Stock Based Compensation Options (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options, Vesting Percentage, After Year One	50.00%
Stock Options, Expiration in Years	10
Options outstanding, beginning	145,950	314,250	317,000
Weighted average exercise price, beginning	$ 27.69	$ 26.74	$ 25.39	$ 25.31
Stock Options, granted	0	0	0
Stock Options, granted, weighted average exercise price	$ 0.00	$ 0.00	$ 0.00
Options exercised	(51,081)	(164,300)	(2,750)
Stock Options, exercised, weighted average exercise price	$ 25.29	$ 24.11	$ 16.34
Stock Options, expired/forfeited	(5,763)	(4,000)	0
Stock Options, expired/forfeited, weighted average exercise price	$ 24.85	$ 28.23	$ 0.00
Options outstanding, ending	89,106	145,950	314,250
Weighted average exercise price, ending	$ 27.69	$ 26.74	$ 25.39	$ 25.31
Stock Options, exercisable	89,106	145,950	314,250
Stock Options, weighted average exercise price	$ 27.69	$ 26.74	$ 25.39
Aggregate intrinsic value of outstanding exercisable shares	$ 0
Aggregate intrinsic value of options exercised	$ 0.3	$ 1.0
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, minimum	$ 25.61
Exercise price, maximum	$ 33.09
Weighted average remaining contractual term, options outstanding (years)	1.5
Weighted average exercise price, beginning	$ 27.69
Weighted average exercise price, ending	$ 27.69