XML 72 R99.htm IDEA: XBRL DOCUMENT v2.4.0.6
Benefit Plans (Details) (USD $)
12 Months Ended
Dec. 31, 2011
Y
Dec. 31, 2010
Y
Dec. 31, 2009
Y
Summary of fair values for stock-based awards granted using the Black-Scholes option pricing model      
Weighted-average fair value of grants $ 5.63 $ 5.30 $ 2.21
Risk-free interest rate (range), Minimum 1.40% 1.40% 1.10%
Risk-free interest rate (range), Maximum 3.00% 2.60% 2.70%
Dividend yield (range), Minimum 3.40% 4.20% 8.60%
Dividend yield (range), Maximum 4.90% 5.60% 24.90%
Expected life (range) 7    
Expected life (range), Minimum   4 3
Expected life (range), Maximum   5 6
Expected volatility (range), Minimum 52.10% 87.00% 58.00%
Expected volatility (range), Maximum 69.00% 97.80% 93.83%