Employee Benefit Plans (Summary Of Fair Value Of Pension Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	$ 1,105,370		$ 1,073,213
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	557,755		577,072
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	513,095		466,588
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	34,520		29,553
Short-Term Investment Fund [Member] | Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	52,076	[1]	17,356	[1]
Short-Term Investment Fund [Member] | Level 2 [Member] | Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	52,076	[1]	17,356	[1]
Short-Term Investment Fund [Member] | Level 3 [Member] | Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[1]
U.S. Long-Term Debt Instruments [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	287,828	[2]	247,968	[2]
U.S. Long-Term Debt Instruments [Member] | Level 1 [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	42,663	[2]	25,859	[2]
U.S. Long-Term Debt Instruments [Member] | Level 2 [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	245,165	[2]	222,109	[2]
U.S. Long-Term Debt Instruments [Member] | Level 3 [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[2]
Low-Duration Fund [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	72,066	[3]	85,659	[3]
Low-Duration Fund [Member] | Level 1 [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	72,066	[3]	85,659	[3]
Low-Duration Fund [Member] | Level 3 [Member] | Fixed-Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[3]
Private Fund [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	34,520	[4]	29,553	[4]	27,323
Private Fund [Member] | Level 3 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	34,520	[4]	29,553	[4]
Real Estate Investment Trust Index Fund [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	19,608	[1]	18,014	[1]
Real Estate Investment Trust Index Fund [Member] | Level 2 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	19,608	[1]	18,014	[1]
Real Estate Investment Trust Index Fund [Member] | Level 3 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[1]
U.S. Large Companies [Member] | S&P 500 Index Fund [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	116,391	[1]	113,869	[1]
U.S. Large Companies [Member] | S&P 500 Index Fund [Member] | Level 2 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	116,391	[1]	113,869	[1]
U.S. Large Companies [Member] | S&P 500 Index Fund [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[1]
U.S. Large Companies [Member] | Growth [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	133,556	[5]	123,153	[5]
U.S. Large Companies [Member] | Growth [Member] | Level 1 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	133,556	[5]	123,153	[5]
U.S. Large Companies [Member] | Growth [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[5]
U.S. Large Companies [Member] | Value [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	138,241	[5]	145,553	[5]
U.S. Large Companies [Member] | Value [Member] | Level 1 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	138,241	[5]	145,553	[5]
U.S. Large Companies [Member] | Value [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[5]
U.S. Small Companies [Member] | Growth [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	36,483	[5]	43,793	[5]
U.S. Small Companies [Member] | Growth [Member] | Level 1 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	36,483	[5]	43,793	[5]
U.S. Small Companies [Member] | Growth [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[5]
U.S. Small Companies [Member] | Value [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	64,764	[5]	68,986	[5]
U.S. Small Companies [Member] | Value [Member] | Level 1 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	64,764	[5]	68,986	[5]
U.S. Small Companies [Member] | Value [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[5]
International [Member] | Growth [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	69,982	[5]	84,069	[5]
International [Member] | Growth [Member] | Level 1 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	69,982	[5]	84,069	[5]
International [Member] | Growth [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[5]
International [Member] | Value [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	79,855	[1]	95,240	[1]
International [Member] | Value [Member] | Level 2 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets	79,855	[1]	95,240	[1]
International [Member] | Value [Member] | Level 3 [Member] | Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Pension Plan Assets				[1]

[1] These funds are not publicly traded and do not have readily determinable fair values. Accordingly, they are valued at their net asset value per share. The underlying investments in the funds consist primarily of publicly traded securities with quoted market prices.

[2] U.S. government securities are valued at their quoted market price, while corporate-debt instruments are generally valued using observable bid-ask spreads or broker-provided pricing.

[3] The low-duration fund is valued at its published net asset value per share.

[4] The fair value of the private real estate fund is based on the fair values of the underlying assets, which consist of commercial and residential properties valued using periodic appraisals.

[5] Publicly traded equity securities are valued at their closing market prices.