Shareholders' Equity (Narrative) (Details) - USD ($)			12 Months Ended
	Sep. 06, 2017	Sep. 27, 2016	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares issued			0	0
Preferred stock, shares outstanding			0
Common stock, shares authorized			200,000,000	200,000,000
Common stock, par value (in dollars per share)			$ 0.01	$ 0.01
Common stock, shares issued			47,281,035	48,536,516
Common stock, shares outstanding			47,281,035	48,536,516
Share repurchase program, authorized amount						$ 250,000,000.0
Common stock repurchased and retired (in shares)			2,200,000	3,100,000	1,300,000
Common stock repurchased and retired, value (in dollars)			$ 73,936,000	$ 79,188,000	$ 32,868,000
Remaining authorized repurchase amount			$ 220,000,000
Cash dividends declared per common share (in dollars per share)	$ 0.14	$ 0.125	$ 0.515	$ 0.125	$ 0
Cash dividends, increase (as a percent)	12.00%
Dividends paid			$ 24,100,000	$ 0
Deferred Stock Unit [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock units, shares outstanding			92,817
Deferred stock unit represents common stock, share			1
Shares forfeited during period			22,545