Share-based payments (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 06, 2012	Jan. 29, 2016	Jan. 30, 2015	Jan. 31, 2014
Share-based payments
Number of shares of common stock authorized for grant		31,142,858
Shares available for future grants		18,556,241
Share-based compensation expense
Pre-tax		$ 38,547	$ 37,338	$ 20,961
Net of tax		23,513	22,780	12,765
Total unrecognized compensation cost		$ 48,200
Expected weighted average expense recognition period (in years)		1 year 8 months 12 days
Board members | Minimum
Share-based payments
Vesting period		1 year
Board members | Maximum
Share-based payments
Vesting period		3 years
Other stock option | Employee
Share-based payments
Vesting period		4 years
MSA Time Options
Options Issued
Balance, at the end of the period (in shares)		173,091
Exercisable at the end of the period (in shares)		173,091
Average Exercise Price
Balance at the end of the period (in dollars per share)		$ 20.36
Remaining Contractual Term
Balance, at the end of the period		3 years 9 months 18 days
Intrinsic Value
Balance at the end of the period		$ 9,500
Intrinsic value of options exercised		$ 6,600	6,800	39,400
MSA Performance Options
Options Issued
Balance, at the end of the period (in shares)		151,097
Exercisable at the end of the period (in shares)		151,097
Average Exercise Price
Balance at the end of the period (in dollars per share)		$ 21.23
Remaining Contractual Term
Balance, at the end of the period		3 years 10 months 24 days
Intrinsic Value
Balance at the end of the period		$ 8,100
Intrinsic value of options exercised		$ 4,900	$ 4,900	$ 39,100
Stock options
Weighted average for key assumptions used in determining the fair value
Expected dividend yield (as a percent)		1.20%	0.00%	0.00%
Expected stock price volatility (as a percent)		25.30%	25.60%	26.20%
Weighted average risk-free interest rate (as a percent)		1.80%	1.90%	1.20%
Expected term of options		6 years 4 months 24 days	6 years 3 months 18 days	6 years 3 months 18 days
Share-based compensation expense
Pre-tax		$ 11,113	$ 8,533	$ 7,634
Net of tax		$ 6,779	$ 5,206	$ 4,649
Stock options | Other stock option
Options Issued
Balance at the beginning of the period (in shares)		2,399,124
Granted (in shares)		1,247,557
Exercise of share-based awards (in shares)		(703,956)
Canceled (in shares)		(512,760)
Balance, at the end of the period (in shares)		2,429,965	2,399,124
Exercisable at the end of the period (in shares)		517,375
Average Exercise Price
Balance at the beginning of the period (in dollars per share)		$ 49.69
Granted (in dollars per share)		74.73
Exercised (in dollars per share)		45.66
Canceled (in dollars per share)		61.67
Balance at the end of the period (in dollars per share)		61.19	$ 49.69
Exercisable at the end of the period (in dollars per share)		$ 47.31
Remaining Contractual Term
Balance, at the end of the period		8 years 1 month 6 days
Exercisable at the end of the period		6 years 8 months 12 days
Intrinsic Value
Balance at the end of the period		$ 33,701
Exercisable at the end of the period		$ 14,355
Weighted average grant date fair value (in dollars per share)		$ 18.48	$ 17.26	$ 13.86
Intrinsic value of options exercised		$ 20,800	$ 2,500	$ 800
Stock options | MSA Time Options and MSA Performance Options
Share-based payments
Vesting period		5 years
Weighted average for key assumptions used in determining the fair value
Contractual term of options		10 years
Performance Share Units
Share-based payments
Vesting period		3 years
Weighted average grant date fair value of awards issued (in dollars per share)		$ 74.72	$ 57.91	$ 48.11
Intrinsic Value
Balance at the end of the period		$ 10,816
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)		212,583
Granted (in shares or rights)		103,666
Converted to common stock (in shares or rights)		(120,417)
Canceled (in shares or rights)		(51,735)
Awards outstanding at the end of the period (in shares or rights)		144,097	212,583
Share-based compensation expense
Pre-tax		$ 4,856	$ 5,461	$ 3,448
Net of tax		$ 2,962	$ 3,332	$ 2,100
Restricted Stock Units
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)		$ 74.67	$ 57.87	$ 48.20
Intrinsic Value
Balance at the end of the period		$ 48,107
Units Issued
Awards outstanding at the beginning of the period (in shares or rights)		714,858
Granted (in shares or rights)		383,134
Converted to common stock (in shares or rights)		(326,383)
Canceled (in shares or rights)		(130,699)
Awards outstanding at the end of the period (in shares or rights)		640,910	714,858
Share-based compensation expense
Pre-tax		$ 22,578	$ 15,968	$ 9,879
Net of tax		$ 13,772	9,742	$ 6,016
Restricted Stock Units | Employee
Share-based payments
Vesting period		3 years
Restricted Stock | Chairman and chief executive officer
Share-based payments
Weighted average grant date fair value of awards issued (in dollars per share)	$ 45.25
Units Issued
Granted (in shares or rights)	326,037
Share-based compensation expense
Pre-tax			7,376
Net of tax			$ 4,500