UNIT-BASED COMPENSATION Table 1 (Details) - The 2006 LTIP [Member] - $ / shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
NSH restricted units, beginning balance	77,080	59,515	60,398
NSH restricted units, granted	44,582	39,054	25,806
NSH restricted units, vested	(26,888)	(21,489)	(21,944)
NSH restricted units, forfeited			(4,745)
NSH restricted units, ending balance	94,774	77,080	59,515
Weighted-average grant date fair value, period start	$ 27.51	$ 31.13	$ 28.83
Weighted-average grant-date fair value, granted	25.42	23.80	34.22
Weighted-average grant date fair value, vested	28.23	30.80	29.22
Weighted-average grant date fair value, forfeited			27.46
Weighted-average grant date fair value, period end	$ 26.32	$ 27.51	$ 31.13
Restricted units, employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
NSH restricted units, beginning balance	53,927	39,090	39,204
NSH restricted units, granted	32,456	26,240	16,895
NSH restricted units, vested	(15,251)	(11,403)	(12,264)
NSH restricted units, forfeited			(4,745)
NSH restricted units, ending balance	71,132	53,927	39,090
Restricted units, non-employee directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
NSH restricted units, beginning balance	23,153	20,425	21,194
NSH restricted units, granted	12,126	12,814	8,911
NSH restricted units, vested	(11,637)	(10,086)	(9,680)
NSH restricted units, forfeited			0
NSH restricted units, ending balance	23,642	23,153	20,425

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ 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 (c)(2)(iii)(3)
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Name Accounting Standards Codification
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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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-Publisher FASB
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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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