Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 2011 Acquisitions [Member]	Dec. 31, 2010 2011 Acquisitions [Member]	Dec. 31, 2013 2013 Acquisitions [Member]	Dec. 31, 2012 2013 Acquisitions [Member]	Dec. 31, 2012 2012 Acquisitions [Member]	Dec. 31, 2011 2012 Acquisitions [Member]
Business Acquisition, Pro Forma Information [Line Items]
Total revenues				$ 1,058,142	$ 1,059,857	$ 1,439,918	$ 1,329,262	$ 1,230,408	$ 1,163,341
Income before income taxes				283,404	291,944	373,175	329,291	315,051	313,706
Net income				$ 171,805	$ 177,464	$ 226,562	$ 198,826	$ 190,228	$ 190,174
Net income per share:
Basic				$ 1.20	$ 1.25	$ 1.57	$ 1.39	$ 1.33	$ 1.33
Diluted				$ 1.19	$ 1.23	$ 1.55	$ 1.36	$ 1.30	$ 1.31
Weighted average number of shares outstanding:
Basic	141,033	139,364	138,582	138,582	137,924	141,033	139,634	139,364	138,582
Diluted	142,624	142,010	140,264	140,264	139,318	142,624	142,010	142,010	140,264

Name:	bro_BusinessAcquisitionProFormaInformationLineItems
Namespace Prefix:	bro_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect per basic share of common stock for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionProFormaIncomeLossFromContinuingOperationsBeforeChangesInAccountingAndExtraordinaryItemsNetOfTaxPerShareBasic
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, per diluted share of common stock for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionProFormaIncomeLossFromContinuingOperationsBeforeChangesInAccountingAndExtraordinaryItemsNetOfTaxPerShareDiluted
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

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

- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

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

- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

+ Details

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

- Details

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

- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

+ Details

Name:	us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1448-109256

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Weighted-Average Number of Common Shares Outstanding

-URI http://asc.fasb.org/extlink&oid=6528421

+ Details

Name:	us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration