Accounting For Stock-Based Compensation (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Oct. 31, 2011 years	Oct. 31, 2010
Accounting For Stock-Based Compensation [Abstract]
Expected life	1
Risk-free interest rate	0.14%
Expected volatility	30.80%
Expected dividend yield	1.00%
Weighted average fair value for options granted, per share	$ 7.43	$ 6.85
Pretax compensation expense associated with stock options	$ 0.8	$ 0.8
Tax benefit associated with stock options	0.3	0.3
Total intrinsic value of options exercised	6.5	10.8
Aggregate intrinsic value of options outstanding	117.7
Aggregate intrinsic value of options exercisable	109.3
Unrecognized compensation cost related to non-vested stock options granted	$ 5.2

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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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.

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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.

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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.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of vested portions of options outstanding and currently exercisable under the option plan as of the balance sheet date.

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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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