Note 2 - Vessel Acquisitions and Dispositions (Details) (USD $)	3 Months Ended		1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended				1 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Feb. 28, 2014 North Sea [Member] Vessel [Member]	Sep. 30, 2011 North Sea [Member] Large Platform Supply Vessel [Member]	Jul. 31, 2012 North Sea [Member] Additional PSV [Member]	Sep. 30, 2011 North Sea [Member] Additional PSV [Member]	Sep. 30, 2013 North Sea [Member]	Sep. 30, 2011 North Sea [Member]	Sep. 30, 2012 Thoma Sea [Member]	Mar. 31, 2014 Americas [Member]	Jun. 30, 2012 Americas [Member]
Note 2 - Vessel Acquisitions and Dispositions (Details) [Line Items]
Property, Plant and Equipment, Additions (in Dollars)			$ 31,000,000
Interest Costs Capitalized (in Dollars)										2,700,000
Number Of Shipyards Use In Agreements						1		3
Number Of Vessels Under Construction				6					2
Number Of Vessels Expected To Operate								7			4
Estimated Cost Of Building Vessels (in Dollars)					60,000,000			288,000,000			168,000,000
Number of Vessels Delivered							5
Number of Vessels, Expected To Be Delivered	3
Increase (Decrease) in Restricted Cash (in Dollars)									52,400,000
Escrow Deposit (in Dollars)	$ 8,745,000	$ 8,742,000