Derivative Instruments And Hedging (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2011
Estimated net amount of gains that are expected to be reclassified out of accumulated other comprehensive income and into earnings within the next 12 months	$ 1.3
Credit Facility borrowings hedged	80
Interest Rate Swap Effective On March 30, 2012 [Member]
Fixed portion of interest rate associated with interest rate swap	1.36%
Credit Facility borrowings hedged	40
Interest Rate Swap Effective On March 31 2010 [Member]
Fixed portion of interest rate associated with interest rate swap	2.00%
Credit Facility borrowings hedged	80
Interest Rate Swap Effective On March 28, 2013 [Member]
Fixed portion of interest rate associated with interest rate swap	1.64%
Credit Facility borrowings hedged	$ 40

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration