Stock-Based Compensation (Details 1) (Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010 Y	Dec. 31, 2009 Y
Stock Options [Member]
Weighted average assumptions used in the option pricing model for options granted
Expected life (years)	5.0	5.0	6.0
Risk-free interest rate	1.80%	2.20%	2.60%
Volatility	40.80%	39.80%	41.20%
Dividend yield	0.90%	1.20%	1.80%
Weighted average fair value per share at grant date	$ 24.20	$ 16.24	$ 12.66