XML 119 R97.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Stockholders' Equity (Details) - USD ($) $ in Thousands |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Jan. 26, 2022 | May 03, 2021 | Jul. 15, 2020 | Dec. 31, 2021 | Dec. 31, 2020
Class of Stock [Line Items] |  |  |  |  |
Total capitalization |  |  |  | $ 1,724,791 | $ 1,495,398
Cumulative Preferred Shares |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Preferred stock, shares authorized (in shares) |  |  |  | 1,500,000 |
Preferred stock, shares outstanding (in shares) |  |  |  | 0 | 0
Cumulative Preference Shares |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Preferred stock, shares authorized (in shares) |  |  |  | 1,000,000 |
Preferred stock, shares outstanding (in shares) |  |  |  | 0 |
OTP |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Equity to total capitalization (as a percent) |  |  |  | 52.50% |
Net assets restricted from distribution |  |  |  | $ 681,200 |
Minimum | Minnesota Public Utilities Commission | OTP |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Public utilities, requested equity capital structure (as a percent) |  |  | 47.50% |  |
Minimum | Minnesota Public Utilities Commission | OTP | Subsequent Event |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Public utilities, approved equity capital structure (as a percent) | 48.00% |  |  |  |
Maximum | OTP |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Total capitalization |  |  |  | $ 1,700,000 |
Maximum | OTP | Subsequent Event |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Total capitalization | $ 1,700,000 |  |  |  |
Maximum | Minnesota Public Utilities Commission | OTP |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Public utilities, requested equity capital structure (as a percent) |  |  | 58.10% |  |
Maximum | Minnesota Public Utilities Commission | OTP | Subsequent Event |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Public utilities, approved equity capital structure (as a percent) | 58.70% |  |  |  |
Second Shelf Registration |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |
Shelf registration (in shares) |  | 1,500,000 |  |  |
Number of shares issued (in shares) |  |  |  | 115,180 |
Number of shares available for grant (in shares) |  |  |  | 1,384,820 |

X
- Definition Represents the ratio of Equity to total capitalization, which includes as equity minority interest and preferred stock as well as all of the components of common equity as presented on the balance sheet. Total capitalization is calculated as equity plus short-term debt plus long-term debt as presented on the balance sheet. + References No definition available. + Details
Name: | ottr_EquityToTotalCapitalizationRatio
Namespace Prefix: | ottr_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents net assets restricted from distribution. + References No definition available. + Details
Name: | ottr_NetAssetsRestrictedFromDistribution
Namespace Prefix: | ottr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Shelf registration for issuance of common shares + References No definition available. + Details
Name: | ottr_ShelfRegistrationShares
Namespace Prefix: | ottr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument. + References No definition available. + Details
Name: | us-gaap_CapitalizationLongtermDebtAndEquity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + 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(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. + 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(28)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_PreferredStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of public utility's approved equity to capital, including debt and equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of public utility's requested equity to capital, including debt and equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares issued or sold by the subsidiary or equity method investee per stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CumulativePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=ottr_CumulativePreferenceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ottr_OtterTailPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=ottr_MinnesotaPublicUtilitiesCommissionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=ottr_SecondShelfRegistrationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |