Subsequent Event (Details Textuals) - Subsequent Event [Member]	Oct. 28, 2018 USD ($) $ / shares shares
Subsequent Event [Line Items]
Business Acquisition Cash Consideration \| $	$ 400,000,000
Business Acquisition, Shares Issued	191,800,000
Stock and Cash Election [Member]
Subsequent Event [Line Items]
Business Acquisition, Share Price \| $ / shares	$ 25.86
Number Of Shares To Be Received By Acquiree Company Shareholders On Acquisition	12.4
All Cash Election [Member]
Subsequent Event [Line Items]
Business Acquisition Cash Consideration \| $	$ 79.80
All Stock Election [Member]
Subsequent Event [Line Items]
Number Of Shares To Be Received By Acquiree Company Shareholders On Acquisition	18.3454

Business Acquisition Cash Consideration

No definition available.

Name:	dnr_BusinessAcquisitionCashConsideration
Namespace Prefix:	dnr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number Of Shares To Be Received By Acquiree Company Shareholders On Acquisition

+ References

No definition available.

+ Details

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Namespace Prefix:	dnr_
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Balance Type:	na
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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