Share Repurchase Programs - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended		50 Months Ended
	Oct. 31, 2018	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Aug. 31, 2014
Class of Stock [Line Items]
Amount authorized to be repurchased under share repurchase programs							$ 370,000,000
Total shares repurchased, value		$ 327,100,000		$ 327,100,000		$ 327,100,000
Amount remaining in program		$ 42,900,000		$ 42,900,000		42,900,000
Shares repurchased during period (in shares)		0	0	0	0
Convertible Senior Notes Due 2020
Class of Stock [Line Items]
Aggregate principal amount of debt repurchased		$ 75,300,000		$ 75,300,000		75,300,000
Aggregate purchase price		57,200,000		57,200,000		57,200,000
Accrued interest		$ 300,000		$ 300,000		$ 300,000
Subsequent Event
Class of Stock [Line Items]
Approved extension of remaining repurchase program	2 years
Common Stock
Class of Stock [Line Items]
Number of shares repurchased (in shares)						8,064,325
Convertible Notes
Class of Stock [Line Items]
Number of shares repurchased (in shares)						75,311