Derivatives (Schedule of Price Risk Derivatives) (Details)	Jun. 30, 2012
Year One [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	3,821,000
Year One [Member] | Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	1,168,000
Year Two [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	3,517,000
Year Two [Member] | Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	420,000
Year Three [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	3,240,000
Year Three [Member] | Coal Purchases [Member]
Derivative [Line Items]
Derivatives Held	720,000
Year Four [Member] | Coal Sales [Member]
Derivative [Line Items]
Derivatives Held	720,000