Note 10 - Capitalization of Interest (Details Textual) - 1.625% convertible senior notes due 2018 [Member] - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Debt Instrument, Increase (Decrease) In Interest Incurred, Net of Interest Capitalized, Valuation of Business Combination	$ 9
Debt Instrument, Interest Rate, Stated Percentage	1.625%	1.625%

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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