FAIR VALUE DISCLOSURES (Details) (USD $) In Thousands	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Fair Value, Measurements, Recurring [Member]
Available-for-sale securities:
U.S. Government agencies	$ 1,497,456	$ 440,442
Government agency issued residential mortgage-backed securities	420,689	320,471
Government agency issued commercial mortgage-backed securities	34,475	25,982
Obligations of states and political subdivisions	519,431	108,958
Collateralized debt obligations		576
Other	9,504	19,448
Mortgage servicing rights	29,159	26,901
Derivative instruments	59,703	58,409
Assets:
Total	2,570,417	1,001,187
Liabilities:
Derivative instruments	58,916	57,159
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]
Available-for-sale securities:
U.S. Government agencies	0	0
Government agency issued residential mortgage-backed securities	0	0
Government agency issued commercial mortgage-backed securities	0	0
Obligations of states and political subdivisions	0	0
Collateralized debt obligations		0
Other	528	473
Mortgage servicing rights	0	0
Derivative instruments	0	0
Assets:
Total	528	473
Liabilities:
Derivative instruments	0	0
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Available-for-sale securities:
U.S. Government agencies	1,497,456	440,442
Government agency issued residential mortgage-backed securities	420,689	320,471
Government agency issued commercial mortgage-backed securities	34,475	25,982
Obligations of states and political subdivisions	519,431	108,958
Collateralized debt obligations		0
Other	8,976	18,975
Mortgage servicing rights	0	0
Derivative instruments	0	0
Assets:
Total	2,481,027	914,828
Liabilities:
Derivative instruments	0	0
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]
Available-for-sale securities:
U.S. Government agencies	0	0
Government agency issued residential mortgage-backed securities	0	0
Government agency issued commercial mortgage-backed securities	0	0
Obligations of states and political subdivisions	0	0
Collateralized debt obligations		576
Other	0	0
Mortgage servicing rights	29,159	26,901
Derivative instruments	59,703	58,409
Assets:
Total	88,862	85,886
Liabilities:
Derivative instruments	58,916	57,159
Fair Value, Measurements, Nonrecurring [Member]
Assets:
Loans held for sale	100,687	125,815
Impaired loans	279,889	242,158
Other real estate owned	162,686	82,647
Fair Value, Measurements, Nonrecurring [Member] \| Level 1 [Member]
Assets:
Loans held for sale	0	0
Impaired loans	0	0
Other real estate owned	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Level 2 [Member]
Assets:
Loans held for sale	100,687	125,815
Impaired loans	0	0
Other real estate owned	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Level 3 [Member]
Assets:
Loans held for sale	0	0
Impaired loans	279,889	242,158
Other real estate owned	162,686	82,647
Fair Value, Measurements, Nonrecurring [Member] \| Total Losses [Member]
Assets:
Loans held for sale	0	0
Impaired loans	(38,657)	(43,584)
Other real estate owned	(16,277)	(8,771)
Mortgage Servicing Rights [Member]
Changes in fair value of net assets (liabilities) classified as Level 3 [Roll Forward]
Beginning Balance	38,642	35,560
Year to date net gains (losses) included in:
Net (loss) income	(9,483)	(8,659)
Other comprehensive income	0	0
Purchases, sales, issuances and settlements, net	0	0
Transfers in and/or out of Level 3	0	0
Ending Balance	29,159	26,901
Net unrealized (loss) gains included in net income for the quarter relating to assets and liabilities held at September 30, 2011	(10,296)	(4,609)
Derivative Instruments, Net [Member]
Changes in fair value of net assets (liabilities) classified as Level 3 [Roll Forward]
Beginning Balance	2,685	844
Year to date net gains (losses) included in:
Net (loss) income	(1,898)	406
Other comprehensive income	0	0
Purchases, sales, issuances and settlements, net	0	0
Transfers in and/or out of Level 3	0	0
Ending Balance	787	1,250
Net unrealized (loss) gains included in net income for the quarter relating to assets and liabilities held at September 30, 2011	380	1,398
Available-for-sale Securities [Member]
Changes in fair value of net assets (liabilities) classified as Level 3 [Roll Forward]
Beginning Balance	0	2,125
Year to date net gains (losses) included in:
Net (loss) income	0	(1,549)
Other comprehensive income	0	0
Purchases, sales, issuances and settlements, net	0	0
Transfers in and/or out of Level 3	0	0
Ending Balance	0	576
Net unrealized (loss) gains included in net income for the quarter relating to assets and liabilities held at September 30, 2011	$ 0	$ (236)

This element represents the portion of the balance sheet assertion valued at fair value by the entity for collateralized debt obligations available-for-sale securities.

Name:	bxs_CollateralizedDebtObligationsAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to net assets (liabilities) measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ Details

Name:	bxs_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetAssetLiabilityPurchasesSalesIssuancesSettlementsNet
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents [net] transfers in to and out of net assets (liabilities) measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.

+ Details

Name:	bxs_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetAssetLiabilityTransfersNet
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents a net asset (liability) measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ Details

Name:	bxs_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisNetAssetLiabilityValue
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets) in trading revenue. Such unrealized (holding) gains or losses relate to those net assets (liabilities) still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3).

+ Details

Name:	bxs_FairValueNetAssetsLiabilitiesMeasuredOnRecurringBasisChangeInUnrealizedGainLossIncludedInEarnings
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	bxs_FairValueNetAssetsLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForwardAbstract
Namespace Prefix:	bxs
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for Government agency issued commercial mortgage-backed available-for-sale securities.

+ Details

Name:	bxs_GovernmentAgencyIssuedCommercialMortgageBackedSecuritiesAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for Government agency issued residential mortgage-backed available-for-sale securities.

+ Details

Name:	bxs_GovernmentAgencyIssuedResidentialMortgageBackedSecuritiesAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for impaired loans.

+ Details

Name:	bxs_ImpairedLoansFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for obligations of states and political subdivisions available-for-sale securities.

+ Details

Name:	bxs_ObligationsOfStatesAndPoliticalSubdivisionsAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for other available-for-sale securities, not otherwise specified.

+ Details

Name:	bxs_OtherAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for other real estate owned.

+ Details

Name:	bxs_OtherRealEstateOwnedFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity for U.S. Government agencies available-for-sale securities.

+ Details

Name:	bxs_UsGovernmentAgenciesAvailableForSaleSecuritiesFairValueDisclosure
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	bxs_YearToDateNetGainsLossesIncludedInAbstract
Namespace Prefix:	bxs
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AvailableForSaleSecuritiesAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13495-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FIN39-1

-Paragraph 10A, 10B

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 4, 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

+ Details

Name:	us-gaap_DerivativeAssets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 10

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 15

-Paragraph 83

-URI http://asc.fasb.org/extlink&oid=6913464&loc=d3e34841-113949

+ Details

Name:	us-gaap_DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the amount of the total realized and unrealized gains or losses for the period which are included in the statement of income (or changes in net assets); the fair value of which assets and liabilities was or is measured on a recurring basis using significant unobservable inputs (Level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarnings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents total gains (losses) for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in other comprehensive income (a separate component of shareholders' equity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-SubTopic 10

-Topic 820

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents loans held-for-sale as presented on the statement of financial position which may include mortgage loans held-for-sale, finance receivables held-for-sale, or any other loans classified as held-for-sale which are due the Company as of the balance sheet date.

+ Details

Name:	us-gaap_LoansHeldForSaleFairValueDisclosure
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4/FIN46(R)-8

-Paragraph B9

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 13A, 13B

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 17

-Subparagraph f(1)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6863725&loc=d3e122625-111746

+ Details

Name:	us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant