Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Comprehensive income (loss) (pretax):
Pretax earnings	$ 132,495	$ 107,433	$ 688,598	$ 549,362
Comprehensive income (loss) (tax effect):
Net earnings (Tax)	(50,726)	(40,893)	(252,165)	(202,101)
Comprehensive income (loss) (net of tax):
Net earnings	81,769	66,540	436,433	347,261
Other comprehensive income (loss):
Foreign currency translation (pretax)	$ (6,727)	$ (3,213)	$ (17,292)	$ (6,752)
Foreign currency translation (tax effect)
Foreign currency translation (net of tax)	$ (6,727)	$ (3,213)	$ (17,292)	$ (6,752)
Unrealized gain (loss) on investments (pretax)	1,025	(2,959)	(19,947)	44,183
Unrealized gain (loss) on investments (tax effect)	(359)	1,036	6,982	(15,464)
Unrealized gain (loss) on investments (net of tax)	666	(1,923)	(12,965)	28,719
Change in fair value of cash flow hedges (pretax)	4,353	1,582	8,958	7,419
Change in fair value of cash flow hedges (tax effect)	(1,654)	(602)	(3,404)	(2,820)
Change in fair value of cash flow hedges (net of tax)	2,699	980	5,554	4,599
Total comprehensive income (loss) (pretax)	131,146	102,843	660,317	594,212
Total comprehensive income (loss) (tax effect)	(52,739)	(40,459)	(248,587)	(220,385)
Total comprehensive income (loss) (net of tax)	$ 78,407	$ 62,384	$ 411,730	$ 373,827