Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 2,357	$ 10,947	$ 8,364	$ 20,923
Unrealized gain (loss) on available-for-sale investment securities, net of taxes of $189 and $224 for the three and six months ended September 30, 2012 and net of taxes of $(43) and $(48) for the three and six months ended September 30, 2011	351	(80)	416	(89)
Foreign currency translation adjustments	2,433	(4,822)	(2,667)	(3,313)
Total comprehensive income	$ 5,141	$ 6,045	$ 6,113	$ 17,521