Income Taxes (Provision For Income Taxes) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 86,053	$ 103,332	$ 73,243
State	14,809	17,972	12,993
Current income tax expense (benefit), total	100,862	121,304	86,236
Deferred:
Federal	(117,549)	27,646	35,797
State	(14,905)	3,385	2,883
Deferred income tax expense (benefit), total	(132,454)	31,031	38,680
Provision for income taxes	$ (31,592)	$ 152,335	$ 124,916