Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Comprehensive income (loss) (pretax):
Pretax earnings	$ 278,991	$ 287,095	$ 512,122	$ 556,103
Comprehensive income (loss) (tax effect):
Net earnings (Tax)	(102,516)	(103,716)	(188,474)	(201,439)
Comprehensive income (loss) (net of tax):
Net earnings	176,475	183,379	323,648	354,664
Other comprehensive income (loss):
Foreign currency translation (pretax)	(1,704)	(13,098)	(1,982)	(10,565)
Foreign currency translation (tax effect)
Foreign currency translation (net of tax)	(1,704)	(13,098)	(1,982)	(10,565)
Unrealized gain (loss) on investments (pretax)	30,790	(31,625)	60,618	(20,972)
Unrealized gain (loss) on investments (tax effect)	(10,777)	11,069	(21,217)	7,341
Unrealized gain (loss) on investments (net of tax)	20,013	(20,556)	39,401	(13,631)
Change in fair value of cash flow hedges (pretax)	3,105	1,235	5,186	4,605
Change in fair value of cash flow hedges (tax effect)	(1,179)	(469)	(1,970)	(1,750)
Change in fair value of cash flow hedges (net of tax)	1,926	766	3,216	2,855
Total comprehensive income (loss) (pretax)	311,182	243,607	575,944	529,171
Total comprehensive income (loss) (tax effect)	(114,472)	(93,116)	(211,661)	(195,848)
Total comprehensive income (loss) (net of tax)	$ 196,710	$ 150,491	$ 364,283	$ 333,323