Stock Based Compensation (Details) - Disclosure of Share-based Compensation Arrangements by Share-based Payment Award - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Share-based Payment Arrangement [Abstract]
Outstanding Beginning Balance	108,463
Granted
Exercised	(21,991)	(38,697)
Forfeited/cancelled/expired
Outstanding Ending Balance	86,472
Exercisable Ending Balance	86,472
Outstanding Beginning Balance, Weighted-Average Exercise Price	$ 8.35
Exercised, Weighted-Average Granted Price
Exercised, Weighted-Average Exercise Price	7.84
Forfeited/cancelled/expired, Weighted-Average Exercise Price
Outstanding Ending Balance, Weighted-Average Exercise Price	8.48
Exercisable Ending Balance, Weighted-Average Exercise Price	$ 8.48
Outstanding Ending Balance - Weighted-Average Remaining Contractual Term (In Years)	2 years 10 months 25 days
Exercisable Ending Balance - Weighted-Average Remaining Contractual Term (In Years)	2 years 10 months 25 days
Outstanding Ending Balance - Aggregate Intrinsic Value	$ 970,370
Exercisable Ending Balance - Aggregate Intrinsic Value	$ 970,370

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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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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 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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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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