Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Comprehensive income (loss) (pretax):
Pretax earnings (loss)	$ 256,392	$ 338,695
Comprehensive income (loss) (tax effect):
Income tax expense	(60,975)	(81,857)
Comprehensive income (loss) (net of tax):
Earnings available to common stockholders	195,417	256,838
Other comprehensive income (loss):
Foreign currency translation (pretax)	204	469
Foreign currency translation (net of tax)	204	469
Unrealized gain (loss) on investments (pretax)	7,465	25,543
Unrealized gain (loss) on investments (tax effect)	(2,052)	(5,199)
Unrealized gain (loss) on investments (net of tax)	5,413	20,344
Change in fair value of cash flow hedges (pre-tax)	2,526	5,093
Change in fair value of cash flow hedges (tax effect)	(621)	(1,251)
Change in fair value of cash flow hedges (net of tax)	1,905	3,842
Amounts reclassified into earnings on hedging activities (pre tax)	1,425	1,150
Amounts reclassified into earnings on hedging activities (tax effect)	(350)	(282)
Amounts reclassified into earnings on hedging activities (net of tax)	1,075	868
Other Comprehensive Income (Loss), before Tax	11,620	29,955
Other Comprehensive Income (Loss), Tax	3,023	6,168
Total other comprehensive income (loss) (net of tax)	8,597	23,787
Total comprehensive income (loss) (pretax)	244,772	368,650
Total comprehensive income (loss) (tax effect)	(57,952)	(88,025)
Total comprehensive income (loss) (net of tax)	$ 186,820	$ 280,625