CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 18,275	$ 58,339
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of income tax: (2018 - $(152,130); 2017 - $86,469)	(573,016)	160,585
Reclassification adjustment for investment amounts included in net income, net of income tax: (2018 - $181; 2017 - $(1,498))	681	(2,782)
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: (2018 - $3; 2017 - $1,994)	11	3,701
Change in accumulated (loss) gain - derivatives, net of income tax: (2018 - $129; 2017 - $(362))	487	(672)
Reclassification adjustment for derivative amounts included in net income, net of income tax: (2018 - $24; 2017 - $72)	89	133
Total other comprehensive income (loss)	(571,748)	160,965
Total comprehensive income (loss)	$ (553,473)	$ 219,304