SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Cash, Cash Equivalents and Restricted Cash (Details)	12 Months Ended
Dec. 31, 2022
Cash, Cash Equivalents and Restricted Cash [Abstract]
Original maturities of deposits classified as cash and cash equivalents	3 months

The original maturity, in months, of deposits classified as cash and cash equivalents, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

No definition available.

Name:	nat_OriginalMaturitiesOfDepositsClassifiedAsCashAndCashEquivalents
Namespace Prefix:	nat_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration