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Significant Accounting Policies - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Oct. 29, 2017
Jan. 28, 2018
Jan. 29, 2017
Jan. 31, 2016
Apr. 30, 2017
Aggregate net investments under cost method of accounting   $ 38,100 $ 27,100    
Impairment of assets $ 4,250 4,250 0 $ 0  
Deferred tax assets (and increase in valuation allowance) recognized for the windfall tax benefits   8,400     $ 8,400
Cumulative effect adjustment to retained earnings from adoption of ASU 2016-09   $ 2,021      
Other Intangible Assets and Long-lived Assets [Abstract]          
Percent of realizable undiscounted cash flows used to determine useful life of acquired finite-lived intangible assets, minimum   90.00%      
Sales and Marketing [Abstract]          
Advertising costs   $ 600 400 200  
Product Development and Engineering [Abstract]          
Recoveries from nonrecurring engineering services   $ 5,400 11,900 $ 21,100  
Cash equivalents | Maximum          
Investment maturity period   90 days      
Other assets          
Aggregate net investments under cost method of accounting   $ 28,000      
Total equity method investments   3,400 $ 2,000    
Retained Earnings          
Cumulative effect adjustment to retained earnings from adoption of ASU 2016-09   2,021     $ 2,021
ASU 2014-09 [Member] | Minimum          
Increase in retained earnings expected from adopting the standard in fiscal 2019   10,000      
ASU 2014-09 [Member] | Maximum          
Increase in retained earnings expected from adopting the standard in fiscal 2019   $ 12,000