XML 120 R75.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Note 8 - Leases - Operating Lease Obligation (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 USD ($)
Operating Lease Obligations, beginning balance | $ 20,369
Non-cash Acquisition of Right-of-Use Assets | 6,318
Lease Adjustments/Modifications | (116)
Lease Obligation Payments | (5,371)
Interest Component of Lease Obligation Payment | 1,129
Operating Lease Obligations, ending balance | 22,329
OTP [Member] |
Operating Lease Obligations, beginning balance | 3,609
Non-cash Acquisition of Right-of-Use Assets | 758
Lease Adjustments/Modifications | 71
Lease Obligation Payments | (1,316)
Interest Component of Lease Obligation Payment | 170
Operating Lease Obligations, ending balance | 3,292
Nonelectric Companies [Member] |
Operating Lease Obligations, beginning balance | 16,760
Non-cash Acquisition of Right-of-Use Assets | 5,560
Lease Adjustments/Modifications | (187)
Lease Obligation Payments | (4,055)
Interest Component of Lease Obligation Payment | 959
Operating Lease Obligations, ending balance | $ 19,037

X
- Definition Amount of operating lease interest expense. + References No definition available. + Details
Name: | ottr_OperatingLeaseInterest
Namespace Prefix: | ottr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of change in operating lease liability related to the lease modifications. + References No definition available. + Details
Name: | ottr_OperatingLeaseLeaseModifications
Namespace Prefix: | ottr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
Name: | us-gaap_OperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918643-209977 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeasePayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of increase in right-of-use asset obtained in exchange for operating lease liability. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(2) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 + Details
Name: | us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=ottr_OTPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=ottr_NonelectricCompaniesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |