Subsequent Events (Details Textual) (USD $)	12 Months Ended			12 Months Ended	0 Months Ended	12 Months Ended						0 Months Ended	1 Months Ended				0 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2013 Restricted Stock [Member]	Aug. 07, 2013 Minimum [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Minimum [Member] Restricted Stock [Member]	Dec. 31, 2012 Minimum [Member] Restricted Stock [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2013 Maximum [Member] Restricted Stock [Member]	Dec. 31, 2012 Maximum [Member] Restricted Stock [Member]	Mar. 14, 2014 Subsequent Event [Member]	Feb. 28, 2014 Subsequent Event [Member]	Mar. 13, 2014 Subsequent Event [Member]	Mar. 07, 2014 Subsequent Event [Member]	Dec. 31, 2012 Subsequent Event [Member]	Mar. 14, 2014 Subsequent Event [Member] Restricted Stock [Member]	Mar. 12, 2014 Subsequent Event [Member] Minimum [Member]	Dec. 31, 2013 Subsequent Event [Member] Minimum [Member]	Feb. 28, 2014 Subsequent Event [Member] Maximum [Member]	Dec. 31, 2013 Subsequent Event [Member] Maximum [Member]	Mar. 12, 2014 Subsequent Event [Member] Third Amended Credit Agreement [Member] Maximum [Member]
Derivative [Line Items]
Borrowing base																						$ 385,000,000
Reduction of borrowing base by issuance of senior unsecured notes covenant					10,000,000.0													10,000,000
Long-term Line of Credit, Noncurrent	200,000,000		150,000,000											250,000,000
Outstanding letters of credit	300,000													300,000		1,300,000
Additional deferred loan cost	1,100,000													800,000	800,000
Unamortized portion of the deferred loan costs	2,100,000
Stock option awards granted	874,000	0										224,962	49,721
Weighted average exercise price, Options granted	$ 8.78											$ 23.40	$ 19.71
Restricted stock grants													19,787				67,690
Fair value of awards												2,200,000	400,000
Fair value of restricted stock awards													400,000				1,500,000
Vesting period of shares	4 years			3 years		3 years	1 year	1 year	4 years	4 years	4 years	4 years							3 years	4 years	4 years
Maximum Termination Outstanding Obligations of Contracts	9,900,000													13,700,000
Minimum outstanding commitments	$ 5,700,000													$ 20,100,000