Stock-Based Compensation - Summary of Information Regarding Options Granted under Executive Incentive Plan (Detail)	6 Months Ended
Jun. 30, 2016 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Limit	$ 0.00
Exercise Price, Upper Limit	$ 84.80
Outstanding Number of Options \| shares	2,223,674
Outstanding Weighted Average Remaining Contractual Life (years)	5 years 8 months 1 day
Outstanding Weighted Average Exercise Price	$ 27.23
Exercisable Number of Options \| shares	2,030,927
Exercisable Weighted Average Exercise Price	$ 27.57
0.00-13.12 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Limit	0.00
Exercise Price, Upper Limit	$ 13.12
Outstanding Number of Options \| shares	39,661
Outstanding Weighted Average Remaining Contractual Life (years)	5 months 5 days
Outstanding Weighted Average Exercise Price	$ 13.12
Exercisable Number of Options \| shares	39,661
Exercisable Weighted Average Exercise Price	$ 13.12
13.13-28.88 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Limit	13.13
Exercise Price, Upper Limit	$ 28.88
Outstanding Number of Options \| shares	1,674,014
Outstanding Weighted Average Remaining Contractual Life (years)	5 years 11 months 23 days
Outstanding Weighted Average Exercise Price	$ 25.10
Exercisable Number of Options \| shares	1,481,267
Exercisable Weighted Average Exercise Price	$ 25.30
28.89-50.88 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Limit	28.89
Exercise Price, Upper Limit	$ 50.88
Outstanding Number of Options \| shares	492,626
Outstanding Weighted Average Remaining Contractual Life (years)	5 years 29 days
Outstanding Weighted Average Exercise Price	$ 33.81
Exercisable Number of Options \| shares	492,626
Exercisable Weighted Average Exercise Price	$ 33.81
50.89-84.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Limit	50.89
Exercise Price, Upper Limit	$ 84.80
Outstanding Number of Options \| shares	17,373
Outstanding Weighted Average Remaining Contractual Life (years)	4 years 1 month 24 days
Outstanding Weighted Average Exercise Price	$ 77.48
Exercisable Number of Options \| shares	17,373
Exercisable Weighted Average Exercise Price	$ 77.48

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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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