Business acquisition earn out payables.

No definition available.

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Namespace Prefix:	bro_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of goodwill not deductible for tax purposes.

+ References

No definition available.

+ Details

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Namespace Prefix:	bro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business acquisitions purchase price allocation adjustment purchase price.

+ References

No definition available.

+ Details

Name:	bro_BusinessAcquisitionsPurchasePriceAllocationAdjustmentPurchasePrice
Namespace Prefix:	bro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business Combination, Number of Customer Accounts Acquired

+ References

No definition available.

+ Details

Name:	bro_BusinessCombinationNumberofCustomerAccountsAcquired
Namespace Prefix:	bro_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Business Combination Pro Forma Information Income Loss Before Income Taxes Of Acquiree Since Acquisition Date Actual

+ References

No definition available.

+ Details

Name:	bro_BusinessCombinationProFormaInformationIncomeLossBeforeIncomeTaxesOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	bro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Earn out payable not deductible until earned paid

+ References

No definition available.

+ Details

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Namespace Prefix:	bro_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

+ Details

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Balance Type:	na
Period Type:	duration

- Details

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

- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting 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)(1)

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

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value portion of asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19190-110258

+ Details

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

- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfBusinessesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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

- Details

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- Details

Name:	us-gaap_ExtinguishmentOfDebtAxis=us-gaap_AccountsPayableMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_NoncompeteAgreementsMember
Namespace Prefix:
Data Type:	na
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- Details

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- Details

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Business Combinations - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015 acquisition customer_account	Mar. 31, 2014 acquisition	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Number of acquisitions	3us-gaap_NumberOfBusinessesAcquired	1us-gaap_NumberOfBusinessesAcquired
Number of customer accounts acquired	2
Aggregate purchase price of acquisitions	$ 634,680
Cash payment for acquisition	36,195,000	1,000,000
Goodwill assigned	29,418,000us-gaap_GoodwillFairValueDisclosure
Goodwill currently deductible for income tax purposes	23,959,000
Goodwill currently non-deductible for income tax purposes	(194,000)
Goodwill related to the recorded earn-out payables	5,653,000
Total revenues related to acquisitions	1,726,000
Income before income taxes related to acquisitions	294,000
Estimated acquisition earn-out payables	77,709,000bro_BusinessAcquisitionEarnOutPayables	48,806,000bro_BusinessAcquisitionEarnOutPayables	75,283,000bro_BusinessAcquisitionEarnOutPayables	43,058,000bro_BusinessAcquisitionEarnOutPayables
Accounts payable
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	29,300,000
Purchased customer accounts
Business Acquisition [Line Items]
Weighted average life (years)	15 years
Non-compete agreements
Business Acquisition [Line Items]
Weighted average life (years)	5 years
Retail
Business Acquisition [Line Items]
Goodwill assigned	26,461,000
National Programs
Business Acquisition [Line Items]
Goodwill assigned	(194,000)
Wholesale Brokerage
Business Acquisition [Line Items]
Goodwill assigned	3,151,000
Other non-current liability
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	$ 48,400,000