Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Comprehensive income (loss) (pretax):
Pretax earnings (loss)	$ 338,695	$ 445,399
Comprehensive income (loss) (tax effect):
Income tax expense	(81,857)	(107,054)
Comprehensive income (loss) (net of tax):
Net earnings	256,838	338,345
Other comprehensive income (loss):
Foreign currency translation (pretax)	469	197
Foreign currency translation (tax effect)	0	0
Foreign currency translation (net of tax)	469	197
Unrealized gain (loss) on investments (pretax)	25,543	(173,046)
Unrealized gain (loss) on investments (tax effect)	(5,199)	36,664
Unrealized gain (loss) on investments (net of tax)	20,344	(136,382)
Change in fair value of cash flow hedges (pretax)	5,093	170
Change in fair value of cash flow hedges (tax effect)	(1,251)	(42)
Change in fair value of cash flow hedges (net of tax)	3,842	128
Amounts reclassifed into earnings on hedging activities (pretax)	(1,150)	566
Amounts reclassified into earnings on hedging activities (tax effect)	282	(139)
Amounts reclassified into earnings on hedging activities (net of tax)	(868)	427
Total other comprehensive income (loss) (pretax)	29,955	(172,113)
Total other comprehensive income (loss) (tax effect)	(6,168)	36,483
Total other comprehensive income (loss) (net of tax)	23,787	(135,630)
Total comprehensive income (pretax)	368,650	273,286
Total comprehensive income (tax effect)	(88,025)	(70,571)
Total comprehensive income (net of tax)	$ 280,625	$ 202,715