Long-Term Debt (Details) (USD $)	3 Months Ended		9 Months Ended								0 Months Ended	3 Months Ended		9 Months Ended								0 Months Ended																0 Months Ended			0 Months Ended									9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Aug. 01, 2014 NuDevco Retail Holdings Spark HoldCo	Sep. 30, 2014 Other Current Assets	Dec. 31, 2013 Other Current Assets	Sep. 30, 2014 Other Noncurrent Assets	Dec. 31, 2013 Other Noncurrent Assets	Dec. 17, 2012 Working Capital Facility	Sep. 30, 2014 Working Capital Facility	Sep. 30, 2013 Working Capital Facility	Sep. 30, 2014 Working Capital Facility	Sep. 30, 2013 Working Capital Facility	Aug. 01, 2014 Working Capital Facility	Dec. 31, 2013 Working Capital Facility	Jul. 31, 2013 Working Capital Facility	Dec. 17, 2012 Working Capital Facility	Jan. 24, 2011 Working Capital Facility	May 30, 2008 Working Capital Facility	Jul. 31, 2013 Working Capital Facility Eurodollar Minimum	Dec. 17, 2012 Working Capital Facility Eurodollar Minimum	Jul. 31, 2013 Working Capital Facility Eurodollar Maximum	Dec. 17, 2012 Working Capital Facility Eurodollar Maximum	Jul. 31, 2013 Working Capital Facility Base Rate Minimum	Dec. 17, 2012 Working Capital Facility Base Rate Minimum	Jul. 31, 2013 Working Capital Facility Base Rate Maximum	Dec. 17, 2012 Working Capital Facility Base Rate Maximum	Jul. 31, 2013 Working Capital Facility Cost of Funds Rate Minimum	Jul. 31, 2013 Working Capital Facility Cost of Funds Rate Maximum	Dec. 17, 2012 Term Loan	Jan. 24, 2011 Term Loan	May 30, 2008 Term Loan	Dec. 17, 2012 Revolving Credit Facility	May 30, 2008 Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Senior Secured Revolving Credit Facility Line of Credit	Sep. 30, 2014 Revolving Credit Facility Senior Secured Revolving Credit Facility Line of Credit	Aug. 01, 2014 Revolving Credit Facility Senior Secured Revolving Credit Facility Line of Credit	Aug. 01, 2014 Revolving Credit Facility Minimum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Maximum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Eurodollar Minimum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Eurodollar Maximum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Base Rate Minimum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Base Rate Maximum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Cost of Funds Rate Minimum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Cost of Funds Rate Maximum Senior Secured Revolving Credit Facility	Aug. 01, 2014 Revolving Credit Facility Base Rate Plus Margin Senior Secured Revolving Credit Facility	Sep. 30, 2014 Letters Of Credit Outstanding More Than Two Business Days Base Rate
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity																		$ 80,000,000	$ 70,000,000	$ 150,000,000	$ 177,500,000.0											$ 125,000,000	$ 130,000,000	$ 100,000,000	$ 30,000,000	$ 35,000,000				$ 70,000,000.0
Working capital facility outstanding																	27,500,000																						20,500,000
Working capital credit facility outstanding portion paid by affiliate																29,000,000	17,500,000
Letters of credit issued and outstanding	11,600,000		11,600,000													15,000,000	10,000,000
Fees on letters of credit issued and outstanding												100,000	100,000	300,000	400,000
Basis spread on variable rate																						3.00%	3.00%	3.25%	3.75%	2.00%	2.00%	2.25%	2.75%	2.50%	2.75%												2.75%	3.00%	1.75%	2.00%	2.25%	2.50%		2.00%
Nonutilization fee											0.50%
Interest expense												600,000	600,000	1,200,000	1,300,000
Commitment fee percentage														0.50%																											0.375%	0.50%
Commitment fee amount, less than												100,000	100,000	100,000	100,000
Deferred financing costs	400,000		400,000		500,000		200,000	400,000	200,000	100,000
Amortization of deferred financing costs	400,000	300,000	600,000	500,000
Capitalized financing costs	300,000
Investment in affiliate transferred						50,000
Contingent maximum borrowing capacity																																								120,000,000.0
Line of credit facility, outstanding																																					$ 10,000,000
Reduction to interest rate if facility utilization is less than fifty percent																																						0.00%
Stated percentage interest rate																																																	2.00%
Used capacity fee percentage																																									2.00%	2.50%