Share-Based Compensation - Activity of Stock Options, Including Performance-Based Options (Detail) - $ / shares	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares
Outstanding at beginning of year	11,073,326	11,384,251	12,273,815
Granted	6,262,501	2,947,199	5,494,969
Exercised	(1,358,761)	(2,017,460)	(4,489,459)
Expired	(193,943)	(14,087)	(33,951)
Forfeited	(1,602,627)	(1,226,577)	(1,861,123)
Outstanding at end of year	14,180,496	11,073,326	11,384,251
Exercisable at end of year	6,181,833	5,025,485	4,235,609
Weighted Average Exercise Price Per Share
Outstanding at beginning of year (USD per share)	$ 10.25	$ 7.62	$ 4.24
Granted (USD per share)	11.16	17.42	11.57
Exercised (USD per share)	6.86	5.19	3.27
Expired (USD per share)	15.52	13.91	3.22
Forfeited (USD per share)	12.93	10.86	7.40
Outstanding at end of year (USD per share)	10.60	10.25	7.62
Exercisable at end of year (USD per share)	$ 8.90	$ 7.13	$ 4.39

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.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net 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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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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