Stockholders' Equity Stockholders' Equity (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Preferred Stock, Shares Issued	104,574
Preferred Stock, Par Value Per Share	$ 1.00	$ 1.00
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Operating Loss Carryforwards		$ 789,700,000
Common Stock Ownership Enabling Preferred Stock Purchase Rights	4.99%
Common Stock Ownership Enabling Preferred Stock Purchase Rights, Incremental	0.50%
Preferred Series B [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Issued	104,574	104,574
Preferred Stock, Par Value Per Share	$ 1.00
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Preferred stock	$ 4,600,000	$ 4,600,000
Preferred Stock, Dividend Rate, Percentage	7.50%	7.50%
Preferred stock dividend condition - minimum pension funding	90.00%
Preferred stock dividend condition - minimum net income preceding quarter	$ 7,500,000
Preferred stock dividend condition - minimum free cash flow preceding four quarters	35,000,000
Preferred stock dividend condition - minimum cash balance preceding quarter	150,000,000
Preferred Stock, Liquidation Preference, Value	117,400,000	$ 111,500,000
Preferred Stock, Cumulative Undeclared Dividend	$ 12,800,000	$ 6,900,000