CONTINGENCIES (Details) $ in Thousands				6 Months Ended	12 Months Ended
	Oct. 23, 2017 regulator	Oct. 14, 2011 regulator	Sep. 08, 2010 patent	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2014 USD ($)	Mar. 12, 2014 patent
Contingencies
Accrued litigation liability						$ 588	$ 736
Massachusetts Division of Banks | Unfavorable regulatory action
Contingencies
Accrued litigation liability						500
Number of Joining Regulators | regulator		34
Massachusetts Division of Banks | Unfavorable regulatory action | Subsequent Event [Member]
Contingencies
Number of Joining Regulators | regulator	0
Pending litigation or appeal | Residential Funding Company
Contingencies
Accrued litigation liability						3,000
Pending litigation or appeal | Lending Tree v. Zillow, Inc.
Contingencies
Accrued litigation liability						0
Number of patents found not infringed upon | patent									2
Settlement amount				$ 1,100	$ 2,300
Number of patents alleged infringement upon, maximum | patent			2
Pending litigation or appeal | Lehman Brothers Holdings, Inc. Demand Letter
Contingencies
Accrued litigation liability						1,000
Minimum | Massachusetts Division of Banks | Unfavorable regulatory action
Contingencies
Estimated range of remaining possible losses due to loan losses						500
Maximum | Massachusetts Division of Banks | Unfavorable regulatory action
Contingencies
Estimated range of remaining possible losses due to loan losses						6,500
Maximum | Pending litigation or appeal | Lending Tree v. Zillow, Inc.
Contingencies
Estimated range of remaining possible losses due to loan losses								$ 9,700
Discontinued Operations, Disposed of by Sale [Member]
Contingencies
Accrued litigation liability						$ 4,000	$ 4,000