Stock Based Compensation Summary of Stock Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Stock-Based Compensation [Abstract]
Options, outstanding, beginning of year (in shares)	5,417
Options, outstanding, beginning of year (in dollars per share)	$ 33.28
Options granted (in shares)	155
Options granted (in dollars per share)	$ 27.67
Options exercised (in shares)	(1,569)
Options exercised (in dollars per share)	$ 24.09
Options forfeited (in shares)	(526)
Options forfeited (in dollars per share)	$ 39.99
Options, outstanding, end of year (in shares)	3,477
Options, outstanding, end of year (in dollars per share)	$ 36.17
Options exercisable, end of year (in shares)	2,995
Options exercisable, end of year (in dollars per share)	$ 37.85