v3.8.0.1

UNIT-BASED COMPENSATION Narrative 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Related party expense, long-term incentive plan			$ 6,400
Cash payments made in connection with DERs	$ 2,965	$ 2,697	$ 0

X

- Definition

Company's share of compensation expense related to various long-term incentive plans provided to employees of the general partner (who provide services to the company).

+ References

No definition available.

+ Details

Name:	ns_RelatedPartyExpenseLongTermIncentivePlans
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of paid and unpaid cash dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsShareBasedCompensationCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration