Income Taxes (Schedule Of Effective Income Tax Rate Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Tax Disclosure [Abstract]
Income tax expense at the statutory rate	$ 20,427	$ 14,687	$ 21,824	$ 20,273
State income taxes, net of U.S. federal income tax benefit	2,049	843	2,063	1,087
Other, net	69	749	107	204
Income tax expense	$ 22,545	$ 16,279	$ 23,994	$ 21,564