Stock-Based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Stock-Based Compensation [Abstract]
Shares outstanding, beginning balance	15,081	21,211
Shares exercised	(14,231)
Shares expired	(350)
Shares forfeited	(500)	(6,130)
Shares outstanding, ending balance		15,081
Shares, exercisable		15,081
Weighted average exercise price outstanding, beginning balance	$ 27.70	$ 27.70
Weighted average exercise price exercised	27.70
Weighted average exercise price expired	27.70
Weighted average exercise price forfeited	$ 27.70	27.70
Weighted average exercise price outstanding, ending balance		27.70
Weighted average exercise price exercisable		$ 27.70
Aggregate intrinsic value outstanding, beginning balance	$ 20
Aggregate intrinsic value exercised	$ 134
Aggregate intrinsic value outstanding, ending balance		20
Aggregate intrinsic value exercisable		$ 20
Weighted-average contractual life remaining in years outstanding (in years)		6 months
Weighted-average contractual life remaining in years exercisable (in years)		6 months

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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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-Publisher FASB
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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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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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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 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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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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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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