ACCOUNTING POLICIES (Details 4) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted vesting period (in years)			3 years
Black-Sholes assumptions [Abstract]
Dividend yield (in hundredths)	6.09%	2.92%	2.92%	3.13%	3.44%
Risk-free interest rate (in hundredths)	1.35%	1.69%	1.69%	2.13%	1.35%
Expected volatility (in hundredths)	32.00%	34.00%	34.00%	42.00%	43.00%
Fair Value Assumptions, Expected Term, Simplified Method	6.0	6.0
Expected life (years)			6 years	7 years	7 years
Grant fair value (in dollars per share)	$ 1.90	$ 6.80	$ 6.80	$ 8.34	$ 7.05
Exercise price (in dollars per share)	$ 13.14	$ 27.40	$ 27.40	$ 25.69	$ 23.28
Shares granted (in shares)	1,670,400	776,750	776,750	624,200	621,000
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted vesting period (in years)			3 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted vesting period (in years)			1 year

Description of the expected term under the specified contract (or assumed time period) the instrument will be outstanding before being exercised, placed into service or terminated, the reason and justification for its use, and the periods for which the method was used.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)
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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(ii)
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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Net number of share options (or share units) granted during the period.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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-Name Accounting Standards Codification
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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 14.D.2)
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-Publisher FASB
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-Publisher SEC
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