Stock-Based Compensation (Details 1) (Stock Option [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding beginning	1,147,320	1,432,228	1,514,884
Options, Grants		111,147	169,088
Options, Exercised	(134,273)	(390,652)	(245,054)
Options, Forfeited	(2,838)	(4,003)	(4,680)
Options, Expired	(1,428)	(1,400)	(2,010)
Options, Outstanding ending	1,008,781	1,147,320	1,432,228
Options, Exercisable at the end period	879,024
Weighted-Average Exercise Price, Outstanding beginning	$ 13.21	$ 10.34	$ 8.82
Weighted Average Exercise Price, Grants		$ 24.68	$ 17.76
Weighted-Average Exercise Price, Exercised	$ 7.93	$ 5.90	$ 5.78
Weighted-Average Exercise Price, Forfeited	$ 22.66	$ 20.28	$ 19.19
Weighted Average Exercise Price, Expired	$ 24.26	$ 15.96	$ 18.85
Weighted-Average Exercise Price, Outstanding ending	$ 13.87	$ 13.21	$ 10.34
Weighted Average Exercise Price, Exercisable at the end period	$ 12.72
Outstanding Weighted Average Remaining Contractual Term	4 years 2 months 12 days	5 years 1 month 6 days	5 years 1 month 6 days
Exercisable, Weighted Average Remaining Contractual Term	3 years 7 months 6 days
Outstanding, Aggregate Intrinsic Value	$ 13,652	$ 13,623	$ 17,220
Exercisable, Aggregate Intrinsic Value	$ 12,905

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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.

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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.

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-Name Accounting Standards Codification

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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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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

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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- Definition

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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- Definition

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

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No definition available.

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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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- Definition

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

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- Definition

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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