Stock-Based Awards - Stock Options (Details) - Stock Options	3 Months Ended
	Oct. 28, 2017 $ / shares shares
Stock Options, Outstanding [Roll Forward]
Beginning balance (in shares) | shares	670,350
Granted (in shares) | shares	18,933
Options exercised (in shares) | shares	(21,325)
Canceled (in shares) | shares	0
Ending balance (in shares) | shares	667,958
Exercisable options (in shares) | shares	518,053
Stock Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Beginning balance (in dollars per shares) | $ / shares	$ 25.24
Options granted (in dollars per shares) | $ / shares	85.15
Options exercised (in dollars per shares) | $ / shares	9.57
Canceled (in dollars per shares) | $ / shares	0.00
Ending balance (in dollars per shares) | $ / shares	27.44
Weighted average remaining contractual life, shares exercisable (In years) | $ / shares	$ 18.70