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	AOCI Attributable to Parent [Member]	AOCI Attributable to Parent [Member] Excluding Life Funds Withheld Assets	AOCI Attributable to Parent [Member] Life Funds Withheld Assets	Retained Earnings (Deficit)	Non-controlling Interest in Equity of Consolidated Subsidiaries
Balance, beginning of year at Dec. 31, 2016					$ 2,669	$ 8,068,503	$ 715,546			$ 2,151,794	$ 2,022,167
Issuance of common shares					10
Buybacks of common shares					(51)	(154,065)				(46,372)
Exercise of stock options					9
Exercise of stock options						23,287
Share-based compensation						(3,564)				(5,782)
Reclassification due to adoption of new accounting pronouncement | Accounting Standards Update 2016-01							0			0
Reclassification due to adoption of new accounting pronouncement | Accounting Standards Update 2018-02							0			0
Change in net unrealized gains (losses) on investments AFS, net of tax			$ 102,622	$ (20,108)				$ 102,622	$ (20,108)
Change in adjustments related to future policy benefit reserves, net of tax	$ 5,132						5,132
Change in net unrealized gains (losses) on affiliate investments, net of tax	(2,462)						(2,462)
Change in net unrealized gains (losses) on other investments, net of tax	1,269						1,269
Change in OTTI losses recognized in other comprehensive income, net of tax	1,442						1,442
Change in underfunded pension liability, net of tax	(357)						(357)
Change in value of cash flow hedge	(48)						(48)
Foreign currency translation adjustments, net of tax	41,938						41,938
Net income (loss) attributable to common shareholders	152,843									152,843
Dividends on common shares										(59,371)
Non-controlling interests - contributions											25
Non-controlling interests											3,036
Non-controlling interest share in change in accumulated other comprehensive income (loss)											514
Balance, end of year at Mar. 31, 2017	13,000,626				2,637	7,934,161	844,974			2,193,112	2,025,742
Balance, beginning of year at Dec. 31, 2017	11,461,320				2,560	7,757,940	889,431			1,198,386	1,613,003
Issuance of common shares					7
Buybacks of common shares					0	(1,191)				(471)
Exercise of stock options					15
Exercise of stock options						48,163
Share-based compensation						4,983				(7,075)
Reclassification due to adoption of new accounting pronouncement | Accounting Standards Update 2016-01	(221,856)	[1]					(221,856)			221,856
Reclassification due to adoption of new accounting pronouncement | Accounting Standards Update 2018-02	3,903						3,903			(3,903)
Change in net unrealized gains (losses) on investments AFS, net of tax			$ (330,728)	$ (35,754)				$ (330,728)	$ (35,754)
Change in adjustments related to future policy benefit reserves, net of tax	4,164						4,164
Change in net unrealized gains (losses) on affiliate investments, net of tax	2,148						2,148
Change in net unrealized gains (losses) on other investments, net of tax	0						0
Change in OTTI losses recognized in other comprehensive income, net of tax	3,616						3,616
Change in underfunded pension liability, net of tax	(189)						(189)
Change in value of cash flow hedge	(48)						(48)
Foreign currency translation adjustments, net of tax	(2,432)						(2,432)
Net income (loss) attributable to common shareholders	152,648									152,648
Dividends on common shares										(57,644)
Non-controlling interests - contributions											438
Non-controlling interests											(7,361)
Non-controlling interest share in change in accumulated other comprehensive income (loss)											613
Balance, end of year at Mar. 31, 2018	$ 11,235,222				$ 2,582	$ 7,809,895	$ 312,255			$ 1,503,797	$ 1,606,693

[1] The reclassification out of AOCI due to the adoption of ASU 2016-01 includes $233.8 million of net unrealized gains less $11.9 million of deferred tax on net unrealized gains as discussed in Note 1(b), "Significant Accounting Policies - Recent Accounting Pronouncements."