Derivative Instruments (Change In Fair Value Of Derivative Instruments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Income Derivative Asset [Member]
Derivatives, Fair Value [Line Items]
Change in Fair Value	$ 1,921	$ 8,241	$ 1,479
Other Income Derivative Liability [Member]
Derivatives, Fair Value [Line Items]
Change in Fair Value	$ (1,921)	$ (8,241)	$ (1,479)

The amount recognized in earnings related to the change in fair value during the period of derivative or nonderivative instruments designated as fair value hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration