Note 2 - Impairment Charges (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015
Maximum [Member]
Day Rates for Vessels	25.00%
U.S. Gulf of Mexico and Southeast Asia [Member]
Impairment of Long-Lived Assets Held-for-use	$ 114,100,000
U.S Gulf of Mexico [Member] | Americas Segment [Member]
Impairment of Long-Lived Assets Held-for-use	94,500,000
Southeast Asia Segment [Member] | Vessel Component [Member]
Impairment of Long-Lived Assets to be Disposed of	600,000
Southeast Asia Segment [Member]
Impairment of Long-Lived Assets Held-for-use	19,600,000
North Sea and Southeast Asia Segments [Member] | Vessel Component [Member]
Impairment of Long-Lived Assets to be Disposed of	2,600,000
North Sea Segment [Member] | Vessel Component [Member]
Impairment of Long-Lived Assets to be Disposed of	$ 2,000,000
Intangible Assets, Net (Including Goodwill)			$ 0
Day Rates for Vessels		50.00%