Stock-Based Compensation - Options Exercised (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Cash received upon exercise	$ 443	$ 3,183	$ 15,812
Intrinsic value (market value on date of exercise less exercise price)	$ 653	$ 3,401	$ 5,788

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.

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

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