Income Taxes (Schedule Of Income Taxes (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Abstract]
Current Federal, Income taxes (benefit)	$ 217,400	$ 158,164	$ 178,450
Deferred Federal Income taxes (benefit)	(4,108)	(31,843)	14,277
Federal Income taxes (benefit) total	213,292	126,321	192,727
Current State, Income taxes (benefit)	26,900	14,027	18,573
Deferred State, Income taxes (benefit)	(4,334)	2,040	11,661
State Income taxes (benefit) total	22,566	16,067	30,234
Income Tax Expense (Benefit), Total	$ 235,858	$ 142,388	$ 222,961