Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Schedule Of Income Tax [Line Items]
Income tax benefit (expense)	$ (679)		$ 0	$ 8,549	$ 2,500
Non-cash impairment charge				76,800	$ 0
Trulia | Trade names and trademarks
Schedule Of Income Tax [Line Items]
Income tax benefit (expense)				$ 9,700
Non-cash impairment charge		$ 71,500
Federal
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards						$ 1,137,600
State
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards						$ 34,300