Common Stock Repurchase Plan (Narrative) (Details) - USD ($)		3 Months Ended	8 Months Ended
	Jul. 29, 2016	Mar. 31, 2017	Mar. 31, 2017
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, repurchased cost		$ 50,000,000
Common Stock [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, expiration date	Jul. 31, 2018
Shares repurchase program, shares repurchased		1,190,021	2,300,000
Shares repurchase program, repurchased cost		$ 50,000,000	$ 93,800,000
Shares repurchase program, average price per share		$ 41.90	$ 40.72
Common Stock [Member] | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount	$ 150,000,000