ACCOUNTING POLICIES (Details 7) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 17, 2018	Dec. 29, 2017	Nov. 08, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings per share
Net loss attributable to stockholders of Overstock.com, Inc.				$ (47,923)	$ (786)	$ (163,743)	$ (14,188)
Less: Preferred stock dividends - declared and accumulated				27	27	80	80
Undistributed loss				(47,950)	(813)	(163,823)	(14,268)
Less: Undistributed loss allocated to participating securities				(1,055)	(22)	(3,728)	(386)
Net loss attributable to common shares				$ (46,895)	$ (791)	$ (160,095)	$ (13,882)
Net loss per common share—basic:
Net loss attributable to common shares-basic (in dollars per share)				$ (1.55)	$ (0.03)	$ (5.47)	$ (0.55)
Weighted average common shares outstanding-basic (in shares)				30,279,000	25,003,000	29,256,000	25,024,000
Effect of dilutive securities:
Stock options and restricted stock awards (in shares)				0	0	0	0
Weighted average common shares outstanding-diluted (in shares)				30,279,000	25,003,000	29,256,000	25,024,000
Net loss attributable to common shares-diluted (in dollars per share)				$ (1.55)	$ (0.03)	$ (5.47)	$ (0.55)
Anti-dilutive securities excluded from computation of earnings per share
Number of securities called by warrants or rights (in shares)	1,250,000	2,472,188	3,722,188
Proceeds from issuance and exercise of stock warrants	$ 50,600	$ 100,000				$ 50,587	$ 0	$ 157,046	$ 0
Proceeds from issuance of stock warrants			$ 6,500
Exercise price of warrants or rights (in dollars per share)			$ 40.45
Stock options and restricted stock units
Anti-dilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share (in shares)				498,000	192,000	578,000	165,000
Common shares issuable under stock warrant
Anti-dilutive securities excluded from computation of earnings per share
Anti-dilutive securities excluded from computation of earnings per share (in shares)				0	0	28,000	0