v3.20.4

LEASE ASSETS AND LIABILITIES Narrative 1 (Details) $ in Millions	Jan. 01, 2019 USD ($)
Leases [Abstract]
Right-of-Use Assets Recognized at Transition	$ 207.0
Lease Liabilities Recognized at Transition	$ 192.0

X

- Definition

Amount of lease liabilities recognized due to the adoption of ASC Topic 842.

+ References

No definition available.

+ Details

Name:	ns_LeaseLiabilitiesRecognizedatTransition
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of right-of-use assets recognized due to the adoption of ASC Topic 842.

+ References

No definition available.

+ Details

Name:	ns_RightofUseAssetsRecognizedatTransition
Namespace Prefix:	ns_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

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