Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Comprehensive income (loss) (pretax):
Net earnings	$ 179,048	$ 127,388
Comprehensive income (loss) (tax effect):
Net earnings	(66,080)	(46,819)
Comprehensive income (loss) (net of tax):
Net earnings	112,968	80,569
Other comprehensive income (loss):
Foreign currency translation (pretax)	(3,762)	(1,929)
Foreign currency translation (tax effect)	0	0
Foreign currency translation (net of tax)	(3,762)	(1,929)
Unrealized gain (loss) on investments (pretax)	89	1,873
Unrealized gain (loss) on investments (tax effect)	(68)	(580)
Unrealized gain (loss) on investments (net of tax)	21	1,293
Change in fair value of cash flow hedges (pretax)	10,196	(515)
Change in fair value of cash flow hedges (tax effect)	(3,874)	196
Change in fair value of cash flow hedges (net of tax)	6,322	(319)
Total comprehensive income (loss) (pretax)	185,571	126,817
Total comprehensive income (loss) (tax effect)	(70,022)	(47,203)
Total comprehensive income (loss) (net of tax)	$ 115,549	$ 79,614