CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 142,098	$ 18,275
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (2019 - $300,430; 2018 - $(152,130))	1,130,190	(573,016)
Reclassification adjustment for investment amounts included in net income, net of income tax: (2019 - $(419); 2018 - $181)	(1,576)	681
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: (2019 - $2,337; 2018 - $3)	8,792	11
Change in accumulated (loss) gain - derivatives, net of income tax: (2019 - $(522); 2018 - $129)	(1,966)
Change in accumulated (loss) gain - derivatives, net of income tax: (2019 - $(522); 2018 - $129)		487
Reclassification adjustment for derivative amounts included in net income, net of income tax: (2019 - $58; 2018 - $24)	(220)
Reclassification adjustment for derivative amounts included in net income, net of income tax: (2019 - $58; 2018 - $24)		89
Total other comprehensive income (loss)	1,135,660	(571,748)
Total comprehensive income (loss)	$ 1,277,758	$ (553,473)