CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 100,626	$ 110,100	$ 347,021	$ 265,707
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (three and nine months 2019 - $227,013 and $793,599; three and nine months 2018 - $(53,488) and $(320,520))	854,000	(201,216)	2,985,443	(1,206,478)
Reclassification adjustment for investment amounts included in net income, net of income tax: (three and nine months 2019 - $(1,022) and $(1,521); three and nine months 2018 - $427 and $(554))	(3,846)	1,605	(5,722)	(2,086)
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; three and nine months 2018 - $— and $6)	(20,008)	0	4,308	22
Change in accumulated (loss) gain - derivatives, net of income tax: (three and nine months 2019 - $(893) and $(2,157); three and nine months 2018 - $61 and $813)	(3,362)		(8,116)
Change in accumulated (loss) gain - derivatives, net of income tax: (three and nine months 2019 - $(893) and $(2,157); three and nine months 2018 - $61 and $813)		229		3,060
Reclassification adjustment for derivative amounts included in net income, net of income tax: (three and nine months 2019 - $157 and $285; three and nine months 2018 - $101 and $168)	589		1,075
Reclassification adjustment for derivative amounts included in net income, net of income tax: (three and nine months 2019 - $157 and $285; three and nine months 2018 - $101 and $168)		380		631
Total other comprehensive income (loss)	827,373	(199,002)	2,976,988	(1,204,851)
Total comprehensive income (loss)	$ 927,999	$ (88,902)	$ 3,324,009	$ (939,144)