GOODWILL (Details) - USD ($) $ in Thousands				3 Months Ended	9 Months Ended	12 Months Ended
	Jul. 01, 2015	Jun. 01, 2015	Apr. 02, 2014	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill, beginning balance					$ 1,138,805	$ 718,587
Acquisition					111,705	421,724
Effect of foreign currency translation					(565)	(1,506)
Goodwill, ending balance				$ 1,249,945	1,249,945	1,138,805
Apartments.com [Member]
Goodwill [Line Items]
Goodwill, period increase			$ 421,724
Apartment Finder [Member]
Goodwill [Line Items]
Goodwill, period increase		$ 107,692
Goodwill [Roll Forward]
Goodwill, ending balance		$ 107,692
Belbex [Member]
Goodwill [Line Items]
Goodwill, period increase	$ 2,400
Independent Distributor Buyout [Member]
Goodwill [Line Items]
Goodwill, period increase				1,613
North America [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance					1,114,363	692,639
Acquisition					109,305	421,724
Effect of foreign currency translation					0	0
Goodwill, ending balance				1,223,668	1,223,668	1,114,363
International [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance					24,442	25,948
Acquisition					2,400	0
Effect of foreign currency translation					(565)	(1,506)
Goodwill, ending balance				$ 26,277	$ 26,277	$ 24,442