Basis of Presentation (Narrative) (Details)	Sep. 30, 2019 property shares	Dec. 31, 2018 shares
Property, Plant and Equipment [Line Items]
Common stock, shares authorized | shares	100,000,000	100,000,000
Vessel/Fleet [Member]
Property, Plant and Equipment [Line Items]
Number of vessels in fleet	46
Charter In Vessels [Member]
Property, Plant and Equipment [Line Items]
Number of vessels in fleet	6
Vessels with Interest In [Member]
Property, Plant and Equipment [Line Items]
Number of vessels in fleet	6