SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Deferred debt issuance cost		$ 2,400
Asset impairment charge	$ 4,400	0	$ 1,323	$ 4,432
Depreciation		10,800	14,400	17,200
Amortization of deferred debt issuance costs		800	700	700
Unamortized debt issuance costs		$ 3,500	1,900
Unamortized debt issuance costs, weighted average amortization period, years		4 years 6 months
Deferred tax assets		$ 35,794	56,064
Decrease in deferred income tax expense from remeasurement of deferred taxes due to change in tax rate (Tax Cuts and Jobs Act)			21,400
Non-cash compensation		17,887	16,295	16,401
Share-based compensation, tax benefit recognized		4,300	6,400	6,400
Advertising expense		$ 7,000	$ 6,500	$ 7,800
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets		3 years
Acquired Names [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of intangible assets		5 years