Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Comprehensive income (loss) (pretax):
Pretax earnings (loss)	$ 454,750	$ 114,318
Comprehensive income (loss) (tax effect):
Income tax expense	(109,575)	(26,592)
Comprehensive income (loss) (net of tax):
Net earnings	345,175	87,726
Other comprehensive income (loss):
Foreign currency translation (pretax)	(3,392)	(2,917)
Foreign currency translation (tax effect)	0	0
Foreign currency translation (net of tax)	(3,392)	(2,917)
Unrealized gain (loss) on investments (pretax)	(92,451)	(58,962)
Unrealized gain (loss) on investments (tax effect)	19,424	13,463
Unrealized gain (loss) on investments (net of tax)	(73,027)	(45,499)
Change in fair value of cash flow hedges (pretax)	(68)	(705)
Change in fair value of cash flow hedges (tax effect)	17	173
Change in fair value of cash flow hedges (net of tax)	(51)	(532)
Amounts reclassifed into earnings on hedging activities (pretax)	987	747
Amounts reclassified into earnings on hedging activities (tax effect)	(242)	(183)
Amounts reclassified into earnings on hedging activities (net of tax)	745	564
Total other comprehensive income (loss) (pretax)	(94,924)	(61,837)
Total other comprehensive income (loss) (tax effect)	19,199	13,453
Total other comprehensive income (loss) (net of tax)	(75,725)	(48,384)
Total comprehensive income (pretax)	359,826	52,481
Total comprehensive income (tax effect)	(90,376)	(13,139)
Total comprehensive income (net of tax)	$ 269,450	$ 39,342