LONG-TERM DEBT (Details)			12 Months Ended
	Aug. 01, 2014 USD ($)	Nov. 27, 2012	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	May 07, 2013 USD ($)
Debt
Senior secured term loan			$ 413,581,000	$ 479,653,000
Less: Debt issuance costs, net			(3,158,000)	(4,486,000)
Less: Unamortized discount, net			(1,142,000)	(1,622,000)
Net long-term debt			409,281,000	473,545,000
Less: Current portion			(5,945,000)	(5,945,000)
Long-term debt, less current portion			403,336,000	467,600,000
Gain on early extinguishment of debt			5,637,000	5,464,000	$ 3,836,000
Debt issuance costs, net			3,158,000	4,486,000
Interest on long-term debt			22,253,000	24,412,000	28,208,000
Senior secured term loan
Debt
Less: Debt issuance costs, net			(3,200,000)	(4,500,000)
Debt instrument accordion feature increase in additional borrowings						$ 200,000,000.0
Debt instrument, maturity period from prior term loans maturity date		1 year
Aggregate amount of each consecutive quarterly scheduled principal installment	$ 1,500,000
Mandatory prepayments owed			0
Extinguishment of debt, amount			$ 60,100,000	$ 51,000,000	$ 49,000,000
Weighted average discount of par received on early extinguishment of debt			10.70%	13.20%	10.30%
Gain on early extinguishment of debt			$ 5,600,000	$ 5,500,000	$ 3,800,000
Interest rate at the end of the period (as a percent)			5.07%
Debt issuance costs, net			$ 3,200,000	4,500,000
Accumulated amortization			(7,100,000)	(5,800,000)
Interest on long-term debt			$ 22,300,000	$ 24,400,000	$ 28,200,000
Senior secured term loan | Maximum
Debt
Leverage ratio to be maintained under the credit facility covenants			3.0
Covenant threshold, leverage ratio			3.50
Number of days within which the entity fails to pay principal when due or interest or any other amount owing on any other obligation under the credit agreement, is considered as event of default			5 days
Amount of principal or interest if failed to pay considered as event of default			$ 40,000,000.000
Amount of debt which results in acceleration of debt if failed to pay considered as event of default			40,000,000.000
Amount of unbonded, undischarged or unstayed debt under entry by court of one or more judgments for certain period to determine as event of default			$ 40,000,000.000
Senior secured term loan | Minimum
Debt
Leverage ratio to be maintained under the credit facility covenants			1.00
Covenant threshold, leverage ratio			1.00
Senior secured term loan | Adjusted Eurodollar Rate
Debt
Reference rate			Adjusted Eurodollar Rate
Fixed interest rate base (as a percent)			1.00%
Interest rate margin (as a percent)			3.50%
Senior secured term loan | Base Rate
Debt
Reference rate			Base Rate
Fixed interest rate base (as a percent)			2.00%
Interest rate margin (as a percent)			2.50%