Common Stock Repurchases (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended	6 Months Ended
	May 31, 2018	May 31, 2019	May 31, 2018	Sep. 30, 2017
Equity [Abstract]
Common stock repurchased and retired (in shares)	1.1	0.7	2.1
Common stock repurchased and retired	$ 45,000	$ 25,000	$ 90,000
Stock repurchase authorization				$ 250,000
Remaining authorized repurchase amount		$ 75,000