Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Condensed Consolidated Balance Sheets
Due from charterers, reserve	$ 484	$ 488
Vessels, accumulated depreciation	629,953	597,214
Deferred drydock, accumulated amortization	9,010	8,086
Other assets, accumulated amortization	14,997	13,162
Fixed assets, accumulated depreciation and amortization	$ 3,539	$ 3,311
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)	44,270,273	44,270,273
Common stock, shares outstanding (in shares)	44,270,273	44,270,273