivable, net	172,679	(15,090)
Deferred commissions	38,216	3,231
Prepaid expenses and other current assets	(64,395)	(32,159)
Other assets	23,444	(76,548)
Deferred revenues	68,895	198,353
Accounts payable, accrued, and other liabilities	(79,322)	108,141
Cash provided by operating activities	426,011	232,267
Investing activities:
Additions to property, equipment and leasehold improvements	(64,631)	(75,619)
Acquisitions - cash paid (net of cash acquired)	(15,855)	(2,641,770)
Divestitures - cash received (net of cash transferred)	520,709	0
Cash provided by (used in) investing activities	440,223	(2,717,389)
Financing activities:
Proceeds from employee stock purchase plan	11,134	8,550
Proceeds from borrowings	0	3,025,000
Payments for deferred financing fees	0	(51,171)
Payments on borrowings	(1,120,290)	(339,624)
Purchases of treasury stock	(104,400)	(37,188)
Cash (used in) provided by financing activities	(1,213,556)	2,605,567
Net (decrease) increase in cash and cash equivalents and restricted cash	(347,322)	120,445
Effects of exchange rates on cash and cash equivalents and restricted cash	(6,444)	28,377
Cash and cash equivalents and restricted cash, beginning of period	213,292	648,176
Cash and cash equivalents and restricted cash, end of period	$ 567,058	$ 499,354