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	$ 75,414	$ 115,348
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (2017 - $85,962; 2016 - $236,350)	159,641	438,936
Reclassification adjustment for investment amounts included in net income, net of income tax: (2017 - $(578); 2016 - $(1,028))	(1,072)	(1,910)
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 - $1,995; 2016 - $159)	3,703	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	161,733	437,320
Total comprehensive income	$ 237,147	$ 552,668