The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Goodwill and Intangible Assets, net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Indefinite-lived Intangible Assets [Line Items]
Impairment and restructuring costs	$ 56,828,000	$ 76,800,000	$ 0
Trulia \| IMT
Indefinite-lived Intangible Assets [Line Items]
Impairment and restructuring costs		68,600,000
Trulia \| Mortgages
Indefinite-lived Intangible Assets [Line Items]
Impairment and restructuring costs		2,900,000
Trade names and trademarks \| Trulia
Indefinite-lived Intangible Assets [Line Items]
Impairment and restructuring costs	$ 0	71,500,000	0
Indefinite-lived intangible asset				$ 108,000,000
Indefinite-lived intangible assets (excluding goodwill), fair value disclosure				$ 36,500,000
Useful life of capitalized purchased content asset	10 years
Technology and development
Indefinite-lived Intangible Assets [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 61,300,000	$ 50,500,000	$ 44,900,000