XML 71 R59.htm IDEA: XBRL DOCUMENT v3.20.2

Note 10 - Short-term and Long-term Borrowings - Breakdown of Assignment of Consolidated Short-term and Long-term Debt Outstanding (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Short-Term Debt		$ 41,239	$ 6,000
Long-Term Debt		727,261	692,351
Less: Current Maturities net of Unamortized Debt Issuance Costs		261	183
Unamortized Long-Term Debt Issuance Costs		2,611	2,587
Total Long-Term Debt net of Unamortized Debt Issuance Costs		724,389	689,581
Total Short-Term and Long-Term Debt (with current maturities)		765,889	695,764
Short-Term Debt		41,239	6,000
The 3.55% Guaranteed Senior Notes, Due December 15, 2026 [Member]
Long-Term Debt		$ 80,000	$ 80,000
Debt Instrument, Interest Rate, Stated Percentage		3.55%	3.55%
Senior Unsecured Notes 4.63%, Series 2011A, due December 1, 2021 [Member]
Long-Term Debt		$ 140,000	$ 140,000
Debt Instrument, Interest Rate, Stated Percentage		4.63%	4.63%
Senior Unsecured Notes 6.15%, Series 2007B, due August 20, 2022 [Member]
Long-Term Debt		$ 30,000	$ 30,000
Debt Instrument, Interest Rate, Stated Percentage		6.15%	6.15%
Senior Unsecured Notes 6.37%, Series C, Due August 20, 2027 [Member]
Long-Term Debt		$ 42,000	$ 42,000
Debt Instrument, Interest Rate, Stated Percentage		6.37%	6.37%
Senior Unsecured Notes 4.68%, Series 2013A, due February 27, 2029 [Member]
Long-Term Debt		$ 60,000	$ 60,000
Debt Instrument, Interest Rate, Stated Percentage		4.68%	4.68%
Senior Unsecured Notes 3.07%, Series 2019A, due October 10, 2029 [Member]
Long-Term Debt	[1]	$ 10,000	$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.07%	3.07%
Senior Unsecured Notes 3.22%, Series 2020A, due February 25, 2030 [Member]
Long-Term Debt		$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.22%
Senior Unsecured Notes 6.47%, Series 2007D, due August 20, 2037 [Member]
Long-Term Debt		$ 50,000	$ 50,000
Debt Instrument, Interest Rate, Stated Percentage		6.47%	6.47%
Senior Unsecured Notes 3.52%, Series 2019B, Due October 10, 2039 [Member]
Long-Term Debt		$ 26,000	$ 26,000
Debt Instrument, Interest Rate, Stated Percentage		3.52%	3.52%
Senior Unsecured Notes 3.62%. Series 2020C, due February 25, 2040 [Member]
Long-Term Debt		$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.62%
Senior Unsecured Notes 5.47%, Series 2013B, due February 27, 2044 [Member]
Long-Term Debt		$ 90,000	$ 90,000
Debt Instrument, Interest Rate, Stated Percentage		5.47%	5.47%
Senior Unsecured Notes 4.07%, Series 2018A, Due February 7, 2048 [Member]
Long-Term Debt		$ 100,000	$ 100,000
Debt Instrument, Interest Rate, Stated Percentage		4.07%	4.07%
Senior Unsecured Notes 3.82%, Series 2019C, due October 10, 2049 [Member]
Long-Term Debt		$ 64,000	$ 64,000
Debt Instrument, Interest Rate, Stated Percentage		3.82%	3.82%
Senior Unsecured Notes 3.92%, Series 2020D, due February 25, 2050 [Member]
Long-Term Debt		$ 15,000
Debt Instrument, Interest Rate, Stated Percentage		3.92%
PACE Note, 2.54%, due March 18, 2021 [Member]
Long-Term Debt		$ 261	$ 351
Debt Instrument, Interest Rate, Stated Percentage		2.54%	2.54%
Parent Company [Member]
Short-Term Debt		$ 41,239	$ 6,000
Long-Term Debt		80,261	80,351
Less: Current Maturities net of Unamortized Debt Issuance Costs		261	183
Unamortized Long-Term Debt Issuance Costs		330	356
Total Long-Term Debt net of Unamortized Debt Issuance Costs		79,670	79,812
Total Short-Term and Long-Term Debt (with current maturities)		121,170	85,995
Short-Term Debt		41,239	6,000
Parent Company [Member] | The 3.55% Guaranteed Senior Notes, Due December 15, 2026 [Member]
Long-Term Debt		$ 80,000	$ 80,000
Debt Instrument, Interest Rate, Stated Percentage		3.55%	3.55%
Parent Company [Member] | PACE Note, 2.54%, due March 18, 2021 [Member]
Long-Term Debt		$ 261	$ 351
Debt Instrument, Interest Rate, Stated Percentage		2.54%	2.54%
Otter Tail Power Company [Member]
Long-Term Debt		$ 647,000	$ 612,000
Unamortized Long-Term Debt Issuance Costs		2,281	2,231
Total Long-Term Debt net of Unamortized Debt Issuance Costs		644,719	609,769
Total Short-Term and Long-Term Debt (with current maturities)		644,719	609,769
Otter Tail Power Company [Member] | Senior Unsecured Notes 4.63%, Series 2011A, due December 1, 2021 [Member]
Long-Term Debt		$ 140,000	$ 140,000
Debt Instrument, Interest Rate, Stated Percentage		4.63%	4.63%
Otter Tail Power Company [Member] | Senior Unsecured Notes 6.15%, Series 2007B, due August 20, 2022 [Member]
Long-Term Debt		$ 30,000	$ 30,000
Debt Instrument, Interest Rate, Stated Percentage		6.15%	6.15%
Otter Tail Power Company [Member] | Senior Unsecured Notes 6.37%, Series C, Due August 20, 2027 [Member]
Long-Term Debt		$ 42,000	$ 42,000
Debt Instrument, Interest Rate, Stated Percentage		6.37%	6.37%
Otter Tail Power Company [Member] | Senior Unsecured Notes 4.68%, Series 2013A, due February 27, 2029 [Member]
Long-Term Debt		$ 60,000	$ 60,000
Debt Instrument, Interest Rate, Stated Percentage		4.68%	4.68%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.07%, Series 2019A, due October 10, 2029 [Member]
Long-Term Debt	[1]	$ 10,000	$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.07%	3.07%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.22%, Series 2020A, due February 25, 2030 [Member]
Long-Term Debt		$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.22%
Otter Tail Power Company [Member] | Senior Unsecured Notes 6.47%, Series 2007D, due August 20, 2037 [Member]
Long-Term Debt		$ 50,000	$ 50,000
Debt Instrument, Interest Rate, Stated Percentage		6.47%	6.47%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.52%, Series 2019B, Due October 10, 2039 [Member]
Long-Term Debt		$ 26,000	$ 26,000
Debt Instrument, Interest Rate, Stated Percentage		3.52%	3.52%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.62%. Series 2020C, due February 25, 2040 [Member]
Long-Term Debt		$ 10,000
Debt Instrument, Interest Rate, Stated Percentage		3.62%
Otter Tail Power Company [Member] | Senior Unsecured Notes 5.47%, Series 2013B, due February 27, 2044 [Member]
Long-Term Debt		$ 90,000	$ 90,000
Debt Instrument, Interest Rate, Stated Percentage		5.47%	5.47%
Otter Tail Power Company [Member] | Senior Unsecured Notes 4.07%, Series 2018A, Due February 7, 2048 [Member]
Long-Term Debt		$ 100,000	$ 100,000
Debt Instrument, Interest Rate, Stated Percentage		4.07%	4.07%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.82%, Series 2019C, due October 10, 2049 [Member]
Long-Term Debt		$ 64,000	$ 64,000
Debt Instrument, Interest Rate, Stated Percentage		3.82%	3.82%
Otter Tail Power Company [Member] | Senior Unsecured Notes 3.92%, Series 2020D, due February 25, 2050 [Member]
Long-Term Debt		$ 15,000
Debt Instrument, Interest Rate, Stated Percentage		3.92%
[1] Holder is COBANK, a cooperative lender. Interest payments are subject to cash credits which may result in a lower effective interest rate.

X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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 http://asc.fasb.org/extlink&oid=119993939&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 http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtLongtermAndShorttermCombinedAmount
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. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ 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 http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: 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 http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: 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 http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 4: 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 http://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 http://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 after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. 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 210.5-02.22)
-URI http://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

- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ 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)(a))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: 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)(a)(1))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: 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(13))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

Name:	us-gaap_ShortTermBorrowings
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_SeniorUnsecuredNotes463Series2011aDueDecember12021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes615Series2007bDueAugust202022Member
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_SeniorUnsecuredNotes468Series2013aDueFebruary272029Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes307Series2019aDueOctober102029Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes322Series2020aDueFebruary252030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes647Series2007dDueAugust202037Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes352Series2019bDueOctober102039Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes362Series2020cDueFebruary252040Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes547Series2013bDueFebruary272044Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes407Series2018ADueFebruary72048Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes382Series2019cDueOctober102049Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_SeniorUnsecuredNotes392Series2020dDueFebruary252050Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=ottr_PaceNote254DueMarch182021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_ConsolidatedEntitiesAxis=ottr_OtterTailPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: