Stock-Based Compensation - Summary of Unrecognized Compensation Cost (Details) $ in Thousands	6 Months Ended
Jun. 30, 2015 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs, equity instruments other than options	$ 4,323
Expected Weighted Average Period of Recognition (in years)	1 year
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs, equity instruments other than options	$ 1,574
Expected Weighted Average Period of Recognition (in years)	11 months 16 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs, options	$ 290
Expected Weighted Average Period of Recognition (in years)	1 year 26 days
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs, equity instruments other than options	$ 1,075
Expected Weighted Average Period of Recognition (in years)	1 year 15 days
Stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs, options	$ 1,384
Expected Weighted Average Period of Recognition (in years)	5 months 12 days

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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

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- Definition

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