CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 218,255	$ 285,443
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and intangible assets amortization	62,197	42,216
Operating lease right-of-use assets expense	15,336	13,912
Deferred income tax benefit	(22,627)	(13,221)
Provision for bad debts	5,799	2,559
Stock-based compensation expense	103,256	84,784
Other	2,294	2,560
Changes in operating assets and liabilities:
Accounts receivable	62,184	(12,610)
Other receivables and current assets	12,735	37,773
Other long-term assets	(12,341)	(2,288)
Accounts payable, accrued expenses and current liabilities	(76,517)	(37,289)
Accrued income taxes	22,010	(2,547)
Deferred revenue	(29,978)	(35,807)
Other long-term liabilities	10,940	(5,000)
Net cash provided by operating activities	373,543	360,485
Cash flows from investing activities:
Acquisitions, net of cash acquired	(100,194)	(294,987)
Capital expenditures	(24,195)	(25,781)
Other investing activities	(6,201)	(12,680)
Net cash used in investing activities	(130,590)	(333,448)
Cash flows from financing activities:
Principal payments on long-term debt	(75,000)	0
Purchase of treasury stock	(161,029)	(59,116)
Restricted stock withholding taxes paid in lieu of issued shares	(66,774)	(37,936)
Proceeds from shares issued for stock-based compensation	26,957	28,633
Other financing activities	0	(1,617)
Net cash used in financing activities	(275,846)	(70,036)
Effect of exchange rate fluctuations on cash and cash equivalents	5,540	(1,456)
Net decrease in cash and cash equivalents	(27,353)	(44,455)
Cash and cash equivalents, beginning of period	872,094	777,139
Cash and cash equivalents, end of period	844,741	732,684
Supplemental disclosure of cash flow information:
Income taxes paid	35,576	73,561
Interest paid	$ 9,985	$ 356