Stock-Based Awards - Stock Options (Details) - Stock Options $ / shares in Units, $ in Thousands	6 Months Ended
	Jan. 27, 2018 USD ($) $ / 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	(52,553)
Canceled (in shares) | shares	0
Ending balance (in shares) | shares	636,730
Exercisable options (in shares) | shares	549,507
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	14.17
Canceled (in dollars per shares) | $ / shares	0.00
Ending balance (in dollars per shares) | $ / shares	27.93
Weighted average remaining contractual life, shares exercisable (In years) | $ / shares	$ 21.63
Weighted Average Remaining Contractual Life (In years), outstanding	4 years 9 months
Aggregate Intrinsic Value (In thousands), outstanding | $	$ 58,176
Weighted Average Remaining Contractual Life (In years). exercisable	4 years 2 months
Aggregate Intrinsic Value (In thousands), exercisable | $	$ 53,670