Pension Plan - Summary of Pension Expense Composed of Components Included in Cost of Goods Sold and Selling, General and Administrative Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2018	Aug. 31, 2017
Components of net periodic benefit cost
Service cost	$ 276	$ 270	$ 553	$ 541
Interest cost	569	567	1,137	1,135
Expected return on plan assets	(1,027)	(948)	(2,054)	(1,897)
Amortization of:
Unrecognized net loss	512	511	1,023	1,021
Net periodic benefit cost	$ 330	$ 400	$ 659	$ 800