CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Noncurrent assets
Vessels and vessel improvements, accumulated depreciation	$ 258,249,266	$ 239,568,767
Other fixed assets, accumulated amortization	373,099	324,691
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	63,003,286	63,003,286
Common stock, shares outstanding (in shares)	63,003,286	63,003,286
Retained earnings, dividends declared	$ 262,118,388	$ 262,118,388