Stockholders' Equity - Summary of Information about Employee and Director Stock Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Number outstanding	1,502,176
Options Outstanding, Weighted average remaining contractual terms (years)	3 years 11 months 5 days
Options Outstanding, Weighted average exercise price	$ 9.77
Options Exercisable, Number Exercisable	1,440,521
Options Exercisable, Weighted average exercise price	$ 9.90
Exercise Price Range One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 6.74
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 6.74
Options Outstanding, Number outstanding	224,421
Options Outstanding, Weighted average remaining contractual terms (years)	4 years 11 months 16 days
Options Outstanding, Weighted average exercise price	$ 6.74
Options Exercisable, Number Exercisable	166,099
Options Exercisable, Weighted average exercise price	$ 6.74
Exercise Price Range Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 7.00
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 8.15
Options Outstanding, Number outstanding	11,500
Options Outstanding, Weighted average remaining contractual terms (years)	3 years 1 month 28 days
Options Outstanding, Weighted average exercise price	$ 7.69
Options Exercisable, Number Exercisable	8,167
Options Exercisable, Weighted average exercise price	$ 7.69
Exercise Price Range Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 8.22
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 8.22
Options Outstanding, Number outstanding	875,000
Options Outstanding, Weighted average remaining contractual terms (years)	5 years 2 months 27 days
Options Outstanding, Weighted average exercise price	$ 8.22
Options Exercisable, Number Exercisable	875,000
Options Exercisable, Weighted average exercise price	$ 8.22
Exercise Price Range Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 11.56
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 14.47
Options Outstanding, Number outstanding	193,980
Options Outstanding, Weighted average remaining contractual terms (years)	5 months 12 days
Options Outstanding, Weighted average exercise price	$ 13.29
Options Exercisable, Number Exercisable	193,980
Options Exercisable, Weighted average exercise price	$ 13.29
Exercise Price Range Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 15.52
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 15.84
Options Outstanding, Number outstanding	84,313
Options Outstanding, Weighted average remaining contractual terms (years)	1 month 6 days
Options Outstanding, Weighted average exercise price	$ 15.62
Options Exercisable, Number Exercisable	84,313
Options Exercisable, Weighted average exercise price	$ 15.62
Exercise Price Range Six [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 16.04
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 16.04
Options Outstanding, Number outstanding	2,500
Options Outstanding, Weighted average remaining contractual terms (years)	7 months 28 days
Options Outstanding, Weighted average exercise price	$ 16.04
Options Exercisable, Number Exercisable	2,500
Options Exercisable, Weighted average exercise price	$ 16.04
Exercise Price Range Seven [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 16.56
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 16.56
Options Outstanding, Number outstanding	5,000
Options Outstanding, Weighted average remaining contractual terms (years)	1 year 4 days
Options Outstanding, Weighted average exercise price	$ 16.56
Options Exercisable, Number Exercisable	5,000
Options Exercisable, Weighted average exercise price	$ 16.56
Exercise Price Range Eight [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 17.26
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 17.26
Options Outstanding, Number outstanding	5,000
Options Outstanding, Weighted average remaining contractual terms (years)	11 months 12 days
Options Outstanding, Weighted average exercise price	$ 17.26
Options Exercisable, Number Exercisable	5,000
Options Exercisable, Weighted average exercise price	$ 17.26
Exercise Price Range Nine [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 17.39
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 17.39
Options Outstanding, Number outstanding	89,462
Options Outstanding, Weighted average remaining contractual terms (years)	9 months
Options Outstanding, Weighted average exercise price	$ 17.39
Options Exercisable, Number Exercisable	89,462
Options Exercisable, Weighted average exercise price	$ 17.39
Exercise Price Range Ten [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Range of exercise prices, Lower Range Limit	$ 19.98
Options Outstanding, Range of exercise prices, Upper Range Limit	$ 19.98
Options Outstanding, Number outstanding	11,000
Options Outstanding, Weighted average remaining contractual terms (years)	1 year 7 months 21 days
Options Outstanding, Weighted average exercise price	$ 19.98
Options Exercisable, Number Exercisable	11,000
Options Exercisable, Weighted average exercise price	$ 19.98