Income Taxes (Reconciliation of Provision for Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Expected tax expense at U.S. federal statutory rate of 35%		$ 59,878	$ 10,667	$ 125,833
State income taxes, net of Federal income tax effect		8,053	2,914	15,042
R&D tax credit		(13,841)	(1,803)	(8,365)
Other		4,581	1,550	886
Provision for income taxes	$ 21,616	$ 58,671	$ 13,328	$ 133,396
Federal statutory rate		35.00%