Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Benefit for income taxes
Current - State	$ 522	$ 426	$ 764
Deferred	234	(13,491)	(930)
Income Tax Expense (Benefit), Total	$ 756	$ (13,065)	$ (166)
Effective Income Tax Rate
Statutory U.S. Federal income tax rate (as a percent)	(35.00%)	(35.00%)	(35.00%)
State income taxes, net of U.S. Federal income tax (as a percent)	(2.20%)	(3.40%)	(2.80%)
Valuation allowance (as a percent)	16.80%	21.50%	38.10%
Permanent items (as a percent)	5.10%	0.50%	1.20%
Deferred item adjustments (as a percent)	18.00%		(1.90%)
Effective income tax rate (as a percent)	2.70%	(16.40%)	(0.40%)
Deferred tax assets
Accounts receivable	$ 588	$ 798
Accrued compensation and pension	6,797	8,045
Inventories	796	1,146
Other assets	2,014	1,315
Unrealized loss on pension	4,160	4,512
Net operating loss carryforwards	83,338	85,694
Deferred tax assets	97,693	101,510
Valuation allowance	(59,715)	(55,037)
Total deferred tax assets	37,978	46,473
Deferred tax liabilities
Accelerated depreciation and amortization	(90,191)	(97,958)
Prepaid assets	(746)	(1,240)
Total deferred tax liabilities	(90,937)	(99,198)
Net deferred tax liability	(52,959)	$ (52,725)
Federal
Operating loss carryforwards
Unused federal net operating loss carryforwards	$ 214,900