Significant Accounting Policies, Convertible Debt (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 2 3/4 percent convertible senior notes [Member]	Aug. 31, 2012 2 3/4 percent convertible senior notes [Member]	Sep. 30, 2014 2 5/8 percent convertible subordinated notes [Member]
Long-term obligations
Debt issued				$ 201.3
Interest rate on convertible debt (in hundredths)	2.75%	2.75%	2.75%		2.625%