Fair Value Measurements - Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 25, 2015
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	$ 16,866	$ 23,271
Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	16,866	23,271
Interest rate cap	0	33
Total financial assets	16,866	23,304
Total financial liabilities	1,457	1,619
Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	16,866	23,271
Interest rate cap	0	0
Total financial assets	16,866	23,271
Total financial liabilities	0	0
Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Interest rate cap	0	33
Total financial assets	0	33
Total financial liabilities	0	0
Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Interest rate cap	0	0
Total financial assets	0	0
Total financial liabilities	1,457	1,619
Recurring | Agency securities
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	16,866	23,271
Recurring | Agency securities | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	16,866	23,271
Recurring | Agency securities | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Recurring | Agency securities | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Available-for-sale securities	0	0
Triune Systems | Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Triune Systems | Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Triune Systems | Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Triune Systems | Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Cycleo [Member] | Recurring
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	1,457	1,619
Cycleo [Member] | Recurring | Level 1
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Cycleo [Member] | Recurring | Level 2
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	0	0
Cycleo [Member] | Recurring | Level 3
Fair Value, Assets Measured On A Recurring Basis [Line Items]
Earn-out liability	$ 1,457	$ 1,619