LONG-TERM DEBT (Narrative) (Details) - USD ($)					12 Months Ended
	Aug. 12, 2019	Jun. 10, 2019	Dec. 10, 2018	Aug. 07, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Long Term Debt Additional Information [Line Items]
Proceeds from issuance of long-term debt					$ 9,000,000	$ 107,607,000	$ 10,000,000
Long-term debt					446,000,000	610,787,000
Debt Issuance Costs, Noncurrent						14,600,000
Deferred financing costs						100,000
Interest expense					48,200,000	50,900,000	55,100,000
Amortization of financing costs					5,600,000	4,500,000	$ 3,900,000
Derivative loss					600,000
Other comprehensive income (loss) reclassification due to de-designation					400,000
Interest Rate Cap [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Derivative, notional amount					300,000,000
Interest Rate Swap [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Derivative, notional amount			$ 300,000,000
Interest Rate Swap Due December 31, 2021 [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Derivative, notional amount			$ 150,000,000
Derivative, maturity date			Dec. 31, 2021
Interest Rate Swap Due January 4, 2022 [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Derivative, notional amount			$ 150,000,000
Derivative, maturity date			Jan. 04, 2022
Revolving Credit Facility [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Line of credit facility, current borrowing capacity					80,000,000
Repayments of debt		$ 109,600,000
Tranche A -1 Term Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Deferred financing costs					$ 800,000
Repayments of debt		$ 44,400,000
BoA Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument period of credit agreement				5 years
Proceeds from issuance of long-term debt				$ 335,000,000
Debt instrument covenant payment percentage of intellectual property disposed liquidation value				50.00%
Debt instrument covenant payment percentage of net proceeds related to other assets constituting collateral				100.00%
Debt instrument orderly liquidation value of registered trademarks percentage benchmark				15.00%
Amortization of financing costs						100,000
Other Noncash Income						$ 300,000
Tranche A [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Maximum loan to value ratio					50.00%
Tranche A [Member] | Revolving Credit Facility [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Consolidated first lien leverage ratio				2.80%
Tranche A -1 Term Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Consolidated first lien leverage ratio					3.00%
Revolving Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Long-term debt				$ 115,000,000
Amended KKR Credit Agreement [Member] | Scenario Plan One [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Percent of consolidated excess cash flow for mandatory prepayment					75.00%
Amended KKR Credit Agreement [Member] | Scenario Plan Two [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Percent of consolidated excess cash flow for mandatory prepayment					50.00%
Amended KKR Credit Agreement [Member] | Scenario Plan Three [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Percent of consolidated excess cash flow for mandatory prepayment					0.00%
FS/KKR Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, face amount				$ 314,000,000
Debt instrument, covenant description				(i) a maximum consolidated total leverage ratio, initially set at 7.25:1.00, decreasing over the term of the Amended FS/KKR Credit Agreement until reaching a final maximum ratio of 6.25:1.00 for the fiscal quarter ending September 30, 2022 and thereafter and (ii) a maximum consolidated first lien leverage ratio, initially set at 3.875:1.00, decreasing over the term of the Amended FS/KKR Credit Agreement until reaching a final maximum ratio of 2.875:1.00 for the fiscal quarter ending September 30, 2022 and thereafter
Debt instrument consolidated total leverage ratio				6.00%
FS/KKR Credit Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				8.75%
FS/KKR Credit Agreement [Member] | Base Rate [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				7.75%
New Amended FS/KKR Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Netting of cash for calculating leverage ratio covenant	$ 5,000,000
Deferred financing costs					$ 3,300,000
Percent of disposed intellectual property for mandatory prepayment					50.00%
Percent of assets disposed of other than intellectual property for mandatory prepayment					100.00%
Debt instrument, covenant compliance					the Company is in compliance with the covenants included in the Amended FS/KKR Credit Agreement
Debt instrument covenant amount regarding minimal borrowings	30,000,000
New Amended FS/KKR Credit Agreement [Member] | Scenario Plan One [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Quarterly amortization payments	0
Consolidated first lien leverage ratio					3.875%
Final consolidated total leverage ratio					7.25%
New Amended FS/KKR Credit Agreement [Member] | Scenario Plan Two [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Quarterly amortization payments	$ 1,000,000
Consolidated first lien leverage ratio					2.875%
Final consolidated total leverage ratio					6.25%
New Amended FS/KKR Credit Agreement [Member] | Scenario Plan Three [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Consolidated total leverage ratio					6.00%
Third Amended BoA Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Long-term debt				$ 335,000,000
Deferred financing costs					$ 1,300,000
Third Amended BoA Credit Agreement [Member] | Scenario Plan One [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Quarterly amortization payments					2,500,000
Third Amended BoA Credit Agreement [Member] | Scenario Plan Two [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Quarterly amortization payments					3,250,000
Third Amended BoA Credit Agreement [Member] | Scenario Plan Three [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Quarterly amortization payments					4,000,000
Third Amended BoA Credit Agreement [Member] | Revolving Credit Facility [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Netting of cash for calculating leverage ratio covenant					$ 5,000,000
Amended BoA Revolving Credit Commitments [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, face amount				$ 130,000,000
Consolidated first lien leverage ratio				3.875%
Final consolidated first lien leverage ratio				2.875%
Line of Credit Facility, Commitment Fee Percentage				0.375%
Third Amended BoA Tranche A-1 Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Long-term debt				$ 70,000,000
Third Amended BoA Tranche A-1 Loans [Member] | London Interbank Offered Rate (LIBOR) [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				7.00%
Third Amended BoA Tranche A-1 Loans [Member] | Base Rate [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				6.00%
Amended BoA Revolving Loans and Amended Tranche A Loans [Member] | London Interbank Offered Rate (LIBOR) [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate					3.50%
Amended BoA Revolving Loans and Amended Tranche A Loans [Member] | Base Rate [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate					2.50%
Third Amended BoA Tranche A Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, face amount				$ 150,000,000
Long-term debt				$ 150,000,000
New Amended BoA Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Consolidated first lien leverage ratio					2.90%
Revolving Credit Facility and Tranche A Loans [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Amortization of financing costs					$ 800,000
Other Noncash Income					$ 800,000
Maximum | Amended KKR Credit Agreement [Member] | Scenario Plan Two [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument consolidated total leverage ratio					4.00%
Maximum | Amended KKR Credit Agreement [Member] | Scenario Plan Three [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument consolidated total leverage ratio					3.00%
Maximum | Third Amended BoA Credit Agreement [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Maximum loan to value ratio				42.50%
Maximum | Third Amended BoA Tranche A-1 Loans [Member] | London Interbank Offered Rate (LIBOR) [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				6.00%
Maximum | Third Amended BoA Tranche A-1 Loans [Member] | Base Rate [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				5.00%
Maximum | Amended BoA Revolving Loans and Amended Tranche A Loans [Member] | London Interbank Offered Rate (LIBOR) [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				3.00%
Maximum | Amended BoA Revolving Loans and Amended Tranche A Loans [Member] | Base Rate [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument, basis spread on variable rate				2.00%
Minimum | Amended KKR Credit Agreement [Member] | Scenario Plan One [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument consolidated total leverage ratio				4.00%
Minimum | Amended KKR Credit Agreement [Member] | Scenario Plan Three [Member]
Disclosure Long Term Debt Additional Information [Line Items]
Debt instrument consolidated total leverage ratio				3.00%