Earnings Per Share (Narrative) (Details) (Convertible Senior Notes 2032 [Member], USD $)	6 Months Ended
Jun. 30, 2013
Convertible Senior Notes 2032 [Member]
Debt Instrument, Convertible, Stock Price Trigger	$ 32.53

Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the debt instrument to become effective.

No definition available.

Name:	us-gaap_DebtInstrumentConvertibleStockPriceTrigger
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration