Stock Option Activity (Detail) - $ / shares	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Share Based Compensation [Line Items]
Forward Interest Rate, Minimum	1.46%
Forward Interest Rate, Maximum	1.93%
Expected Volatility Rate, Maximum	58.05%
Expected Volatility Rate, Minimum	53.87%
Stock Option [Member]
Share Based Compensation [Line Items]
Number of Options Outstanding, Beginning Balance	277,536
Stock Options Granted, Number of Shares	590,647	250,000
Stock Options Exercised, Number of Shares	(15,380)
Stock Options Canceled, Forfeited or Expired, Number of Shares	(14,309)
Number of Options Outstanding, Ending Balance	838,494	277,536
Stock Options Exerciseable, Number of Shares	62,500
Options Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 26.40
Stock Options Granted, Weighted Average Exercise Price	31.73
Stock Options Exercised, Weighted Average Exercise Price	25.93
Stock Options Canceled, Forfeited or Expired, Weighted Average Exercise Price	25.16
Options Outstanding, Ending Balance, Weighted Average Exercise Price	$ 30.18	$ 26.40
Options Outstanding, Weighted Average Contractual Life	9 years 3 months 22 days	8 years 11 months 26 days
Stock Options Exerciseable, Weighted Average Exercise Price	$ 26.65
Stock Options Exerciseable, Weighted Average Contractual Life	8 years 11 months 16 days
Stock Option [Member] \| Maximum [Member]
Share Based Compensation [Line Items]
Expected Term	6 years 9 months 4 days
Fair Value	$ 23.21
Stock Option [Member] \| Minimum [Member]
Share Based Compensation [Line Items]
Expected Term	5 years 6 months
Fair Value	$ 13.45

The calculated fair value of a stock-based compensation award

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The estimated measure of the maximum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

No definition available.

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The estimated measure of the minimum percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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- 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)
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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.

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- Definition

For presentations that combine terminations, 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 or that expired.

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Weighted average price of options that were either forfeited or expired.

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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

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

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- Definition

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

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- Definition

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

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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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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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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.

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

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