Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Comprehensive income (loss) (pretax):
Pretax earnings (loss)	$ 463,639	$ 538,876	$ 904,695	$ 993,626
Comprehensive income (loss) (tax effect):
Income tax expense	(111,624)	(128,978)	(218,678)	(238,553)
Comprehensive income (loss) (net of tax):
Net earnings	352,015	409,898	686,017	755,073
Other comprehensive income (loss):
Foreign currency translation (pretax)	(739)	992	(542)	(2,400)
Foreign currency translation (tax effect)	0	0	0	0
Foreign currency translation (net of tax)	(739)	992	(542)	(2,400)
Unrealized gain (loss) on investments (pretax)	(137,836)	52,525	(310,882)	(39,926)
Unrealized gain (loss) on investments (tax effect)	29,392	(11,143)	66,056	8,281
Unrealized gain (loss) on investments (net of tax)	(108,444)	41,382	(244,826)	(31,645)
Change in fair value cash flow hedges (pretax)	8,336	(74)	8,506	(142)
Change in fair value of cash flow hedges (tax effect)	(2,047)	18	(2,089)	35
Change in fair value of cash flow hedges, (net of tax)	6,289	(56)	6,417	(107)
Amounts reclassified into earnings on hedging activities (pre tax)	24	1,003	590	1,990
Amounts reclassified into earnings on hedging activities (tax effect)	(5)	(246)	(144)	(488)
Amounts reclassified into earnings on hedging activities (net of tax)	19	757	446	1,502
Total other comprehensive income (loss) (pretax)	(130,215)	54,446	(302,328)	(40,478)
Total other comprehensive income (loss) (tax effect)	27,340	(11,371)	63,823	7,828
Total other comprehensive income (loss) (net of tax)	(102,875)	43,075	(238,505)	(32,650)
Total comprehensive income (loss) (pretax)	333,424	593,322	602,367	953,148
Total comprehensive income (loss) (tax effect)	(84,284)	(140,349)	(154,855)	(230,725)
Total comprehensive income (loss) (net of tax)	$ 249,140	$ 452,973	$ 447,512	$ 722,423