Income Taxes (Components of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
U.S. Federal	$ 40,542	$ 8,809	$ 20,808
State	13,886	2,416	3,521
Current Total	54,428	11,225	24,329
Deferred:
U.S. Federal	(9,943)	16,484	(372)
State	(3,252)	5,456	(285)
Deferred Total	(13,195)	21,940	(657)
Income tax expense	$ 41,233	$ 33,165	$ 23,672