Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (527,777)	$ (162,115)	$ (305,361)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	129,780	110,031	87,467
Share-based compensation	311,686	197,550	198,902
Amortization of right of use assets	22,705	24,338	23,142
Amortization of contract cost assets	41,577	36,494	35,323
Amortization of debt discount and debt issuance costs	104,437	102,401	52,097
Gain (loss) on extinguishment of debt	17,119	(1,448)	0
Impairment and restructuring costs	56,828	76,800	0
Inventory valuation adjustment	407,921	0	0
Deferred income taxes	(2,746)	(7,523)	(4,258)
Other adjustments to reconcile net loss to cash provided by (used in) operating activities	15,249	4,761	3,602
Changes in operating assets and liabilities:
Accounts receivable	(82,312)	(5,585)	(3,694)
Mortgage loans held for sale	223,990	(294,251)	(1,098)
Inventory	(3,826,713)	345,277	(673,798)
Prepaid expenses and other assets	(81,614)	(15,957)	(978)
Contract cost assets	(26,323)	(42,004)	(34,713)
Lease liabilities	(29,276)	(2,149)	(18,940)
Accounts payable	4,699	12,972	(496)
Accrued expenses and other current liabilities	61,462	15,321	19,573
Accrued compensation and benefits	13,203	9,861	6,417
Deferred revenue	789	9,248	5,667
Other long-term liabilities	(11,378)	10,175	(1,028)
Net cash provided by (used in) operating activities	(3,176,694)	424,197	(612,174)
Investing activities
Proceeds from maturities of investments	2,206,344	2,230,705	1,126,058
Proceeds from sales of investments	0	116,394	0
Purchases of investments	(516,346)	(3,287,071)	(1,495,477)
Purchases of property and equipment	(73,305)	(84,940)	(67,044)
Purchases of intangible assets	(31,094)	(23,577)	(19,591)
Proceeds from sale of equity investment	0	10,000	0
Cash paid for acquisition, net	(497,320)	0	0
Net cash provided by (used in) investing activities	1,088,279	(1,038,489)	(456,054)
Financing activities
Proceeds from issuance of convertible senior notes, net of issuance costs	0	553,282	1,157,675
Premiums paid for capped call confirmations	0	0	(159,677)
Proceeds from issuance of Class C capital stock, net of issuance costs	544,557	411,522	0
Proceeds from issuance of term loan, net of issuance costs	1,138,227	0	0
Proceeds from borrowings on credit facilities	3,618,299	348,684	688,489
Repayments of borrowings on credit facilities	(1,779,869)	(679,042)	(113,665)
Net borrowings (repayments) on warehouse lines of credit and repurchase agreements	(197,083)	278,616	(2,590)
Repurchases of Class C capital stock	(302,297)	0	0
Settlement of convertible senior notes	(1,297)	(194,768)
Proceeds from exercise of stock options	127,222	444,028	65,465
Value of equity awards withheld for tax liability	(129)	(4)	(3)
Net cash provided by financing activities	3,147,630	1,162,318	1,635,694
Net increase in cash, cash equivalents and restricted cash during period	1,059,215	548,026	567,466
Cash, cash equivalents and restricted cash at beginning of period	1,778,935	1,230,909	663,443
Cash, cash equivalents and restricted cash at end of period	2,838,150	1,778,935	1,230,909
Supplemental disclosures of cash flow information
Cash paid for interest	108,928	50,755	42,156
Noncash transactions:
Beneficial interests in securitizations	63,289	0	0
Write-off of fully amortized intangible assets	57,995	62,622	9,999
Write-off of fully depreciated property and equipment	48,626	115,086	36,159
Capitalized share-based compensation	30,372	16,557	11,947
Property and equipment purchased on account	$ 1,357	$ 335	$ 8,775