Stock-Based Incentive Plans - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Options outstanding, Beginning Balance	299,107	350,642	565,615
Number of Options, Granted	144,296	19,222	46,529
Number of Options, Exercised	(802)	(559)	0
Number of Options, Forfeited	(24,324)	(30,758)	(19,423)
Number of Options, Expired	(98,579)	(39,440)	(242,079)
Number of Options outstanding, Ending Balance	318,901	299,107	350,642
Number of Options exercisable, end of year	161,984	249,853	235,755
Number of Options vested or expected to vest	287,202	249,176	306,225
Weighted Average Exercise Price, Option outstanding, Beginning Balance	$ 36.75	$ 36.75	$ 39.70
Weighted Average Exercise Price, Granted	$ 19.33	$ 17.95	$ 14.60
Weighted Average Exercise Price, Exercised	$ 14.98	$ 14.25
Weighted Average Exercise Price, Forfeited	$ 17.12	$ 17.40	$ 18.95
Weighted Average Exercise Price, Expired	$ 43.63	$ 43.05	$ 40.80
Weighted Average Exercise Price, Option outstanding, Ending Balance	$ 28.34	$ 36.75	$ 36.75
Weighted Average Exercise Price, Options exercisable, end of year	$ 37.14	$ 40.50	$ 43.05
Weighted Average Exercise Price, Options vested or expected to vest	$ 29.34	$ 37.40	$ 37.30

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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.

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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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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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.

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

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

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

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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