Debt (Schedule Of Convertible Debt Interest Expense) (Details) (3.95 % Convertible Senior Unsecured Notes [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
3.95 % Convertible Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Interest expense	$ 1,828	$ 4,218	$ 5,782
Amortization of discount	0	1,334	2,191
Net interest expense	$ 1,828	$ 5,552	$ 7,973