Segment Information and Revenue - Revenue Categories (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue:
Revenue	$ 8,147,376	$ 3,339,817	$ 2,742,837
Cost of revenue	6,394,177	1,866,392	1,544,099
Gross profit	1,753,199	1,473,425	1,198,738
Operating expenses:
Sales and marketing	1,076,235	691,119	728,631
Technology and development	474,396	390,172	350,923
General and administrative	448,773	356,722	366,019
Impairment and restructuring costs	72,173	76,800	0
Acquisition-related costs	8,615	0	0
Integration costs	680	0	650
Total operating expenses	2,080,872	1,514,813	1,446,223
Loss from operations	(327,673)	(41,388)	(247,485)
Other income	10,188	25,529	39,658
Interest expense	(191,910)	(155,227)	(101,792)
Loss before income taxes	(526,514)	(169,638)	(309,619)
Operating Segments
Operating expenses:
Loss before income taxes	(388,697)	(52,756)	(277,022)
Homes
Revenue:
Revenue	6,015,778	1,715,375	1,365,250
Cost of revenue	6,106,944	1,634,755	1,324,464
Homes | Operating Segments
Revenue:
Revenue	6,015,778	1,715,375	1,365,250
Cost of revenue	6,106,944	1,634,755	1,324,464
Gross profit	(91,166)	80,620	40,786
Operating expenses:
Sales and marketing	414,797	190,818	171,571
Technology and development	124,513	106,218	69,962
General and administrative	118,790	87,034	81,383
Impairment and restructuring costs	71,247	0	0
Acquisition-related costs	0	0	0
Integration costs	0	0	0
Total operating expenses	729,347	384,070	322,916
Loss from operations	(820,513)	(303,450)	(282,130)
Other income	2,878	0	0
Interest expense	(63,829)	(16,804)	(29,990)
Loss before income taxes	(881,464)	(320,254)	(312,120)
Homes | Zillow Offers | Operating Segments
Revenue:
Revenue	5,982,357	1,710,535	1,365,250
Homes | Premier Agent | Operating Segments
Revenue:
Revenue	0	0	0
Homes | Other | Operating Segments
Revenue:
Revenue	33,421	4,840	0
Homes | Mortgages | Operating Segments
Revenue:
Revenue	0	0	0
IMT
Revenue:
Revenue	1,885,782	1,450,232	1,276,896
Cost of revenue	203,449	193,097	193,885
IMT | Operating Segments
Revenue:
Revenue	1,885,782	1,450,232	1,276,896
Cost of revenue	203,449	193,097	193,885
Gross profit	1,682,333	1,257,135	1,083,011
Operating expenses:
Sales and marketing	552,592	440,517	503,473
Technology and development	317,663	260,277	255,964
General and administrative	258,161	224,757	243,514
Impairment and restructuring costs	0	73,900	0
Acquisition-related costs	8,615	0	0
Integration costs	680	0	0
Total operating expenses	1,137,711	999,451	1,002,951
Loss from operations	544,622	257,684	80,060
Other income	0	5,300	0
Interest expense	(32)	0	0
Loss before income taxes	544,590	262,984	80,060
IMT | Zillow Offers | Operating Segments
Revenue:
Revenue	0	0	0
IMT | Premier Agent | Operating Segments
Revenue:
Revenue	1,395,723	1,046,954	923,876
IMT | Other | Operating Segments
Revenue:
Revenue	490,059	403,278	353,020
IMT | Mortgages | Operating Segments
Revenue:
Revenue	0	0	0
Mortgages
Revenue:
Revenue	245,816	174,210	100,691
Cost of revenue	83,784	38,540	25,750
Mortgages | Operating Segments
Revenue:
Revenue	245,816	174,210	100,691
Cost of revenue	83,784	38,540	25,750
Gross profit	162,032	135,670	74,941
Operating expenses:
Sales and marketing	108,846	59,784	53,587
Technology and development	32,220	23,677	24,997
General and administrative	71,822	44,931	41,122
Impairment and restructuring costs	926	2,900	0
Acquisition-related costs	0	0	0
Integration costs	0	0	650
Total operating expenses	213,814	131,292	120,356
Loss from operations	(51,782)	4,378	(45,415)
Other income	5,019	2,369	1,409
Interest expense	(5,060)	(2,233)	(956)
Loss before income taxes	(51,823)	4,514	(44,962)
Mortgages | Zillow Offers | Operating Segments
Revenue:
Revenue	0	0	0
Mortgages | Premier Agent | Operating Segments
Revenue:
Revenue	0	0	0
Mortgages | Other | Operating Segments
Revenue:
Revenue	0	0	0
Mortgages | Mortgages | Operating Segments
Revenue:
Revenue	$ 245,816	$ 174,210	$ 100,691