XML 144 R120.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Capital expenditures related to oil and natural gas producing activities (Details 3) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2015 | [1] | Dec. 31, 2014 | Dec. 31, 2013
Acquisitions: |  |  |  |  |
Proved properties | $ 0 | $ 87,919 | [2] | $ 1,817 | [2]
Unproved properties | 0 | 138,683 | [2] | 4,608 | [2]
Exploration | 0 | 16,879 | [2] | 26,975 | [2]
Development | 0 | 331,400 | [2] | 355,421 | [2]
Total capital expenditures | $ 0 | 574,881 | [2] | 388,821 | [2]
Net change in property, plant and equipment related to future liabilities for asset retirement obligations that are excluded |  | (9,000) |  | (10,700) |
Proceeds from sale of oil and gas property and equipment |  | $ 246,600 |  | $ 83,600 |
[1] | No wells were drilled in 2015.
[2] | Excludes net additions/(reductions) to property, plant and equipment related to the recognition of future liabilities for asset retirement obligations associated with the plugging and abandonment of oil and natural gas wells of $(9.0) million and $(10.7) million for the years ended December 31, 2014 and 2013, respectively.

X
- Definition Net change in property, plant and equipment related to future liabilitie for asset retirement obligations that are excluded. + References No definition available. + Details
Name: | mdu_NetChangeInPropertyPlantAndEquipmentRelatedToFutureLiabilitieForAssetRetirementObligationsThatAreExcluded
Namespace Prefix: | mdu_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Costs incurred, including capitalized costs and costs charged to expense, associated with the acquisition of oil and gas properties that have proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 18 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62014-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62038-109447 + Details
Name: | us-gaap_CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Costs incurred, including capitalized costs and costs charged to expense, associated with the acquisition of oil and gas properties that have unproved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62038-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 18 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62014-109447 + Details
Name: | us-gaap_CostsIncurredAcquisitionOfUnprovedOilAndGasProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Development costs incurred, including capitalized costs and costs charged to expense, in oil and gas activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 18 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62014-109447 + Details
Name: | us-gaap_CostsIncurredDevelopmentCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Exploration costs incurred, including capitalized costs and costs charged to expense, in oil and gas activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Exploration -URI http://asc.fasb.org/extlink&oid=6512329 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 18 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62014-109447 + Details
Name: | us-gaap_CostsIncurredExplorationCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of costs incurred related to oil and gas property acquisition, exploration and development activities, including capitalized costs and costs charged to expense. + References No definition available. + Details
Name: | us-gaap_CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_CostsIncurredOilAndGasPropertyAcquisitionExplorationAndDevelopmentActivitiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations. + 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 (c) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfOilAndGasPropertyAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration