Indebtedness (Interest Expense Recognized On Convertible Senior Subordinated Notes) (Details) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
1 3/4% Convertible Senior Subordinated Notes Due December 31, 2033 [Member]
Interest expense	$ 0.4	$ 3.0	$ 0.9	$ 5.9
1 1/4% Convertible Senior Subordinated Notes Due December 15, 2036 [Member]
Interest expense	$ 2.7	$ 2.5	$ 5.4	$ 5.1

Interest expense related to convertible debt instruments which has been recognized for the period, including the contractual interest coupon and amortization of the debt discount, if any.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number APB14-1
-Paragraph 33
-Subparagraph b

Name:	us-gaap_DebtInstrumentConvertibleInterestExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration