CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 523,710	$ 454,627	$ 433,887
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	114,563	106,867	85,275
Operating lease right-of-use assets expense	22,721	22,193	20,971
Deferred income tax benefit	(130,716)	(34,490)	(30,932)
Provision for bad debts	6,222	1,006	6,438
Stock-based compensation expense	168,128	166,338	145,615
Gain on equity investment	0	(15,139)	0
Other	4,680	2,708	2,180
Changes in operating assets and liabilities:
Accounts receivable	(114,986)	(149,017)	(160,319)
Other receivables and current assets	30,259	(64,316)	(2,312)
Other long-term assets	(3,613)	(3,217)	(14,818)
Accounts payable, accrued expenses and current liabilities	(8,250)	53,846	21,362
Accrued income taxes	99	(18,429)	19,713
Deferred revenue	33,003	26,547	5,448
Other long-term liabilities	(14,817)	(42)	14,802
Net cash provided by operating activities	631,003	549,482	547,310
Cash flows from investing activities:
Acquisitions, net of cash acquired	(386,264)	(510,805)	(572,328)
Capital expenditures	(24,370)	(23,018)	(35,370)
Other investing activities	(734)	(2,990)	(6,555)
Net cash used in investing activities	(411,368)	(536,813)	(614,253)
Cash flows from financing activities:
Proceeds from long-term debt	0	0	375,000
Principal payments on long-term debt	0	(45,000)	(75,000)
Purchase of treasury stock	(205,571)	(134,679)	(161,029)
Restricted stock withholding taxes paid in lieu of issued shares	(64,242)	(97,037)	(71,019)
Proceeds from shares issued for stock-based compensation	25,595	31,377	29,560
Other financing activities	(1,290)	(513)	(915)
Net cash (used in) provided by financing activities	(245,508)	(245,852)	96,597
Effect of exchange rate fluctuations on cash and cash equivalents	(27,403)	(11,822)	10,924
Net (decrease) increase in cash and cash equivalents	(53,276)	(245,005)	40,578
Cash and cash equivalents, beginning of period	667,667	912,672	872,094
Cash and cash equivalents, end of period	614,391	667,667	912,672
Supplemental disclosures of cash flow information:
Income taxes paid	115,339	130,426	54,174
Interest paid	20,844	11,146	11,941
Fair value of unpaid consideration and common stock issued in connection with acquisitions	$ 5,391	$ 0	$ 232,690