XML 69 R51.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Interest Rate Swap Summary (Details) - Jun. 30, 2015 - USD ($) $ in Thousands | Total
--- | ---
Interest Rate Swap One |  |
Interest rate swap derivative financial instruments |  |
Forecasted Notional Amount |  | $ 160,000
Variable Interest Rate | [1] | 3 month LIBOR
Fixed Interest Rate | [1] | 3.378%
Term, Effective Date | [2] | Oct. 21, 2014
Term, Maturity Date | [2] | Oct. 21, 2021
Interest Rate Swap Two |  |
Interest rate swap derivative financial instruments |  |
Forecasted Notional Amount |  | $ 100,000
Variable Interest Rate | [1] | 3 month LIBOR
Fixed Interest Rate | [1] | 2.498%
Term, Effective Date | [2] | Nov. 30, 2015
Term, Maturity Date | [2] | Nov. 30, 2022
[1] | The Company pays the fixed interest rate and the counterparty pays the Company the variable interest rate.
[2] | No cash will be exchanged prior to the beginning of the payment term.

X
- Definition The reference rate for the variable rate of the interest rate derivative, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. + References No definition available. + Details
Name: | gbci_DerivativeVariableInterestRateBasis
Namespace Prefix: | gbci_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fixed interest rate related to the interest rate derivative. + References No definition available. + Details
Name: | us-gaap_DerivativeFixedInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date the entity entered into the derivative contract, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_DerivativeInceptionDates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal or face amount used to calculate payments on the derivative liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Notional Amount -URI http://asc.fasb.org/extlink&oid=6519104 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579245-113959 + Details
Name: | us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date the derivative contract matures, in CCYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_DerivativeMaturityDates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeByNatureAxis=gbci_InterestRateSwapOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeByNatureAxis=gbci_InterestRateSwapTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |