Income Taxes (Details) - The income tax effects of temporary differences that comprise deferred tax assets and liabilities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current deferred tax assets:
Accounts receivable	$ 294	$ 268
Employee benefits	444	901
Other accrued expenses	331	507
Gross current deferred tax asset	1,069	1,676
Less valuation allowance	(1,003)	(977)
Net current deferred tax asset	66	699
Noncurrent deferred tax assets (liabilities)
Property, plant and equipment	(1,187)	(6,306)
Employee benefits	5,205	4,774
Other noncurrent assets	94	109
Contribution carryforward	279
AMT credit	631	631
Net operating loss	15,633	9,844
Gross non-current deferred tax assets (liabilities)	20,655	9,052
Less valuation allowance	(20,721)	(9,751)
Net noncurrent deferred tax assets (liabilities)	$ (66)	$ (699)