Intangible Assets - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Favorable lease terms	$ (292)	$ (291)	$ (583)	$ (583)
Total	$ (292)	$ (291)	$ (583)	$ (583)

The aggregate amortization of the asset/liability arising from the market value of the time charter chartered-out assumed from a vessel acquisition net of any acceleration of intangibles.

No definition available.

Name:	nmm_AmortizationOfFairValueOfIntangibleAssets
Namespace Prefix:	nmm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration