Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 6,007	$ 9,976
Unrealized gain (loss) on available-for-sale investment securities, net of taxes of $35 and $(5) for the three months ended June 30, 2012 and 2011	65	(9)
Foreign currency translation adjustments	(5,100)	1,509
Total comprehensive income	$ 972	$ 11,476