Stocked Based Compensation Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs
Stock-based compensation expense	$ 4,232	$ 3,040	$ 13,111	$ 9,991
Income tax benefit	(1,482)	(1,161)	(4,856)	(3,816)
Net stock-based compensation expense	$ 2,750	$ 1,879	$ 8,255	$ 6,175

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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Publisher SEC

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