Stock-Based Compensation Plans - Additional Information 2 (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total intrinsic value of stock options and SARs exercised	$ 27,100,000	$ 30,300,000	$ 61,000,000
Aggregate intrinsic value of the awards outstanding	4,200,000
Aggregate intrinsic value of the awards exercisable	4,200,000
Weighted average remaining contractual life of awards exercisable	1 year 7 months 6 days
Stock-based compensation expense	70,681,000	64,369,000	52,770,000
Stock Appreciation Rights (SARs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of fully vested awards and awards expected to vest	2.0
Weighted average exercise price of fully vested awards and awards expected to vest	$ 59.72
Weighted average exercise price of fully vested awards and awards expected to vest in years	1 year 10 months 24 days
Aggregate intrinsic value of fully vested awards and awards expected to vest	4,200,000
Unrecognized compensation related to Awards	3,900,000
Weighted average period	1 year 1 month 6 days
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation related to Awards	10,500,000
Weighted average period	2 years 3 months 18 days
Stock-based compensation expense	$ 7,700,000	$ 0

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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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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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Weighted average remaining contractual term for fully vested and expected to vest options that are exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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