Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income	$ 21,588	$ 33,999	$ 61,252	$ 72,636
Foreign currency translation adjustment, net of tax	1,197	(107)	(17,956)	2,320
Total comprehensive income	$ 22,785	$ 33,892	$ 43,296	$ 74,956