CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 59,762	$ 190,424	$ 298,832	$ 486,936
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (three and nine months 2020 - $127,602 and $334,656; three and nine months 2019 - $226,235 and $789,876)	480,024	851,075	1,258,943	2,971,442
Reclassification adjustment for investment amounts included in net income, net of income tax: (three and nine months 2020 - $7,513 and $16,011; three and nine months 2019 - $(1,022) and $(1,517))	28,265	(3,846)	60,231	(5,710)
Change in net unrealized gains (losses) for which a credit loss has been recognized in operations, net of income tax: (three and nine months 2020 - $7,290 and $6,821)	27,426	0	25,659	0
Change in net unrealized gains (losses) relating to other-than-temporary impaired investments for which a portion has been recognized in earnings, net of income tax: (three and nine months 2019 - $(5,318) and $1,146)	0	(20,008)	0	4,308
Change in accumulated (loss) gain - derivatives, net of income tax: (three and nine months 2020 - $405 and $(233); three and nine months 2019 - $(893) and $(2,157))	1,524	(3,362)	(877)	(8,116)
Reclassification adjustment for derivative amounts included in net income, net of income tax: (three and nine months 2020 - $84 and $645; three and nine months 2019 - $157 and $285)	317	589	2,427	1,075
Total other comprehensive income	537,556	824,448	1,346,383	2,962,999
Total comprehensive income	$ 597,318	$ 1,014,872	$ 1,645,215	$ 3,449,935