INCOME TAXES - Deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Investment in Focus LLC	$ 74,415	$ 62,618
Net operating loss carryforwards	429	5,842
Business interest carryforwards		1,219
Intangible assets	586	532
Deferred rent and other	629	410
Gross deferred tax assets	76,059	70,621
Deferred tax liabilities:
Intangible assets	(13,184)	(6,248)
Fixed assets and other	(270)	(288)
Gross deferred tax liabilities	(13,454)	(6,536)
Net deferred tax assets (liabilities)	62,605	64,085
Other liabilities
Deferred tax liabilities:
Gross deferred tax liabilities	$ (12,848)	$ (5,924)