XML 99 R66.htm IDEA: XBRL DOCUMENT v2.4.0.6
Stock Compensation Plans - Principal Assumptions for SSAR's Granted Fair Value (Detail) (USD $)
12 Months Ended
Dec. 31, 2012
Option
Dec. 31, 2011
Option
Dec. 31, 2010
Option
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]      
Weighted average fair value of SSAR's granted during the period $ 10.39 $ 11.47 $ 10.41
Risk-free interest rate 0.90% 1.70% 2.20%
Expected volatility 22.50% 23.20% 29.80%
Expected dividend yield 2.10% 2.10% 2.20%
Expected life, in years 5 years 5 years 5 years
Termination rate 1.05% 0.99% 1.09%
Exercise multiple 1.44 1.43 1.38