Income Taxes (Difference In Income Tax Expense And Expected Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit) [Abstract]
Federal income tax expense at the 'expected' rate of 35%	$ 235,954	$ 201,278	$ 150,724
State income taxes, net of federal benefit	19,565	18,210	14,259
State tax matters	884	737	1,238
Other, net	(2,784)	(3,073)	(937)
Total income tax expense	$ 253,619	$ 217,152	$ 165,284
Expected rate of federal income tax expense	35.00%	35.00%	35.00%