HELD-TO-MATURITY SECURITIES (Details) (USD $)	12 Months Ended
Dec. 31, 2011
Schedule of Held-to-maturity Securities [Line Items]
Amortized cost of held-to-maturity securities reclassified to available-for-sale	$ 1,600,000,000
Fair value of held-to-maturity securities reclassified to available-for-sale	1,700,000,000
Increase in other comprehensive income due to transfers to available-for-sale securities	19,700,000
Gross gains recognized on held-to-maturity securities	37,000
Gross losses recognized on held-to-maturity securities	$ 0

This item represents the gross gains realized on the sale of held-to-maturity securities disposed of during the period.

No definition available.

Name:	bxs_HeldToMaturitySecuritiesSoldSecurityRealizedGainExcludingOtherThanTemporaryImpairments
Namespace Prefix:	bxs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the gross losses realized on the sale of held-to-maturity securities disposed of during the period.

+ References

No definition available.

+ Details

Name:	bxs_HeldToMaturitySecuritiesSoldSecurityRealizedLossExcludingOtherThanTemporaryImpairments
Namespace Prefix:	bxs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

For any transfer of securities categorized as held-to-maturity, this item represents the fair value of the transferred security to another category of investments in debt and equity securities (trading or available-for-sale).

+ References

No definition available.

+ Details

Name:	bxs_HeldToMaturitySecuritiesTransferredSecurityAtFairValue
Namespace Prefix:	bxs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For any transfer of securities categorized as held-to-maturity, this item represents the net carrying amount of the transferred security to another category of investments in debt and equity securities (trading or available-for-sale).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27405-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesTransferredSecurityAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the unrealized gain (loss) recognized in other comprehensive income (a separate component of shareholders' equity) as a result of securities categorized as held-to-maturity being transferred to the available-for-sale securities category.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27405-111563

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13, 22

-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.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesTransferredToAvailableForSaleSecuritiesUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfHeldToMaturitySecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration