Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income	$ 87,240	$ 85,762	$ 104,690
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	8,946	7,987	8,613
Equity-based compensation	33,355	31,841	19,864
Loss (gain) on disposal of equipment	21	(429)	59
Deferred income taxes	1,036	(1,406)	(4,265)
Unrealized foreign currency loss (gain)	897	(708)	298
Changes in operating assets and liabilities:
Accounts receivable, net	(6,592)	(1,065)	(9,341)
Other assets	(971)	(8,924)	(4,357)
Accounts payable, accrued and other liabilities	(3,097)	20,812	18,603
Income taxes	1,886	1,180	(4,390)
Deferred revenue	18,164	11,858	7,575
Net cash provided by operating activities	140,885	146,908	137,349
Investing activities:
Purchases of property and equipment	(2,730)	(15,193)	(7,306)
Purchases of short-term investments			(14,584)
Maturities of short-term investments		1,439	12,052
Net cash used in investing activities	(2,730)	(13,754)	(9,838)
Financing activities:
Purchase of common stock	(43,561)	(121,487)	(149,322)
Net cash used in financing activities	(43,561)	(121,487)	(149,322)
Foreign currency impact on cash	(567)	(115)	(4,585)
Net change in cash and cash equivalents	94,027	11,552	(26,396)
Cash and cash equivalents at beginning of period	110,678	99,126	125,522
Cash and cash equivalents at end of period	204,705	110,678	99,126
Supplemental disclosures of cash flow information:
Cash paid for taxes	$ 23,766	$ 30,492	$ 40,215