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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Number of options vested.

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Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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Stock Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jul. 31, 2009	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Apr. 28, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price				$ 18.48	$ 18.48	$ 18.57	$ 18.39
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				175,000	269,589	470,356	622,945
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term				1 year 2 months	2 years 2 months	3 years 1 month	4 years 1 month
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				175,000	164,589	316,356
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				0	0	0
MaximumNumberOfSharesAvailableToBeGrantedUnderAwardStockPlan				14,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				5,174,190				0
Stock Issued During Period, Shares, Share-based Compensation, Gross								12,610
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value				$ 18.1	$ 6.8	$ 8.4
IncrementalIncreasesInAverageStockPriceFromInitialGrantPrice				20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			20 years	15 years
AttainmentAgeOfStockPlan				attainment of age 64
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedSharesOutstandingNumber				1,003,275
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsDistributedSharesOutstandingNumber				4,170,915
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit				$ 13.65
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit				$ 25.68
PerformanceStockPlan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodAwardedShares				506,422	208,889	277,009
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(92,517)	(117,528)	(165,647)
ShareBasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedInPeriod				4,000	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				0	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodPriorYearAwardsIssuedGrantedInCurrentYear				0	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsNotYetAwardedInPeriod				0	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedInPeriodWeightedAverageGrantDateFairValue				0	0	0.00
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNotYetAwardedInPeriod				(4,000)	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageGrantDateFairValue				10.23	9.03	8.71	8.62
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value				$ 6.39	$ 5.55	$ 16.76
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				(506,422)	(208,889)	(277,009)
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodAwardedShares				(88,517)	(100,110)	(115,630)
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodNotYetAwardedShares				(4,000)	(17,418)	(50,017)
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodSharesNotAwarded				0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value				$ 10.52	$ 9.78	$ 9.75
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedSharesOutstandingNumber				1,003,275	1,602,214	1,928,631	2,371,287
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesNotYetAwardedOutstandingNumber				0	8,000	25,418	75,435
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 0	$ 0	$ 0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedSharesOutstandingNumber				1,003,275	1,594,214	1,903,213	2,295,852
Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodAwardedShares				(166,884)	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period				(954,131)	(863,241)	(369,626)
ShareBasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedInPeriod				1,431,319	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				972,099	481,166	422,572
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodPriorYearAwardsIssuedGrantedInCurrentYear				182,653	164,646	113,088
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsNotYetAwardedInPeriod				789,446	316,520	309,484
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedInPeriodWeightedAverageGrantDateFairValue				25	0	0.00
ShareBasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsGrantedSharesAwardedInPeriod				0		0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNotYetAwardedInPeriod				(1,431,319)	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageGrantDateFairValue				29.96	28.74	28.19		27.96
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodUnderIncentiveSubPlan									2,375,892
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				972,099	481,166	422,572	3,719,974			187,040
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares				182,653	164,646	113,088	891,399
Stock Issued During Period, Shares, Share-based Compensation, Gross	12,627	11,682		16,860	15,700	9,870			36,919
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				3,729,566
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value				$ 27	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				(166,884)	0	0
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodAwardedShares				(175,788)	(95,542)	(47,915)
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriodNotYetAwardedShares				(778,343)	(767,699)	(321,711)
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodSharesNotAwarded				0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value				$ 25.34	$ 26.32	$ 27.41
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedSharesOutstandingNumber				6,128,056	6,276,972	6,659,047		6,606,101
SharesAvailableForIssuanceUnderStockIncentivePlan											6,046,768
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesNotYetAwardedOutstandingNumber				3,726,762	5,146,978	5,598,157		5,610,384
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 35.52	$ 32	$ 31.02
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAwardedSharesOutstandingNumber				2,401,294	1,129,994	1,060,890		995,717
Stock Incentive Plan [Member] \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestingPeriod				5 years	5 years	3 years	3 years
Stock Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestingPeriod					7 years	6 years	7 years
DecusInsuranceBrokersLimited [Member] \| Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodUnderIncentiveSubPlan									24,670	5,205
Arrowhead General Insurance Agency, Inc. [Member] \| Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross								814,545
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				17,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant				4,680,263
EighteenPointFourEightExercisePrice [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price				$ 18.48
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				175,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term				1 year 2 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				175,000