XML 64 R52.htm IDEA: XBRL DOCUMENT
v3.20.2

Note 6 - Share-based Payments - Stock Incentive Awards Granted to Officers Under the 2014 Stock Incentive Plan (Details) | 9 Months Ended
--- | ---
Sep. 30, 2020 $ / shares shares
Restricted Stock Units (RSUs) [Member] | The 2014 Stock Incentive Plan [Member] | February 3, 2020 [Member] | Management [Member] |
Shares/units granted (in shares) | shares | 3,000
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 54.0450
Shares/units granted, vesting date | 25% per year through February 6, 2024
Restricted Stock Units (RSUs) [Member] | The 2014 Stock Incentive Plan [Member] | February 12, 2020 [Member] | Executive Officer [Member] |
Shares/units granted (in shares) | shares | 15,300
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 54.0607
Shares/units granted, vesting date | 25% per year through February 6, 2024
Restricted Stock Units (RSUs) [Member] | The 2014 Stock Incentive Plan [Member] | April 20, 2020 [Member] | Non-executive Employees [Member] |
Shares/units granted (in shares) | shares | 14,975
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 40.18
Shares/units granted, vesting date | 100% April 8, 2024
Performance Shares [Member] | The 2014 Stock Incentive Plan [Member] | February 12, 2020 [Member] |
Shares/units granted (in shares) | shares | 47,600
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 47.10
Shares/units granted, vesting date | December 31, 2022
Performance Shares [Member] | The 2014 Stock Incentive Plan Under Legacy Agreement [Member] | February 12, 2020 [Member] |
Shares/units granted (in shares) | shares | 7,400
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 52.20
Shares/units granted, vesting date | December 31, 2022
Restricted Stock [Member] | The 2014 Stock Incentive Plan [Member] | April 20, 2020 [Member] | Nonemployee Directors [Member] |
Shares/units granted (in shares) | shares | 17,400
Shares/units granted, weighted average grant-date fair value per award (in dollars per share) | $ / shares | $ 44.85
Shares/units granted, vesting date | 33% per year through April 8, 2023

X
- Definition Represents the award vesting date under a share-based compensation arrangement. + References No definition available. + Details
Name: | ottr_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingDate
Namespace Prefix: | ottr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + 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 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + 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 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=ottr_The2014StockIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=ottr_February32020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_ManagementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=ottr_February122020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=srt_ExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardDateAxis=ottr_April202020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=ottr_NonExecutiveEmployeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=ottr_The2014StockIncentivePlanUnderLegacyAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_TitleOfIndividualAxis=ottr_NonemployeeDirectorsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |