v3.21.1

PARTNERS' EQUITY Narrative (Details)	3 Months Ended
	Mar. 31, 2021
Partners' Capital Notes [Abstract]
Percent of available cash distributed	100.00%
Number of days within which distribution is paid to common unitholders	45

X

- Definition

Number of days within which distribution must be paid to common unitholders after end of quarter (per the terms of the partnership agreement).

+ References

No definition available.

+ Details

Name:	ns_NumberofDaysWithinWhichDistributionIsPaidToCommonUnitholders
Namespace Prefix:	ns_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percent of available cash distributed to partners (per the terms of the partnership agreement).

+ References

No definition available.

+ Details

Name:	ns_PercentOfAvailableCashDistributed
Namespace Prefix:	ns_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

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