XML 150 R117.htm IDEA: XBRL DOCUMENT v2.4.1.9

Capitalized costs and AD&D related to oil and natural gas producing activities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Subject to amortization	$ 3,205,036mdu_SubjectToAmortization	$ 2,893,010mdu_SubjectToAmortization	$ 2,531,562mdu_SubjectToAmortization
Not subject to amortization	132,141us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative	124,869us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative	191,794us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative
Total capitalized costs	3,337,177us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross	3,017,879us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross	2,723,356us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross
Less accumulated depreciation, depletion and amortization	1,752,566us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	1,562,116us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	1,383,386us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Net capitalized costs	$ 1,584,611us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet	$ 1,455,763us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet	$ 1,339,970us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet

X

- Definition

The sum of capitalized costs subject to amortization relating to oil and gas producing activities before accounting for accumulated depreciation.

+ References

No definition available.

+ Details

Name:	mdu_SubjectToAmortization
Namespace Prefix:	mdu_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating to oil and gas producing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The sum of the capitalized costs incurred, as of the balance sheet date, of unproved properties excluded from amortization including acquisition costs, exploration costs, development costs, and production costs.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-10.(c)(7)(ii))

-URI http://asc.fasb.org/extlink&oid=27015464&loc=d3e511914-122862

+ Details

Name:	us-gaap_CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The sum of capitalized costs relating to oil and gas producing activities before accounting for accumulated depreciation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Net amount of capitalized costs relating to oil and gas producing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_OilAndGasExplorationAndProductionIndustriesDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration