Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) (Notes, Notes Due February 1, 2033)	Mar. 31, 2015	Jan. 31, 2013
Notes \| Notes Due February 1, 2033
Convertible senior notes interest rate	3.00%	3.00%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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