Stock-Based Compensation - Summary of Share Option Activity of Stock Option and Stock Appreciation Rights Under 2001 Plan (Detail) (2001 Plan [Member], USD $)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, Shares Outstanding, beginning balance	80,800	205,800
Stock based compensation, Shares, Granted
Stock based compensation, Shares, Exercised	(11,600)	(5,600)
Stock based compensation, Shares, Forfeited/Expired	(15,400)	(119,400)
Stock based compensation, Shares Outstanding, ending balance	53,800	80,800
Stock based compensation, Shares, Exercisable	53,800	78,160
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance	$ 52.43	$ 53.12
Stock based compensation, Weighted Average Fair Value Per Share, Granted
Stock based compensation, Weighted Average Fair Value Per Share, Exercised	$ 30.39	$ 20.12
Stock based compensation, Weighted Average Fair Value Per Share, Forfeited/Expired	$ 63.58	$ 55.13
Stock based compensation, Weighted Average Fair Value Per Share, ending balance	$ 53.99	$ 52.43
Stock based compensation, Weighted Average Fair Value Per Share, Exercisable	$ 53.99	$ 56.81
Stock based compensation, Weighted Average Remaining Contractual Term, Outstanding	3 years 9 months 18 days
Stock based compensation, Weighted Average Remaining Contractual Term, Exercisable	3 years 9 months 18 days	3 years 11 months 23 days
Stock based compensation, Aggregate Intrinsic Value, Outstanding	$ 46,950
Stock based compensation, Aggregate Intrinsic Value, Exercisable	46,950	21,780
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation, Shares Outstanding, beginning balance	80,800	205,800
Stock based compensation, Shares, Granted
Stock based compensation, Shares, Exercised	(11,600)	(5,600)
Stock based compensation, Shares, Forfeited/Expired	(15,400)	(119,400)
Stock based compensation, Shares Outstanding, ending balance	53,800	80,800
Stock based compensation, Shares, Exercisable	53,800	78,160
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance	$ 1.12	$ 0.93
Stock based compensation, Weighted Average Fair Value Per Share, Granted
Stock based compensation, Weighted Average Fair Value Per Share, Exercised	$ 4.29	$ 5.07
Stock based compensation, Weighted Average Fair Value Per Share, Forfeited/Expired	$ 0.46	$ 0.73
Stock based compensation, Weighted Average Fair Value Per Share, ending balance	$ 1.61	$ 1.12
Stock based compensation, Weighted Average Fair Value Per Share, Exercisable	$ 1.61	$ 0.92
Stock based compensation, Weighted Average Remaining Contractual Term, Outstanding	3 years 9 months 18 days
Stock based compensation, Weighted Average Remaining Contractual Term, Exercisable	3 years 9 months 18 days	3 years 11 months 23 days
Stock based compensation, Aggregate Intrinsic Value, Outstanding	25,281
Stock based compensation, Aggregate Intrinsic Value, Exercisable	$ 25,281	$ 11,728

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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

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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

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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

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- Definition

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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- 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.

+ References

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-Publisher FASB

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-SubTopic 10

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-Paragraph 2

-Subparagraph (c)(1)(iv)(3)-(4)

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- Definition

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

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)-(4)

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- Definition

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

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No definition available.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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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 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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- Definition

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

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No definition available.

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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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No definition available.

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

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-Name Regulation S-X (SX)

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