Receivable from Sale of Bidding Rights and Oil and Gas Properties (Details) (USD $)	1 Months Ended	3 Months Ended
Mar. 31, 2012	Mar. 31, 2015
Receivable from Sale of Bidding Rights and Oil and Gas Properties (Textual)
Proceed from sale of Principle Petroleum Ltd.	$ 7,000,000
Percentage sale of share in SAHF's	50.00%
Percentage of interest in the concession	9.00%dltz_PercentageOfInterestInConcession
Proceed from sale of share in SAHF's	500,000
Maximum limit to provide funds to the operating entities	10,000,000
Amount received as deposit for purchase exploration and exploitation rights		4,299,891
Receivable from the sale of bidding rights and oil and gas properties		3,200,109dltz_ReceivableFromSaleOfBiddingRights
Reserve for doubtful accounts		$ 3,200,069us-gaap_ProvisionForDoubtfulAccounts

Amount received as deposit for purchase exploration and exploitation rights.

No definition available.

Name:	dltz_AmountReceivedAsDepositForPurchaseExplorationAndExploitationRights
Namespace Prefix:	dltz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum limit to provide funds to the operating entities.

+ References

No definition available.

+ Details

Name:	dltz_MaximumLimitToProvideFundsToOperatingEntities
Namespace Prefix:	dltz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of interest in the concession.

+ References

No definition available.

+ Details

Name:	dltz_PercentageOfInterestInConcession
Namespace Prefix:	dltz_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Receivable from sale of bidding rights.

+ References

No definition available.

+ Details

Name:	dltz_ReceivableFromSaleOfBiddingRights
Namespace Prefix:	dltz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	dltz_ReceivableFromSaleOfBiddingRightsAndOilAndGasPropertiesTextualAbstract
Namespace Prefix:	dltz_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The net cash outflow or inflow associated with the acquisition or sale of a business segment during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

+ Details

Name:	us-gaap_PaymentsForProceedsFromBusinessesAndInterestInAffiliates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.5)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_ProvisionForDoubtfulAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of subsidiary's or equity investee's stock owned by parent company after stock transaction.

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration