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Common Stock - Summary of Information and Changes in Stock Options with Regard to Stock Option Plans (Detail) (USD $) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |  |  |
Number of shares under stock option, Beginning of the year | 9,473,482 | 10,481,750 | 11,039,544
Number of Shares Granted | 2,832,587 | 2,239,088 | 2,277,946
Number of Shares Exercised | (1,366,459) | (3,019,219) | (2,594,566)
Number of Shares Cancelled | (303,417) | (228,137) | (241,174)
Number of shares under stock option, End of the year | 10,636,193 | 9,473,482 | 10,481,750
Number of stock options vested and expected to be vest | 10,466,014 |  |
Number of stock options vested and expected to be vest, exercisable | 5,831,091 | 4,823,331 | 5,073,965
Weighted average exercise price, Beginning of year | $ 58.69 | $ 47.20 | $ 38.01
Weighted Average Exercise Price, Stock Options granted | $ 69.37 | $ 84.58 | $ 79.68
Weighted Average Exercise Price, Stock Options Cancelled | $ 72.43 | $ 60.28 | $ 40.20
Weighted Average Exercise Price, Stock Options Exercised | $ 77.44 | $ 82.26 | $ 36.84
Weighted Average Exercise Price, End of the year | $ 63.29 | $ 58.69 | $ 47.20
Weighted Average Exercise Price, Stock options vested or expected to be vest | $ 63.29 |  |
Weighted Average Exercise Price, Stock options vested or expected to be vest exercisable | $ 53.46 | $ 43.99 | $ 38.47
Weighted Remaining Contractual Term, Outstanding on Beginning | 6 years 10 months 10 days |  |
Weighted Remaining Contractual Term, Outstanding at Ending | 6 years 9 months 26 days | 6 years 10 months 10 days |
Weighted Remaining Contractual Term, Vested | 6 years 9 months 26 days |  |
Weighted Remaining Contractual Term, Exercisable | 5 years 4 months 13 days |  |
Stock Options Aggregate Intrinsic Value, Beginning | $ 150,667,018 |  |
Stock Options Aggregate Intrinsic Value, Ending | 183,849,267 | 150,667,018 |
Stock Options Aggregate Intrinsic Value, Vested and Expected to Vest | 180,907,679 |  |
Stock Options Aggregate Intrinsic Value, Aggregate Intrinsic Value | $ 155,892,094 |  |

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- Definition 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. + 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 + Details
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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 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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- Definition Net number of share options (or share units) granted during the period. + 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)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding. + 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 + Details
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