Vectren Fuels Acquisition (Schedule of Business Acquisition) (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Use of proceeds from new debt facility:
Cash		$ 350,000
Deferred financing costs		(6,884)
Vectren Fuels [Member]
Assets received:
Accounts receivable	25,109	25,109
Advance royalties	685	685
Prepaid expense	909	909
Land and mineral rights	103,577	103,577
Building and equipment	174,180	174,180
Total assets received	339,120	339,120
Liabilities assumed:
Accounts payable and accrued liabilities	12,808	12,808
Asset retirement obligations	6,550	6,550
Total liabilities assumed	19,358	19,358
Total consideration paid	319,762	319,762
Use of proceeds from new debt facility:
Cash		1,805
Consideration paid for VFI	(320,000)	319,762
Deferred financing costs		6,163
Payments on bank debt		16,149
Closing expenses		6,121
Total		350,000
Vectren Fuels [Member] | Coal [Member]
Assets received:
Inventory	21,484	21,484
Vectren Fuels [Member] | Replacement Parts [Member]
Assets received:
Inventory	$ 13,176	$ 13,176