CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 58,339	$ 158,617
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (2017 - $86,469; 2016 - $235,285)	160,585	436,956
Reclassification adjustment for investment amounts included in net income, net of income tax: (2017 - $(1,498); 2016 - $(1,022))	(2,782)	(1,897)
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: (2017 - $1,994; 2016 - $159)	3,701	294
Change in accumulated (loss) gain - derivatives, net of income tax: (2017 - $(362); 2016 - $0)	(672)	0
Reclassification adjustment for derivative amounts included in net income, net of income tax: (2017 - $72; 2016 - $0)	133	0
Total other comprehensive income	160,965	435,353
Total comprehensive income	$ 219,304	$ 593,970