Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flow from operating activities:
Net income from consolidated operations	$ 402,562,000	$ 48,003,000
Adjustments to reconcile net income to net cash provided by operating activities:
Equity-based compensation	10,862,000	5,154,000
Depreciation and amortization	7,513,000	1,840,000
Noncash lease expense	682,000	345,000
Loss on disposal of fixed asset	779,000	352,000
Amortization of premium of marketable securities	5,490,000	327,000
Provision for credit losses	4,107,000	441,000
Deferred taxes	(6,574,000)	(1,083,000)
Unrecognized tax benefits	157,000	389,000
Net loss on marketable securities	595,000
Equity loss in investee		631,000
Gain (loss) on equity-method investments	(3,734,000)	2,591,000
Other	(22,000)	(7,000)
Changes in operating assets and liabilities:
Trade accounts receivable	65,003,000	(84,557,000)
Other current and long-term assets	(2,086,000)	(19,176,000)
Accounts payable	(9,002,000)	14,675,000
Accrued liabilities and other liabilities	(953,000)	22,169,000
Income tax payable	(35,444,000)	14,603,000
Contract liabilities	(18,697,000)
Customer deposit	40,902,000
Operating and finance lease liabilities	(649,000)	(325,000)
Net cash provided by operating activities	461,491,000	6,372,000
Cash flow from investing activities:
Purchases of fixed assets	(17,829,000)	(11,336,000)
Proceeds from sale of fixed assets	22,000	8,000
Purchase of marketable securities	(523,939,000)	(13,563,000)
Purchase of redeemable preferred stock	(20,000,000)
Proceeds from sale of marketable securities	155,809,000	8,072,000
Maturities of marketable securities	61,516,000	13,119,000
Acquisition of businesses, net of cash acquired	(61,868,000)
Investment in equity-method investees		(3,971,000)
Net cash used in investing activities	(406,289,000)	(7,671,000)
Cash flow from financing activities:
Proceeds from public offerings of common stock, net of issuance costs	75,626,000	42,292,000
Proceeds from noncontrolling interest	10,000
Proceeds from exercise of stock options	85,000	102,000
Principal paid for finance lease	(3,000)
Common stock withholding for employee tax obligations	(3,467,000)	(46,000)
Net cash provided by financing activities	72,251,000	42,348,000
Effect of exchange rate changes on cash and cash equivalents	(2,000)	17,000
Net increase in cash and cash equivalents	127,451,000	41,066,000
Cash and cash equivalents at beginning of period	87,426,000	11,965,000
Cash and cash equivalents at end of period	214,877,000	53,031,000
Supplemental disclosures of cash flow information:
Income taxes paid	169,540,000	28,000
Supplemental disclosures of non-cash investing and financing activities:
Purchases of marketable securities in other current liabilities	20,092,000
Contingent consideration for business acquisition included in other current liabilities	8,500,000
Purchases of fixed assets in accounts payable	2,279,000	2,822,000
Operating lease right-of-use assets obtained in exchange for lease liabilities	1,706,000	393,000
Operating lease right-of-use assets reduced due to lease modification and termination	$ 399,000
Public offerings proceeds included in other current assets		8,407,000
Public offerings costs included in accounts payable		$ 374,000