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Fair Value of Employee Stock Options Granted as Determined by Black-Scholes Valuation Model Assumptions (Detail) (Nonqualified Stock Options [Member])
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3 Months Ended | |
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Mar. 31, 2012
Y
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Jun. 30, 2011
Y
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Nonqualified Stock Options [Member]
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| Stockholders Equity Note [Line Items] | ||
| Expected life (in years) | 7.5 | 7.5 |
| Risk-free interest rate | 1.63% | 2.90% |
| Expected volatility | 25.06% | 24.26% |
| Expected dividend yield | 2.77% | 2.77% |
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- Definition
The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The period of time an equity-based award is expected to be outstanding. An equity-based award's expected term is generally determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The range of expected volatilities used and the weighted-average expected volatility for an entity using a valuation technique with different volatilities during the contractual term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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