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Share-Based Compensation - Additional Information (Detail) - USD ($) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | May 31, 2018 | Dec. 31, 2015 | May 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock options granted | 1,040,000 | 1,807,000 | 1,077,000 |  |  |
Stock options outstanding | 5,746,000 | 6,356,000 | 6,112,000 |  | 5,507,000 |
Number of common stock available for future grant | 6,800,000 |  |  |  |  |
Weighted-average fair values of stock options granted | $ 43.42 | $ 25.11 | $ 21.49 |  |  |
Weighted average remaining contractual term for stock options outstanding | 6 years 8 months 12 days |  |  |  |  |
Share-based compensation expense | $ 58,068,000 | $ 42,522,000 | $ 28,464,000 |  |  |
Number of stock options exercisable | 3,900,000 |  |  |  |  |
Stock options exercisable, weighted average exercise price | $ 31.07 |  |  |  |  |
Stock options exercisable, weighted-average remaining contractual term | 5 years 10 months 24 days |  |  |  |  |
Stock options exercised in period intrinsic value | $ 117,000,000 | 61,400,000 | 13,200,000 |  |  |
Stock options intrinsic value of options outstanding | 186,300,000 |  |  |  |  |
Stock options intrinsic value of options exercisable | 158,200,000 |  |  |  |  |
Cash received from stock option exercises | $ 29,500,000 | $ 13,900,000 | $ 2,400,000 |  |  |
Minimum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Share-based compensation, term | 3 years |  |  |  |  |
Maximum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Share-based compensation, term | 4 years |  |  |  |  |
Share-based compensation, contractual term | 10 years |  |  |  |  |
Restricted Stock Units (RSUs) |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Restricted stock units granted | 540,000 | 588,000 | 326,000 |  |  |
Share-based compensation expense | $ 21,900,000 | $ 13,900,000 | $ 8,300,000 |  |  |
Unrecognized compensation cost | $ 51,600,000 |  |  |  |  |
Stock vesting period | 2 years 3 months 18 days |  |  |  |  |
Total intrinsic value vested in period | $ 35,500,000 | 14,900,000 | 12,200,000 |  |  |
Intrinsic value outstanding | $ 80,900,000 |  |  |  |  |
Restricted Stock Units (RSUs) | Minimum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 4 years |  |  |  |  |
Stock Options |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Share-based compensation expense | $ 35,400,000 | $ 28,200,000 | $ 18,400,000 |  |  |
Unrecognized compensation cost | $ 55,400,000 |  |  |  |  |
Stock vesting period | 2 years 3 months 18 days |  |  |  |  |
Stock Options | Minimum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 3 years |  |  |  |  |
Share-based compensation, term | 7 years |  |  |  |  |
Stock Options | Maximum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 4 years |  |  |  |  |
Share-based compensation, term | 10 years |  |  |  |  |
Performance-based RSUs |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Restricted stock units granted | 200,000 | 0 | 200,000 |  |  |
Share-based compensation expense | $ 0 | $ 400,000 | $ 1,800,000 |  |  |
Unrecognized compensation cost | 19,700,000 |  |  |  |  |
Intrinsic value outstanding | $ 23,600,000 |  |  |  |  |
Performance restricted stock units earned during period | 0 | 200,000 | 0 |  |  |
Performance-based RSUs | Minimum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 4 years |  |  |  |  |
Performance-based RSUs | Maximum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 5 years |  |  |  |  |
Employees |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock options granted | 70,000 | 410,000 | 0 |  |  |
Stock vesting period | 4 years | 4 years |  |  |  |
Stock options outstanding | 245,162 |  |  |  |  |
Employees | Restricted Stock Units (RSUs) |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Restricted stock units granted | 20,000 | 12,500 | 0 |  |  |
RSUs outstanding | 245,162 |  |  |  |  |
Employees | Restricted Stock Units (RSUs) | Minimum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 3 years | 3 years |  |  |  |
Employees | Restricted Stock Units (RSUs) | Maximum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Stock vesting period | 4 years | 4 years |  |  |  |
ESPP |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Number of common stock authorized for issuance | 300,000 |  |  | 300,000 |  |
Number of shares purchased | 0 |  |  |  |  |
Share-based compensation expense | $ 800,000 |  |  |  |  |
ESPP | Maximum |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Discounted purchase price percentage of common stock authorized for issuance | 85.00% |  |  |  |  |
2011 Plan |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Number of common stock authorized for issuance |  |  |  |  |  | 19,000,000
Share Based Compensation Arrangement Award |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Number of common stock authorized for issuance | 7,200,000 |  |  |  |  |
PRSUs Converted into Common Shares | Performance-based RSUs |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |
Intrinsic value outstanding |  | $ 8,800,000 |  |  |  |

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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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -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=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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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). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&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://fasb.org/us-gaap/role/ref/legacyRef -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=109197908&loc=d3e5070-113901 + Details
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- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -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=109197908&loc=d3e5070-113901 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of shares purchased on the open market during the period for issuance to employees under the plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 + Details
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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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