LONG-TERM DEBT / INTEREST EXPENSE - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument
Net carrying amount	$ 1,509,760	$ 1,540,453
Debt issuance costs	(1,817)	(2,306)
Less: current maturities	0	(12,562)
Long-term debt	1,509,760	1,527,891
Term Loan Facility
Debt Instrument
Discount	1,200	1,600
Net carrying amount	1,129,977	1,170,486
Credit Facility \| Revolving Credit Facility
Debt Instrument
Net carrying amount	131,000	127,000
Convertible Senior Notes \| 1.5% Convertible Senior Notes, Due 2020
Debt Instrument
Discount	32,445	37,179
Net carrying amount	$ 250,600	$ 245,273

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Amount, after accumulated amortization, of debt discount.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

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