INDEBTEDNESS - Additional information (Details)			1 Months Ended		12 Months Ended
	Dec. 02, 2019 USD ($) shares	Nov. 29, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 27, 2018 USD ($)	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2014 USD ($) D $ / shares
Short-term Debt, Percentage Bearing Fixed Interest Rate	3.00%				3.00%
Debt Instrument, Interest Rate, Effective Percentage			8.50%		7.40%	8.50%
Amortization of Debt Issuance Costs					$ 1,377,000	$ 1,463,000	$ 845,000
Debt Instrument, Maturity Date				Dec. 01, 2019
Gain (Loss) on Repurchase of Debt Instrument					0	(468,000)	0
Adjustments To Additional Paid In Capital Repurchase Of Convertible Notes And Unwinding Of Call Option Overlay Net					1,700,000
Long-term Debt, Current Maturities			$ 3,256,000		$ 9,941,000	3,256,000
Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares					1,709,002
Bond Hedge [Member]
Underlying Shares Of Common Stock Bond Hedge | shares	1,709,002
Delayed Draw Term Loan [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 118,000,000
Delayed Draw Term Loan [Member] | Maximum
Debt Instrument, Basis Spread on Variable Rate				2.75%
Delayed Draw Term Loan [Member] | Minimum
Debt Instrument, Basis Spread on Variable Rate				1.50%
Senior Secured Credit Facility [Member]
Debt Instrument, Description of Variable Rate Basis				LIBOR rate plus 1.50% to 2.75% per annum, depending on our total leverage ratio or an alternative base rate plus an applicable base rate margin, which varies within a range of 0.50% to 1.75%,
Debt Instrument, Covenant Description				which is, as of December 31, 2019 no greater than 3.50 to 1.00 and a minimum fixed charge coverage ratio, which shall be greater than or equal to 1.25 to 1.00.
Line of Credit Facility, Maximum Borrowing Capacity				$ 265,200,000
Senior Secured Credit Facility [Member] | Delayed Draw Term Loan [Member]
Long-term Debt, Gross					$ 118,000,000
Debt Issuance Costs, Net					500,000
Debt Issuance Costs, Noncurrent, Net					400,000
Debt Issuance Costs, Current, Net					100,000
Proceeds from exercise of option to borrow		$ 118,000,000
Long-term Debt, Current Maturities					5,900,000
Credit Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity							125,000,000
Prepaid Expenses and Other Current Assets [Member] | Revolving Credit Facility [Member]
Debt Issuance Costs, Current, Net					200,000
Other Long-Term Assets [Member] | Revolving Credit Facility [Member]
Debt Issuance Costs, Noncurrent, Net					800,000
Line of Credit Facility, Maximum Borrowing Capacity			75,000,000			75,000,000	$ 50,000,000
Convertible Senior Notes [Member]
Long-term Debt, Gross			118,750,000		0	118,750,000		$ 143,800,000
Proceeds from Issuance of Debt								$ 122,600,000
Short-term Debt, Percentage Bearing Fixed Interest Rate								3.00%
Underlying Shares Of Common Stock Convertible Debt | shares	1,709,002
Per Note Principal | $ / shares								$ 1,000
Debt Instrument, Convertible, Threshold Percentage of Stock Price and Conversion Price Trigger								98.00%
Debt Instrument, Unamortized Discount			5,648,000		0	5,648,000		$ 33,600,000
Deferred Offering Costs								$ 5,500,000
Exercise Price Of Bond Hedge | $ / shares								$ 69.48
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares								$ 96.21
Net Adjustments To Additional Paid In Capital Bond Hedge Acquired Warrant Issued Net								$ 15,600,000
Amortization of Debt Issuance Costs								4,200,000
Payments of Stock Issuance Costs								$ 1,300,000
Debt Issuance Costs, Net			639,000		$ 0	639,000
Debt Instrument, Repurchase Amount			25,000,000			25,000,000
Trading days | D								20
Debt Instrument, Percent, Conversion Price								130.00%
Consecutive trading days | D								30
Cash Received From Unwinding Call Option Overlay			400,000
Number of note holders elected for conversion	50,000
Number of shares issued upon conversion | shares	33
Line of Credit [Member] | Maximum
Line of Credit Facility, Commitment Fee Percentage					0.50%
Line of Credit [Member] | Minimum
Line of Credit Facility, Commitment Fee Percentage					0.25%
Term Loan [Member] | Senior Secured Credit Facility [Member]
Long-term Debt, Gross			$ 72,200,000		$ 69,500,000	$ 72,200,000
Debt Issuance Costs, Net					1,300,000
Debt Instrument, Face Amount				$ 72,200,000
Debt Issuance Costs, Noncurrent, Net					900,000
Debt Issuance Costs, Current, Net					$ 400,000
Debt Instrument, Maturity Date				Dec. 27, 2023	Dec. 27, 2023
Long-term Debt, Current Maturities					$ 4,500,000
Term Loan [Member] | Senior Secured Credit Facility [Member] | Maximum
Debt Instrument, Basis Spread on Variable Rate					1.75%
Term Loan [Member] | Senior Secured Credit Facility [Member] | Minimum
Debt Instrument, Basis Spread on Variable Rate					0.50%
Term Loan [Member] | Revolving Credit Facility [Member]
Debt Issuance Costs, Net					$ 1,000,000