Out Of Period Adjustments (Details) (USD $)	3 Months Ended	6 Months Ended	3 Months Ended	12 Months Ended
Jun. 30, 2012	Dec. 31, 2011 Scenario, Previously Reported [Member]	Jun. 30, 2012 Other Comprehensive Income Adjustment [Member]	Mar. 31, 2012 Other Comprehensive Income Adjustment [Member]	Sep. 30, 2011 Net Charter Revenue Adjustment [Member]	Sep. 30, 2011 Leases Adjustment [Member]	Dec. 31, 2012 Pre-Tax Income Adjustment [Member]	Dec. 31, 2012 Net Income Adjustment [Member]	Dec. 31, 2013 Oslo Bulk AS [Member]	Dec. 31, 2012 Oslo Bulk AS [Member]	Jul. 31, 2011 Oslo Bulk AS [Member]	Dec. 31, 2009 Oslo Bulk AS [Member]
Equity investee ownership interest									25.00%	25.00%	25.00%	25.00%
Amount of ineffectiveness on investment hedges		$ 674,000
Out of period adjustments	$ 631,000		$ 674,000	$ 42,000	$ (324,000)	$ 239,000	$ (85,000)	$ 631,000

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant