Base fee percentage.

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Employee Stock Purchase Plan Maximum Number of Shares that May be Purchase by Eligible Participants

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Share Based Compensation Arrangement By Employee Stock Purchase Plan Stock Purchases as Percentage Of Employee Compensation Maximum.

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Share based Compensation Arrangement by Share based Payment Award, Equity Instruments Other than Options, Granted in Period, Weighted Average Remaining Contractual Term.

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Share Based Compensation Arrangement By Share Based Payment Award Exercisable Price Percentage Of Closing Price Of Another Class Of Stock.

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Share based compensation arrangement by share based payment award expiry period from date of grant.

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Share Based Compensation Arrangement By Share Based Payment Award Maximum Share Value Authorized For Purchase Under Employee Stock Purchase Plan.

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Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Outstanding, Intrinsic Value.

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Share Based Compensation Arrangement by Share Based Payment Award Percentage of Shares Achieved

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Share Based Compensation Arrangement by Share Based Payment Award Percentage of Shares Authorized for Grant.

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Share based Compensation Arrangement by Share based Payment Award, Equity Instruments Other Than Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value.

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Unrecognized cost of unvested share-based compensation awards.

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-Name Accounting Standards Codification
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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The cash inflow associated with the amount received from the stock plan during the period.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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 number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Stock-Based Compensation (Detail) - USD ($)	12 Months Ended
Stock-Based Compensation (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant	7,000,000
Stock-based compensation expense	$ 46,149,000	$ 38,845,000	$ 34,735,000
Total share-based compensation cost not yet recognized	$ 47,900,000
Remaining weighted average service period	2 years 73 days
Aggregate intrinsic value of outstanding shares	$ 45,800,000
Aggregate intrinsic value of shares vested and exercisable	$ 23,700,000
Grants during period (in shares)	300,000
Award percentage of shares achieved	160.00%
Weighted average remaining contractual term	1 year
Target Amount \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares authorized for grant	0.00%
Target Amount \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares authorized for grant	200.00%
Executive Officer \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants during period (in shares)	200,000
Executive Officer \| Service-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants during period (in shares)	300,000
Unvested
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding shares unvested	800,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan, stock purchases as a percentage of employee compensation, maximum	10.00%
Maximum share value authorized for purchase under employee stock purchase plan	$ 23,750
Exercisable price percentage of closing price of another class of stock	95.00%
Maximum number of shares that may be purchased by eligible participants	1,000,000
Proceeds from stock grants	$ 7,500,000	$ 7,800,000	6,000,000
Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining weighted average service period	6 years 1 month 10 days
Award vesting period	4 years
Award expiry period from date of grant	7 years
Total compensation cost not yet recognized, period for recognition	4 years
Outstanding shares unvested	1,300,000	1,400,000
Grants during period (in shares)	300,000
Stock Appreciation Rights (SARs) \| Non Executive
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants during period (in shares)	300,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding shares unvested	1,400,000	1,400,000
Grants during period (in shares)	600,000
Restricted Stock Units (RSUs) \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Grants during period (in shares)	600,000
Restricted Stock Units (RSUs) \| Service-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Common Stock Equivalents (CSEs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding shares unvested	105,664	104,203
Grants during period (in shares)	7,443
Base fee percentage	50.00%
Retirement Eligible Employees Equity Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 20,100,000	$ 14,800,000	$ 12,500,000