Earnings Per Share (Calculation of Basic and Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Nov. 30, 2012	Aug. 31, 2012	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Earnings Per Share [Abstract]
Income from continuing operations (in dollars)	$ 10,775	$ 5,353	$ 4,527	$ 11,949	$ 17,221	$ 14,426	$ 18,432	$ 16,263	$ 32,604	$ 66,342	$ 62,568
Weighted average shares outstanding									62,881	65,705	63,957
Dilutive impact from common stock equivalents									860	1,835	2,255
Diluted weighted average shares outstanding									63,741	67,540	66,212
Continuing operations per share, basic (in dollars per share)	$ 0.17	$ 0.08	$ 0.07	$ 0.19	$ 0.27	$ 0.22	$ 0.28	$ 0.24	$ 0.52	$ 1.01	$ 0.98
Continuing operations per share, diluted (in dollars per share)	$ 0.17	$ 0.08	$ 0.07	$ 0.19	$ 0.27	$ 0.21	$ 0.27	$ 0.23	$ 0.51	$ 0.98	$ 0.94

This element represents the income or loss from continuing operations attributable to the parent which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests, if any.

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- Definition

The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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- Definition

The amount of net income (loss) derived from continuing operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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