Derivative Instruments and Hedging Activities (Details)			3 Months Ended	9 Months Ended
	Feb. 28, 2015 MMBTU	Jan. 31, 2015 MMBTU	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($) bbl	Sep. 30, 2014 USD ($) MMBTU $ / MMBTU	Dec. 31, 2014 USD ($)
Commodity Contract
Derivatives, Fair Value [Line Items]
Notional quantity (in bbl) | bbl				320
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Premiums received			$ 750,000	$ 2,495,000
Notional principal amount					$ 250,000,000
Interest Rate Swap | Interest Expense
Derivatives, Fair Value [Line Items]
Premiums received			750,000	2,495,000
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative liability, fair value			358,000	358,000		$ 0
Not Designated as Hedging Instrument | Fair Value of Derivatives | Commodity Contract
Derivatives, Fair Value [Line Items]
Derivative liability, fair value			$ 358,000	$ 358,000		$ 0
Call Option | Commodity Contract
Derivatives, Fair Value [Line Items]
Notional quantity (in MMBtu) | MMBTU	1,286,242	2,345,498			3,631,740
Strike price (in dollars per MMBtu) | $ / MMBTU					4.50