Stock-Based Compensation - Summary of the Activity For Cash Settled Non-Employee Directors Stock Unit Awards (Details) - Subject To Cash Settlement [Member] - Non-employee director stock unit awards [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 26, 2015	Jan. 25, 2015
Number of Units
Beginning balance (in shares)	24
Stock units granted (in shares)	28
Stock units vested (in shares)	(24)
Stock units forfeited (in shares)	0
Ending balance (in shares)	28	24
Recorded Liability
Beginning balance	$ 5,214
Change in liability	(1,447)
Ending balance	$ 3,767	$ 5,214
Weighted Averaged Grant Date Fair Value (per unit)
Beginning balance (in dollars per share)	$ 26.59
Stock units granted (in dollars per share)	19.70
Stock units vested (in dollars per share)	26.59
Stock units forfeited (in dollars per share)	0.00
Ending balance (in dollars per share)	$ 19.70	$ 26.59
Aggregate Unrecognized Compensation
Beginning balance	$ 275
Ending balance	$ 472	$ 275
Period Over Which Expected to be Recognized (in years)
Weighted average period over which expected to be recognized	11 months	5 months