Assets (Details 7) (USD $) In Thousands, unless otherwise specified	12 Months Ended						1 Months Ended	12 Months Ended						1 Months Ended			12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Feb. 28, 2010 Other income	Dec. 31, 2012 Commitment Letter		Dec. 31, 2011 Whitebox Revolving Credit Facility		Dec. 31, 2011 RBC Revolving Credit Facility		Apr. 30, 2011 RBC Revolving Credit Facility Interest expense		May 31, 2011 RBC Revolving Credit Facility Other income	Dec. 31, 2011 RBC Revolving Credit Facility Other income
Deferred Finance Costs [Roll Forward]
Balance at the beginning of the period	$ 12,987		$ 11,794		$ 10,819
Capitalized	0	[1]	6,422	[1]	4,570	[1]		800	[1]	5,900	[1]
Amortized	(4,074)	[2]	(4,108)	[2]	(2,784)	[2]								(1,100)	[2]
Write-offs associated with early extinguishment of debt	0	[3]	(1,121)	[3]	(811)	[3]	(800)					(1,100)	[3]			(1,100)	(1,100)	[3]
Balance at the end of the period	$ 8,913		$ 12,987		$ 11,794

[1] In 2012, the Company recorded $0.8 million in deferred financing costs in connection with the Avista Commitment Letter. In 2011, the Company recorded $5.9 million in deferred financing costs in connection with the amended and restated credit agreement for the Whitebox Revolving Credit Facility.

[2] In April 2011, the Company wrote off $1.1 million of deferred financing costs in connection with Amendment No. 4 to the RBC Revolving Credit Facility which modified the final maturity date. This amount is included in interest expense in the consolidated statement of operations.

[3] In May 2011, the Company wrote off $1.1 million of deferred financing costs in connection with the early extinguishment of the RBC Revolving Credit Facility which is included in other income (expense) in the Company’s consolidated statement of operations. In February 2010, in connection with the closing of the acquisition of PGS Onshore, the Company wrote off $0.8 million of deferred financing costs related to the early extinguishment of certain debt which is included in other income (expense) in the Company’s consolidated statement of operations.