Shareholders' Equity Transactions Options Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Days Following a Public Announcement of Beneficial Ownership Acquisition	10 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at January 1 Weighted Average Exercise Price	$ 28.99		$ 29.60		$ 29.28
Options outstanding at January 1	4,455,365		4,484,195		4,619,528
Granted	761,892		608,896		646,797
Granted Weighted Average Exercise Price	$ 13.44		$ 24.57		$ 25.22
Excercised	(9,417)		(178,744)		(399,144)
Excercised Weighted Average Exercise Price	$ 10.70		$ 23.15		$ 23.08
Canceled	(543,206)		(458,982)		(382,986)
Canceled Weighted Average Exercise Price	$ 31.52		$ 31.42		$ 25.07
Options outstanding at December 31	4,664,634		4,455,365		4,484,195
Options outstanding at December 31 Weighted Average Exercise Price	$ 26.21		$ 28.99		$ 29.60
Options exercise price range at December 31, Lower Limit	$ 13.37		$ 10.70		$ 10.70
Share based Compensation Arrangement by Share Based Payment Award Percentage of Options Vested in Year Following Issuance	25.00%
Percentage of Class A Preferred Stock per Right	0.10%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	10 years
Options exercise price range at December 31, Upper Limit	$ 47.80		$ 47.80		$ 47.80
Options exercisable at December 31	3,074,275		2,960,317		2,941,772
Options available for grant at December 31	6,800,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options available for grant at December 31	1,248,033	[1]	1,914,574	[1]	2,478,905	[1]
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Net Restricted Stock Award Activity	694,337
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	118,200		101,329		92,900
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years

[1] *Options available for grant as of December 31, 2012 reduced by net restricted stock award activity of 694,337.