Company Sponsored Wholly-Owned Business Trusts, Number

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- Definition

Payments for Repurchase of Trust Preferred Securities, Held by Subsidary Trust

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- Definition

Subordinated Borrowing, Liquidation Amount Per Security

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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

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Fair value amount of debt instrument that was repurchased.

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Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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=6876686&loc=d3e534808-122878

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- Definition

Cash dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations that are returns of capital. Excludes dividends or distributions from equity method investments classified as operating activities.

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- Definition

Amount that would be paid, determined under the conditions specified in the contract, if the holder of the share has the right to redeem the shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6940734&loc=d3e22047-110879

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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.

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Subordinated Debentures Held by Subsidiary Trusts - Subordinated Debentures (Details) $ in Thousands			1 Months Ended				12 Months Ended
	Dec. 26, 2014 USD ($)	Dec. 15, 2014 USD ($)	Jan. 31, 2008 USD ($)	Dec. 31, 2007 USD ($)	Nov. 30, 2007 USD ($)	Oct. 31, 2007 USD ($)	Dec. 31, 2015 USD ($) trusts	Dec. 31, 2014 USD ($)
Subordinated Borrowing
Number of company sponsored wholly-owned business trusts \| trusts							6
Subordinated debentures held by subsidiary trusts							$ 82,477	$ 82,477
First Interstate Statutory Trust II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts						$ 10,310	$ 10,310	10,310
Debt instrument, interest rate at period end							2.58%
First Interstate Statutory Trust II \| Junior Subordinated Deferrable Interest Debentures Issued by FIST II \| LIBOR
Subordinated Borrowing
Debt instrument, basis spread on variable rate						2.25%
First Interstate Statutory Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts					$ 15,464		$ 15,464	15,464
Debt instrument, interest rate at period end							3.26%
First Interstate Statutory Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| Debt Instrument, Redemption, At Issuance through Year Five
Subordinated Borrowing
Debt instrument, interest rate, stated percentage					7.50%
First Interstate Statutory Trust I \| Junior Subordinated Deferrable Interest Debentures Issued by FIST I \| LIBOR \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate					2.75%
First Interstate Statutory Trust III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts				$ 20,619			$ 20,619	20,619
Debt instrument, interest rate at period end							2.91%
First Interstate Statutory Trust III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| Debt Instrument, Redemption, At Issuance through Year Five
Subordinated Borrowing
Debt instrument, interest rate, stated percentage				6.88%
First Interstate Statutory Trust III \| Junior Subordinated Deferrable Interest Debentures Issued by FIST III \| LIBOR \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate				2.40%
First Interstate Statutory Trust IV \| Junior Subordinated Deferrable Interest Debentures Issued by FIST IV
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts							$ 15,464	15,464
Debt instrument, interest rate at period end							3.03%
First Interstate Statutory Trust IV \| Junior Subordinated Deferrable Interest Debentures Issued by FIST IV \| LIBOR
Subordinated Borrowing
Debt instrument, basis spread on variable rate				2.70%
First Interstate Statutory Trust V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts			$ 10,310				$ 10,310	10,310
Debt instrument, interest rate at period end							3.08%
First Interstate Statutory Trust V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| Debt Instrument, Redemption, At Issuance through Year Five
Subordinated Borrowing
Debt instrument, interest rate, stated percentage			6.78%
First Interstate Statutory Trust V \| Junior Subordinated Deferrable Interest Debentures Issued by FIST V \| LIBOR \| Debt Instrument, Redemption, After Period Five
Subordinated Borrowing
Debt instrument, basis spread on variable rate			2.75%
First Interstate Statutory Trust VI \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI
Subordinated Borrowing
Subordinated debentures held by subsidiary trusts			$ 10,310				$ 10,310	$ 10,310
Debt instrument, interest rate at period end							3.08%
First Interstate Statutory Trust VI \| Junior Subordinated Deferrable Interest Debentures Issued by FIST VI \| LIBOR
Subordinated Borrowing
Debt instrument, basis spread on variable rate			2.75%
Mountain West Trusts [Member] \| Junior Subordinated Deferrable Interest Debenture Issues by MWFC [Member]
Subordinated Borrowing
Redemption price	$ 6,006	$ 14,433
Liquidation amount per security	1	1
Mandatory redemption of trust preferred securities	5,825	14,000
Capitalization of subsidiaries	$ 181	$ 433
Mountain West Trusts [Member] \| Junior Subordinated Deferrable Interest Debenture Issues by MWFC [Member] \| LIBOR
Subordinated Borrowing
Debt instrument, basis spread on variable rate	3.10%	1.85%
Trust Preferred Securities Subject to Mandatory Redemption \| Mountain West Trusts [Member]
Subordinated Borrowing
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount							$ 19,825
Common Stock Subject to Mandatory Redemption \| Mountain West Trusts [Member]
Subordinated Borrowing
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount							$ 614