Stockholder's Equity (Summary Of Stock Option Plan Activity) (Details) - $ / shares	12 Months Ended			104 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Options Outstanding
Granted (in shares)				9,948,220
Outstanding as of End of Period (in shares)	4,530,982			4,530,982
Exercisable (in shares)	1,792,242			1,792,242
Stock Option Plan [Member]
Options Outstanding
Outstanding as of Beginning of Period (in shares)	4,712,330	4,356,630
Granted (in shares)	893,220	955,000
Exercised (in shares)	(813,838)	(314,300)
Cancelled/Forfeited (in shares)	(260,730)	(285,000)
Outstanding as of End of Period (in shares)	4,530,982	4,712,330	4,356,630	4,530,982
Exercisable (in shares)	1,792,242	1,972,330		1,792,242
Weighted Average Exercise Price
Outstanding as of Beginning of Period (in dollars per share)	$ 38.52	$ 34.06
Granted (in dollars per share)	42.00	56.00
Exercised (in dollars per share)	23.47	24.49
Cancelled/Forfeited (in dollars per share)	45.84	44.39
Outstanding as of End of Period (in dollars per share)	41.49	38.52	$ 34.06	$ 41.49
Exercisable (in dollars per share)	$ 31.00	$ 27.89		$ 31.00
Weighted Average Remaining Life
Outstanding	4 years 10 months 20 days	4 years 7 months 2 days	4 years 7 months 27 days
Granted	8 years 4 months 27 days	8 years 4 months 27 days
Exercisable	2 years 1 month 24 days	2 years 6 months 3 days