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	$ 184,558	$ 142,968	$ 114,758
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	50,280	56,102	49,656
Stock-based compensation expense	58,437	49,366	38,621
Reduction in the carrying amount of operating lease right-of-use assets	20,188	21,783	26,326
Fair value mark-to-market of short-term investments	17,044	(1,209)	5,139
Unrealized foreign currency exchange gain, net	(1,363)	(16,643)	(3,821)
Deferred income tax benefit	(31,742)	(19,552)	(20,326)
Allowance/(reversal) for expected credit losses	2,453	683	(464)
Loss on settlement of convertible notes	0	0	12,845
Fair value changes in contingent consideration	1,900	8,250	0
Amortization of non-cash interest expense related to convertible notes	0	0	1,795
Others, net	948	510	168
Change in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(49,242)	(68,121)	(37,684)
Other current assets	(9,506)	(7,709)	(1,179)
Income taxes payable, net	(18,282)	8,779	(12,062)
Other assets	(14,833)	(10,723)	227
Accounts payable	(2,757)	2,385	(614)
Deferred revenue	(877)	2,473	(12,733)
Accrued employee costs	14,090	5,551	46,475
Accrued expenses and other liabilities	10,083	14,475	2,934
Operating lease liabilities	(20,181)	(23,227)	(25,674)
Net cash provided by operating activities	211,198	166,141	184,387
Cash flows from investing activities:
Purchases of property and equipment	(52,803)	(44,836)	(37,248)
Proceeds from sale of property and equipment	739	266	1,300
Business acquisition (net of cash and cash equivalents acquired)	0	(3,872)	(76,831)
Purchases of investments	(235,369)	(212,607)	(96,011)
Proceeds from redemption of investments	276,036	164,503	94,520
Investment in equity affiliate	(600)	0	0
Net cash used for investing activities	(11,997)	(96,546)	(114,270)
Cash flows from financing activities:
Principal payments of finance lease liabilities	(169)	(142)	(201)
Proceeds from borrowings	80,000	35,000	300,000
Repayments of borrowings	(130,000)	(45,000)	(329,031)
Payment of contingent consideration	(5,000)	0	0
Acquisition of treasury stock	(131,847)	(72,642)	(118,357)
Proceeds from issuance of common stock	5,566	1,060	710
Net cash used for financing activities	(181,450)	(81,724)	(146,879)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,029	(6,060)	(4,947)
Net increase/(decrease) in cash, cash equivalents and restricted cash	19,780	(18,189)	(81,709)
Cash, cash equivalents and restricted cash at the beginning of the period	125,621	143,810	225,519
Cash, cash equivalents and restricted cash at the end of the period	145,401	125,621	143,810
Cash paid during the period for:
Interest	13,895	8,189	6,589
Income taxes	104,882	57,058	49,997
Supplemental disclosure of non-cash investing and financing activities:
Settlement of portion of convertible notes through issuance of treasury stock	0	0	36,742
Assets acquired under finance lease	$ 461	$ 312	$ 71