Employee Benefit Plans And Other Postretirement Benefits (Schedule Of Fair Value Of Postretirement Healthcare Plan Assets) (Details) (Postretirement Healthcare Benefits [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	$ 89,909	$ 90,280
Total fixed-income holdings	17,393	16,380
Total postretirement healthcare plan assets	109,160	121,064	109,143
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	89,456	89,942
Total fixed-income holdings	7,237	3,507
Total postretirement healthcare plan assets	96,693	93,449
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	453	338
Total fixed-income holdings	10,156	12,873
Total postretirement healthcare plan assets	12,467	27,615
Cash And Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash and cash equivalents	1,858	14,404
Cash And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash and cash equivalents	1,858	14,404
U.S. Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	79,544	80,915
U.S. Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	79,091	80,577
U.S. Companies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	453	338
Foreign Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	10,365	9,365
Foreign Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	10,365	9,365
U.S. Treasuries [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	7,237	3,507
U.S. Treasuries [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	7,237	3,507
Federal Agencies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	4,172	6,116
Federal Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	4,172	6,116
Corporate Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,537	6,158
Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,537	6,158
Foreign Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	307	459
Foreign Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	307	459
Municipal Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	140	140
Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	$ 140	$ 140