Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to nonvested awards, unrecognized	$ 32,800
Weighted-average period to recognize compensation cost (in years)	3 years
Aggregate intrinsic value for outstanding options and RSUs	$ 95,400	$ 104,200
Aggregate intrinsic value for vested options and RSUs	$ 52,900	62,000
Weighted-average remaining contractual life for outstanding options and RSUs (in years)	6 years
Weighted-average remaining contractual life for exercisable options and RSUs (in years)	5 years
Share-based compensation	$ 16,892	19,719	$ 17,717
Income tax benefit	$ 4,600	$ 7,900	$ 7,100
Weighted-average, risk-free interest	2.30%	1.60%	2.00%
Weighted-average, dividend yield	2.80%	2.70%	2.60%
Weighted-average, annual historical volatility factor	19.00%	19.00%	19.00%
Weighted-average, expected life (in years)	6 years	6 years	6 years
Fair value of shares vested	$ 15,500	$ 18,200	$ 15,200
Weighted-average grant date fair value of options and SARs granted (in dollars per share)	$ 13.89	$ 13.52	$ 13.53
Aggregate intrinsic value of options exercised	$ 16,800	$ 48,200	$ 30,100
Granted (in shares)	171
Excess tax benefit, share-based compensation	$ 3,134
Excess tax benefit, operating activities	3,134	12,021	7,024
Excess tax benefits, financing activities	$ 0	12,021	7,024
Scenario, Previously Reported [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit, operating activities		$ 12,021
Excess tax benefits, financing activities			$ 7,024
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	746	724	711
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	171	170	176

Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount

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- Definition

Share based compensation arrangement by share based payment award options and stock appreciation rights grants in period weighted average grant date fair value.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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- Definition

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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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Amount of cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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-URI http://asc.fasb.org/extlink&oid=96864182&loc=d3e11374-113907

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Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

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- Definition

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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- Definition

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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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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- Definition

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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- Definition

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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