REVENUE - Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 204,575	$ 234,979	$ 620,569	$ 726,147
Revenue recognized when services are performed or assets are sold
Disaggregation of Revenue [Line Items]
Revenue	173,581		527,743
Revenue related to technology platforms and professional services
Disaggregation of Revenue [Line Items]
Revenue	24,179		68,856
Reimbursable expenses revenue
Disaggregation of Revenue [Line Items]
Revenue	6,815	9,866	23,970	31,786
Operating Segment | Mortgage Market
Disaggregation of Revenue [Line Items]
Revenue	175,960	199,262	521,960	614,180
Operating Segment | Mortgage Market | Servicer Solutions
Disaggregation of Revenue [Line Items]
Revenue	162,490		483,970
Operating Segment | Mortgage Market | Origination Solutions
Disaggregation of Revenue [Line Items]
Revenue	13,470		37,990
Operating Segment | Mortgage Market | Revenue recognized when services are performed or assets are sold
Disaggregation of Revenue [Line Items]
Revenue	146,618		434,666
Operating Segment | Mortgage Market | Revenue recognized when services are performed or assets are sold | Servicer Solutions
Disaggregation of Revenue [Line Items]
Revenue	135,395		404,015
Operating Segment | Mortgage Market | Revenue recognized when services are performed or assets are sold | Origination Solutions
Disaggregation of Revenue [Line Items]
Revenue	11,223		30,651
Operating Segment | Mortgage Market | Revenue related to technology platforms and professional services
Disaggregation of Revenue [Line Items]
Revenue	22,725		64,501
Operating Segment | Mortgage Market | Revenue related to technology platforms and professional services | Servicer Solutions
Disaggregation of Revenue [Line Items]
Revenue	20,565		57,363
Operating Segment | Mortgage Market | Revenue related to technology platforms and professional services | Origination Solutions
Disaggregation of Revenue [Line Items]
Revenue	2,160		7,138
Operating Segment | Mortgage Market | Reimbursable expenses revenue
Disaggregation of Revenue [Line Items]
Revenue	6,617		22,793
Operating Segment | Mortgage Market | Reimbursable expenses revenue | Servicer Solutions
Disaggregation of Revenue [Line Items]
Revenue	6,530		22,592
Operating Segment | Mortgage Market | Reimbursable expenses revenue | Origination Solutions
Disaggregation of Revenue [Line Items]
Revenue	87		201
Operating Segment | Real Estate Market
Disaggregation of Revenue [Line Items]
Revenue	13,010	22,121	52,435	67,314
Operating Segment | Real Estate Market | Consumer Real Estate Solutions
Disaggregation of Revenue [Line Items]
Revenue	2,693		6,412
Operating Segment | Real Estate Market | Real Estate Investor Solutions
Disaggregation of Revenue [Line Items]
Revenue	10,317		46,023
Operating Segment | Real Estate Market | Revenue recognized when services are performed or assets are sold
Disaggregation of Revenue [Line Items]
Revenue	12,825		51,292
Operating Segment | Real Estate Market | Revenue recognized when services are performed or assets are sold | Consumer Real Estate Solutions
Disaggregation of Revenue [Line Items]
Revenue	2,693		6,410
Operating Segment | Real Estate Market | Revenue recognized when services are performed or assets are sold | Real Estate Investor Solutions
Disaggregation of Revenue [Line Items]
Revenue	10,132		44,882
Operating Segment | Real Estate Market | Revenue related to technology platforms and professional services
Disaggregation of Revenue [Line Items]
Revenue	0		0
Operating Segment | Real Estate Market | Revenue related to technology platforms and professional services | Consumer Real Estate Solutions
Disaggregation of Revenue [Line Items]
Revenue	0		0
Operating Segment | Real Estate Market | Revenue related to technology platforms and professional services | Real Estate Investor Solutions
Disaggregation of Revenue [Line Items]
Revenue	0		0
Operating Segment | Real Estate Market | Reimbursable expenses revenue
Disaggregation of Revenue [Line Items]
Revenue	185		1,143
Operating Segment | Real Estate Market | Reimbursable expenses revenue | Consumer Real Estate Solutions
Disaggregation of Revenue [Line Items]
Revenue	0		2
Operating Segment | Real Estate Market | Reimbursable expenses revenue | Real Estate Investor Solutions
Disaggregation of Revenue [Line Items]
Revenue	185		1,141
Other Businesses, Corporate and Eliminations
Disaggregation of Revenue [Line Items]
Revenue	15,605	$ 13,596	46,174	$ 44,653
Other Businesses, Corporate and Eliminations | Revenue recognized when services are performed or assets are sold
Disaggregation of Revenue [Line Items]
Revenue	14,138		41,785
Other Businesses, Corporate and Eliminations | Revenue related to technology platforms and professional services
Disaggregation of Revenue [Line Items]
Revenue	1,454		4,355
Other Businesses, Corporate and Eliminations | Reimbursable expenses revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 13		$ 34