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, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 47,405	$ 33,848	$ 42,198	$ 37,224	$ 56,363	$ 43,549	$ 47,884	$ 49,831	$ 160,675	$ 197,627	$ 221,433
Operating income/(loss)	5,860	(4,076)	(636)	(3,045)	1,360	(50,689)	(2,885)	(4,182)	(1,897)	(56,396)	(18,594)
Net (loss)/income	$ 6,976	$ (4,295)	$ (1,180)	$ (3,273)	$ 1,110	$ (50,878)	$ (2,704)	$ (3,613)	$ (1,772)	$ (56,085)	$ (15,519)
(Loss)/earnings per share - basic and diluted	$ 0.12	$ (0.06)	$ (0.02)	$ (0.05)	$ 0.02	$ (0.76)	$ (0.04)	$ (0.05)	$ (0.03)	$ (0.83)	$ (0.28)
Weighted average common shares outstanding, Basic	57,630,635	67,490,820	67,371,869	67,241,626	67,330,288	67,271,211	67,224,593	67,065,741	64,912,368	67,231,463
Weighted average common shares outstanding, Diluted	58,011,641	67,490,820	67,371,869	67,241,626	67,621,961	67,271,211	67,224,593	67,065,741	64,912,368	67,231,463