Selected Quarterly Financial Data (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 56,363	$ 43,549	$ 47,884	$ 49,831	$ 61,694	$ 52,204	$ 54,860	$ 52,675	$ 197,627	$ 221,433	$ 230,813
Operating income/(loss)	1,360	(50,689)	(2,885)	(4,182)	(38)	(9,294)	(2,486)	(6,776)	(56,396)	(18,594)	(8,663)
Net (loss)/income	$ 1,110	$ (50,878)	$ (2,704)	$ (3,613)	$ 4,197	$ (9,701)	$ (2,938)	$ (7,077)	$ (56,085)	$ (15,519)	$ (9,596)
(Loss)/earnings per share - basic and diluted	$ 0.02	$ (0.76)	$ (0.04)	$ (0.05)					$ (0.83)	$ (0.28)	$ (0.18)
(Loss)/earnings per share - basic					$ 0.07	$ (0.18)	$ (0.05)	$ (0.13)		$ (0.28)
Weighted average common shares outstanding, Basic	67,330,288	67,271,211	67,224,593	67,065,741	59,014,889	54,989,823	54,765,846	54,715,573	67,231,463	55,880,896
Weighted average common shares outstanding, Diluted	67,621,961	67,271,211	67,224,593	67,065,741	59,605,829	54,989,823	54,765,846	54,715,573	67,231,463	55,880,896