Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Comprehensive income (loss) (pretax):
Pretax earnings (loss)	$ 441,056	$ 454,750
Comprehensive income (loss) (tax effect):
Income tax expense	(107,054)	(109,575)
Comprehensive income (loss) (net of tax):
Net earnings	334,002	345,175
Other comprehensive income (loss):
Foreign currency translation (pretax)	197	(3,392)
Foreign currency translation (tax effect)	0	0
Foreign currency translation (net of tax)	197	(3,392)
Unrealized gain (loss) on investments (pretax)	(173,046)	(92,451)
Unrealized gain (loss) on investments (tax effect)	36,664	19,424
Unrealized gain (loss) on investments (net of tax)	(136,382)	(73,027)
Change in fair value of cash flow hedges (pretax)	170	(68)
Change in fair value of cash flow hedges (tax effect)	(42)	17
Change in fair value of cash flow hedges (net of tax)	128	(51)
Amounts reclassifed into earnings on hedging activities (pretax)	566	987
Amounts reclassified into earnings on hedging activities (tax effect)	(139)	(242)
Amounts reclassified into earnings on hedging activities (net of tax)	427	745
Total other comprehensive income (loss) (pretax)	(172,113)	(94,924)
Total other comprehensive income (loss) (tax effect)	36,483	19,199
Total other comprehensive income (loss) (net of tax)	(135,630)	(75,725)
Total comprehensive income (pretax)	268,943	359,826
Total comprehensive income (tax effect)	(70,571)	(90,376)
Total comprehensive income (net of tax)	$ 198,372	$ 269,450