New Accounting Principles and Recent Accounting Pronouncements (Summary Of Adjustments From Change In Accounting Principle) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred charges and other assets	$ 227,031	$ 62,582	[1]
Long-term debt	$ (3,040,594)	(2,517,669)	[1],[2]
As Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred charges and other assets		81,151
Long-term debt		(2,536,238)
Adjustment Effect [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred charges and other assets		(18,569)
Long-term debt		$ 18,569

[1] Reclassified to conform to current presentation.

[2] Reclassified to current presentation