XML 29 R71.htm IDEA: XBRL DOCUMENT

Stock Plans - Average Assumptions Used To Value Option Awards (Details) (USD$) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Stock Plans - Average Assumptions Used To Value Option Awards Details Usd
Weighted average grant date fair value	$ 3.21	$ 2.53
Expected dividend yield	1.91%	3.12%
Expected volatility	28.01%	28.74%
Risk free interest rate	1.94%	2.02%
Expected term (years)	10 years	10 years
Expected forfeiture	0.00%	0.00%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References+ Details