Note 3 - Impairment Charges (Details Textual) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) $ / bbl	Dec. 31, 2016 $ / bbl	Sep. 30, 2016 $ / bbl	Jun. 30, 2016 $ / bbl
Impairment of Long-Lived Assets to be Disposed of	$ 2.6
Oil Price | $ / bbl	30	50	40	40
Impairment of Long-Lived Assets Held-for-use	$ 114.1
Americas Segment [Member] | U.S Gulf of Mexico [Member]
Impairment of Long-Lived Assets Held-for-use	94.5
Southeast Asia Segment [Member]
Impairment of Long-Lived Assets to be Disposed of	0.6
Impairment of Long-Lived Assets Held-for-use	19.6
North Sea [Member]
Impairment of Long-Lived Assets to be Disposed of	$ 2.0