GOODWILL AND INTANGIBLE ASSETS - Future Amortization, rollforward (Details) - Parent Company - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 144,067
Foreign currency translation	(50)
Goodwill, Ending Balance	144,017	$ 144,067
Impairments of goodwill	0	0
Credit Group
Goodwill [Roll Forward]
Goodwill, Beginning Balance	32,196
Goodwill, Ending Balance	32,196	32,196
Private Equity Group
Goodwill [Roll Forward]
Goodwill, Beginning Balance	58,600
Goodwill, Ending Balance	58,600	58,600
Real Estate Group
Goodwill [Roll Forward]
Goodwill, Beginning Balance	53,271
Foreign currency translation	(50)
Goodwill, Ending Balance	$ 53,221	$ 53,271