Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Corporate Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		$ 1,272,253		$ 1,226,970	$ 1,310,427
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(6,719)		10,022	(32,452)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		408,995		312,720	243,871	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		(89,248)		(60,399)	3,949	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(285,958)		(195,016)	279,495	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		47,360		14,098	15,455
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		12,973		28,987	(20,556)
Fair Value, Asset Value, End of period		1,337,272		1,272,253	1,226,970
Canadian Provincial Governments [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		475,965		416,076	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		104,797		47,692	70,144
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	343,144
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0	0
Fair Value, Asset Value, End of period		593,942		475,965	416,076
Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		160,291		330,649	188,094
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		2,341		(1,621)	(944)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		76,792		103,553	249,208	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		(28,043)		(167,684)	985	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(18,988)		(38,495)	39,494	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		9,100		1,728	2,853
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		93,994		65,091	(66,113)
Fair Value, Asset Value, End of period		107,882		160,291	330,649
Asset-backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		219,280		303,836	572,960
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		7,044		(2,696)	(2,490)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		45,215		138,522	229,220	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0		(38,681)	13,105	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(87,328)		(61,770)	98,918	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		85,152		56,105	13,542
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		147,910		177,938	(402,707)
Fair Value, Asset Value, End of period		123,474		219,280	303,836
US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		24,488		26,265	28,529
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		19		39	(602)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		465	[1]	508	544	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		2,000	[1]	(1,837)	1,925	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0		0	0
Fair Value, Asset Value, End of period		22,511		24,488	26,265
US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		41,666		38,342	42,711
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(15)		962	(3,055)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0	[1]	6,952	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		843	[1]	(599)	492	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		7,294		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(6,844)		4,206	(835)
Fair Value, Asset Value, End of period		41,203		41,666	38,342
Foreign Government Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		12,869		14,065	19,663
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(252)		110	(7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		496	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0	[1]	0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		672	[1]	(1,306)	1,258	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(7,348)		0	(4,333)
Fair Value, Asset Value, End of period		5,092		12,869	14,065
Commercial Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		21,145		68,563	86,746
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(71)		(5,887)	(337)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0	[1]	1,545	42	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		3,720	[1]	(41,143)	6,153	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		5,404	[1]	(552)	7,226	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		1,302		0	12,828
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(10,132)		2,182	(15,417)
Fair Value, Asset Value, End of period		3,234		21,145	68,563
Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		(22,529)		(76,698)	22,094
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					0
Fair Value, Asset Value, End of period		122,194		(22,529)	(76,698)
Nonredeemable Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period				0	7,904
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)					(412)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]				4,529
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales					0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					(12,021)
Fair Value, Asset Value, End of period					0
Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		26,958		14,996	7,727
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		4,343		(1,133)	(959)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					0
Fair Value, Asset Value, End of period		40,659		26,958	14,996
Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		3,346		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		11		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	3,703		3,365
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	335		19
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		(3,629)		0
Fair Value, Asset Value, End of period		3,096		3,346	0
Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales		0		0	0
Fair Value, Liability Value, Beginning of period		990,308		1,070,584	1,085,166
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases		(55,237)		(12,725)	42,798	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		79,213		74,458	71,131	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3					0
Fair Value, Liability Value, End of period		1,014,228		990,308	1,070,584
Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales		0		0	0
Fair Value, Liability Value, Beginning of period		(2,462)		2,619	(797)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases		0		0	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		1,700		329	0	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3					0
Fair Value, Liability Value, End of period		(1,683)		(2,462)	2,619
Investment Income [Member] | Corporate Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(1,429)		(2,399)	(3,517)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(1,457)		(2,343)	(3,396)
Investment Income [Member] | Canadian Provincial Governments [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		13,180		12,197	2,788
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		13,180		12,197	2,788
Investment Income [Member] | Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(346)		(595)	(1,754)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(196)		(158)	(1,753)
Investment Income [Member] | Asset-backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		1,776		801	4,526
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		669		734	2,465
Investment Income [Member] | US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(461)		(487)	(48)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(461)		(487)	(48)
Investment Income [Member] | US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(55)		215	32
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(54)		215	32
Investment Income [Member] | Foreign Government Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(1)		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(1)		0	0
Investment Income [Member] | Commercial Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		709		1,677	2,817
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		1,552	2,718
Investment Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0
Investment Related Gains Losses [Member] | Corporate Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		4,991		(4,756)	(2,814)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(5,389)		(817)	(2,278)
Investment Related Gains Losses [Member] | Canadian Provincial Governments [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		729		(2,153)	(216)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(346)		(231)	0
Investment Related Gains Losses [Member] | Asset-backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		245		1,101	808
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | US Treasury and Government [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	(233)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Investment Related Gains Losses [Member] | US States and Political Subdivisions Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	(19)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Investment Related Gains Losses [Member] | Foreign Government Debt Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Investment Related Gains Losses [Member] | Commercial Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(595)		(876)	(4,737)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					(3,593)
Investment Related Gains Losses [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		144,723		54,169	(98,792)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		144,723		54,169	(98,792)
Investment Related Gains Losses [Member] | Nonredeemable Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings					0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Investment Related Gains Losses [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Investment Related Gains Losses [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0
Investment Related Gains Losses [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(32,166)		(7,834)	33,191
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		23,472		(4,579)	(43,496)
Investment Related Gains Losses [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Nonredeemable Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings					0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Interest Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Interest Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		80,062		(10,709)	(19,440)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(159,276)		(63,748)	(51,691)
Interest Income [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0		0	0
Other Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0			0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0			0
Other Income [Member] | Nonredeemable Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings					0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)					0
Other Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		9,358		13,095	8,228
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		9,358		13,095	8,228
Other Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0		0	0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0			0
Other Income [Member] | Mortality Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(921)		172	(1,822)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ (921)		$ (172)	$ 1,822

[1] The amount reported within purchases, sales and settlements is the purchase price (for purchases) and the sales/settlement proceeds (for sales and settlements) based upon the actual date purchased or sold/settled. Items purchased and sold/settled in the same period are excluded from the rollforward. The Company had no issuances during the period.