Income Taxes (Reconciliation Of Effective Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Tax computed at statutory rate	$ 422,999	$ 163,625	$ 405,790
State income taxes, net of federal tax benefit	40,385	13,641	21,363
Domestic production activities deduction	(35,200)	(20,998)	(22,101)
Noncontrolling interest in net income	(24,155)	(17,431)	(12,378)
Uncertain tax positions	0	0	(193)
Other	2,031	2,335	(905)
Income tax provision total	$ 406,060	$ 141,172	$ 391,576