CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
REVENUES
Commissions and fees	$ 403,781us-gaap_InsuranceCommissionsAndFees	$ 362,007us-gaap_InsuranceCommissionsAndFees
Investment income	220us-gaap_InvestmentIncomeNonoperating	103us-gaap_InvestmentIncomeNonoperating
Other income, net	297us-gaap_OtherIncome	1,484us-gaap_OtherIncome
Total revenues	404,298us-gaap_Revenues	363,594us-gaap_Revenues
EXPENSES
Employee compensation and benefits	205,305bro_EmployeeCompensationAndBenefits	184,110bro_EmployeeCompensationAndBenefits
Non-cash stock-based compensation	6,357us-gaap_ShareBasedCompensation	7,515us-gaap_ShareBasedCompensation
Other operating expenses	61,093us-gaap_OtherCostAndExpenseOperating	52,461us-gaap_OtherCostAndExpenseOperating
Gain on disposal	(257)us-gaap_GainLossOnDispositionOfAssets1	0us-gaap_GainLossOnDispositionOfAssets1
Amortization	21,625us-gaap_AdjustmentForAmortization	17,876us-gaap_AdjustmentForAmortization
Depreciation	5,183us-gaap_Depreciation	4,640us-gaap_Depreciation
Interest	9,851us-gaap_InterestExpense	4,072us-gaap_InterestExpense
Change in estimated acquisition earn-out payables	1,363	6,083
Total expenses	310,520us-gaap_OperatingExpenses	276,757us-gaap_OperatingExpenses
Income before income taxes	93,778	86,837
Income taxes	36,827us-gaap_IncomeTaxExpenseBenefit	34,422us-gaap_IncomeTaxExpenseBenefit
Net income	$ 56,951us-gaap_NetIncomeLoss	$ 52,415us-gaap_NetIncomeLoss
Net income per share:
Basic (in dollars per share)	$ 0.40us-gaap_EarningsPerShareBasic	$ 0.36us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 0.39us-gaap_EarningsPerShareDiluted	$ 0.36us-gaap_EarningsPerShareDiluted
Dividends declared per share (in dollars per share)	$ 0.11	$ 0.10

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The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including pension and other postretirement benefit expense, but excluding share-based compensation.)

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The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Income from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products.

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Amount of the cost of borrowed funds accounted for as interest expense.

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The aggregate amount of income from investments (for example, dividends) not considered a component of the entity's core operations.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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