Investments (Tables)

12 Months Ended

Dec. 31, 2015

Available-for-sale Securities [Table Text Block]

The following tables provide information relating to investments in fixed maturity and equity securities by sector as of December 31, 2015 and 2014 (dollars in thousands):



December 31, 2015:	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value		% of Total		Other-than- temporary impairments in AOCI
Available-for-sale:
Corporate securities	$	17,575,507	$	599,718	$	467,069	$	17,708,156	59.7	%	$	—
Canadian and Canadian provincial governments	2,469,009		1,110,282		2,532		3,576,759		12.1		—
Residential mortgage-backed securities	1,277,998		45,152		11,673		1,311,477		4.4		(300		)
Asset-backed securities	1,219,000		12,052		18,376		1,212,676		4.1		354
Commercial mortgage-backed securities	1,456,848		37,407		11,168		1,483,087		5.0		(1,609		)
U.S. government and agencies	1,423,791		15,586		57,718		1,381,659		4.7		—
State and political subdivisions	480,067		40,014		9,067		511,014		1.7		—
Other foreign government, supranational and foreign government-sponsored enterprises	2,420,757		78,964		41,644		2,458,077		8.3		—
Total fixed maturity securities	$	28,322,977	$	1,939,175	$	619,247	$	29,642,905	100.0	%	$	(1,555	)
Non-redeemable preferred stock	$	85,645	$	7,837	$	5,962	$	87,520	69.5	%
Other equity securities	40,584		—		2,242		38,342		30.5
Total equity securities	$	126,229	$	7,837	$	8,204	$	125,862	100.0	%



December 31, 2014:	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value		% of Total		Other-than- temporary impairments in AOCI
Available-for-sale:
Corporate securities	$	14,010,604	$	965,523	$	90,544	$	14,885,583	58.4	%	$	—
Canadian and Canadian provincial governments	2,668,852		1,196,420		7		3,865,265		15.2		—
Residential mortgage-backed securities	991,867		52,640		6,611		1,037,896		4.1		(300		)
Asset-backed securities	1,059,660		20,301		10,375		1,069,586		4.2		354
Commercial mortgage-backed securities	1,453,657		87,593		8,659		1,532,591		6.0		(1,609		)
U.S. government and agencies	501,352		25,014		515		525,851		2.0		—
State and political subdivisions	378,457		51,117		3,498		426,076		1.7		—
Other foreign government, supranational and foreign government-sponsored enterprises	2,041,148		110,065		13,089		2,138,124		8.4		—
Total fixed maturity securities	$	23,105,597	$	2,508,673	$	133,298	$	25,480,972	100.0	%	$	(1,555	)
Non-redeemable preferred stock	$	93,540	$	7,350	$	1,527	$	99,363	78.3	%
Other equity securities	26,994		597		94		27,497		21.7
Total equity securities	$	120,534	$	7,947	$	1,621	$	126,860	100.0	%

Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block]

The following table includes fixed maturity securities pledged and received as collateral, and assets in trust held to satisfy collateral requirements under certain third-party reinsurance treaties as of December 31, 2015 and 2014 (dollars in thousands):



	2015				2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Fixed maturity securities pledged as collateral	$	169,678	$	176,782	$	127,229	$	134,863
Fixed maturity securities received as collateral	n/a		242,914		n/a		117,227
Securities held in trust	10,535,729		10,928,393		10,197,489		10,922,947

Concentration Risk Disclosure [Text Block]

The Company’s exposure to concentrations of credit risk of single issuers greater than 10% of the Company’s stockholders’ equity included securities of the U.S. government and its agencies as of December 31, 2015, as well as the securities disclosed below as of December 31, 2015 and 2014 (dollars in thousands).



	2015				2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Fixed maturity securities guaranteed or issued by:
Canadian province of Ontario	$	864,444	$	1,199,080	$	979,908	$	1,359,339
Canadian province of Quebec	943,484		1,525,903		1,006,315		1,599,673

Investments Classified By Contractual Maturity Date [Table Text Block]

Asset and mortgage-backed securities are shown separately in the table below, as they are not due at a single maturity date.



	Amortized Cost		Estimated Fair Value
Available-for-sale:
Due in one year or less	$	731,706	$	739,485
Due after one year through five years	5,615,811		5,763,489
Due after five years through ten years	8,290,362		8,408,708
Due after ten years	9,731,252		10,723,983
Asset and mortgage-backed securities	3,953,846		4,007,240
Total	$	28,322,977	$	29,642,905

Fixed Maturity Holdings Industry Types [Table Text Block]

The tables below show the major industry types of the Company’s corporate fixed maturity holdings as of December 31, 2015 and 2014 (dollars in thousands):



December 31, 2015:	Amortized Cost		Estimated Fair Value		% of Total
Finance	$	5,408,791	$	5,555,044	31.4	%
Industrial	10,211,426		10,129,917		57.2
Utility	1,955,290		2,023,195		11.4
Total	$	17,575,507	$	17,708,156	100.0	%

December 31, 2014:	Amortized Cost		Estimated Fair Value		% of Total
Finance	$	4,789,568	$	5,066,408	34.0	%
Industrial	7,639,330		8,086,067		54.3
Utility	1,581,706		1,733,108		11.7
Total	$	14,010,604	$	14,885,583	100.0	%

Roll Forward Of Cumulative Credit Loss Component Of Otti Income Loss [Table Text Block]

The following table sets forth the amount of pre-tax credit loss impairments on fixed maturity securities held by the Company as of the dates indicated, for which a portion of the OTTI loss was recognized in AOCI, and the corresponding changes in such amounts (dollars in thousands):



	2015		2014			2013
Balance, beginning of period	$	7,284	$	11,696		$	16,675
Additional impairments - credit loss OTTI recognized on securities previously impaired	—		—			134
Credit loss OTTI previously recognized on securities impaired to fair value during the period	—		—			(1,449		)
Credit loss previously recognized on securities which matured, paid down, prepaid or were sold during the period	—		(4,412		)	(3,664		)
Balance, end of period	$	7,284	$	7,284		$	11,696

AccountingForCertainLoansAndDebtSecuritiesAcquiredInTransferDisclosureTextBlock

The following tables present information on the Company’s purchased credit impaired securities, which are included in fixed maturity securities available-for-sale as of December 31, 2015 and 2014 (dollars in thousands):



	2015		2014
Outstanding principal and interest balance⁽¹⁾	$	343,640	$	226,121
Carrying value, including accrued interest⁽²⁾	$	287,663	$	185,842


(1)	Represents the contractually required payments which is the sum of contractual principal, whether or not currently due, and accrued interest.


(2)	Estimated fair value plus accrued interest.

Schedule Of Certain Loans Acquired In Transfer Accounted For As Available For Sale Debt Securities At Acquisition Date [Table Text Block]

The following table presents information about purchased credit impaired investments acquired during the periods ended December 31, 2015 and 2014, as of the acquisition dates (dollars in thousands).



	2015		2014
Contractually required payments (including interest)	$	217,187	$	96,617
Cash flows expected to be collected⁽¹⁾	$	179,025	$	76,551
Fair value of investments acquired	$	137,399	$	53,950


(1)	Represents undiscounted principal and interest cash flow expectations at the date of acquisition.

Schedule Of Certain Loans Acquired In Transfer Accounted For As Available For Sale Debt Securities Accretable Yield [Table Text Block]

The following table presents activity for the accretable yield on purchased credit impaired securities for the years ended December 31, 2015 and 2014 (dollars in thousands):



	2015			2014
Balance, beginning of period	$	67,171		$	69,469
Investments purchased	41,626			22,601
Accretion	(11,402		)	(9,339		)
Disposals	(1,109		)	(379		)
Reclassification from nonaccretable difference	(8,270		)	(15,181		)
Balance, end of period	$	88,016		$	67,171

Investments In Debt And Equity Securities Gross Unrealized Losses Disclosures [Table Text Block]

The following table presents the total gross unrealized losses for the 2,080 and 932 fixed maturity and equity securities at December 31, 2015 and 2014, respectively, where the estimated fair value had declined and remained below amortized cost by the indicated amount (dollars in thousands):



	2015				2014
	Gross Unrealized Losses		% of Total		Gross Unrealized Losses		% of Total
Less than 20%	$	463,109	73.8	%	$	111,965	83.0	%
20% or more for less than six months	142,495		22.7		13,698		10.1
20% or more for six months or greater	21,847		3.5		9,256		6.9
Total	$	627,451	100.0	%	$	134,919	100.0	%

Fair Value And Investments In Debt And Equity Securities Disclosures [Table Text Block]

These investments are presented by class and grade of security, as well as the length of time the related fair value has remained below amortized cost.



	Less than 12 months				12 months or greater				Total
December 31, 2015:	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
Investment grade securities:
Corporate securities	$	6,388,148	$	323,961	$	294,755	$	40,861	$	6,682,903	$	364,822
Canadian and Canadian provincial governments	122,746		2,532		—		—		122,746		2,532
Residential mortgage-backed securities	452,297		7,036		82,314		4,057		534,611		11,093
Asset-backed securities	581,701		9,825		199,298		7,100		780,999		16,925
Commercial mortgage-backed securities	514,877		9,806		31,177		997		546,054		10,803
U.S. government and agencies	1,010,387		57,718		—		—		1,010,387		57,718
State and political subdivisions	157,837		5,349		13,016		3,718		170,853		9,067
Other foreign government, supranational and foreign government-sponsored enterprises	702,962		18,279		38,379		4,206		741,341		22,485
Total investment grade securities	9,930,955		434,506		658,939		60,939		10,589,894		495,445
Below investment grade securities:
Corporate securities	554,688		71,171		114,427		31,076		669,115		102,247
Residential mortgage-backed securities	22,646		282		7,679		298		30,325		580
Asset-backed securities	6,772		201		9,335		1,250		16,107		1,451
Commercial mortgage-backed securities	3,253		248		767		117		4,020		365
Other foreign government, supranational and foreign government-sponsored enterprises	60,668		7,356		31,693		11,803		92,361		19,159
Total below investment grade securities	648,027		79,258		163,901		44,544		811,928		123,802
Total fixed maturity securities	$	10,578,982	$	513,764	$	822,840	$	105,483	$	11,401,822	$	619,247
Non-redeemable preferred stock	$	12,331	$	2,175	$	12,191	$	3,787	$	24,522	$	5,962
Other equity securities	38,327		2,242		—		—		38,327		2,242
Total equity securities	$	50,658	$	4,417	$	12,191	$	3,787	$	62,849	$	8,204



	Less than 12 months				12 months or greater				Total
December 31, 2014:	Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses
Investment grade securities:
Corporate securities	$	1,225,767	$	27,784	$	614,294	$	30,040	$	1,840,061	$	57,824
Canadian and Canadian provincial governments	—		—		1,235		7		1,235		7
Residential mortgage-backed securities	78,864		846		135,414		5,247		214,278		6,093
Asset-backed securities	332,785		4,021		109,411		4,289		442,196		8,310
Commercial mortgage-backed securities	78,632		564		28,375		2,461		107,007		3,025
U.S. government and agencies	81,317		89		32,959		426		114,276		515
State and political subdivisions	13,780		17		18,998		3,438		32,778		3,455
Other foreign government, supranational and foreign government-sponsored enterprises	156,725		7,007		76,111		2,946		232,836		9,953
Total investment grade securities	1,967,870		40,328		1,016,797		48,854		2,984,667		89,182
Below investment grade securities:
Corporate securities	415,886		29,316		32,567		3,404		448,453		32,720
Residential mortgage-backed securities	22,836		293		6,284		225		29,120		518
Asset-backed securities	12,448		274		7,108		1,791		19,556		2,065
Commercial mortgage-backed securities	3,288		249		5,580		5,385		8,868		5,634
State and political subdivisions	964		43		—		—		964		43
Other foreign government, supranational and foreign government-sponsored enterprises	13,986		3,136		—		—		13,986		3,136
Total below investment grade securities	469,408		33,311		51,539		10,805		520,947		44,116
Total fixed maturity securities	$	2,437,278	$	73,639	$	1,068,336	$	59,659	$	3,505,614	$	133,298
Non-redeemable preferred stock	$	11,619	$	235	$	19,100	$	1,292	$	30,719	$	1,527
Other equity securities	—		—		3,545		94		3,545		94
Total equity securities	$	11,619	$	235	$	22,645	$	1,386	$	34,264	$	1,621

Investment Income [Table Text Block]

Major categories of investment income, net of related expenses consist of the following (dollars in thousands):



	2015			2014			2013
Fixed maturity securities available-for-sale	$	1,177,706		$	1,052,715		$	966,759
Mortgage loans on real estate	149,564			148,417			121,476
Policy loans	62,955			55,248			57,099
Funds withheld at interest	343,031			447,364			545,550
Short-term investments	2,567			2,118			2,236
Other invested assets	66,716			70,149			58,771
Investment income	1,802,539			1,776,011			1,751,891
Investment expense	(68,044		)	(62,320		)	(52,026		)
Investment income, net of related expenses	$	1,734,495		$	1,713,691		$	1,699,865

Gain (Loss) on Investments [Table Text Block]

Investment related gains (losses), net, consist of the following (dollars in thousands):



	2015			2014			2013
Fixed maturity and equity securities available for sale:
Other-than-temporary impairment losses on fixed maturity securities recognized in earnings	$	(57,380	)	$	(7,766	)	$	(12,901	)
Gain on investment activity	73,079			65,435			82,744
Loss on investment activity	(71,893		)	(31,295		)	(60,575		)
Other impairment losses and change in mortgage loan provision	(6,953		)	(5,315		)	(6,933		)
Derivatives and other, net	(101,603		)	165,134			61,655
Total investment related gains (losses), net	$	(164,750	)	$	186,193		$	63,990

Schedule of Repurchase Agreements [Table Text Block]

The following table includes the amount of borrowed securities, repurchased securities pledged and repurchased/reverse repurchased securities pledged and received as of December 31, 2015 and 2014 (dollars in thousands).



	2015				2014
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Borrowed securities	$	259,540	$	266,297	$	201,050	$	212,946
Repurchase program securities pledged	—		—		92,446		107,158
Repurchase program/reverse repurchase program:
Securities pledged	443,435		465,889		298,466		314,160
Securities received	n/a		481,197		n/a		338,929

Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block]

The following table presents information on the securities pledged as collateral by the Company related to its repurchase/reverse repurchase program as of December 31, 2015 (dollars in thousands). Collateral associated with certain borrowed securities is not included within the table as the collateral pledged to each counterparty is the right to reinsurance treaty cash flows.



	December 31, 2015
	Remaining Contractual Maturity of the Agreements
	Overnight and Continuous		Up to 30 Days		30-90 Days		Greater than 90 Days		Total
Collateral on repurchase program
Corporate securities	$	—	$	2,951	$	—	$	147,324	$	150,275
Residential mortgage-backed securities	—		—		—		97,639		97,639
U.S. government and agencies	—		—		—		199,431		199,431
Foreign government	—		—		—		3,358		3,358
Other	15,186		—		—		—		15,186
Total borrowings	$	15,186	$	2,951	$	—	$	447,752	$	465,889

Gross amount of recognized liabilities for repurchase agreement in preceding table									$	481,197
Amounts related to agreements not included in offsetting disclosure									$	15,308

Disclosure Of Real Estate Holdings By Property Type [Table Text Block]

The distribution of mortgage loans, gross of valuation allowances, by property type is as follows as of December 31, 2015 and 2014 (dollars in thousands):



	2015				2014
	Recorded Investment		Percentage of Total		Recorded Investment		Percentage of Total
Property type:
Office building	$	980,858	31.3	%	$	851,749	31.3	%
Retail	1,026,018		32.7		802,466		29.6
Industrial	527,485		16.8		466,583		17.2
Apartment	420,014		13.4		376,430		13.8
Other commercial	182,389		5.8		221,481		8.1
Total	$	3,136,764	100.0	%	$	2,718,709	100.0	%

Disclosure of Real Estate Holdings Classified By Contractual Maturity Date [Table Text Block]

The maturities of the mortgage loans, gross of valuation allowances, as of December 31, 2015 and 2014 are as follows (dollars in thousands):



	2015				2014
	Recorded Investment		% of Total		Recorded Investment		% of Total
Due within five years	$	873,280	27.8	%	$	860,362	31.6	%
Due after five years through ten years	1,561,535		49.8		1,165,530		42.9
Due after ten years	701,949		22.4		692,817		25.5
Total	$	3,136,764	100.0	%	$	2,718,709	100.0	%

Mortgage Loan Internal Credit Risk Grade [Table Text Block]

Information regarding the Company’s credit quality indicators, as determined by the Company's internal evaluation methodology for its recorded investment in mortgage loans, gross of valuation allowances, as of December 31, 2015 and 2014 are as follows (dollars in thousands):



	2015				2014
Internal credit quality grade:	Recorded Investment		% of Total		Recorded Investment		% of Total
High investment grade	$	1,621,601	51.7	%	$	1,326,199	48.8	%
Investment grade	1,397,996		44.6		1,235,046		45.4
Average	87,196		2.8		118,152		4.4
Watch list	13,550		0.4		22,285		0.8
In or near default	16,421		0.5		17,027		0.6
Total	$	3,136,764	100.0	%	$	2,718,709	100.0	%

Recorded Investment And Allowance For Credit Losses [Table Text Block]

The following table presents the recorded investment in mortgage loans, by method of measuring impairment, and the related valuation allowances, as of December 31, 2015 and 2014 (dollars in thousands):



	2015		2014
Mortgage loans:
Individually measured for impairment	$	16,421	$	17,027
Collectively measured for impairment	3,120,343		2,701,682
Mortgage loans, gross of valuation allowances	3,136,764		2,718,709
Valuation allowances:
Individually measured for impairment	588		816
Collectively measured for impairment	6,225		5,655
Total valuation allowances	6,813		6,471
Mortgage loans, net of valuation allowances	$	3,129,951	$	2,712,238

Allowance For Loan And Lease Losses Provision For Loss Net [Table Text Block]

Information regarding the Company’s loan valuation allowances for mortgage loans as of December 31, 2015, 2014 and 2013 are as follows (dollars in thousands):



	2015		2014			2013
Balance, beginning of period	$	6,471	$	10,106		$	11,580
Charge-offs, net of recoveries	—		(2,731		)	(3,431		)
Provision	342		(904		)	1,957
Balance, end of period	$	6,813	$	6,471		$	10,106

Impaired Financing Receivables [Table Text Block]

Information regarding the portion of the Company’s mortgage loans that were impaired as of December 31, 2015 and 2014 is as follows (dollars in thousands):



	Unpaid Principal Balance		Recorded Investment		Related Allowance		Carrying Value
December 31, 2015:
Impaired mortgage loans with no valuation allowance recorded	$	4,033	$	4,033	$	—	$	4,033
Impaired mortgage loans with valuation allowance recorded	12,898		12,388		588		11,800
Total impaired mortgage loans	$	16,931	$	16,421	$	588	$	15,833
December 31, 2014:
Impaired mortgage loans with no valuation allowance recorded	$	7,314	$	6,711	$	—	$	6,711
Impaired mortgage loans with valuation allowance recorded	10,279		10,316		816		9,500
Total impaired mortgage loans	$	17,593	$	17,027	$	816	$	16,211

The Company’s average investment balance of impaired mortgage loans and the related interest income are reflected in the table below for the years ended December 31, 2015, 2014 and 2013 (dollars in thousands):



	2015				2014				2013
	Average Investment⁽¹⁾		Interest Income		Average Investment⁽¹⁾		Interest Income		Average Investment⁽¹⁾		Interest Income
Impaired mortgage loans with no valuation allowance recorded	$	6,033	$	330	$	13,227	$	647	$	15,023	$	852
Impaired mortgage loans with valuation allowance recorded	11,592		770		13,827		637		22,818		951
Total	$	17,625	$	1,100	$	27,054	$	1,284	$	37,841	$	1,803


(1)	Average recorded investment represents the average loan balances as of the beginning of period and all subsequent quarterly end of period balances.

Schedule of Other Assets [Table Text Block]

Other invested assets represented approximately 3.1% and 3.3% of the Company’s total investments as of December 31, 2015 and 2014, respectively. Carrying values of these assets as of December 31, 2015 and 2014 are as follows (dollars in thousands):



	2015		2014
Equity securities	$	125,862	$	126,860
Limited partnerships and real estate joint ventures	567,697		446,604
Structured loans	45,422		164,309
Derivatives	256,178		216,966
FVO contractholder-directed unit-linked investments	197,547		140,344
Other	105,414		103,236
Total other invested assets	$	1,298,120	$	1,198,319