Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Condensed Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 20,777	$ 249,813	$ 76,062	$ 507,950
Other comprehensive income (loss):
Foreign currency translation gains (losses)	1,692	(7,917)	(6,502)	(5,116)
Pension liability adjustment, net of tax	(157)	840	3,360	2,382
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during the period, net of tax	(214)	(16,106)	795	(8,269)
Other comprehensive income (loss)	1,321	(23,183)	(2,347)	(11,003)
Comprehensive income	$ 22,098	$ 226,630	$ 73,715	$ 496,947