<SEC-DOCUMENT>0000950103-22-000867-index.html : 20220120
<SEC-HEADER>0000950103-22-000867.hdr.sgml : 20220120
<ACCEPTANCE-DATETIME>20220120170135
ACCESSION NUMBER:		0000950103-22-000867
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		16
CONFORMED PERIOD OF REPORT:	20220119
ITEM INFORMATION:		Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers
ITEM INFORMATION:		Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year
ITEM INFORMATION:		Submission of Matters to a Vote of Security Holders
ITEM INFORMATION:		Other Events
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20220120
DATE AS OF CHANGE:		20220120

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
		CENTRAL INDEX KEY:			0000860413
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				810331430
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22542991

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918
		BUSINESS PHONE:		4062555300

	MAIL ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
		DATE OF NAME CHANGE:	19930615
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>dp165365_8k.htm
<DESCRIPTION>FORM 8-K
<TEXT>
Document 1 - file: dp165365_8k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.SCH
<SEQUENCE>2
<FILENAME>fibk-20220119.xsd
<DESCRIPTION>XBRL SCHEMA FILE
<TEXT>
Document 2 - file: fibk-20220119.xsd

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.LAB
<SEQUENCE>3
<FILENAME>fibk-20220119_lab.xml
<DESCRIPTION>XBRL LABEL FILE
<TEXT>
Document 3 - file: fibk-20220119_lab.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.PRE
<SEQUENCE>4
<FILENAME>fibk-20220119_pre.xml
<DESCRIPTION>XBRL PRESENTATION FILE
<TEXT>
Document 4 - file: fibk-20220119_pre.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-3.1
<SEQUENCE>5
<FILENAME>dp165365_ex0301.htm
<DESCRIPTION>EXHIBIT 3.1
<TEXT>
Document 5 - file: dp165365_ex0301.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>6
<FILENAME>dp165365_ex9901.htm
<DESCRIPTION>EXHIBIT 99.1
<TEXT>
Document 6 - file: dp165365_ex9901.htm

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

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

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>9
<FILENAME>R1.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 9 - file: R1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>10
<FILENAME>dp165365_8k_htm.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 10 - file: dp165365_8k_htm.html

Document 10 - RAW XML: dp165365_8k_htm.xml

</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>14
<FILENAME>FilingSummary.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 14 - file: FilingSummary.html

Document 14 - RAW XML: FilingSummary.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>JSON
<SEQUENCE>16
<FILENAME>MetaLinks.json
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 16 - file: MetaLinks.json

</DOCUMENT>
<DOCUMENT>
<TYPE>ZIP
<SEQUENCE>17
<FILENAME>0000950103-22-000867-xbrl.zip
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
Document 17 - file: 0000950103-22-000867-xbrl.zip

</DOCUMENT>
</SEC-DOCUMENT>