Note 3 - Vessel Acquisitions and Dispositions (Details) - Vessels Under Construction (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 T ft hp
Large Platform Supply Vessel Two [Member] | Thoma Sea [Member] | Americas [Member]
Significant Acquisitions and Disposals [Line Items]
Expected Delivery	Q1 2015
Length (feet)	271
BHP	9,990	[1]
DWT	3,600	[2]
Expected Cost	$ 36
Large Platform Supply Vessel Two [Member] | BAE Systems [Member] | Americas [Member]
Significant Acquisitions and Disposals [Line Items]
Expected Delivery	Q3 2015
Length (feet)	286
BHP	10,960	[1]
DWT	5,300	[2]
Expected Cost	48
Large Platform Supply Vessel One [Member] | BAE Systems [Member] | Americas [Member]
Significant Acquisitions and Disposals [Line Items]
Expected Delivery	Q2 2015
Length (feet)	286
BHP	10,960	[1]
DWT	5,300	[2]
Expected Cost	48
Large Platform Supply Vessel One [Member] | Simek [Member] | North Sea [Member]
Significant Acquisitions and Disposals [Line Items]
Expected Delivery	Q4 2015
Length (feet)	304
BHP	11,935	[1]
DWT	4,700	[2]
Expected Cost	$ 60

[1] BHP - Brake Horsepower

[2] DWT - Deadweight Tons