Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Current income tax expense:
Current income tax expense, Federal	$ 15,826	$ 10,585	$ 13,197
Current income tax expense, State	2,266	1,421	1,268
Current income tax expense, Foreign	1,035	1,032	1,104
Current income tax expense, Total	19,127	13,038	15,569
Deferred income tax expense (benefit), Federal	5,161	5,603	2,967
Deferred income tax expense (benefit), State	320	44	492
Deferred income tax expense (benefit), Foreign	(1,481)	(195)	0
Deferred income tax expense (benefit), Total	4,000	5,452	3,459
Income tax expense (benefit), Total	$ 23,127	$ 18,490	$ 19,028