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		9 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Components of net periodic benefit cost
Service cost	$ 271	$ 292	$ 812	$ 875
Interest cost	567	593	1,702	1,779
Expected return on plan assets	(948)	(917)	(2,845)	(2,749)
Amortization of:
Unrecognized net loss	510	671	1,531	2,012
Net periodic benefit cost	$ 400	$ 639	$ 1,200	$ 1,917