UNAUDITED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Excluding Life Funds Withheld Assets	Life Funds Withheld Assets	Common Shares	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Excluding Life Funds Withheld Assets	Accumulated Other Comprehensive Income (Loss) Life Funds Withheld Assets	Retained Earnings (Deficit)	Non-controlling Interest in Equity of Consolidated Subsidiaries
Balance, beginning of year at Dec. 31, 2015				$ 2,947	$ 8,910,167	$ 686,616			$ 2,077,349	$ 1,977,384
Issuance of common shares				16	23
Buybacks of common shares				(262)	(790,541)				(115,334)
Exercise of stock options				3
Exercise of stock options					5,731
Share-based compensation					39,761				(3,595)
Change in net unrealized gains (losses) on investments, net of tax		$ 530,344	$ 206,480				$ 530,344	$ 206,480
Change in adjustments related to future policy benefit reserves, net of tax	$ 27,820					27,820
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	(31,091)					(31,091)
Change in OTTI losses recognized in other comprehensive income, net of tax	5,580					5,580
Change in underfunded pension liability, net of tax	3,088					3,088
Change in value of cash flow hedge	(134)					(134)
Foreign currency translation adjustments, net of tax	91,102					91,102
Net income (loss) attributable to common shareholders	136,268								136,268
Dividends on common shares									(170,172)
Non-controlling interests - contributions										6,393
Non-controlling interests - distributions										(7,958)
Non-controlling interests - redeemed										0
Non-controlling interests										5,916
Non-controlling interest share in change in accumulated other comprehensive income (loss)										(1,021)
Balance, end of year at Sep. 30, 2016	13,592,880			2,704	8,165,141	1,519,805			1,924,516	1,980,714
Balance, beginning of year at Dec. 31, 2016	12,960,679			2,669	8,068,503	715,546			2,151,794	2,022,167
Issuance of common shares				11	18
Buybacks of common shares	(571,500)			(138)	(416,609)				(154,839)
Exercise of stock options				18
Exercise of stock options					49,622
Share-based compensation					40,011				(6,153)
Change in net unrealized gains (losses) on investments, net of tax		$ 258,923	$ (46,643)				$ 258,923	$ (46,643)
Change in adjustments related to future policy benefit reserves, net of tax	13,981					13,981
Change in net unrealized gains (losses) on affiliate and other investments, net of tax	(15,391)					(15,391)
Change in OTTI losses recognized in other comprehensive income, net of tax	4,660					4,660
Change in underfunded pension liability, net of tax	(1,241)					(1,241)
Change in value of cash flow hedge	(144)					(144)
Foreign currency translation adjustments, net of tax	39,237					39,237
Net income (loss) attributable to common shareholders	(589,226)								(589,226)
Dividends on common shares									(174,762)
Non-controlling interests - contributions										49,473
Non-controlling interests - distributions										(26,092)
Non-controlling interests - redeemed										(431,282)
Non-controlling interests										(25,953)
Non-controlling interest share in change in accumulated other comprehensive income (loss)										350
Balance, end of year at Sep. 30, 2017	$ 11,528,510			$ 2,560	$ 7,741,545	$ 968,928			$ 1,226,814	$ 1,588,663