    <SEC-DOCUMENT>0001466593-24-000147-index.html : 20241216
    <SEC-HEADER>0001466593-24-000147.hdr.sgml : 20241216
    <ACCEPTANCE-DATETIME>20241216152342
    ACCESSION NUMBER:		0001466593-24-000147
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		17
    CONFORMED PERIOD OF REPORT:	20241211
    ITEM INFORMATION:		Entry into a Material Definitive Agreement
    ITEM INFORMATION:		Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20241216
    DATE AS OF CHANGE:		20241216

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			Otter Tail Corp
    		CENTRAL INDEX KEY:			0001466593
    		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
    		ORGANIZATION NAME:           	01 Energy & Transportation
    		IRS NUMBER:				270383995
    		STATE OF INCORPORATION:			MN
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-53713
    		FILM NUMBER:		241551575

    	BUSINESS ADDRESS:
    		STREET 1:		215 S CASCADE ST
    		STREET 2:		PO BOX 496
    		CITY:			FERGUS FALLS
    		STATE:			MN
    		ZIP:			56538-0496
    		BUSINESS PHONE:		866-410-8780

    	MAIL ADDRESS:
    		STREET 1:		215 S CASCADE ST
    		STREET 2:		PO BOX 496
    		CITY:			FERGUS FALLS
    		STATE:			MN
    		ZIP:			56538-0496

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	Otter Tail Holding Co
    		DATE OF NAME CHANGE:	20090618
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>ottr-20241211.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: ottr-20241211.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.1
    <SEQUENCE>2
    <FILENAME>ottertailcorporationsixtha.htm
    <DESCRIPTION>EX-10.1
    <TEXT>
    Document 2 - file: ottertailcorporationsixtha.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.2
    <SEQUENCE>3
    <FILENAME>ottertailpowercompanyfifth.htm
    <DESCRIPTION>EX-10.2
    <TEXT>
    Document 3 - file: ottertailpowercompanyfifth.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>4
    <FILENAME>ottr-20241211.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 4 - file: ottr-20241211.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>5
    <FILENAME>ottr-20241211_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 5 - file: ottr-20241211_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>6
    <FILENAME>ottr-20241211_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 6 - file: ottr-20241211_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>image_0.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: image_0.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>image_0a.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: image_0a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>10
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 10 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>11
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 11 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>12
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 12 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>15
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 15 - file: FilingSummary.html

    Document 15 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>17
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 17 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>18
    <FILENAME>0001466593-24-000147-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 18 - file: 0001466593-24-000147-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>19
    <FILENAME>ottr-20241211_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 19 - file: ottr-20241211_htm.html

    Document 19 - RAW XML: ottr-20241211_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>