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Common Stock - Summary of Stock Options (Detail) - $ / shares | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |  |  |
Number of shares under stock option, Beginning of the year | 10,881,133 | 11,535,566 | 10,274,477
Number of Shares Granted | 5,746,153 | 3,389,547 | 3,072,086
Number of Shares Spun-off |  | (1,567,348) |
Number of Shares Cancelled | (886,356) | (498,967) | (329,002)
Number of Shares Exercised | (310,623) | (1,977,665) | (1,481,995)
Number of shares under stock option, End of the year | 15,430,307 | 10,881,133 | 11,535,566
Number of stock options vested and expected to be vest, exercisable | 7,498,414 | 5,903,712 | 6,324,117
Weighted Average Exercise Price, Beginning of year | $ 61.22 | $ 58.36 | $ 54.11
Weighted Average Exercise Price, Stock Options Granted | 54.74 | 69.00 | 63.96
Weighted Average Exercise Price, Stock Options Spun off |  | 70.56 |
Weighted Average Exercise Price, Stock Options Canceled | 62.73 | 70.32 | 66.78
Weighted Average Exercise Price, Stock Options Exercised | 22.56 | 53.56 | 38.75
Weighted Average Exercise Price, End of the year | 59.50 | 61.22 | 58.36
Weighted Average Exercise Price, Stock Options Exercisable | $ 60.30 | $ 55.06 | $ 49.29

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- Definition 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. + 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)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition 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 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 + Details
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- Definition 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. + 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)(iv)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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