Note 11 - Lease Obligations - Future Minimum Annual Lease Commitments (Details) $ in Thousands	Sep. 30, 2025 USD ($)
2025	$ 286
2026	0
Lessee, Operating Lease, Minimum Lease Commitments, to be Paid	$ 286

Amount of minimum lease commitments for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

No definition available.

Name:	bdco_LesseeOperatingLeaseMinimumLeaseCommitmentsToBePaidYearOne
Namespace Prefix:	bdco_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant