Immaterial Restatement of Prior Period Financial Statements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 26, 2020	Oct. 27, 2019	Jul. 28, 2019	Apr. 28, 2019	Jan. 27, 2019	Oct. 28, 2018	Jul. 29, 2018	Apr. 29, 2018	Jan. 26, 2020	Jan. 27, 2019	Jan. 28, 2018	Jan. 29, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Selling, general and administrative									$ 163,106	$ 145,246	$ 148,146
Product development and engineering									107,368	109,047	105,070
Total operating costs and expenses									284,675	271,523	285,350
Operating income	$ 10,196	$ 17,877	$ 11,769	$ 12,167	$ 27,167	$ 44,784	$ 35,221	$ (1,673)	52,009	105,499	66,621
Income before taxes and equity in net gains (losses) of equity method investments									44,585	70,120	57,756
Provision for income taxes									12,828	355	22,853
Net income before equity in net gains (losses) of equity method investments									31,757	69,765	34,903
Net income									$ 31,866	$ 69,639	$ 34,649
Basic earnings (loss) per common share (in dollars per share)	$ 0.04	$ 0.21	$ 0.03	$ 0.19	$ 0.21	$ 0.22	$ 0.41	$ 0.21	$ 0.48	$ 1.06	$ 0.52
Diluted earnings (loss) per common share (in dollars per share)	$ 0.04	$ 0.21	$ 0.03	$ 0.19	$ 0.20	$ 0.22	$ 0.40	$ 0.20	$ 0.47	$ 1.02	$ 0.51
Comprehensive income									$ 29,307	$ 67,232	$ 34,743
Deferred tax assets	$ 20,094				$ 14,261				20,094	14,261	4,574
Assets	1,052,433				1,062,780				1,052,433	1,062,780	1,086,114
Additional paid-in capital	458,579				451,884				458,579	451,884	417,171
Retained earnings	611,607				579,736				611,607	579,736	500,569
Total stockholders’ equity	676,954				682,580				676,954	682,580	665,351
Total equity	677,200				682,580				677,200	682,580	665,351	$ 605,263
Total liabilities and equity	$ 1,052,433				1,062,780				$ 1,052,433	1,062,780	1,086,114
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Selling, general and administrative										151,397	146,303
Product development and engineering										109,918	104,798
Total operating costs and expenses										278,545	283,235
Operating income		$ 22,165	$ 15,548	$ 12,817	$ 26,771	$ 41,867	$ 32,936	$ (3,097)		98,477	68,736
Income before taxes and equity in net gains (losses) of equity method investments										63,098	59,871
Provision for income taxes										(84)	23,191
Net income before equity in net gains (losses) of equity method investments										63,182	36,680
Net income										$ 63,056	$ 36,426
Basic earnings (loss) per common share (in dollars per share)		$ 0.27	$ 0.08	$ 0.20	$ 0.20	$ 0.18	$ 0.38	$ 0.19		$ 0.96	$ 0.55
Diluted earnings (loss) per common share (in dollars per share)		$ 0.26	$ 0.08	$ 0.20	$ 0.20	$ 0.18	$ 0.37	$ 0.18		$ 0.92	$ 0.54
Comprehensive income										$ 60,649	$ 36,520
Deferred tax assets					$ 14,362					14,362	4,236
Assets					1,062,881					1,062,881	1,085,776
Additional paid-in capital					456,791					456,791	415,056
Retained earnings					574,930					574,930	502,346
Total stockholders’ equity					682,681					682,681	665,013
Total equity					682,681					682,681	665,013
Total liabilities and equity					$ 1,062,881					$ 1,062,881	$ 1,085,776