Employee Benefit Plans (Summary Of The Change In Fair Value For Pension Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Balance	$ 1,105,370		$ 1,073,213
Real Estate [Member] | Private Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	29,553	[1]	27,323
Actual return on plan assets, Relating to assets still held at the reporting date	4,967		2,230
Balance	$ 34,520	[1]	$ 29,553	[1]

[1] 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.