CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 165,105	$ 154,414	$ 239,070	$ 296,512
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (three and six months 2020 - $598,707 and $207,054; three and six months 2019 - $263,211 and $563,641)	2,252,281	990,177	778,919	2,120,367
Reclassification adjustment for investment amounts included in net income, net of income tax: (three and six months 2020 - $5,847 and $8,498; three and six months 2019 - $(76) and $(495))	21,994	(288)	31,966	(1,864)
Change in net unrealized gains (losses) for which a credit loss has been recognized in operations, net of income tax: (three and six months 2020 - $1,266 and $(469))	4,762		(1,767)
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 six months 2019 - $4,127 and $6,464)		15,524		24,316
Change in accumulated (loss) gain - derivatives, net of income tax: (three and six months 2020 - $594 and $(638); three and six months 2019 - $(742) and $(1,264))	2,235	(2,788)	(2,401)	(4,754)
Reclassification adjustment for derivative amounts included in net income, net of income tax: (three and six months 2020 - $308 and $561; three and six months 2019 - $70 and $128)	1,159	266	2,110	486
Total other comprehensive income	2,282,431	1,002,891	808,827	2,138,551
Total comprehensive income	$ 2,447,536	$ 1,157,305	$ 1,047,897	$ 2,435,063