ACCOUNTING POLICIES - Impairment for Equity Securities Without Readily Determinable Fair Values (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Accounting Policies [Abstract]
Impairments and downward adjustments of equity securities without readily determinable fair values	$ 0	$ 2,958

Equity Securities without Readily Determinable Fair Value, Impairment Loss And Downward Adjustments

No definition available.

Name:	ostk_EquitySecuritieswithoutReadilyDeterminableFairValueImpairmentLossAndDownwardAdjustments
Namespace Prefix:	ostk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration