On-Balance Sheet Derivative Instruments And Hedging Activities (Schedule Of Derivative Instruments, Effect On Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
On-Balance Sheet Derivative Instruments And Hedging Activities
Balance at beginning of year, net	$ 8,953	$ 6,617	$ 9,370	$ 12,040
Unrealized gain (loss) on cash flow hedges	(641)	(8,343)
Tax effect	224	2,920
Net of tax change	(417)	(5,423)
Balance at end of period, net	$ 8,953	$ 6,617	$ 9,370	$ 12,040

Net of tax effect change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges, that is attributable to the parent entity. The change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569616-111683

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=6921930&loc=SL4573702-111684

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 30
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=6921628&loc=SL4569643-111683

+ Details

- Definition

Total tax effect of the change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. The change includes an entity's share of an equity investee's increase or decrease in deferred hedging gains or losses. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

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