Debt Additional disclosures related to the 6.00% Convertible Guaranteed Notes due 2030 (Details) (6% Convertible Guaranteed Note [Member], USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2010
6% Convertible Guaranteed Note [Member]
Debt Instrument [Line Items]
Principal amount of debt component	$ 24,786,000		$ 24,786,000		$ 28,991,000	$ 115,000,000
Unamortized discount	(966,000)		(966,000)		(1,500,000)
Carrying amount of debt component	23,820,000		23,820,000		27,491,000
Carrying amount of equity component	(28,229,000)		(28,229,000)		(26,032,000)
Effective interest rate	8.10%		8.10%		8.10%
Aggregate if-converted value in excess of aggregate principal amount			11,520,000		14,296,000
Coupon interest	375,000	473,000	1,196,000	1,871,000
Discount amortization	107,000	137,000	340,000	534,000
Interest Expense	$ 482,000	$ 610,000	$ 1,536,000	$ 2,405,000