Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 7,648	$ 30,306	$ 36,647
Unrealized gain (loss) on available-for-sale investment securities, net of taxes of $68 in 2013, $(30) in 2012 and $(22) in 2011	128	(55)	(40)
Changes in defined benefit plan accumulated net actuarial income (loss), net of taxes, $418 in 2013, $415 in 2012 and $577 in 2011	(1,821)	(1,369)	1,089
Foreign currency translation adjustments	(3,490)	(4,249)	4,834
Total comprehensive income	$ 2,465	$ 24,633	$ 42,530