Note 4 - Related Party Transactions (Details Textual)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
General and Administrative Reimbursement, Maximum Percentage	5.00%	5.00%

The maximum percentage for reimbursement of general and administrative costs.

No definition available.

Name:	dmlp_GeneralAndAdministrativeReimbursementMaximumPercentage
Namespace Prefix:	dmlp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration