Income Taxes (Reconciliation of Provision for Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal statutory rate		35.00%	35.00%	35.00%
Expected tax expense at U.S. federal statutory rate of 35%		$ 49,658	$ 122,279	$ 59,878
State income taxes, net of Federal income tax effect		4,783	13,274	8,053
R&D tax credit	$ (16,500)	(29,363)	(18,655)	(13,841)
Release of tax reserves on previously unrecognized tax benefits		(13,438)	(38,612)	0
Foreign earnings at other than US rates		5,310	2,959	821
Other		2,294	1,325	3,760
Provision for income taxes		$ 19,244	$ 82,570	$ 58,671