INTANGIBLE ASSETS, NET - Intangible Assets, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Total	$ 47,568	$ 38,060
Tradenames [Member]
Finite Lived Intangible Assets [Line Items]
Total	26,352	21,234
Referral Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Total	18,092	14,859
Accumulated amortization	$ 6,741	5,275
Referral Relationships [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	6 years
Referral Relationships [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	16 years
Non-compete Agreements [Member]
Finite Lived Intangible Assets [Line Items]
Total	$ 3,124	1,967
Accumulated amortization	$ 4,012	$ 3,380
Non-compete Agreements [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	5 years
Non-compete Agreements [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Estimated useful life	6 years