Stockholders' Equity - Stock Options Outstanding Rollforward (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Options
Outstanding at December 31, 2011 (in shares)	1,021,791
Granted (in shares)	326,496
Exercised (in shares)	(53,232)
Expired, canceled or forfeited (in shares)	(90,452)
Outstanding at December 31, 2012 (in shares)	1,204,603
Exercisable at December 31, 2012 (in shares)	489,674
Weighted Average Exercise Price
Outstanding at December 31, 2011 (in dollars per share)	$ 11.55
Granted (in dollars per share)	$ 11.74
Exercised (in dollars per share)	$ 8.85
Expired, canceled or forfeited (in dollars per share)	$ 12.55
Outstanding at December 31, 2012 (in dollars per share)	$ 11.65
Exercisable at December 31, 2012 (in dollars per share)	$ 11.87
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Stock options, Outstanding, Weighted Average Remaining Contractual Life	2 years 8 months 19 days
Stock options, Exercisable, Weighted Average Remaining Contractual Life	1 year 9 months 3 days
Stock options, Outstanding, Aggregate Intrinsic Value	$ 1,814
Stock options, Exercisable, Aggregate Intrinsic Value	761
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number	1,164,544
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price	$ 11.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	2 years 8 months 1 day
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	1,768
Stock options
Number of Options
Exercisable at December 31, 2012 (in shares)		349,449,000	290,911
Weighted Average Exercise Price
Exercisable at December 31, 2012 (in dollars per share)		$ 11.90	$ 10.52
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Stock options, Outstanding, Weighted Average Remaining Contractual Life		2 years 9 months 29 days	3 years 3 months 11 days
Stock options, Exercisable, Weighted Average Remaining Contractual Life		2 years 2 months 15 days	1 year 9 months 11 days
Stock options, Outstanding, Aggregate Intrinsic Value		1,958	112
Stock options, Exercisable, Aggregate Intrinsic Value		$ 619	$ 85

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

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

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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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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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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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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 per share amount at which grantees can acquire shares of common stock by exercise of options.

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