Common Stock Repurchases (Details) - USD ($) shares in Millions	3 Months Ended	9 Months Ended
	Aug. 31, 2016	Aug. 31, 2016	Aug. 31, 2015	Mar. 31, 2016
Common Stock Repurchases [Abstract]
Common stock repurchased and retired (in shares)	0.4	2.8	1.3
Common stock repurchased and retired	$ 11,500,000	$ 71,500,000	$ 32,900,000
Remaining authorized repurchase amount	$ 143,000,000	$ 143,000,000		$ 202,800,000
March 2016 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized amount for share repurchase programs				$ 100,000,000.0