QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) $ / shares in Units, shares in Thousands		3 Months Ended																12 Months Ended
	Aug. 08, 2018 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares		Sep. 30, 2018 USD ($) $ / shares shares		Jun. 30, 2018 USD ($) $ / shares shares		Mar. 31, 2018 USD ($) $ / shares shares		Dec. 31, 2017 USD ($) $ / shares shares		Sep. 30, 2017 USD ($) $ / shares shares	[7],[8]	Jun. 30, 2017 USD ($) $ / shares shares	[7],[8]	Mar. 31, 2017 USD ($) $ / shares shares	[7],[8]	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Apr. 30, 2018 USD ($)	Apr. 03, 2018 USD ($)	Dec. 27, 2017 subsidiary
Unrealized (loss) gain on investment in equity securities		$ (8,800,000)		$ 1,800,000		$ 1,500,000		$ (7,500,000)										$ (12,972,000)	$ 0	$ 0
Loss on debt refinancing																		4,434,000	0	0
Proceeds from the sale of business, first installment																		15,000,000	0	0
Future proceeds from the sale of business, second installment																		3,000,000
Gain on sale of business																		13,688,000	0	0
Restructuring charges																		11,560,000	0	0
Estimate of possible loss		6,200,000																6,200,000
Loss in the period		400,000		5,900,000														6,200,000
Net tax benefit																		(4,098,000)	276,256,000	(12,935,000)
Operating loss carryforwards		1,355,500,000								$ 1,339,600,000								1,355,500,000	1,339,600,000
Deferred tax assets, net		309,089,000								303,707,000								309,089,000	303,707,000
Income tax expense, adjustment of deferred tax asset																			6,300,000
Income tax expense, foreign income tax reserves																			10,500,000
Revenue		217,633,000	[1],[2],[3],[4],[5],[6],[7]	204,575,000	[1],[2],[3],[4],[5],[6],[7]	218,556,000	[1],[2],[3],[4],[5],[6],[7]	197,438,000	[1],[2],[3],[4],[5],[6],[7]	216,066,000	[7],[8]	$ 234,979,000		$ 250,685,000		$ 240,483,000		838,202,000	942,213,000	997,303,000
Gross profit		53,448,000	[1],[2],[3],[4],[5],[6],[7]	56,995,000	[1],[2],[3],[4],[5],[6],[7]	55,350,000	[1],[2],[3],[4],[5],[6],[7]	50,244,000	[1],[2],[3],[4],[5],[6],[7]	54,445,000	[7],[8]	60,081,000		65,292,000		62,530,000		216,037,000	242,348,000	307,258,000
(Loss) income before income taxes and non-controlling interests		(12,829,000)	[1],[2],[3],[4],[5],[6],[7]	16,129,000	[1],[2],[3],[4],[5],[6],[7]	3,071,000	[1],[2],[3],[4],[5],[6],[7]	(4,972,000)	[1],[2],[3],[4],[5],[6],[7]	3,112,000	[7],[8]	10,357,000		12,160,000		9,746,000		1,399,000	35,375,000	44,321,000
Net (loss) income		(10,868,000)	[1],[2],[3],[4],[5],[6],[7]	9,521,000	[1],[2],[3],[4],[5],[6],[7]	2,255,000	[1],[2],[3],[4],[5],[6],[7]	(3,607,000)	[1],[2],[3],[4],[5],[6],[7]	286,983,000	[7],[8]	7,766,000		9,722,000		7,160,000		(2,699,000)	311,631,000	31,386,000
Net (loss) income attributable to Altisource		$ (11,485,000)	[1],[2],[3],[4],[5],[6],[7]	$ 8,667,000	[1],[2],[3],[4],[5],[6],[7]	$ 1,568,000	[1],[2],[3],[4],[5],[6],[7]	$ (4,132,000)	[1],[2],[3],[4],[5],[6],[7]	$ 286,350,000	[7],[8]	$ 6,961,000		$ 9,035,000		$ 6,545,000		$ (5,382,000)	$ 308,891,000	$ 28,693,000
(Loss) earnings per share:
Basic (in dollars per share) | $ / shares		$ (0.69)	[1],[2],[3],[4],[5],[6],[7]	$ 0.51	[1],[2],[3],[4],[5],[6],[7]	$ 0.09	[1],[2],[3],[4],[5],[6],[7]	$ (0.24)	[1],[2],[3],[4],[5],[6],[7]	$ 16.16	[7],[8]	$ 0.39		$ 0.49		$ 0.35		$ (0.32)	$ 16.99	$ 1.53
Diluted (in dollars per share) | $ / shares		$ (0.69)	[1],[2],[3],[4],[5],[6],[7]	$ 0.49	[1],[2],[3],[4],[5],[6],[7]	$ 0.09	[1],[2],[3],[4],[5],[6],[7]	$ (0.24)	[1],[2],[3],[4],[5],[6],[7]	$ 15.72	[7],[8]	$ 0.38		$ 0.48		$ 0.34		$ (0.32)	$ 16.53	$ 1.46
Weighted average shares outstanding:
Basic (in shares) | shares		16,745	[1],[2],[3],[4],[5],[6],[7]	17,033	[1],[2],[3],[4],[5],[6],[7]	17,142	[1],[2],[3],[4],[5],[6],[7]	17,378	[1],[2],[3],[4],[5],[6],[7]	17,724	[7],[8]	18,023		18,335		18,662		17,073	18,183	18,696
Diluted (in shares) | shares		16,745	[1],[2],[3],[4],[5],[6],[7]	17,575	[1],[2],[3],[4],[5],[6],[7]	17,553	[1],[2],[3],[4],[5],[6],[7]	17,378	[1],[2],[3],[4],[5],[6],[7]	18,211	[7],[8]	18,429		18,836		19,304		17,073	18,692	19,612
2017 Subsidiary Merger
Net tax benefit										$ 284,100,000
Number of wholly-owned subsidiaries merged | subsidiary																							2
Operating loss carryforwards										1,300,000,000									$ 1,300,000,000
Deferred tax assets, net										$ 300,900,000									$ 300,900,000
Employee Severance and Professional Service Fees
Restructuring charges		$ 8,100,000		$ 3,400,000
Rental Property Management Business
Goodwill, written off																		$ 2,256,000
Buy-Renovate-Lease-Sell Business
Goodwill, written off																		2,640,000
Buy-Renovate-Lease-Sell Business | Real Estate Market
Goodwill, written off		$ 2,600,000																2,600,000
Discontinued Operations, Disposed of by Sale | Rental Property Management Business
Total proceeds from the sale of business	$ 18,000,000
Proceeds from the sale of business, first installment	$ 15,000,000
Future proceeds from the sale of business, second installment																		3,000,000
Gain on sale of business				$ 13,700,000														13,700,000
Goodwill, written off																		$ 2,300,000
Senior secured term loans
Loss on debt refinancing						$ 4,400,000
April 3, 2018 Credit Agreement | Term B Loans
Debt instrument, face amount																					$ 412,000,000.0	$ 412,000,000

[1] Effective January 1, 2018, the Company adopted Accounting Standards Update No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, which requires certain equity investments to be measured at fair value with changes in fair value recognized in net income. Previously, changes in the fair value of the Company’s available for sale securities were included in comprehensive income. During the three months ended March 31, 2018, June 30, 2018, September 30, 2018 and December 31, 2018, we recognized unrealized (losses) gains from our investment in RESI common shares of $(7.5) million, $1.5 million, $1.8 million and $(8.8) million, respectively. See Note 6.

[2] In April 2018, Altisource entered into the Credit Agreement, pursuant to which, among other things, Altisource borrowed $412.0 million in the form of Term B Loans. Proceeds from the Term B Loans were used to repay the Company’s prior senior secured term loan. In connection with the refinancing, we recognized a loss of $4.4 million from the write-off of the unamortized debt issuance costs and debt discount in the second quarter of 2018. See Note 14.

[3] In August 2018, we initiated Project Catalyst, a restructuring plan intended to optimize our operations and reduce costs to align our cost structure with our anticipated revenues and improve our operating margins. During the three months ended September 30, 2018 and December 31, 2018, we incurred $3.4 million and $8.1 million, respectively, of severance costs, facility shut-down costs and professional services fees related to the restructuring plan. See Note 24.

[4] In August 2018, we sold our rental property management business to RESI for total transaction proceeds of $18.0 million, $15.0 million of which was received on the closing date of August 8, 2018 and $3.0 million of which will be received on the earlier of a RESI change of control or August 8, 2023. We recognized a $13.7 million pretax gain on the sale of this business during the third quarter of 2018. See Note 4.

[5] In November 2018, the Company announced its plans to sell its BRS Inventory and discontinue the Company’s BRS business. The Company recorded a write-off of goodwill related to its plan to discontinue the BRS business of $2.6 million during the three months ended December 31, 2018. See Notes 9 and 11.

[6] In connection with a United States Supreme Court decision in June 2018, the Company is analyzing its services for potential exposure to sales tax in various jurisdictions in the United States and believes that the Company has a related estimated probable loss of $6.2 million. The Company recognized $5.9 million and $0.4 million during the three months ended September 30, 2018 and December 31, 2018, respectively. See Note 25.

[7] The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is due to the effects of rounding and changes in the number of weighted average shares outstanding for each period.

[8] During the three months ended December, 31, 2017, the Company recognized net tax benefits of $284.1 million. On December 27, 2017, two of the Company’s wholly-owned subsidiaries, Altisource Solutions S.à r.l. and Altisource Holdings S.à r.l., merged, with Altisource Holdings S.à r.l. as the surviving entity. For Luxembourg tax purposes, the merger was recognized at fair value and generated an NOL of $1.3 billion and a deferred tax asset, net of valuation allowance, of $300.9 million. This deferred tax benefit was partially offset by $6.3 million of income tax from changes in U.S. and Luxembourg income tax rates and a $10.5 million increase in certain foreign income tax reserves (and related interest). See Note 22.