XML 59 R49.htm IDEA: XBRL DOCUMENT
v3.22.2

Short-Term and Long-Term Borrowings - Breakdown of Outstanding Long-term Debt (Details) - USD ($) $ in Thousands | Jun. 30, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Instrument [Line Items] |  |
Long-term debt | $ 857,000 | $ 767,000
Current Maturities, Net of Unamortized Debt Issuance Costs | 29,996 | 29,983
Unamortized Long-Term Debt Issuance Costs | 3,305 | 3,003
Total Long-Term Debt, Net of Unamortized Debt Issuance Costs | $ 823,699 | 734,014
Guaranteed Senior Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.55% |
Long-term debt | $ 80,000 | 80,000
Series 2007B Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 6.15% |
Long-term debt | $ 30,000 | 30,000
Series 2007C Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 6.37% |
Long-term debt | $ 42,000 | 42,000
Series 2013A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 4.68% |
Long-term debt | $ 60,000 | 60,000
Series 2019A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.07% |
Long-term debt | $ 10,000 | 10,000
Series 2020A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.22% |
Long-term debt | $ 10,000 | 10,000
Series 2020B Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.22% |
Long-term debt | $ 40,000 | 40,000
Series 2021A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 2.74% |
Long-term debt | $ 40,000 | 40,000
Series 2007D Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 6.47% |
Long-term debt | $ 50,000 | 50,000
Series 2019B Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.52% |
Long-term debt | $ 26,000 | 26,000
Series 2020C Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.62% |
Long-term debt | $ 10,000 | 10,000
Series 2013B Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 5.47% |
Long-term debt | $ 90,000 | 90,000
Series 2018A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 4.07% |
Long-term debt | $ 100,000 | 100,000
Series 2019C Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.82% |
Long-term debt | $ 64,000 | 64,000
Series 2020D Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.92% |
Long-term debt | $ 15,000 | 15,000
Series 2021B Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.69% |
Long-term debt | $ 100,000 | 100,000
Series 2022A Senior Unsecured Notes |  |
Debt Instrument [Line Items] |  |
Rate | 3.77% |
Long-term debt | $ 90,000 | $ 0

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 1B -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

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_DebtInstrumentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after accumulated amortization, of debt discount. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28541-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 1D -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611 + Details
Name: | us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 55 -Paragraph 69C -URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 55 -Paragraph 69B -URI https://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 1D -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebtNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_The355GuaranteedSeniorNotesDueDecember152026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes615SeriesBDueAugust202022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes637SeriesCDueAugust202027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes468SeriesADueFebruary272029Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes307SeriesADueOctober102029Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes322SeriesADueFebruary252030Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes322SeriesBDueAugust202030Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes274SeriesADueNovember292031Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes647SeriesDDueAugust202037Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes352SeriesBDueOctober102039Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes362SeriesCDueFebruary252040Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes547SeriesBDueFebruary272044Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes407SeriesADueFebruary72048Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes382SeriesCDueOctober102049Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes392SeriesDDueFebruary252050Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes369SeriesBDueNovember292051Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes377SeriesADueMay202052Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |