Stock Based Compensation - Textual (Details) $ / shares in Units, $ in Thousands		9 Months Ended
Feb. 08, 2018	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Conversion ratio	2
Stock-based compensation expense		$ 9,818	$ 6,486
Unrecognized stock-based compensation expense related to stock options		56
Unrecognized stock-based compensation expense related to non-vested stock awards		$ 21,129
Period unrecognized expenses is expected to be recognized		1 year 10 months 24 days
Intrinsic value of stock options outstanding		$ 4,884
Intrinsic value of stock options exercisable		$ 4,680
Share price (in dollars per share) \| $ / shares		$ 29.45
Stock options exercised		$ 1,155	$ 1,012
Stock options granted \| shares		0	0

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
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-Section S99
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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB
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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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Unrecognized cost of unvested options awarded to employees as compensation.

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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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- Definition

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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Price of a single share of a number of saleable stocks of a company.

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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

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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