The amount of interest that was capitalized during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 34

-Paragraph 21

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Name:	us-gaap_InterestCostsCapitalized
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Vessel Acquisitions and Dispositions (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended							1 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Oct. 31, 2011 Vessel	Oct. 21, 2011	Oct. 31, 2011 Remontowa [Member] Vessel	Oct. 31, 2011 Rosetti Marino [Member] Vessel	Oct. 31, 2011 Simek [Member] Vessel	Oct. 31, 2011 North Sea [Member]
Property, Plant and Equipment [Line Items]
No. of vessel under construction					6		3	2	1
Agreement to sell vessel from North Sea Fleet										$ 2.9
Expected gain from sale of vessel						2.0
Vessel Acquisitions and Dispositions (Textual) [Abstract]
No. of vessel being held for sale but not included in fleet					1
Estimated cost of building vessels	245.0
Capitalization of interest	$ 0	$ 0.1	$ 0	$ 1.4