LONG-TERM DEBT AND CREDIT AGREEMENT Debt Disclosurre (Details) - USD ($) $ in Thousands							3 Months Ended		9 Months Ended
	Sep. 07, 2018	May 10, 2018	Feb. 08, 2018	Dec. 15, 2017	Mar. 14, 2017	Feb. 26, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Nov. 09, 2017	Jun. 15, 2015
Debt Instrument, Periodic Payment, Principal							$ 351		$ 351
Term Loan, net of unamortized debt issuance costs of $3,444 at June 30, 2017 and $4,042 at December 31, 2016							122,982		122,982		$ 102,751
Notes, net of unamortized original issue discount and debt issuance costs of $20,449 at June 30, 2017 and $23,413 at December 31, 2016, respectively							106,331		106,331		105,974
Other Long-term Debt							1,517		1,517		1,679
Total debt							230,830		230,830		210,404
Short-term debt							1,401		1,401		5,906
Long-term Debt							229,429		229,429		204,498
Line of Credit, Current							0		0
Interest Expense							5,725	$ 4,701	17,362	$ 13,465
Convertible Debt Retired	3,000		2,000	2,000
Convertible Debt Issued	121,000,000		123,000,000										125,000,000
Extinguishment of Debt, Amount	$ 3,000		$ 2,000	$ 2,000
Repayments of Debt	$ 2,700		$ 1,700	$ 1,700
Convertible Notes unamortized issue discount and debt issuance costs							14,430		14,430
Long-term Debt, Maturities, Repayments of Principal in Year Two							1,407		1,407
Long-term Debt, Maturities, Repayments of Principal in Year Three							120,373		120,373
Long-term Debt, Maturities, Repayments of Principal in Year Four							4,934		4,934
Long-term Debt, Maturities, Repayments of Principal in Year Five							6,539		6,539
Long-term Debt, Maturities, Repayments of Principal after Year Five							111,656		111,656
Total debt							245,260		245,260
Other Debt Obligations [Member]
Debt Instrument, Periodic Payment, Principal							32		32
Short-term debt							126		126
Long-term Debt							1,391		1,391
Convertible Notes unamortized issue discount and debt issuance costs							0		0
Long-term Debt, Maturities, Repayments of Principal in Year Two							132		132
Long-term Debt, Maturities, Repayments of Principal in Year Three							142		142
Long-term Debt, Maturities, Repayments of Principal in Year Four							153		153
Long-term Debt, Maturities, Repayments of Principal in Year Five							164		164
Long-term Debt, Maturities, Repayments of Principal after Year Five							894		894
Total debt							1,517		1,517
Cerberus Business Finance LLC [Member]
Debt Instrument, Periodic Payment, Principal							319		319
Short-term debt							1,275		1,275
Long-term Debt							121,707		121,707
Convertible Notes unamortized issue discount and debt issuance costs							2,761		2,761
Long-term Debt, Maturities, Repayments of Principal in Year Two							1,275		1,275
Long-term Debt, Maturities, Repayments of Principal in Year Three							2,231		2,231
Long-term Debt, Maturities, Repayments of Principal in Year Four							4,781		4,781
Long-term Debt, Maturities, Repayments of Principal in Year Five							6,375		6,375
Long-term Debt, Maturities, Repayments of Principal after Year Five							110,762		110,762
Total debt							125,743		125,743
Convertible Debt [Member]
Debt Instrument, Periodic Payment, Principal							0		0
Short-term debt							0		0
Long-term Debt							106,331		106,331
Long-term Debt, Gross													$ 125,000
Debt Instrument, Interest Rate, Stated Percentage													2.00%
Interest Expense							2,200		6,600
Convertible Notes unamortized issue discount and debt issuance costs							11,669		11,669		17,026
Long-term Debt, Maturities, Repayments of Principal in Year Two							0		0
Long-term Debt, Maturities, Repayments of Principal in Year Three							118,000		118,000
Long-term Debt, Maturities, Repayments of Principal in Year Four							0		0
Long-term Debt, Maturities, Repayments of Principal in Year Five							0		0
Long-term Debt, Maturities, Repayments of Principal after Year Five							0		0
Total debt							118,000		118,000
Cerberus Business Finance LLC [Member]
Debt Instrument, Collateral						We granted a security interest on substantially all of our assets to secure the obligations under the Term Loan and the Credit Facility.
Debt Instrument, Covenant Description		On May 10, 2018, we entered into an amendment to the Financing Agreement, which extended the maturity of the Financing Agreement to May 2023, and increased the Term Loan by $22.7 million and the amount available under the Credit Facility by $12.5 million. Under the terms of the amendment, aggregate quarterly principal repayments beginning September 30, 2018 through June 30, 2020 will be $318,750, then from July 1, 2020 through June 30, 2021 equal to $796,875, finally from July 1, 2021 through May 10, 2023 equal to $1,593,750. Following the amendment effective date, interest accrues on outstanding borrowings under the Term Loan and Credit Facility (each as defined in the Financing Agreement) at a rate of either the LIBOR Rate (as defined in the Financing Agreement) plus 6.625% or a Reference Rate (as defined in the Financing Agreement) plus 5.625%, at our option. The amendment modified the covenant requiring us to maintain a Leverage Ratio (defined to mean the ratio of (a) the sum of indebtedness under the Term Loan and Credit Facility, capitalized leases and non-cash collateralized letters of credit to (b) consolidated EBITDA) of no greater than 3.00:1.00 for the four quarters ended June 30, 2018 through December 31, 2018, 2.50:1.00 for the four quarters ending March 31, 2019 through December 31, 2019, 2.25:1.00 for the four quarters ending March 31, 2020 through March 31, 2021, 2.00:1.00 for the four quarters ending June 30, 2021 through December 31, 2022, respectively, and thereafter declining to 1.50:1.00.			The Financing Agreement contains customary representations and warranties, covenants, mandatory prepayments, and events of default under which our payment obligations may be accelerated.
additional long term debt												$ 15,000
Cerberus Business Finance LLC [Member] | Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 22,500				$ 5,000
Cerberus Business Finance LLC [Member] | Long-term Debt [Member]
Unamortized Debt Issuance Expense							2,761		2,761		$ 3,499
Long-term Debt						$ 100,000
Debt Instrument, Payment Terms						The Term Loan requires us to use 50% of excess cash flow, as defined in the Financing Agreement, to repay outstanding principal of the loans under the Financing Agreement.
Interest Expense, Long-term Debt							$ 2,900		$ 7,900
Cerberus Business Finance LLC [Member] | Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity						$ 5,000