EARNINGS PER SHARE - EARNINGS PER SHARE (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Payments for Repurchase of Common Stock	$ 106,792,000	$ 4,818,000	$ 155,805,000
Treasury Stock, Shares, Acquired	1,778,537		2,468,576
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	0	3,674,000	6,314,000
Stock Appreciation Rights (SARs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share	1,300,000	1,200,000
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Convertible, Conversion Price	$ 28.87
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	11,951,932
Dilutive Securities, Effect on Basic Earnings Per Share		$ 0.17	$ 0.60
Treasury Stock, Common [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Treasury Stock, Common, Shares		2,468,576
Payments for Repurchase of Common Stock	$ 100,000,000		$ 150,000,000
Treasury Stock, Shares, Acquired	1,778,537

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
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The price per share of the conversion feature embedded in the debt instrument.

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise stock options, restrictive stock units (RSUs), convertible preferred stock of an employee stock ownership plan (ESOP), and other dilutive convertible securities.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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The cash outflow to reacquire common stock during the period.

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