XML 76 R51.htm IDEA: XBRL DOCUMENT v2.4.1.9

Derivative instruments (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	$ 7,127us-gaap_DerivativeFairValueOfDerivativeAsset	$ 18,335us-gaap_DerivativeFairValueOfDerivativeAsset	$ 330us-gaap_DerivativeFairValueOfDerivativeAsset
Derivative liability fair value gross liability	0us-gaap_DerivativeFairValueOfDerivativeLiability	0us-gaap_DerivativeFairValueOfDerivativeLiability	12,186us-gaap_DerivativeFairValueOfDerivativeLiability
Commodity contract [Member] | Not designated as hedging instrument [Member] | Commodity derivative instruments - current assets [Member]
Derivatives, Fair Value [Line Items]
Other derivatives not designated as hedging instruments assets at fair value	7,127us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsAssetsCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	18,335us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsAssetsCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	81us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsAssetsCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember
Commodity contract [Member] | Not designated as hedging instrument [Member] | Other assets noncurrent [Member]
Derivatives, Fair Value [Line Items]
Other derivatives not designated as hedging instruments assets at fair value	0us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_OtherAssetsNoncurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	0us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_OtherAssetsNoncurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	249us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_OtherAssetsNoncurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember
Commodity contract [Member] | Not designated as hedging instrument [Member] | Commodity derivative instruments - current liabilities [Member]
Derivatives, Fair Value [Line Items]
Other derivatives not designated as hedging instruments liabilities at fair value	$ 0us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsLiabilitiesCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	$ 0us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsLiabilitiesCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember	$ 12,186us-gaap_OtherDerivativesNotDesignatedAsHedgingInstrumentsLiabilitiesAtFairValue / us-gaap_BalanceSheetLocationAxis = mdu_CommodityDerivativeInstrumentsLiabilitiesCurrentMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_CommodityContractMember / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember

X

- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

+ Details

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

X

- Definition

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

+ Details

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

X

- Definition

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as an asset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

+ Details

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

X

- Details

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

X

- Definition

Fair value of all derivative liabilities not designated as a hedging instrument.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

+ Details

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

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: