CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 500,412	$ 523,710	$ 454,627
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	132,504	114,563	106,867
Operating lease right-of-use assets expense	23,514	22,721	22,193
Deferred income tax benefit	(91,306)	(130,716)	(34,490)
Provision for bad debts	2,704	6,222	1,006
Stock-based compensation expense	221,891	168,128	166,338
Gain on equity investment	0	0	(15,139)
Other	1,238	4,680	2,708
Changes in operating assets and liabilities:
Accounts receivable	(102,516)	(114,986)	(149,017)
Other receivables and current assets	(30,204)	30,259	(64,316)
Other long-term assets	(8,563)	(3,613)	(3,217)
Accounts payable, accrued expenses and current liabilities	27,853	(8,250)	53,846
Accrued income taxes	13,731	99	(18,429)
Deferred revenue	34,507	33,003	26,547
Other long-term liabilities	(8,643)	(14,817)	(42)
Net cash provided by operating activities	717,122	631,003	549,482
Cash flows from investing activities:
Acquisitions, net of cash acquired	(208,911)	(386,264)	(510,805)
Capital expenditures	(25,318)	(24,370)	(23,018)
Other investing activities	(5,813)	(734)	(2,990)
Net cash used in investing activities	(240,042)	(411,368)	(536,813)
Cash flows from financing activities:
Principal payments on long-term debt	0	0	(45,000)
Purchase of treasury stock	(196,494)	(205,571)	(134,679)
Restricted stock withholding taxes paid in lieu of issued shares	(63,645)	(64,242)	(97,037)
Proceeds from shares issued for stock-based compensation	30,114	25,595	31,377
Other financing activities	(1,294)	(1,290)	(513)
Net cash used in financing activities	(231,319)	(245,508)	(245,852)
Effect of exchange rate fluctuations on cash and cash equivalents	49	(27,403)	(11,822)
Net increase (decrease) in cash and cash equivalents	245,810	(53,276)	(245,005)
Cash and cash equivalents, beginning of period	614,391	667,667	912,672
Cash and cash equivalents, end of period	860,201	614,391	667,667
Supplemental disclosures of cash flow information:
Income taxes paid	144,117	115,339	130,426
Interest paid	46,069	20,844	11,146
Non-cash and unpaid consideration in connection with acquisitions	$ 5,056	$ 5,391	$ 0