Share-Based Compensation - Components of Share-Based Compensation Awards (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	$ 894	$ 823	$ 2,546	$ 1,884
Income tax benefit	(220)	(289)	(1,105)	(1,473)
Total share-based compensation expense, net of income taxes	674	534	1,441	411
Stock and ESPP Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	39	23	88	93
Income tax benefit	(15)	(9)	(153)	(313)
Total share-based compensation expense, net of income taxes	24	14	(65)	(220)
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-tax compensation expense	855	800	2,458	1,791
Income tax benefit	(205)	(280)	(952)	(1,160)
Total share-based compensation expense, net of income taxes	$ 650	$ 520	$ 1,506	$ 631

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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