Acquisitions - Additional Information (Detail)			3 Months Ended								4 Months Ended	12 Months Ended
	Sep. 29, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jan. 31, 2016 USD ($)	Oct. 31, 2015 USD ($)	Jul. 31, 2015 USD ($)	Apr. 30, 2015 USD ($)	Jan. 31, 2015 USD ($)	Oct. 31, 2014 USD ($)	Jul. 31, 2014 USD ($)	Apr. 30, 2014 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2016 USD ($) Business	Jan. 31, 2015 USD ($)	Jan. 31, 2014 USD ($)
Business Acquisition [Line Items]
Number of businesses acquired | Business												2
Net income			$ 17,590,000	$ 10,482,000	$ 13,406,000	$ 12,982,000	$ 13,326,000	$ 10,258,000	$ 9,578,000	$ 7,221,000		$ 54,460,000	$ 40,383,000	$ 23,615,000
Total revenues			114,270,000	$ 106,921,000	$ 98,107,000	$ 89,923,000	$ 87,012,000	$ 83,825,000	$ 75,664,000	$ 66,721,000		$ 409,221,000	$ 313,222,000	$ 210,151,000
Zinc Ahead Inc [Member]
Business Acquisition [Line Items]
Business acquisition date												Sep. 29, 2015
Closing cash consideration for purchase	$ 119,935,000
Working capital adjustment, not yet paid	300,000											$ 339,000
Business acquisition deferred consideration	$ 10,000,000
Business acquisition deferred consideration payment period	3 years
Deferred consideration annual payment rate	33.33%
Business acquisition-related transaction costs			2,200,000								$ 2,200,000	$ 2,200,000
Net income											(8,000,000)
Total revenues											6,700,000
Qforma CrowdLink [Member]
Business Acquisition [Line Items]
Business acquisition date												Mar. 31, 2015
Closing cash consideration for purchase		$ 9,750,000
Business acquisition-related transaction costs			$ 400,000								$ 400,000	$ 400,000
Contingent cash payments												0
In-process research and development												$ 0
Maximum [Member]
Business Acquisition [Line Items]
Measurement Period For Goodwill Adjustment												1 year