DERIVATIVE INSTRUMENTS (Details) (USD $)	Jun. 30, 2011	Jun. 30, 2010
Forward Commitments to Sell Fixed-Rate Mortgage Loans [Member]
Derivative [Line Items]
Notional amount	$ 131,100,000	$ 158,400,000
Difference in carrying value and fair value, reflecting a loss	149,000	1,800,000
Commitments To Fund Fixed-Rate Mortgage Loans [Member]
Derivative [Line Items]
Notional amount	83,600,000	127,800,000
Difference in carrying value and fair value, reflecting a gain	990,000	2,200,000
Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount	$ 504,300,000
Average maturity (in months)	68M
Average interest receive rate (in hundredths)	2.50%
Average interest pay rate (in hundredths)	6.00%

- Definition

The difference in the carrying value and fair value of the derivative instrument, reflecting a gain as of the reporting date.

+ Details

Name:	bxs_DifferenceInCarryingValueAndFairValueReflectingGain
Namespace Prefix:	bxs
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The difference in the carrying value and fair value of the derivative instrument, reflecting a loss as of the reporting date.

+ Details

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

- Definition

Monetary amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ Details

Name:	us-gaap_DerivativeAverageFixedInterestRate
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The average time remaining until maturity on the group of derivatives identified.

+ Details

Name:	us-gaap_DerivativeAverageRemainingMaturity
Namespace Prefix:	us-gaap
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	instant

- Definition

Average variable interest rate related to the group of interest rate derivatives.

+ Details

Name:	us-gaap_DerivativeAverageVariableInterestRate
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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.

+ Details

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