Pension Plan (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012	Nov. 30, 2011
Components of net periodic benefit cost
Service cost	$ 322	$ 304	$ 963	$ 911
Interest cost	600	631	1,801	1,892
Expected return on plan assets	(802)	(804)	(2,406)	(2,411)
Amortization of:
Prior service cost	(37)	(36)	(109)	(108)
Unrecognized net loss	456	315	1,368	946
Net periodic benefit cost	$ 539	$ 410	$ 1,617	$ 1,230