Income Taxes (Reconciliation Of Income Tax Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Income tax expense computed by applying the statutory rate	$ 105,514	$ 13,791	$ 111,651
State income tax, net of federal benefit	8,290	1,084	8,941
Statutory depletion and other	2,919	1,351	2,543
Total income taxes	$ 116,723	$ 16,226	$ 123,135