Income Taxes (Difference In Income Tax Expense And Expected Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal income tax expense at the 'expected' rate of 35%	$ 289,107	$ 275,602	$ 249,714
State income taxes, net of federal benefit	21,613	20,549	16,683
Other, net	(1,061)	(2,867)	(1,565)
Total income tax expense	$ 309,659	$ 293,284	$ 264,832
Expected rate of federal income tax expense	35.00%	35.00%	35.00%
Effective income tax rate	37.50%	37.20%	37.10%