Retirement and Postretirement Benefit Plans - Components of Net Periodic Benefit Cost and Changes Recognized Other Comprehensive Income, Postretirement Benefit Plan (Detail) - Postretirement Benefit Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Feb. 29, 2016	Feb. 28, 2015	Feb. 28, 2014
Components of net periodic benefit cost:
Service cost	$ 335	$ 368	$ 431
Interest cost	2,028	2,545	2,397
Expected return on plan assets	(2,687)	(2,882)	(3,067)
Amortization of prior service credit	(699)	(1,304)	(1,303)
Amortization of actuarial gain	(1,702)	(1,435)	(1,043)
Defined benefit plan, net periodic benefit cost, total	(2,725)	(2,708)	(2,585)
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Actuarial gain	(2,777)	(3,818)	(1,659)
Amortization of actuarial gain	1,702	1,435	1,043
Amortization of prior service credit	699	1,304	1,303
Total recognized in other comprehensive income	(376)	(1,079)	687
Total recognized in net periodic benefit cost and other comprehensive income	$ (3,101)	$ (3,787)	$ (1,898)