Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ (18,566)	$ 78,481	$ 98,983
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation	30,237	21,647	11,775
Amortization of intangible assets and developed software	85,212	64,293	40,073
Stock-based compensation	72,879	55,261	32,748
Deferred taxes	(7,726)	1,724	(31,179)
Other	8,531	5,552	2,457
Change in assets and liabilities, net of the effects of business acquisitions:
Accounts receivable	(11,591)	(6,092)	(26,236)
Income taxes receivable	5,989	(1,356)	(1,597)
Prepaid expenses and other assets	(13,854)	(16,270)	5,516
Restaurant food liability	4,380	2,921	8,576
Accounts payable	1,978	11,160	(4,244)
Accrued payroll	1,804	3,621	5,537
Other accruals	23,349	4,585	11,735
Net cash provided by operating activities	182,622	225,527	154,144
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of investments	(85,989)	(57,197)	(154,758)
Proceeds from maturity of investments	51,366	67,166	215,983
Capitalized website and development costs	(48,524)	(31,180)	(21,325)
Purchases of property and equipment	(55,167)	(43,033)	(18,971)
Acquisition of other intangible assets	(9,980)	(11,851)	(25,147)
Acquisitions of businesses, net of cash acquired	127	(517,909)	(333,301)
Other cash flows from investing activities	(250)		557
Net cash used in investing activities	(148,417)	(594,004)	(336,962)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	500,000	222,000	200,000
Repayments of borrowings under the credit facility	(342,313)	(53,906)	(25,781)
Proceeds from the issuance of common stock		200,000
Taxes paid related to net settlement of stock-based compensation awards	(23,753)	(35,599)	(10,556)
Proceeds from exercise of stock options	4,469	14,190	16,375
Payments for debt issuance costs	(9,136)		(1,979)
Net cash provided by financing activities	129,267	346,685	178,059
Net change in cash, cash equivalents, and restricted cash	163,472	(21,792)	(4,759)
Effect of exchange rates on cash, cash equivalents and restricted cash	320	(645)	784
Cash, cash equivalents, and restricted cash at beginning of year	215,802	238,239	242,214
Cash, cash equivalents, and restricted cash at end of the period	379,594	215,802	238,239
SUPPLEMENTAL DISCLOSURE OF NON-CASH ITEMS
Cash paid for income taxes	1,163	7,895	19,148
Capitalized property, equipment and website and development costs in accounts payable at period end	5,627	7,463	2,960
Net working capital adjustment receivable		127	737
Fair value of equity awards assumed on acquisition		2,966	274
RECONCILIATION OF CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Cash and cash equivalents	375,909	211,245	$ 234,090
Restricted cash included in prepaid expenses and other current assets	$ 501	$ 1,398
Restricted Cash, Current, Asset, Statement of Financial Position [Extensible List]	us-gaap:PrepaidExpenseAndOtherAssetsCurrent	us-gaap:PrepaidExpenseAndOtherAssetsCurrent	us-gaap:PrepaidExpenseAndOtherAssetsCurrent
Restricted cash included in other assets	$ 3,184	$ 3,159	$ 4,149
Restricted Cash, Noncurrent, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Total cash, cash equivalents, and restricted cash	$ 379,594	$ 215,802	$ 238,239