(2) Bill and Hold (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended	24 Months Ended		48 Months Ended
	Jun. 30, 2013 T	Mar. 31, 2013	Mar. 31, 2015 T	Mar. 31, 2014 T	May 31, 2016	Dec. 31, 2013 T
Bill And Hold Inventory [Abstract]
TonsOfCoalAgreedToStorePerCustomer	145,000			250,000
MinimumStoragePeriod		1 year
MaximumStoragePeriod				2 years
undefined					2
IncreaseDecreaseInCoalInStorage			50,000
undefined	0
RevenueFromBillAndHold (in Dollars)						$ 7.3
TonsCoalStoredFirstCustomerReportingDate						300,000
TonsCoalStoredSecondCustomerReportingDate						250,000