American National (ANG-PB) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Nov. 05, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-31911
Entity Registrant Name	American Equity Investment Life Holding Co
Entity Incorporation, State or Country Code	IA
Entity Tax Identification Number	42-1447959
Entity Address, Address Line One	6000 Westown Parkway
Entity Address, City or Town	West Des Moines
Entity Address, State or Province	IA
Entity Address, Postal Zip Code	50266
City Area Code	515
Local Phone Number	221-0002
Title of 12(b) Security	Common stock, par value $1
Trading Symbol	AEL
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		91,046,262
Entity Central Index Key	0001039828
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investments:
Fixed maturity securities, available for sale, at fair value (amortized cost: 2019 - $48,170,556; 2018 - $46,131,190)	$ 51,854,384	$ 45,923,727
Mortgage loans on real estate	3,212,075	2,943,091
Derivative instruments	963,081	205,149
Other investments	694,416	355,531
Total investments	56,723,956	49,427,498
Cash and cash equivalents	1,138,737	344,396
Coinsurance deposits	5,072,015	4,954,068
Accrued investment income	497,291	468,729
Deferred policy acquisition costs	2,883,599	3,535,838
Deferred sales inducements	1,952,353	2,516,721
Deferred income taxes	0	291,169
Income taxes recoverable	30,277	26,537
Other assets	31,765	60,608
Total assets	68,329,993	61,625,564
Liabilities:
Policy benefit reserves	61,348,138	57,606,009
Other policy funds and contract claims	259,939	270,858
Notes payable	494,982	494,591
Subordinated debentures	243,311	242,982
Amounts due under repurchase agreements	48,931	109,298
Deferred income taxes	143,195	0
Other liabilities	1,664,781	502,725
Total liabilities	64,203,277	59,226,463
Stockholders' equity:
Preferred stock, par value $1 per share, 2,000,000 shares authorized, 2019 and 2018 - no shares issued and outstanding	0	0
Common stock, par value $1 per share, 200,000,000 shares authorized; issued and outstanding: 2019 - 91,006,950 shares (excluding 1,393,973 treasury shares); 2018 - 90,369,229 shares (excluding 1,535,960 treasury shares)	91,007	90,369
Additional paid-in capital	820,362	811,186
Accumulated other comprehensive income (loss)	1,639,429	(52,432)
Retained earnings	1,575,918	1,549,978
Total stockholders' equity	4,126,716	2,399,101
Total liabilities and stockholders' equity	$ 68,329,993	$ 61,625,564

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fixed maturity securities, available for sale, amortized cost	$ 48,170,556	$ 46,131,190
Stockholders' equity:
Preferred stock, par value (dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (dollars per share)	$ 1	$ 1
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	91,006,950	90,369,229
Common stock, shares outstanding	91,006,950	90,369,229
Common stock, shares held in treasury	1,393,973	1,535,960

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Premiums and other considerations	$ 5,152	$ 7,240	$ 14,688	$ 22,050
Annuity product charges	63,647	58,365	177,313	164,094
Net investment income	590,412	549,391	1,719,418	1,593,457
Change in fair value of derivatives	(20,042)	595,311	440,472	276,433
Net realized gains (losses) on investments, excluding other than temporary impairment (OTTI) losses	4,328	(2,196)	(67)	(40,275)
OTTI losses on investments:
Total OTTI losses	(101)	(14,373)	(1,099)	(16,025)
Portion of OTTI losses recognized from other comprehensive income	0	0	(215)	(1,651)
Net OTTI losses recognized in operations	(101)	(14,373)	(1,314)	(17,676)
Total revenues	643,396	1,193,738	2,350,510	1,998,083
Benefits and expenses:
Insurance policy benefits and change in future policy benefits	7,627	10,721	23,865	32,091
Interest sensitive and index product benefits	500,285	413,089	888,062	1,355,135
Amortization of deferred sales inducements	(55,769)	55,244	(2,675)	233,779
Change in fair value of embedded derivatives	212,278	383,716	1,306,163	(585,465)
Interest expense on notes payable	6,382	6,376	19,141	19,122
Interest expense on subordinated debentures	3,968	3,942	12,113	11,450
Amortization of deferred policy acquisition costs	(120,934)	81,053	(45,856)	336,741
Other operating costs and expenses	38,554	31,924	114,959	95,704
Total benefits and expenses	592,391	986,065	2,315,772	1,498,557
Income before income taxes	51,005	207,673	34,738	499,526
Income tax expense	13,645	38,345	8,798	95,333
Net income	$ 37,360	$ 169,328	$ 25,940	$ 404,193
Earnings per common share	$ 0.41	$ 1.87	$ 0.28	$ 4.48
Earnings per common share - assuming dilution	$ 0.41	$ 1.85	$ 0.28	$ 4.42
Weighted average common shares outstanding: earnings per common share	91,251,590	90,485,567	91,080,681	90,278,209
Weighted average common shares outstanding: earnings per common share - assuming dilution	91,710,557	91,650,886	91,747,862	91,355,410

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net income		$ 37,360	$ 169,328	$ 25,940	$ 404,193
Other comprehensive income (loss):
Change in net unrealized investment gains/losses (1)	[1]	742,756	(138,863)	2,136,989	(971,451)
Noncredit component of OTTI losses (1)	[1]	0	0	103	775
Reclassification of unrealized investment gains/losses to net income (1)	[1]	2,681	(525)	3,809	(19,026)
Other comprehensive income (loss) before income tax		745,437	(139,388)	2,140,901	(989,702)
Income tax effect related to other comprehensive income (loss)		(155,992)	29,270	(449,040)	207,837
Other comprehensive income (loss)		589,445	(110,118)	1,691,861	(781,865)
Comprehensive income (loss)		$ 626,805	$ 59,210	$ 1,717,801	$ (377,672)
[1]	Net of related adjustments to amortization of deferred sales inducements and deferred policy acquisition costs.

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Stockholders' equity at beginning of period at Dec. 31, 2017	$ 2,850,157	$ 89,331	$ 791,446	$ 724,599	$ 1,244,781
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	404,193				404,193
Other comprehensive income (loss)	(781,865)			(781,865)
Implementation of accounting standard related to the reclassification of certain tax effects				127,554	(127,554)
Share-based compensation	8,444		8,444
Issuance of common stock under compensation plans	8,367	947	7,420
Stockholders' equity at end of period at Sep. 30, 2018	2,489,296	90,278	807,310	70,288	1,521,420
Stockholders' equity at beginning of period at Jun. 30, 2018	2,426,825	90,233	804,094	180,406	1,352,092
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	169,328				169,328
Other comprehensive income (loss)	(110,118)			(110,118)
Share-based compensation	2,398		2,398
Issuance of common stock under compensation plans	863	45	818
Stockholders' equity at end of period at Sep. 30, 2018	2,489,296	90,278	807,310	70,288	1,521,420
Stockholders' equity at beginning of period at Dec. 31, 2018	2,399,101	90,369	811,186	(52,432)	1,549,978
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25,940				25,940
Other comprehensive income (loss)	1,691,861			1,691,861
Share-based compensation	9,402		9,402
Issuance of common stock under compensation plans	412	638	(226)
Stockholders' equity at end of period at Sep. 30, 2019	4,126,716	91,007	820,362	1,639,429	1,575,918
Stockholders' equity at beginning of period at Jun. 30, 2019	3,497,475	90,936	817,997	1,049,984	1,538,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	37,360				37,360
Other comprehensive income (loss)	589,445			589,445
Share-based compensation	2,042		2,042
Issuance of common stock under compensation plans	394	71	323
Stockholders' equity at end of period at Sep. 30, 2019	$ 4,126,716	$ 91,007	$ 820,362	$ 1,639,429	$ 1,575,918

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Shares of common stock issued under compensation plans	70,626	44,280	637,721	946,539

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net income	$ 25,940	$ 404,193
Adjustments to reconcile net income to net cash provided by operating activities:
Interest sensitive and index product benefits	888,062	1,355,135
Amortization of deferred sales inducements	(2,675)	233,779
Annuity product charges	(177,313)	(164,094)
Change in fair value of embedded derivatives	1,306,163	(585,465)
Change in traditional life and accident and health insurance reserves	(5,113)	2,241
Policy acquisition costs deferred	(344,293)	(289,131)
Amortization of deferred policy acquisition costs	(45,856)	336,741
Provision for depreciation and other amortization	2,863	2,584
Amortization of discounts and premiums on investments	21,762	15,315
Realized gains (losses) on investments and net OTTI losses recognized in operations	1,381	57,951
Distributions from equity method investments	1,160	1,043
Change in fair value of derivatives	(440,272)	(276,688)
Deferred income taxes	(14,676)	(4,750)
Share-based compensation	9,402	8,444
Change in accrued investment income	(28,562)	(52,991)
Change in income taxes recoverable/payable	(3,740)	(47,997)
Change in other assets	(2,009)	(469)
Change in other policy funds and contract claims	(16,465)	(16,203)
Change in collateral held for derivatives	737,103	(335,548)
Change in collateral held for securities lending	365,592	0
Change in other liabilities	20,670	(48,663)
Other	(10,844)	(9,188)
Net cash provided by operating activities	2,288,280	586,239
Sales, maturities, or repayments of investments:
Fixed maturity securities, available for sale	2,184,662	2,797,834
Mortgage loans on real estate	207,054	239,135
Derivative instruments	352,634	1,252,754
Other investments	7,887	156,536
Acquisitions of investments:
Fixed maturity securities, available for sale	(4,214,476)	(5,215,295)
Mortgage loans on real estate	(474,734)	(465,473)
Derivative instruments	(620,638)	(642,849)
Other investments	(344,652)	(67,646)
Purchases of property, furniture and equipment	(3,148)	(3,510)
Net cash used in investing activities	(2,905,411)	(1,948,514)
Financing activities
Receipts credited to annuity and single premium universal life policyholder account balances	4,035,051	3,255,014
Coinsurance deposits	67,858	(53,806)
Return of annuity policyholder account balances	(2,626,214)	(2,248,876)
Net proceeds from amounts due under repurchase agreements	(60,367)	116,399
Proceeds from issuance of common stock	412	8,367
Change in checks in excess of cash balance	(5,268)	(19,626)
Net cash provided by financing activities	1,411,472	1,057,472
Increase (decrease) in cash and cash equivalents	794,341	(304,803)
Cash and cash equivalents at beginning of period	344,396	1,434,045
Cash and cash equivalents at end of period	1,138,737	1,129,242
Cash paid during period for interest:
Interest expense	26,490	24,009
Cash paid during period for income taxes:
Income taxes	28,193	148,157
Non-cash operating activity:
Deferral of sales inducements	$ 140,960	$ 135,015

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Consolidation and Basis of Presentation The accompanying consolidated financial statements of American Equity Investment Life Holding Company ("we", "us" or "our") have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and notes required by GAAP for complete financial statements. The consolidated financial statements reflect all adjustments, consisting only of normal recurring items, which are necessary to present fairly our financial position and results of operations on a basis consistent with the prior audited consolidated financial statements. Operating results for the three and nine month periods ended September 30, 2019 are not necessarily indicative of the results that may be expected for the year ended December 31, 2019 . All significant intercompany accounts and transactions have been eliminated. The preparation of financial statements requires the use of management estimates. For further information related to a description of areas of judgment and estimates and other information necessary to understand our financial position and results of operations, refer to the audited consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2018 . Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued an accounting standards update (“ASU”) that requires recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This ASU affects accounting and disclosure more dramatically for lessees as accounting and disclosure for lessors is mainly unchanged. We adopted this ASU on January 1, 2019. The adoption of this ASU resulted in the recognition of a lease asset and lease liability of $3.8 million , respectively, on our consolidated balance sheet at September 30, 2019 . In March 2017, the FASB issued an ASU that applies to certain callable debt securities where the amortized cost basis is at a premium to the price repayable by the issuer at the earliest call date. Under this guidance, the premium is amortized to the first call date. We adopted this ASU on January 1, 2019. The adoption of this ASU did not have a material impact on our consolidated financial statements. In June 2018, the FASB issued an ASU that expands the scope of Accounting Standards Codification 718, Compensation-Stock Compensation, to include share-based payment transactions for acquiring goods and services to nonemployees and eliminates the existing accounting model for nonemployee share-based payment awards. We adopted this ASU on January 1, 2019. While this ASU results in an earlier measurement date for our nonemployee restricted stock units that have not vested as of January 1, 2019, there was no impact to our consolidated financial statements upon adoption. New Accounting Pronouncements In June 2016, the FASB issued an ASU that significantly changes the impairment model for most financial assets that are measured at amortized cost and certain other instruments from an incurred loss model to an expected loss model that requires these assets be presented at the net amount expected to be collected. In addition, credit losses on available for sale debt securities will be recorded through an allowance account. This ASU will be effective for us on January 1, 2020, with early adoption permitted. Our implementation procedures to date relative to this standard include, but are not limited to, identifying financial assets within the scope of this guidance, developing a current expected credit loss model for our commercial mortgage loans and refining internal processes for financial assets impacted by this guidance. We believe the new impairment model will lead to earlier recognition of credit losses for our commercial mortgage loans. In August 2018, the FASB issued an ASU that revises certain aspects of the measurement models and disclosure requirements for long duration insurance and investment contracts. The FASB’s objective in issuing this ASU is to improve, simplify, and enhance the accounting for long-duration contracts. The revisions include updating cash flow assumptions in the calculation of the liability for traditional life products, introducing the term ‘market risk benefit’ ("MRB") and requiring all contract features meeting the definition of an MRB to be measured at fair value, simplifying the method used to amortize deferred policy acquisition costs and deferred sales inducements to a constant basis over the expected term of the related contracts rather than based on gross profits and enhancing disclosure requirements. While this ASU is effective for us on January 1, 2022, the transition date (the remeasurement date) is January 1, 2020. Early adoption of this ASU is permitted. We are in the process of evaluating the impact this guidance will have on our consolidated financial statements.

Fair Values of Financial Instru

Fair Values of Financial Instruments	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Values of Financial Instruments	Fair Values of Financial Instruments The following sets forth a comparison of the carrying amounts and fair values of our financial instruments: September 30, 2019 December 31, 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) Assets Fixed maturity securities, available for sale $ 51,854,384 $ 51,854,384 $ 45,923,727 $ 45,923,727 Mortgage loans on real estate 3,212,075 3,293,106 2,943,091 2,920,612 Derivative instruments 963,081 963,081 205,149 205,149 Other investments 694,416 694,416 355,531 348,970 Cash and cash equivalents 1,138,737 1,138,737 344,396 344,396 Coinsurance deposits 5,072,015 4,602,181 4,954,068 4,553,790 Interest rate caps 17 17 597 597 Interest rate swap — — 354 354 Counterparty collateral — — 33,101 33,101 Liabilities Policy benefit reserves 60,996,752 51,320,260 57,249,510 49,180,143 Single premium immediate annuity (SPIA) benefit reserves 259,634 267,876 270,406 279,077 Notes payable 494,982 526,760 494,591 489,985 Subordinated debentures 243,311 247,283 242,982 215,514 Amounts due under repurchase agreements 48,931 48,931 109,298 109,298 Interest rate swap 906 906 — — Fair value is the price that would be received to sell an asset or paid to transfer a liability (exit price) in an orderly transaction between market participants at the measurement date. The objective of a fair value measurement is to determine that price for each financial instrument at each measurement date. We meet this objective using various methods of valuation that include market, income and cost approaches. We categorize our financial instruments into three levels of fair value hierarchy based on the priority of inputs used in determining fair value. The hierarchy defines the highest priority inputs (Level 1) as quoted prices in active markets for identical assets or liabilities. The lowest priority inputs (Level 3) are our own assumptions about what a market participant would use in determining fair value such as estimated future cash flows. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, a financial instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the financial instrument. We categorize financial assets and liabilities recorded at fair value in the consolidated balance sheets as follows: Level 1— Quoted prices are available in active markets for identical financial instruments as of the reporting date. We do not adjust the quoted price for these financial instruments, even in situations where we hold a large position and a sale could reasonably impact the quoted price. Level 2— Quoted prices in active markets for similar financial instruments, quoted prices for identical or similar financial instruments in markets that are not active; and models and other valuation methodologies using inputs other than quoted prices that are observable. Level 3— Models and other valuation methodologies using significant inputs that are unobservable for financial instruments and include situations where there is little, if any, market activity for the financial instrument. The inputs into the determination of fair value require significant management judgment or estimation. Financial instruments that are included in Level 3 are securities for which no market activity or data exists and for which we used discounted expected future cash flows with our own assumptions about what a market participant would use in determining fair value. Transfers of securities among the levels occur at times and depend on the type of inputs used to determine fair value of each security. There were no transfers between levels during any period presented. Our assets and liabilities which are measured at fair value on a recurring basis as of September 30, 2019 and December 31, 2018 are presented below based on the fair value hierarchy levels: Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Dollars in thousands) September 30, 2019 Assets Fixed maturity securities, available for sale: United States Government full faith and credit $ 12,343 $ 6,421 $ 5,922 $ — United States Government sponsored agencies 695,030 — 695,030 — United States municipalities, states and territories 4,517,661 — 4,517,661 — Foreign government obligations 207,420 — 207,420 — Corporate securities 32,897,127 15 32,897,112 — Residential mortgage backed securities 1,557,156 — 1,557,156 — Commercial mortgage backed securities 5,839,510 — 5,839,510 — Other asset backed securities 6,128,137 — 6,128,137 — Other investments: equity securities 309,313 301,870 7,443 — Derivative instruments 963,081 — 963,081 — Cash and cash equivalents 1,138,737 1,138,737 — — Interest rate caps 17 — 17 — $ 54,265,532 $ 1,447,043 $ 52,818,489 $ — Liabilities Interest rate swap $ 906 $ — $ 906 $ — Fixed index annuities - embedded derivatives 9,381,094 — — 9,381,094 $ 9,382,000 $ — $ 906 $ 9,381,094 December 31, 2018 Assets Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,652 $ 5,900 $ 5,752 $ — United States Government sponsored agencies 1,138,529 — 1,138,529 — United States municipalities, states and territories 4,126,267 — 4,126,267 — Foreign government obligations 230,274 — 230,274 — Corporate securities 28,371,514 7 28,371,507 — Residential mortgage backed securities 1,202,159 — 1,202,159 — Commercial mortgage backed securities 5,379,003 — 5,379,003 — Other asset backed securities 5,464,329 — 5,464,329 — Other investments: equity securities 7,437 — 7,437 — Derivative instruments 205,149 — 205,149 — Cash and cash equivalents 344,396 344,396 — — Interest rate caps 597 — 597 — Interest rate swap 354 — 354 — Counterparty collateral 33,101 — 33,101 — $ 46,514,761 $ 350,303 $ 46,164,458 $ — Liabilities Fixed index annuities - embedded derivatives $ 8,165,405 $ — $ — $ 8,165,405 The following methods and assumptions were used in estimating the fair values of financial instruments during the periods presented in these consolidated financial statements. Fixed maturity securities The fair values of fixed maturity securities in an active and orderly market are determined by utilizing independent pricing services. The independent pricing services incorporate a variety of observable market data in their valuation techniques, including: • reported trading prices, • benchmark yields, • broker-dealer quotes, • benchmark securities, • bids and offers, • credit ratings, • relative credit information, and • other reference data. The independent pricing services also take into account perceived market movements and sector news, as well as a security's terms and conditions, including any features specific to that issue that may influence risk and marketability. Depending on the security, the priority of the use of observable market inputs may change as some observable market inputs may not be relevant or additional inputs may be necessary. The independent pricing services provide quoted market prices when available. Quoted prices are not always available due to market inactivity. When quoted market prices are not available, the third parties use yield data and other factors relating to instruments or securities with similar characteristics to determine fair value for securities that are not actively traded. We generally obtain one value from our primary external pricing service. In situations where a price is not available from this service, we may obtain quotes or prices from additional parties as needed. Market indices of similar rated asset class spreads are considered for valuations and broker indications of similar securities are compared. Inputs used by the broker include market information, such as yield data and other factors relating to instruments or securities with similar characteristics. Valuations and quotes obtained from third party commercial pricing services are non-binding and do not represent quotes on which one may execute the disposition of the assets. We validate external valuations at least quarterly through a combination of procedures that include the evaluation of methodologies used by the pricing services, comparison of the prices to a secondary pricing source, analytical reviews and performance analysis of the prices against trends, and maintenance of a securities watch list. Additionally, as needed we utilize discounted cash flow models or perform independent valuations on a case-by-case basis using inputs and assumptions similar to those used by the pricing services. Although we do identify differences from time to time as a result of these validation procedures, we did not make any significant adjustments as of September 30, 2019 and December 31, 2018 . Mortgage loans on real estate Mortgage loans on real estate are not measured at fair value on a recurring basis. The fair values of mortgage loans on real estate are calculated using discounted expected cash flows using competitive market interest rates currently being offered for similar loans. The fair values of impaired mortgage loans on real estate that we have considered to be collateral dependent are based on the fair value of the real estate collateral (based on appraised values) less estimated costs to sell. The inputs utilized to determine fair value of all mortgage loans are unobservable market data (competitive market interest rates); therefore, fair value of mortgage loans falls into Level 3 in the fair value hierarchy. Derivative instruments The fair values of derivative instruments, primarily call options, are based upon the amount of cash that we will receive to settle each derivative instrument on the reporting date. These amounts are determined by our investment team using industry accepted valuation models and are adjusted for the nonperformance risk of each counterparty net of any collateral held. Inputs include market volatility and risk free interest rates and are used in income valuation techniques in arriving at a fair value for each option contract. The nonperformance risk for each counterparty is based upon its credit default swap rate. We have no performance obligations related to the call options purchased to fund our fixed index annuity policy liabilities. Other investments Equity securities are the only financial instruments included in other investments that are measured at fair value on a recurring basis (see determination of fair value above). Financial instruments included in other investments that are not measured at fair value on a recurring basis are policy loans, equity method investments and company owned life insurance ("COLI"). We have not attempted to determine the fair values associated with our policy loans, as we believe any differences between carrying values and the fair values afforded these instruments are immaterial to our consolidated financial position and, accordingly, the cost to provide such disclosure does not justify the benefit to be derived. The fair values of our equity method investments are obtained from third parties and determined by calculating the present value of future cash flows discounted by a risk free rate, a risk spread and a liquidity discount. As the risk spread and liquidity discount are unobservable market inputs, the fair value of our equity method investments falls within Level 3 of the fair value hierarchy. The fair value of our COLI approximates the cash surrender value of the policies and falls within Level 2 of the fair value hierarchy. Cash and cash equivalents Amounts reported in the consolidated balance sheets for these instruments are reported at their historical cost which approximates fair value due to the nature of the assets assigned to this category. Interest rate swap and caps The fair values of our pay fixed/receive variable interest rate swap and our interest rate caps are obtained from third parties and are determined by discounting expected future cash flows using a projected London Interbank Offered Rate ("LIBOR") for the term of the swap and caps. Counterparty collateral Amounts reported in other assets in the consolidated balance sheets for these instruments are reported at their historical cost which approximates fair value due to the nature of the assets assigned to this category. Policy benefit reserves, coinsurance deposits and SPIA benefit reserves The fair values of the liabilities under contracts not involving significant mortality or morbidity risks (principally deferred annuities), are stated at the cost we would incur to extinguish the liability (i.e., the cash surrender value) as these contracts are generally issued without an annuitization date. The coinsurance deposits related to the annuity benefit reserves have fair values determined in a similar fashion. For period-certain annuity benefit contracts, the fair value is determined by discounting the benefits at the interest rates currently in effect for newly issued immediate annuity contracts. We are not required to and have not estimated the fair value of the liabilities under contracts that involve significant mortality or morbidity risks, as these liabilities fall within the definition of insurance contracts that are exceptions from financial instruments that require disclosures of fair value. Policy benefit reserves, coinsurance deposits and SPIA benefit reserves are not measured at fair value on a recurring basis. All of the fair values presented within these categories fall within Level 3 of the fair value hierarchy as most of the inputs are unobservable market data. Notes payable The fair values of our senior unsecured notes are based upon pricing matrices developed by a third party pricing service when quoted market prices are not available and are categorized as Level 2 within the fair value hierarchy. Notes payable are not remeasured at fair value on a recurring basis. Subordinated debentures Fair values for subordinated debentures are estimated using discounted cash flow calculations based principally on observable inputs including our incremental borrowing rates, which reflect our credit rating, for similar types of borrowings with maturities consistent with those remaining for the debt being valued. These fair values are categorized as Level 2 within the fair value hierarchy. Subordinated debentures are not measured at fair value on a recurring basis. Amounts due under repurchase agreements The amounts reported in the consolidated balance sheets for short term indebtedness under repurchase agreements with variable interest rates approximate their fair values. Fixed index annuities - embedded derivatives We estimate the fair value of the embedded derivative component of our fixed index annuity policy benefit reserves at each valuation date by (i) projecting policy contract values and minimum guaranteed contract values over the expected lives of the contracts and (ii) discounting the excess of the projected contract value amounts at the applicable risk free interest rates adjusted for our nonperformance risk related to those liabilities. The projections of policy contract values are based on our best estimate assumptions for future policy growth and future policy decrements. Our best estimate assumptions for future policy growth include assumptions for the expected index credit on the next policy anniversary date which are derived from the fair values of the underlying call options purchased to fund such index credits and the expected costs of annual call options we will purchase in the future to fund index credits beyond the next policy anniversary. The projections of minimum guaranteed contract values include the same best estimate assumptions for policy decrements as were used to project policy contract values. Within this determination we have the following significant unobservable inputs: 1) the expected cost of annual call options we will purchase in the future to fund index credits beyond the next policy anniversary and 2) our best estimates for future policy decrements, primarily lapse, partial withdrawal and mortality rates. As of September 30, 2019 and December 31, 2018 , we utilized an estimate of 2.90% and 3.10% , respectively, for the expected cost of annual call options, which are based on estimated long-term account value growth and a historical review of our actual option costs. Our best estimate assumptions for lapse, partial withdrawal and mortality rates are based on our actual experience and our outlook as to future expectations for such assumptions. These assumptions, which are consistent with the assumptions used in calculating deferred policy acquisition costs and deferred sales inducements, are reviewed on a quarterly basis and are revised as our experience develops and/or as future expectations change. The following table presents average lapse rate and partial withdrawal rate assumptions, by contract duration, used in estimating the fair value of the embedded derivative component of our fixed index annuity policy benefit reserves at each reporting date: Average Lapse Rates Average Partial Withdrawal Rates Contract Duration (Years) September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 1 - 5 0.86% 2.05% 3.35% 3.33% 6 - 10 1.30% 7.28% 4.14% 3.33% 11 - 15 3.48% 11.35% 4.17% 3.35% 16 - 20 9.45% 11.90% 4.08% 3.22% 20+ 7.00% 11.57% 3.86% 3.22% Lapse rates are generally expected to increase as surrender charge percentages decrease. Lapse expectations reflect a significant increase in the year in which the surrender charge period on a contract ends. We review assumptions quarterly and as a result of this review we lowered lapse rate assumptions in the third quarter of 2019 as our experience indicates lapse rates have been lower than previously estimated. The following table provides a reconciliation of the beginning and ending balances for our Level 3 liabilities, which are measured at fair value on a recurring basis using significant unobservable inputs for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Fixed index annuities - embedded derivatives Beginning balance $ 9,281,117 $ 8,351,151 $ 8,165,405 $ 8,790,427 Premiums less benefits 74,979 399,234 333,459 1,354,881 Change in fair value, net 24,998 196,808 882,230 (1,198,115 ) Ending balance $ 9,381,094 $ 8,947,193 $ 9,381,094 $ 8,947,193 The fair value of our fixed index annuities embedded derivatives is net of coinsurance ceded of $614.6 million and $538.8 million as of September 30, 2019 and December 31, 2018 , respectively. Change in fair value, net for each period in our embedded derivatives is included in change in fair value of embedded derivatives in the unaudited consolidated statements of operations. Certain derivatives embedded in our fixed index annuity contracts are our most significant financial instrument measured at fair value that are categorized as Level 3 in the fair value hierarchy. The contractual obligations for future annual index credits within our fixed index annuity contracts are treated as a "series of embedded derivatives" over the expected life of the applicable contracts. We estimate the fair value of these embedded derivatives at each valuation date by the method described above under fixed index annuities - embedded derivatives . The projections of minimum guaranteed contract values include the same best estimate assumptions for policy decrements as were used to project policy contract values. The most sensitive assumption in determining policy liabilities for fixed index annuities is the rates used to discount the excess projected contract values. As indicated above, the discount rate reflects our nonperformance risk. If the discount rates used to discount the excess projected contract values at September 30, 2019 , were to increase by 100 basis points, the fair value of the embedded derivatives would decrease by $902.0 million recorded through operations as a decrease in the change in fair value of embedded derivatives and there would be a corresponding decrease of $370.5 million to our combined balance for deferred policy acquisition costs and deferred sales inducements recorded through operations as an increase in amortization of deferred policy acquisition costs and deferred sales inducements. A decrease by 100 basis points in the discount rate used to discount the excess projected contract values would increase the fair value of the embedded derivatives by $1.1 billion recorded through operations as an increase in the change in fair value of embedded derivatives and there would be a corresponding increase of $462.4 million

Investments

Investments	9 Months Ended
	Sep. 30, 2019
Investments [Abstract]
Investments	Investments At September 30, 2019 and December 31, 2018 , the amortized cost and fair value of fixed maturity securities were as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,832 $ 511 $ — $ 12,343 United States Government sponsored agencies 663,662 33,420 (2,052 ) 695,030 United States municipalities, states and territories 4,053,836 464,539 (714 ) 4,517,661 Foreign government obligations 186,979 20,441 — 207,420 Corporate securities 30,042,589 2,959,486 (104,948 ) 32,897,127 Residential mortgage backed securities 1,434,116 124,648 (1,608 ) 1,557,156 Commercial mortgage backed securities 5,564,871 279,881 (5,242 ) 5,839,510 Other asset backed securities 6,212,671 107,933 (192,467 ) 6,128,137 $ 48,170,556 $ 3,990,859 $ (307,031 ) $ 51,854,384 December 31, 2018 Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,872 $ 102 $ (322 ) $ 11,652 United States Government sponsored agencies 1,208,468 13,095 (83,034 ) 1,138,529 United States municipalities, states and territories 3,880,703 261,222 (15,658 ) 4,126,267 Foreign government obligations 226,860 7,573 (4,159 ) 230,274 Corporate securities 28,483,138 727,105 (838,729 ) 28,371,514 Residential mortgage backed securities 1,134,623 71,661 (4,125 ) 1,202,159 Commercial mortgage backed securities 5,492,271 21,558 (134,826 ) 5,379,003 Other asset backed securities 5,693,255 41,308 (270,234 ) 5,464,329 $ 46,131,190 $ 1,143,624 $ (1,351,087 ) $ 45,923,727 The amortized cost and fair value of fixed maturity securities at September 30, 2019 , by contractual maturity, are shown below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. All of our mortgage and other asset backed securities provide for periodic payments throughout their lives and are shown below as separate lines. Available for sale Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 404,010 $ 409,265 Due after one year through five years 5,612,668 5,824,616 Due after five years through ten years 10,399,862 11,063,045 Due after ten years through twenty years 10,051,773 11,398,510 Due after twenty years 8,490,585 9,634,145 34,958,898 38,329,581 Residential mortgage backed securities 1,434,116 1,557,156 Commercial mortgage backed securities 5,564,871 5,839,510 Other asset backed securities 6,212,671 6,128,137 $ 48,170,556 $ 51,854,384 Net unrealized gains (losses) on available for sale fixed maturity securities reported as a separate component of stockholders' equity were comprised of the following: September 30, 2019 December 31, 2018 (Dollars in thousands) Net unrealized gains (losses) on available for sale fixed maturity securities $ 3,683,828 $ (207,463 ) Adjustments for assumed changes in amortization of deferred policy acquisition costs and deferred sales inducements (1,637,819 ) 112,571 Deferred income tax valuation allowance reversal 22,534 22,534 Deferred income tax benefit (expense) (429,114 ) 19,926 Net unrealized gains (losses) reported as accumulated other comprehensive income (loss) $ 1,639,429 $ (52,432 ) The National Association of Insurance Commissioners ("NAIC") assigns designations to fixed maturity securities. These designations range from Class 1 (highest quality) to Class 6 (lowest quality). In general, securities are assigned a designation based upon the ratings they are given by the Nationally Recognized Statistical Rating Organizations ("NRSRO’s"). The NAIC designations are utilized by insurers in preparing their annual statutory statements. NAIC Class 1 and 2 designations are considered "investment grade" while NAIC Class 3 through 6 designations are considered "non-investment grade." Based on the NAIC designations, we had 98% and 97% of our fixed maturity portfolio rated investment grade at September 30, 2019 and December 31, 2018 , respectively. The following table summarizes the credit quality, as determined by NAIC designation, of our fixed maturity portfolio as of the dates indicated: September 30, 2019 December 31, 2018 NAIC Designation Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) 1 $ 27,657,160 $ 30,351,227 $ 26,588,352 $ 26,921,843 2 19,171,556 20,232,420 17,901,161 17,528,072 3 1,179,714 1,145,174 1,396,650 1,269,242 4 126,833 101,830 173,987 137,991 5 29,759 16,920 23,836 19,453 6 5,534 6,813 47,204 47,126 $ 48,170,556 $ 51,854,384 $ 46,131,190 $ 45,923,727 The following table shows our investments' gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities (consisting of 886 and 2,715 securities, respectively) have been in a continuous unrealized loss position, at September 30, 2019 and December 31, 2018 : Less than 12 months 12 months or more Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: United States Government sponsored agencies $ 119,718 $ (282 ) $ 203,230 $ (1,770 ) $ 322,948 $ (2,052 ) United States municipalities, states and territories 97,111 (668 ) 3,116 (46 ) 100,227 (714 ) Corporate securities: Finance, insurance and real estate 330,617 (3,576 ) 144,633 (2,095 ) 475,250 (5,671 ) Manufacturing, construction and mining 135,697 (1,003 ) 56,550 (3,921 ) 192,247 (4,924 ) Utilities and related sectors 56,274 (2,272 ) 50,072 (4,928 ) 106,346 (7,200 ) Wholesale/retail trade 18,356 (293 ) 121,902 (13,234 ) 140,258 (13,527 ) Services, media and other 188,946 (10,486 ) 424,760 (63,140 ) 613,706 (73,626 ) Residential mortgage backed securities 116,116 (614 ) 11,918 (994 ) 128,034 (1,608 ) Commercial mortgage backed securities 239,503 (1,355 ) 203,268 (3,887 ) 442,771 (5,242 ) Other asset backed securities 1,739,759 (48,538 ) 2,386,760 (143,929 ) 4,126,519 (192,467 ) $ 3,042,097 $ (69,087 ) $ 3,606,209 $ (237,944 ) $ 6,648,306 $ (307,031 ) December 31, 2018 Fixed maturity securities, available for sale: United States Government full faith and credit $ 543 $ (3 ) $ 7,785 $ (319 ) $ 8,328 $ (322 ) United States Government sponsored agencies 30,089 (949 ) 953,421 (82,085 ) 983,510 (83,034 ) United States municipalities, states and territories 340,103 (6,816 ) 162,997 (8,842 ) 503,100 (15,658 ) Foreign government obligations 98,511 (1,748 ) 11,859 (2,411 ) 110,370 (4,159 ) Corporate securities: Finance, insurance and real estate 2,501,640 (87,220 ) 884,870 (77,507 ) 3,386,510 (164,727 ) Manufacturing, construction and mining 2,045,859 (84,972 ) 349,738 (34,635 ) 2,395,597 (119,607 ) Utilities and related sectors 2,313,271 (82,119 ) 591,482 (45,838 ) 2,904,753 (127,957 ) Wholesale/retail trade 1,032,603 (51,228 ) 198,805 (26,326 ) 1,231,408 (77,554 ) Services, media and other 4,618,477 (196,520 ) 1,072,722 (152,364 ) 5,691,199 (348,884 ) Residential mortgage backed securities 145,613 (2,638 ) 22,689 (1,487 ) 168,302 (4,125 ) Commercial mortgage backed securities 2,141,560 (37,150 ) 2,090,835 (97,676 ) 4,232,395 (134,826 ) Other asset backed securities 4,073,249 (252,265 ) 271,994 (17,969 ) 4,345,243 (270,234 ) $ 19,341,518 $ (803,628 ) $ 6,619,197 $ (547,459 ) $ 25,960,715 $ (1,351,087 ) The unrealized losses at September 30, 2019 are principally related to timing of the purchases of these securities, which carry less yield than those available at September 30, 2019 . Approximately 68% and 87% of the unrealized losses on fixed maturity securities shown in the above table for September 30, 2019 and December 31, 2018 , respectively, are on securities that are rated investment grade, defined as being the highest two NAIC designations. Because we did not have the intent to sell fixed maturity securities with unrealized losses and it was not more likely than not that we would be required to sell these securities prior to recovery of the amortized cost, which may be maturity, we did not consider these investments to be other than temporarily impaired as of September 30, 2019 and December 31, 2018 . Changes in net unrealized gains/losses on investments for the three and nine months ended September 30, 2019 and 2018 are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Fixed maturity securities held for investment carried at amortized cost $ — $ 2,947 $ — $ (5,519 ) Fixed maturity securities available for sale carried at fair value $ 990,481 $ (311,954 ) $ 3,891,291 $ (2,122,555 ) Adjustment for effect on other balance sheet accounts: Deferred policy acquisition costs and deferred sales inducements (245,044 ) 172,566 (1,750,390 ) 1,132,853 Deferred income tax asset/liability (155,992 ) 29,270 (449,040 ) 207,837 (401,036 ) 201,836 (2,199,430 ) 1,340,690 Change in net unrealized gains/losses on investments carried at fair value $ 589,445 $ (110,118 ) $ 1,691,861 $ (781,865 ) Proceeds from sales of available for sale securities for the nine months ended September 30, 2019 and 2018 were $707.5 million and $1.8 billion , respectively. Scheduled principal repayments, calls and tenders for available for sale fixed maturity securities for the nine months ended September 30, 2019 and 2018 were $1.5 billion and $997.6 million , respectively. Realized gains and losses on sales are determined on the basis of specific identification of investments based on the trade date. Net realized gains (losses) on investments, excluding net OTTI losses for the three and nine months ended September 30, 2019 and 2018 , are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Available for sale fixed maturity securities: Gross realized gains $ 6,164 $ 505 $ 12,590 $ 2,845 Gross realized losses (1,586 ) (1,913 ) (5,667 ) (43,648 ) 4,578 (1,408 ) 6,923 (40,803 ) Other investments: Gross realized gains — — 7,296 — Gross realized losses — — (14,446 ) — — — (7,150 ) — Mortgage loans on real estate: Increase (decrease) in allowance for credit losses (250 ) (1,255 ) 160 (785 ) Recovery of specific allowance — 467 — 1,189 Gain on sale of mortgage loans — — — 124 (250 ) (788 ) 160 528 $ 4,328 $ (2,196 ) $ (67 ) $ (40,275 ) Losses on available for sale fixed maturity securities in 2019 and 2018 were realized primarily due to strategies to reposition the fixed maturity security portfolio that result in improved net investment income, credit risk or duration profiles as they pertain to our asset liability management. We review and analyze all investments on an ongoing basis for changes in market interest rates and credit deterioration. This review process includes analyzing our ability to recover the amortized cost basis of each investment that has a fair value that is materially lower than its amortized cost and requires a high degree of management judgment and involves uncertainty. The evaluation of securities for other than temporary impairments is a quantitative and qualitative process, which is subject to risks and uncertainties. We have a policy and process to identify securities that could potentially have impairments that are other than temporary. This process involves monitoring market events and other items that could impact issuers. The evaluation includes but is not limited to such factors as: • the length of time and the extent to which the fair value has been less than amortized cost or cost; • whether the issuer is current on all payments and all contractual payments have been made as agreed; • the remaining payment terms and the financial condition and near-term prospects of the issuer; • the lack of ability to refinance due to liquidity problems in the credit market; • the fair value of any underlying collateral; • the existence of any credit protection available; • our intent to sell and whether it is more likely than not we would be required to sell prior to recovery for debt securities; • consideration of rating agency actions; and • changes in estimated cash flows of mortgage and asset backed securities. We determine whether other than temporary impairment losses should be recognized for debt securities by assessing all facts and circumstances surrounding each security. Where the decline in fair value of debt securities is attributable to changes in market interest rates or to factors such as market volatility, liquidity and spread widening, and we anticipate recovery of all contractual or expected cash flows, we do not consider these investments to be other than temporarily impaired because we do not intend to sell these investments and it is not more likely than not we will be required to sell these investments before a recovery of amortized cost, which may be maturity. If we intend to sell a debt security or if it is more likely than not that we will be required to sell a debt security before recovery of its amortized cost basis, other than temporary impairment has occurred and the difference between amortized cost and fair value will be recognized as a loss in operations. If we do not intend to sell and it is not more likely than not we will be required to sell the debt security but also do not expect to recover the entire amortized cost basis of the security, an impairment loss would be recognized in operations in the amount of the expected credit loss. We determine the amount of expected credit loss by calculating the present value of the cash flows expected to be collected discounted at each security's acquisition yield based on our consideration of whether the security was of high credit quality at the time of acquisition. The difference between the present value of expected future cash flows and the amortized cost basis of the security is the amount of credit loss recognized in operations. The remaining amount of the other than temporary impairment is recognized in other comprehensive income (loss). The determination of the credit loss component of a mortgage backed security is based on a number of factors. The primary consideration in this evaluation process is the issuer's ability to meet current and future interest and principal payments as contractually stated at time of purchase. Our review of these securities includes an analysis of the cash flow modeling under various default scenarios considering independent third party benchmarks, the seniority of the specific tranche within the structure of the security, the composition of the collateral and the actual default, loss severity and prepayment experience exhibited. With the input of third party assumptions for default projections, loss severity and prepayment expectations, we evaluate the cash flow projections to determine whether the security is performing in accordance with its contractual obligation. We utilize the models from a leading structured product software specialist serving institutional investors. These models incorporate each security's seniority and cash flow structure. In circumstances where the analysis implies a potential for principal loss at some point in the future, we use the "best estimate" cash flow projection discounted at the security's effective yield at acquisition to determine the amount of our potential credit loss associated with this security. The discounted expected future cash flows equates to our expected recovery value. Any shortfall of the expected recovery when compared to the amortized cost of the security will be recorded as the credit loss component of other than temporary impairment. The cash flow modeling is performed on a security-by-security basis and incorporates actual cash flows on the residential mortgage backed securities through the current period, as well as the projection of remaining cash flows using a number of assumptions including default rates, prepayment rates and loss severity rates. The default curves we use are tailored to the Prime or Alt-A residential mortgage backed securities that we own, which assume lower default rates and loss severity for Prime securities versus Alt-A securities. These default curves are scaled higher or lower depending on factors such as current underlying mortgage loan performance, rating agency loss projections, loan to value ratios, geographic diversity, as well as other appropriate considerations. The determination of the credit loss component of a corporate bond is based on the underlying financial performance of the issuer and their ability to meet their contractual obligations. Considerations in our evaluation include, but are not limited to, credit rating changes, financial statement and ratio analysis, changes in management, significant changes in credit spreads, breaches of financial covenants and a review of the economic outlook for the industry and markets in which they trade. In circumstances where an issuer appears unlikely to meet its future obligation, or the security's price decline is deemed other than temporary, an estimate of credit loss is determined. Credit loss is calculated using default probabilities as derived from the credit default swaps markets in conjunction with recovery rates derived from independent third party analysis or a best estimate of credit loss. This credit loss rate is then incorporated into a present value calculation based on an expected principal loss in the future discounted at the yield at the date of purchase and compared to amortized cost to determine the amount of credit loss associated with the security. In addition, for debt securities which we do not intend to sell and it is not more likely than not we will be required to sell, but our intent changes due to changes or events that could not have been reasonably anticipated, an other than temporary impairment charge is recognized. Once an impairment charge has been recorded, we then continue to review the other than temporarily impaired securities for appropriate valuation on an ongoing basis. Unrealized losses may be recognized in future periods through a charge to earnings should we later conclude that the decline in fair value below amortized cost is other than temporary pursuant to our accounting policy described above. The use of different methodologies and assumptions to determine the fair value of investments and the timing and amount of impairments may have a material effect on the amounts presented in our consolidated financial statements. The following table summarizes other than temporary impairments for the three and nine months ended September 30, 2019 and 2018 , by asset type: Number of Securities Total OTTI Losses Portion of OTTI Losses Recognized in (from) Other Comprehensive Income Net OTTI Losses Recognized in Operations (Dollars in thousands) Three months ended September 30, 2019 Fixed maturity securities, available for sale: Residential mortgage backed securities 1 $ (101 ) $ — $ (101 ) Three months ended September 30, 2018 Fixed maturity securities, available for sale: Corporate securities: Capital goods 1 $ (719 ) $ — $ (719 ) Consumer discretionary 6 (5,968 ) — (5,968 ) Energy 2 (1,212 ) — (1,212 ) Financials 5 (3,495 ) — (3,495 ) Information technology 1 (550 ) — (550 ) Telecommunications 2 (249 ) — (249 ) Transportation 1 (178 ) — (178 ) Utilities 1 (94 ) — (94 ) Commercial mortgage backed securities 1 (1,908 ) — (1,908 ) 20 $ (14,373 ) $ — $ (14,373 ) Nine months ended September 30, 2019 Fixed maturity securities, available for sale: Residential mortgage backed securities 3 $ (101 ) $ (215 ) $ (316 ) Commercial mortgage backed securities 1 (349 ) — (349 ) Other asset backed securities 1 (649 ) — (649 ) 5 $ (1,099 ) $ (215 ) $ (1,314 ) Nine months ended September 30, 2018 Fixed maturity securities, available for sale: Corporate securities: Capital goods 1 $ (719 ) $ — $ (719 ) Consumer discretionary 7 (6,875 ) — (6,875 ) Energy 2 (1,212 ) — (1,212 ) Financials 5 (3,495 ) — (3,495 ) Information technology 1 (550 ) — (550 ) Telecommunications 2 (249 ) — (249 ) Transportation 1 (178 ) — (178 ) Utilities 1 (94 ) — (94 ) Residential mortgage backed securities 3 (63 ) (295 ) (358 ) Commercial mortgage backed securities 1 (1,908 ) — (1,908 ) Other asset backed securities 1 (682 ) (1,356 ) (2,038 ) 25 $ (16,025 ) $ (1,651 ) $ (17,676 ) The cumulative portion of other than temporary impairments determined to be credit losses which have been recognized in operations for debt securities are summarized as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Cumulative credit loss at beginning of period $ (165,651 ) $ (156,469 ) $ (175,398 ) $ (157,066 ) Additions for the amount related to credit losses for which OTTI has not previously been recognized — (14,373 ) (998 ) (16,025 ) Additional credit losses on securities for which OTTI has previously been recognized (101 ) — (316 ) (1,651 ) Accumulated losses on securities that were disposed of during the period 10,775 — 21,735 3,900 Cumulative credit loss at end of period $ (154,977 ) $ (170,842 ) $ (154,977 ) $ (170,842 ) The following table summarizes the cumulative noncredit portion of OTTI and the change in fair value since recognition of OTTI, both of which were recognized in other comprehensive income, by major type of security, for securities that are part of our investment portfolio at September 30, 2019 and December 31, 2018 : Amortized Cost OTTI Recognized in Other Comprehensive Income (Loss) Change in Fair Value Since OTTI was Recognized Fair Value (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: Corporate securities $ 28,728 $ (3,700 ) $ 10,088 $ 35,116 Residential mortgage backed securities 198,959 (151,562 ) 180,704 228,101 Commercial mortgage backed securities 12,867 — 271 13,138 Other asset backed securities 977 — 326 1,303 $ 241,531 $ (155,262 ) $ 191,389 $ 277,658 December 31, 2018 Fixed maturity securities, available for sale: Corporate securities $ 69,580 $ (3,700 ) $ 6,195 $ 72,075 Residential mortgage backed securities 245,691 (167,846 ) 199,191 277,036 Commercial mortgage backed securities 35,244 — — 35,244 Other asset backed securities 1,692 — 326 2,018 $ 352,207 $ (171,546 ) $ 205,712 $ 386,373

Mortgage Loans on Real Estate

Mortgage Loans on Real Estate	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Mortgage Loans on Real Estate	Mortgage Loans on Real Estate Our mortgage loan portfolio is summarized in the following table. There were commitments outstanding of $173.3 million at September 30, 2019 . September 30, 2019 December 31, 2018 (Dollars in thousands) Principal outstanding $ 3,221,152 $ 2,952,464 Loan loss allowance (8,079 ) (8,239 ) Deferred prepayment fees (998 ) (1,134 ) Carrying value $ 3,212,075 $ 2,943,091 The portfolio consists of commercial mortgage loans collateralized by the related properties and diversified as to property type, location and loan size. Our mortgage lending policies establish limits on the amount that can be loaned to one borrower and other criteria to attempt to reduce the risk of default. The mortgage loan portfolio is summarized by geographic region and property type as follows: September 30, 2019 December 31, 2018 Principal Percent Principal Percent (Dollars in thousands) Geographic distribution East $ 600,204 18.6 % $ 586,773 19.9 % Middle Atlantic 240,241 7.5 % 168,969 5.7 % Mountain 372,437 11.6 % 357,642 12.1 % New England 9,220 0.3 % 9,418 0.3 % Pacific 579,831 18.0 % 521,363 17.7 % South Atlantic 739,498 22.9 % 694,599 23.5 % West North Central 281,067 8.7 % 291,890 9.9 % West South Central 398,654 12.4 % 321,810 10.9 % $ 3,221,152 100.0 % $ 2,952,464 100.0 % Property type distribution Office $ 249,703 7.7 % $ 268,932 9.1 % Medical Office 30,930 1.0 % 33,467 1.1 % Retail 1,185,510 36.8 % 1,091,627 37.0 % Industrial/Warehouse 859,410 26.7 % 762,887 25.8 % Apartment 695,726 21.6 % 600,638 20.3 % Agricultural 39,205 1.2 % 25,000 0.9 % Mixed use/other 160,668 5.0 % 169,913 5.8 % $ 3,221,152 100.0 % $ 2,952,464 100.0 % Our financing receivables currently consist of one portfolio segment which is our commercial mortgage loan portfolio. These are mortgage loans with collateral consisting of commercial real estate and borrowers consisting mostly of limited liability partnerships or limited liability corporations. We evaluate our mortgage loan portfolio for the establishment of a loan loss allowance by specific identification of impaired loans and the measurement of an estimated loss for each individual loan identified. A mortgage loan is impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. If we determine that the value of any specific mortgage loan is impaired, the carrying amount of the mortgage loan will be reduced to its fair value, based upon the present value of expected future cash flows from the loan discounted at the loan's effective interest rate, or the fair value of the underlying collateral less estimated costs to sell. In addition, we analyze the mortgage loan portfolio for the need of a general loan allowance for probable losses on all other loans on a quantitative and qualitative basis. The amount of the general loan allowance is based upon management's evaluation of the collectability of the loan portfolio, historical loss experience, delinquencies, credit concentrations, underwriting standards and national and local economic conditions. We rate each of the mortgage loans in our portfolio based on factors such as historical operating performance, loan to value ratio and economic outlook, among others. We calculate a loss factor to apply to each rating based on historical losses we have recognized in our mortgage loan portfolio. We apply the loss factors to the total principal outstanding within each rating category to determine an appropriate estimate of the general loan loss allowance. We also assess the portfolio qualitatively and apply a loss rate to all loans without a specific allowance based on management's assessment of economic conditions, and we apply an additional amount of loss allowance to a group of loans that we have identified as having higher risk of loss. The following table presents a rollforward of our specific and general valuation allowances for mortgage loans on real estate: Three Months Ended Three Months Ended Specific Allowance General Allowance Specific Allowance General Allowance (Dollars in thousands) Beginning allowance balance $ (229 ) $ (7,600 ) $ (696 ) $ (5,630 ) Charge-offs — — — — Recoveries — — 467 — Change in provision for credit losses — (250 ) (1,255 ) — Ending allowance balance $ (229 ) $ (7,850 ) $ (1,484 ) $ (5,630 ) Nine Months Ended Nine Months Ended Specific Allowance General Allowance Specific Allowance General Allowance (Dollars in thousands) Beginning allowance balance $ (229 ) $ (8,010 ) $ (1,418 ) $ (6,100 ) Charge-offs — — — — Recoveries — — 1,189 — Change in provision for credit losses — 160 (1,255 ) 470 Ending allowance balance $ (229 ) $ (7,850 ) $ (1,484 ) $ (5,630 ) The specific allowance represents the total credit loss allowances on loans which are individually evaluated for impairment. The general allowance is for the group of loans discussed above which are collectively evaluated for impairment. The following table presents the total outstanding principal of loans evaluated for impairment by basis of impairment method: September 30, 2019 December 31, 2018 (Dollars in thousands) Individually evaluated for impairment $ 1,235 $ 1,253 Collectively evaluated for impairment 3,219,917 2,951,211 Total loans evaluated for impairment $ 3,221,152 $ 2,952,464 Charge-offs include allowances that have been established on loans that were satisfied either by taking ownership of the collateral or by some other means such as discounted pay-off or loan sale. When ownership of the property is taken it is recorded at the lower of the mortgage loan's carrying value or the property's fair value (based on appraised values) less estimated costs to sell. The real estate owned is recorded as a component of Other investments and the mortgage loan is recorded as fully paid, with any allowance for credit loss that has been established charged off. Fair value of the real estate is determined by third party appraisal. Recoveries are situations where we have received a payment from the borrower in an amount greater than the carrying value of the loan (principal outstanding less specific allowance). We did not own any real estate during the three and nine months ended September 30, 2019 and 2018 . We analyze credit risk of our mortgage loans by analyzing all available evidence on loans that are delinquent and loans that are in a workout period. September 30, 2019 December 31, 2018 (Dollars in thousands) Credit Exposure - By Payment Activity Performing $ 3,221,152 $ 2,952,464 In workout — — Collateral dependent — — $ 3,221,152 $ 2,952,464 Loans that are categorized as "in workout" consist of loans that we have agreed to lower or no mortgage payments for a period of time while the borrowers address cash flow and/or operational issues. The key features of these workouts have been determined on a loan-by-loan basis. Most of these loans are in a period of low cash flow due to tenants vacating their space or tenants requesting rent relief during difficult economic periods. Generally, we have allowed the borrower a six month interest only period and in some cases a twelve month period of interest only. Interest only workout loans are expected to return to their regular debt service payments after the interest only period. Interest only loans that are not fully amortizing will have a larger balance at their balloon date than originally contracted. Fully amortizing loans that are in interest only periods will have larger debt service payments for their remaining term due to lost principal payments during the interest only period. In limited circumstances we have allowed borrowers to pay the principal portion of their loan payment into an escrow account that can be used for capital and tenant improvements for a period of not more than twelve months. In these situations new loan amortization schedules are calculated based on the principal not collected during this twelve month workout period and larger payments are collected for the remaining term of each loan. In all cases, the original interest rate and maturity date have not been modified, and we have not forgiven any principal amounts. Mortgage loans are considered delinquent when they become 60 days or more past due. In general, when loans become 90 days past due, become collateral dependent or enter a period with no debt service payments required we place them on non-accrual status and discontinue recognizing interest income. If payments are received on a delinquent loan, interest income is recognized to the extent it would have been recognized if normal principal and interest would have been received timely. If payments are received to bring a delinquent loan back to current we will resume accruing interest income on that loan. There were no loans in non-accrual status at September 30, 2019 and December 31, 2018 , respectively. We define collateral dependent loans as those mortgage loans for which we will depend on the value of the collateral real estate to satisfy the outstanding principal of the loan. All of our commercial mortgage loans depend on the cash flow of the borrower to be at a sufficient level to service the principal and interest payments as they come due. In general, cash inflows of the borrowers are generated by collecting monthly rent from tenants occupying space within the borrowers' properties. Our borrowers face collateral risks such as tenants going out of business, tenants struggling to make rent payments as they become due, and tenants canceling leases and moving to other locations. We have a number of loans where the real estate is occupied by a single tenant. Our borrowers sometimes face both a reduction in cash flow on their mortgage property as well as a reduction in the fair value of the real estate collateral. If borrowers are unable to replace lost rent revenue and increases in the fair value of their property do not materialize, we could potentially incur more losses than what we have allowed for in our specific and general loan loss allowances. Aging of financing receivables is summarized in the following table, with loans in a "workout" period as of the reporting date considered current if payments are current in accordance with agreed upon terms: 30 - 59 Days 60 - 89 Days 90 Days and Over Total Past Due Current Collateral Dependent Receivables Total Financing Receivables (Dollars in thousands) Commercial Mortgage Loans September 30, 2019 $ — $ — $ — $ — $ 3,221,152 $ — $ 3,221,152 December 31, 2018 $ — $ — $ — $ — $ 2,952,464 $ — $ 2,952,464 Financing receivables summarized in the following two tables represent all loans that we are either not currently collecting, or those we feel it is probable we will not collect all amounts due according to the contractual terms of the loan agreements (all loans that we have worked with the borrower to alleviate short-term cash flow issues, loans delinquent for 60 days or more at the reporting date, loans we have determined to be collateral dependent and loans that we have recorded specific impairments on that we feel may continue to have performance issues). Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) September 30, 2019 Mortgage loans with an allowance $ 1,006 $ 1,235 $ (229 ) Mortgage loans with no related allowance — — — $ 1,006 $ 1,235 $ (229 ) December 31, 2018 Mortgage loans with an allowance $ 1,024 $ 1,253 $ (229 ) Mortgage loans with no related allowance — — — $ 1,024 $ 1,253 $ (229 ) Average Recorded Investment Interest Income Recognized (Dollars in thousands) Three months ended September 30, 2019 Mortgage loans with an allowance $ 1,009 $ 17 Mortgage loans with no related allowance — — $ 1,009 $ 17 Three months ended September 30, 2018 Mortgage loans with an allowance $ 2,337 $ 37 Mortgage loans with no related allowance — — $ 2,337 $ 37 Nine months ended September 30, 2019 Mortgage loans with an allowance $ 1,015 $ 52 Mortgage loans with no related allowance — — $ 1,015 $ 52 Nine months ended September 30, 2018 Mortgage loans with an allowance $ 2,386 $ 136 Mortgage loans with no related allowance — — $ 2,386 $ 136 A Troubled Debt Restructuring ("TDR") is a situation where we have granted a concession to a borrower for economic or legal reasons related to the borrower's financial difficulties that we would not otherwise consider. A mortgage loan that has been granted new terms, including workout terms as described previously, would be considered a TDR if it meets conditions that would indicate a borrower is experiencing financial difficulty and the new terms constitute a concession on our part. We analyze all loans where we have agreed to workout terms and all loans that we have refinanced to determine if they meet the definition of a TDR. We consider the following factors in determining whether or not a borrower is experiencing financial difficulty: • borrower is in default, • borrower has declared bankruptcy, • there is growing concern about the borrower's ability to continue as a going concern, • borrower has insufficient cash flows to service debt, • borrower's inability to obtain funds from other sources, and • there is a breach of financial covenants by the borrower. If the borrower is determined to be in financial difficulty, we consider the following conditions to determine if the borrower is granted a concession: • assets used to satisfy debt are less than our recorded investment, • interest rate is modified, • maturity date extension at an interest rate less than market rate, • capitalization of interest, • delaying principal and/or interest for a period of three months or more, and • partial forgiveness of the balance or charge-off. Mortgage loan workouts, refinances or restructures that are classified as TDRs are individually evaluated and measured for impairment. There were no mortgage loans on commercial real estate that we determined to be a TDR at September 30, 2019 and December 31, 2018

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments None of our derivatives qualify for hedge accounting, thus, any change in the fair value of the derivatives is recognized immediately in the consolidated statements of operations. The fair value of our derivative instruments, including derivative instruments embedded in fixed index annuity contracts, presented in the consolidated balance sheets are as follows: September 30, 2019 December 31, 2018 (Dollars in thousands) Assets Derivative instruments Call options $ 963,081 $ 205,149 Other assets Interest rate caps 17 597 Interest rate swap — 354 $ 963,098 $ 206,100 Liabilities Policy benefit reserves - annuity products Fixed index annuities - embedded derivatives, net $ 9,381,094 $ 8,165,405 Other liabilities Interest rate swap 906 — $ 9,382,000 $ 8,165,405 The changes in fair value of derivatives included in the unaudited consolidated statements of operations are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Change in fair value of derivatives: Call options $ (19,997 ) $ 594,872 $ 442,111 $ 273,946 Interest rate swap (3 ) 258 (1,059 ) 1,658 Interest rate caps (42 ) 181 (580 ) 829 $ (20,042 ) $ 595,311 $ 440,472 $ 276,433 Change in fair value of embedded derivatives: Fixed index annuities - embedded derivatives $ 24,998 $ 196,808 $ 882,230 $ (1,198,115 ) Other changes in difference between policy benefit reserves computed using derivative accounting vs. long-duration contracts accounting 187,280 186,908 423,933 612,650 $ 212,278 $ 383,716 $ 1,306,163 $ (585,465 ) The amounts presented as "Other changes in difference between policy benefit reserves computed using derivative accounting vs. long-duration contracts accounting" represents the total change in the difference between policy benefit reserves for fixed index annuities computed under the derivative accounting standard and the long-duration contracts accounting standard at each balance sheet date, less the change in fair value of our fixed index annuities embedded derivatives that is presented as Level 3 liabilities in Note 2. We have fixed index annuity products that guarantee the return of principal to the policyholder and credit interest based on a percentage of the gain in a specified market index. When fixed index annuity deposits are received, a portion of the deposit is used to purchase derivatives consisting of call options on the applicable market indices to fund the index credits due to fixed index annuity policyholders. Substantially all such call options are one year options purchased to match the funding requirements of the underlying policies. The call options are marked to fair value with the change in fair value included as a component of revenues. The change in fair value of derivatives includes the gains or losses recognized at the expiration of the option term and the changes in fair value for open positions. On the respective anniversary dates of the index policies, the index used to compute the index credit is reset and we purchase new call options to fund the next index credit. We manage the cost of these purchases through the terms of our fixed index annuities, which permit us to change caps, participation rates, and/or asset fees, subject to guaranteed minimums on each policy's anniversary date. By adjusting caps, participation rates, or asset fees, we can generally manage option costs except in cases where the contractual features would prevent further modifications. Our strategy attempts to mitigate any potential risk of loss due to the nonperformance of the counterparties to these call options through a regular monitoring process which evaluates the program's effectiveness. We do not purchase call options that would require payment or collateral to another institution and our call options do not contain counterparty credit-risk-related contingent features. We are exposed to risk of loss in the event of nonperformance by the counterparties and, accordingly, we purchase our option contracts from multiple counterparties and evaluate the creditworthiness of all counterparties prior to purchase of the contracts. All of these options have been purchased from nationally recognized financial institutions with a Standard and Poor's credit rating of A- or higher at the time of purchase and the maximum credit exposure to any single counterparty is subject to concentration limits. We also have credit support agreements that allow us to request the counterparty to provide collateral to us when the fair value of our exposure to the counterparty exceeds specified amounts. The notional amount and fair value of our call options by counterparty and each counterparty's current credit rating are as follows: September 30, 2019 December 31, 2018 Counterparty Credit Rating (S&P) Credit Rating (Moody's) Notional Amount Fair Value Notional Amount Fair Value (Dollars in thousands) Bank of America A+ Aa2 $ 3,938,470 $ 46,637 $ 6,518,808 $ 6,704 Barclays A A2 4,549,168 141,155 2,301,414 27,032 Canadian Imperial Bank of Commerce A+ Aa2 4,321,739 126,868 4,856,150 29,313 Citibank, N.A. A+ Aa3 4,064,075 83,451 4,792,208 27,239 Credit Suisse A+ A1 4,739,536 77,910 2,877,916 12,887 J.P. Morgan A+ Aa2 4,772,783 101,072 3,701,964 17,564 Morgan Stanley A+ A1 1,990,733 21,001 3,560,044 1,561 Royal Bank of Canada AA- A2 2,720,343 82,946 1,871,305 14,011 Societe Generale A A1 3,205,393 106,016 2,343,165 21,681 SunTrust A- Baa1 2,017,444 58,986 1,755,030 12,047 Wells Fargo A+ Aa2 3,656,074 112,408 4,618,569 33,398 Exchange traded 201,850 4,631 224,204 1,712 $ 40,177,608 $ 963,081 $ 39,420,777 $ 205,149 As of September 30, 2019 and December 31, 2018 , we held $0.9 billion and $0.2 billion , respectively, of cash and cash equivalents and other investments from counterparties for derivative collateral, which is included in Other liabilities on our consolidated balance sheets. This derivative collateral limits the maximum amount of economic loss due to credit risk that we would incur if parties to the call options failed completely to perform according to the terms of the contracts to $68.4 million and $16.1 million at September 30, 2019 and December 31, 2018 , respectively. The future index credits on our fixed index annuities are treated as a "series of embedded derivatives" over the expected life of the applicable contract. We do not purchase call options to fund the index liabilities which may arise after the next policy anniversary date. We must value both the call options and the related forward embedded options in the policies at fair value. We entered into an interest rate swap and interest rate caps to manage interest rate risk associated with the floating rate component on certain of our subordinated debentures. See Note 10 in our Annual Report on Form 10-K for the year ended December 31, 2018 for more information on our subordinated debentures. The terms of the interest rate swap provide that we pay a fixed rate of interest and receive a floating rate of interest. The terms of the interest rate caps limit the three month LIBOR to 2.50% . The interest rate swap and caps are not effective hedges under accounting guidance for derivative instruments and hedging activities. Therefore, we record the interest rate swap and caps at fair value and any net cash payments received or paid are included in the change in fair value of derivatives in the unaudited consolidated statements of operations. Details regarding the interest rate swap are as follows: Notional Pay September 30, 2019 December 31, 2018 Maturity Date Amount Receive Rate Rate Counterparty Fair Value (Dollars in thousands) March 15, 2021 $ 85,500 LIBOR 2.415 % SunTrust $ (906 ) $ 354 Details regarding the interest rate caps are as follows: Notional Cap September 30, 2019 December 31, 2018 Maturity Date Amount Floating Rate Rate Counterparty Fair Value (Dollars in thousands) July 7, 2021 $ 40,000 LIBOR 2.50 % SunTrust $ 8 $ 302 July 8, 2021 12,000 LIBOR 2.50 % SunTrust 3 91 July 29, 2021 27,000 LIBOR 2.50 % SunTrust 6 204 $ 79,000 $ 17 $ 597 The interest rate swap converts floating rates to fixed rates until March 2021. The interest rate caps cap our interest rates until July 2021. As of September 30, 2019 , we deposited $0.8 million of collateral with the counterparty to the swap.

Notes Payable and Amounts Due U

Notes Payable and Amounts Due Under Repurchase Agreements	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Notes Payable and Amounts Due Under Repurchase Agreements	Notes Payable and Amounts Due Under Repurchase Agreements Notes payable includes the following: September 30, 2019 December 31, 2018 (Dollars in thousands) Senior notes due 2027 Principal $ 500,000 $ 500,000 Unamortized debt issue costs (4,733 ) (5,102 ) Unamortized discount (285 ) (307 ) $ 494,982 $ 494,591 On June 16, 2017, we issued $500 million aggregate principal amount of senior unsecured notes due 2027 which bear interest at 5.0% per year and will mature on June 15, 2027 (the "2027 Notes"). The 2027 Notes were issued at a $0.3 million discount, which is being amortized over the term of the 2027 Notes using the effective interest method. Contractual interest is payable semi-annually in arrears each June 15th and December 15th. The initial transaction fees and costs totaling $5.8 million were capitalized as deferred financing costs and are being amortized over the term of the 2027 Notes using the effective interest method. As part of our investment strategy, we enter into securities repurchase agreements (short-term collateralized borrowings). When we do borrow cash on these repurchase agreements, we pledge collateral in the form of debt securities with fair values approximately equal to the amount due and we use the cash to purchase debt securities ahead of the time we collect the cash from selling annuity policies to avoid a lag between the investment of funds and the obligation to credit interest to policyholders. We earn investment income on the securities purchased with these borrowings at a rate in excess of the cost of these borrowings. Such borrowings averaged $9.7 million and $39.4 million during the three and nine months ended September 30, 2019 , respectively, compared to $5.1 million and $41.4 million for the same periods in 2018 . The maximum amount borrowed was $243.6 million and $544.1 million during the nine months ended September 30, 2019 and 2018 , respectively. The weighted average interest rate on amounts due under repurchase agreements was 2.25% and 2.97% for the three and nine months ended September 30, 2019 , respectively, compared to 0.00% and 1.66% for the same periods in 2018 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We are occasionally involved in litigation, both as a defendant and as a plaintiff. In addition, state regulatory bodies, such as state insurance departments, the Securities and Exchange Commission ("SEC"), the Department of Labor, and other regulatory bodies regularly make inquiries and conduct examinations or investigations concerning our compliance with, among other things, insurance laws, securities laws, and the Employee Retirement Income Security Act of 1974, as amended. In accordance with applicable accounting guidelines, we establish an accrued liability for litigation and regulatory matters when those matters present loss contingencies that are both probable and estimable. As a litigation or regulatory matter is developing we, in conjunction with outside counsel, evaluate on an ongoing basis whether the matter presents a loss contingency that meets conditions indicating the need for accrual and/or disclosure, and if not the matter will continue to be monitored for further developments. If and when the loss contingency related to litigation or regulatory matters is deemed to be both probable and estimable, we will establish an accrued liability with respect to that matter and will continue to monitor the matter for further developments that may affect the amount of the accrued liability. There can be no assurance that any pending or future litigation will not have a material adverse effect on our business, financial condition, or results of operations. In addition to our commitments to fund mortgage loans, we have unfunded commitments at September 30, 2019 to limited partnerships of $32.3 million and to fixed maturity securities of $138.5 million

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of earnings per common share and earnings per common share - assuming dilution: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands, except per share data) Numerator: Net income - numerator for earnings per common share $ 37,360 $ 169,328 $ 25,940 $ 404,193 Denominator: Weighted average common shares outstanding 91,251,590 90,485,567 91,080,681 90,278,209 Effect of dilutive securities: Stock options and deferred compensation agreements 190,137 705,465 326,306 750,588 Restricted stock and restricted stock units 268,830 459,854 340,875 326,613 Denominator for earnings per common share - assuming dilution 91,710,557 91,650,886 91,747,862 91,355,410 Earnings per common share $ 0.41 $ 1.87 $ 0.28 $ 4.48 Earnings per common share - assuming dilution $ 0.41 $ 1.85 $ 0.28 $ 4.42 During the three months ended September 30, 2019 , there were 551,585 options to purchase shares of our common stock outstanding, with an exercise price of $24.79 , excluded from the computation of diluted earnings per share. There were no options to purchase shares of our common stock outstanding excluded from the computation of diluted earnings per share during the nine months ended September 30, 2019 or during the three and nine months ended September 30, 2018

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Adopted and New Accounting Pronouncements, Policy	Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (“FASB”) issued an accounting standards update (“ASU”) that requires recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This ASU affects accounting and disclosure more dramatically for lessees as accounting and disclosure for lessors is mainly unchanged. We adopted this ASU on January 1, 2019. The adoption of this ASU resulted in the recognition of a lease asset and lease liability of $3.8 million , respectively, on our consolidated balance sheet at September 30, 2019 . In March 2017, the FASB issued an ASU that applies to certain callable debt securities where the amortized cost basis is at a premium to the price repayable by the issuer at the earliest call date. Under this guidance, the premium is amortized to the first call date. We adopted this ASU on January 1, 2019. The adoption of this ASU did not have a material impact on our consolidated financial statements. In June 2018, the FASB issued an ASU that expands the scope of Accounting Standards Codification 718, Compensation-Stock Compensation, to include share-based payment transactions for acquiring goods and services to nonemployees and eliminates the existing accounting model for nonemployee share-based payment awards. We adopted this ASU on January 1, 2019. While this ASU results in an earlier measurement date for our nonemployee restricted stock units that have not vested as of January 1, 2019, there was no impact to our consolidated financial statements upon adoption. New Accounting Pronouncements In June 2016, the FASB issued an ASU that significantly changes the impairment model for most financial assets that are measured at amortized cost and certain other instruments from an incurred loss model to an expected loss model that requires these assets be presented at the net amount expected to be collected. In addition, credit losses on available for sale debt securities will be recorded through an allowance account. This ASU will be effective for us on January 1, 2020, with early adoption permitted. Our implementation procedures to date relative to this standard include, but are not limited to, identifying financial assets within the scope of this guidance, developing a current expected credit loss model for our commercial mortgage loans and refining internal processes for financial assets impacted by this guidance. We believe the new impairment model will lead to earlier recognition of credit losses for our commercial mortgage loans. In August 2018, the FASB issued an ASU that revises certain aspects of the measurement models and disclosure requirements for long duration insurance and investment contracts. The FASB’s objective in issuing this ASU is to improve, simplify, and enhance the accounting for long-duration contracts. The revisions include updating cash flow assumptions in the calculation of the liability for traditional life products, introducing the term ‘market risk benefit’ ("MRB") and requiring all contract features meeting the definition of an MRB to be measured at fair value, simplifying the method used to amortize deferred policy acquisition costs and deferred sales inducements to a constant basis over the expected term of the related contracts rather than based on gross profits and enhancing disclosure requirements. While this ASU is effective for us on January 1, 2022, the transition date (the remeasurement date) is January 1, 2020. Early adoption of this ASU is permitted. We are in the process of evaluating the impact this guidance will have on our consolidated financial statements.
Fair Values of Financial Instruments, Policy	Fair value is the price that would be received to sell an asset or paid to transfer a liability (exit price) in an orderly transaction between market participants at the measurement date. The objective of a fair value measurement is to determine that price for each financial instrument at each measurement date. We meet this objective using various methods of valuation that include market, income and cost approaches. We categorize our financial instruments into three levels of fair value hierarchy based on the priority of inputs used in determining fair value. The hierarchy defines the highest priority inputs (Level 1) as quoted prices in active markets for identical assets or liabilities. The lowest priority inputs (Level 3) are our own assumptions about what a market participant would use in determining fair value such as estimated future cash flows. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, a financial instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the financial instrument. We categorize financial assets and liabilities recorded at fair value in the consolidated balance sheets as follows: Level 1— Quoted prices are available in active markets for identical financial instruments as of the reporting date. We do not adjust the quoted price for these financial instruments, even in situations where we hold a large position and a sale could reasonably impact the quoted price. Level 2— Quoted prices in active markets for similar financial instruments, quoted prices for identical or similar financial instruments in markets that are not active; and models and other valuation methodologies using inputs other than quoted prices that are observable. Level 3— Models and other valuation methodologies using significant inputs that are unobservable for financial instruments and include situations where there is little, if any, market activity for the financial instrument. The inputs into the determination of fair value require significant management judgment or estimation. Financial instruments that are included in Level 3 are securities for which no market activity or data exists and for which we used discounted expected future cash flows with our own assumptions about what a market participant would use in determining fair value.
Investments, Policy	We review and analyze all investments on an ongoing basis for changes in market interest rates and credit deterioration. This review process includes analyzing our ability to recover the amortized cost basis of each investment that has a fair value that is materially lower than its amortized cost and requires a high degree of management judgment and involves uncertainty. The evaluation of securities for other than temporary impairments is a quantitative and qualitative process, which is subject to risks and uncertainties. We have a policy and process to identify securities that could potentially have impairments that are other than temporary. This process involves monitoring market events and other items that could impact issuers. The evaluation includes but is not limited to such factors as: • the length of time and the extent to which the fair value has been less than amortized cost or cost; • whether the issuer is current on all payments and all contractual payments have been made as agreed; • the remaining payment terms and the financial condition and near-term prospects of the issuer; • the lack of ability to refinance due to liquidity problems in the credit market; • the fair value of any underlying collateral; • the existence of any credit protection available; • our intent to sell and whether it is more likely than not we would be required to sell prior to recovery for debt securities; • consideration of rating agency actions; and • changes in estimated cash flows of mortgage and asset backed securities. We determine whether other than temporary impairment losses should be recognized for debt securities by assessing all facts and circumstances surrounding each security. Where the decline in fair value of debt securities is attributable to changes in market interest rates or to factors such as market volatility, liquidity and spread widening, and we anticipate recovery of all contractual or expected cash flows, we do not consider these investments to be other than temporarily impaired because we do not intend to sell these investments and it is not more likely than not we will be required to sell these investments before a recovery of amortized cost, which may be maturity. If we intend to sell a debt security or if it is more likely than not that we will be required to sell a debt security before recovery of its amortized cost basis, other than temporary impairment has occurred and the difference between amortized cost and fair value will be recognized as a loss in operations. If we do not intend to sell and it is not more likely than not we will be required to sell the debt security but also do not expect to recover the entire amortized cost basis of the security, an impairment loss would be recognized in operations in the amount of the expected credit loss. We determine the amount of expected credit loss by calculating the present value of the cash flows expected to be collected discounted at each security's acquisition yield based on our consideration of whether the security was of high credit quality at the time of acquisition. The difference between the present value of expected future cash flows and the amortized cost basis of the security is the amount of credit loss recognized in operations. The remaining amount of the other than temporary impairment is recognized in other comprehensive income (loss). The determination of the credit loss component of a mortgage backed security is based on a number of factors. The primary consideration in this evaluation process is the issuer's ability to meet current and future interest and principal payments as contractually stated at time of purchase. Our review of these securities includes an analysis of the cash flow modeling under various default scenarios considering independent third party benchmarks, the seniority of the specific tranche within the structure of the security, the composition of the collateral and the actual default, loss severity and prepayment experience exhibited. With the input of third party assumptions for default projections, loss severity and prepayment expectations, we evaluate the cash flow projections to determine whether the security is performing in accordance with its contractual obligation. We utilize the models from a leading structured product software specialist serving institutional investors. These models incorporate each security's seniority and cash flow structure. In circumstances where the analysis implies a potential for principal loss at some point in the future, we use the "best estimate" cash flow projection discounted at the security's effective yield at acquisition to determine the amount of our potential credit loss associated with this security. The discounted expected future cash flows equates to our expected recovery value. Any shortfall of the expected recovery when compared to the amortized cost of the security will be recorded as the credit loss component of other than temporary impairment. The cash flow modeling is performed on a security-by-security basis and incorporates actual cash flows on the residential mortgage backed securities through the current period, as well as the projection of remaining cash flows using a number of assumptions including default rates, prepayment rates and loss severity rates. The default curves we use are tailored to the Prime or Alt-A residential mortgage backed securities that we own, which assume lower default rates and loss severity for Prime securities versus Alt-A securities. These default curves are scaled higher or lower depending on factors such as current underlying mortgage loan performance, rating agency loss projections, loan to value ratios, geographic diversity, as well as other appropriate considerations. The determination of the credit loss component of a corporate bond is based on the underlying financial performance of the issuer and their ability to meet their contractual obligations. Considerations in our evaluation include, but are not limited to, credit rating changes, financial statement and ratio analysis, changes in management, significant changes in credit spreads, breaches of financial covenants and a review of the economic outlook for the industry and markets in which they trade. In circumstances where an issuer appears unlikely to meet its future obligation, or the security's price decline is deemed other than temporary, an estimate of credit loss is determined. Credit loss is calculated using default probabilities as derived from the credit default swaps markets in conjunction with recovery rates derived from independent third party analysis or a best estimate of credit loss. This credit loss rate is then incorporated into a present value calculation based on an expected principal loss in the future discounted at the yield at the date of purchase and compared to amortized cost to determine the amount of credit loss associated with the security. In addition, for debt securities which we do not intend to sell and it is not more likely than not we will be required to sell, but our intent changes due to changes or events that could not have been reasonably anticipated, an other than temporary impairment charge is recognized. Once an impairment charge has been recorded, we then continue to review the other than temporarily impaired securities for appropriate valuation on an ongoing basis. Unrealized losses may be recognized in future periods through a charge to earnings should we later conclude that the decline in fair value below amortized cost is other than temporary pursuant to our accounting policy described above. The use of different methodologies and assumptions to determine the fair value of investments and the timing and amount of impairments may have a material effect on the amounts presented in our consolidated financial statements.
Mortgage Loans on Real Estate, Allowance for Loan Losses, Policy	We evaluate our mortgage loan portfolio for the establishment of a loan loss allowance by specific identification of impaired loans and the measurement of an estimated loss for each individual loan identified. A mortgage loan is impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. If we determine that the value of any specific mortgage loan is impaired, the carrying amount of the mortgage loan will be reduced to its fair value, based upon the present value of expected future cash flows from the loan discounted at the loan's effective interest rate, or the fair value of the underlying collateral less estimated costs to sell. In addition, we analyze the mortgage loan portfolio for the need of a general loan allowance for probable losses on all other loans on a quantitative and qualitative basis. The amount of the general loan allowance is based upon management's evaluation of the collectability of the loan portfolio, historical loss experience, delinquencies, credit concentrations, underwriting standards and national and local economic conditions. We rate each of the mortgage loans in our portfolio based on factors such as historical operating performance, loan to value ratio and economic outlook, among others. We calculate a loss factor to apply to each rating based on historical losses we have recognized in our mortgage loan portfolio. We apply the loss factors to the total principal outstanding within each rating category to determine an appropriate estimate of the general loan loss allowance. We also assess the portfolio qualitatively and apply a loss rate to all loans without a specific allowance based on management's assessment of economic conditions, and we apply an additional amount of loss allowance to a group of loans that we have identified as having higher risk of loss.
Mortgage Loans on Real Estate, Real Estate Acquired Through Foreclosure, Policy	Charge-offs include allowances that have been established on loans that were satisfied either by taking ownership of the collateral or by some other means such as discounted pay-off or loan sale. When ownership of the property is taken it is recorded at the lower of the mortgage loan's carrying value or the property's fair value (based on appraised values) less estimated costs to sell. The real estate owned is recorded as a component of Other investments and the mortgage loan is recorded as fully paid, with any allowance for credit loss that has been established charged off. Fair value of the real estate is determined by third party appraisal. Recoveries are situations where we have received a payment from the borrower in an amount greater than the carrying value of the loan (principal outstanding less specific allowance).
Mortgage Loans on Real Estate, Non-Accrual Loan Status, Policy	Loans that are categorized as "in workout" consist of loans that we have agreed to lower or no mortgage payments for a period of time while the borrowers address cash flow and/or operational issues. The key features of these workouts have been determined on a loan-by-loan basis. Most of these loans are in a period of low cash flow due to tenants vacating their space or tenants requesting rent relief during difficult economic periods. Generally, we have allowed the borrower a six month interest only period and in some cases a twelve month period of interest only. Interest only workout loans are expected to return to their regular debt service payments after the interest only period. Interest only loans that are not fully amortizing will have a larger balance at their balloon date than originally contracted. Fully amortizing loans that are in interest only periods will have larger debt service payments for their remaining term due to lost principal payments during the interest only period. In limited circumstances we have allowed borrowers to pay the principal portion of their loan payment into an escrow account that can be used for capital and tenant improvements for a period of not more than twelve months. In these situations new loan amortization schedules are calculated based on the principal not collected during this twelve month workout period and larger payments are collected for the remaining term of each loan. In all cases, the original interest rate and maturity date have not been modified, and we have not forgiven any principal amounts. Mortgage loans are considered delinquent when they become 60 days or more past due. In general, when loans become 90 days
Mortgage Loans on Real Estate, Troubled Debt Restructuring, Policy	A Troubled Debt Restructuring ("TDR") is a situation where we have granted a concession to a borrower for economic or legal reasons related to the borrower's financial difficulties that we would not otherwise consider. A mortgage loan that has been granted new terms, including workout terms as described previously, would be considered a TDR if it meets conditions that would indicate a borrower is experiencing financial difficulty and the new terms constitute a concession on our part. We analyze all loans where we have agreed to workout terms and all loans that we have refinanced to determine if they meet the definition of a TDR. We consider the following factors in determining whether or not a borrower is experiencing financial difficulty: • borrower is in default, • borrower has declared bankruptcy, • there is growing concern about the borrower's ability to continue as a going concern, • borrower has insufficient cash flows to service debt, • borrower's inability to obtain funds from other sources, and • there is a breach of financial covenants by the borrower. If the borrower is determined to be in financial difficulty, we consider the following conditions to determine if the borrower is granted a concession: • assets used to satisfy debt are less than our recorded investment, • interest rate is modified, • maturity date extension at an interest rate less than market rate, • capitalization of interest, • delaying principal and/or interest for a period of three months or more, and • partial forgiveness of the balance or charge-off.
Commitments and Contingencies, Policy	In accordance with applicable accounting guidelines, we establish an accrued liability for litigation and regulatory matters when those matters present loss contingencies that are both probable and estimable. As a litigation or regulatory matter is developing we, in conjunction with outside counsel, evaluate on an ongoing basis whether the matter presents a loss contingency that meets conditions indicating the need for accrual and/or disclosure, and if not the matter will continue to be monitored for further developments. If and when the loss contingency related to litigation or regulatory matters is deemed to be both probable and estimable, we will establish an accrued liability with respect to that matter and will continue to monitor the matter for further developments that may affect the amount of the accrued liability.

Fair Values of Financial Inst_2

Fair Values of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Carrying Amounts and Fair Values of Financial Instruments	The following sets forth a comparison of the carrying amounts and fair values of our financial instruments: September 30, 2019 December 31, 2018 Carrying Amount Fair Value Carrying Amount Fair Value (Dollars in thousands) Assets Fixed maturity securities, available for sale $ 51,854,384 $ 51,854,384 $ 45,923,727 $ 45,923,727 Mortgage loans on real estate 3,212,075 3,293,106 2,943,091 2,920,612 Derivative instruments 963,081 963,081 205,149 205,149 Other investments 694,416 694,416 355,531 348,970 Cash and cash equivalents 1,138,737 1,138,737 344,396 344,396 Coinsurance deposits 5,072,015 4,602,181 4,954,068 4,553,790 Interest rate caps 17 17 597 597 Interest rate swap — — 354 354 Counterparty collateral — — 33,101 33,101 Liabilities Policy benefit reserves 60,996,752 51,320,260 57,249,510 49,180,143 Single premium immediate annuity (SPIA) benefit reserves 259,634 267,876 270,406 279,077 Notes payable 494,982 526,760 494,591 489,985 Subordinated debentures 243,311 247,283 242,982 215,514 Amounts due under repurchase agreements 48,931 48,931 109,298 109,298 Interest rate swap 906 906 — —
Assets and Liabilities Measured at Fair Value on a Recurring Basis, By Fair Value Hierarchy Level	Our assets and liabilities which are measured at fair value on a recurring basis as of September 30, 2019 and December 31, 2018 are presented below based on the fair value hierarchy levels: Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Dollars in thousands) September 30, 2019 Assets Fixed maturity securities, available for sale: United States Government full faith and credit $ 12,343 $ 6,421 $ 5,922 $ — United States Government sponsored agencies 695,030 — 695,030 — United States municipalities, states and territories 4,517,661 — 4,517,661 — Foreign government obligations 207,420 — 207,420 — Corporate securities 32,897,127 15 32,897,112 — Residential mortgage backed securities 1,557,156 — 1,557,156 — Commercial mortgage backed securities 5,839,510 — 5,839,510 — Other asset backed securities 6,128,137 — 6,128,137 — Other investments: equity securities 309,313 301,870 7,443 — Derivative instruments 963,081 — 963,081 — Cash and cash equivalents 1,138,737 1,138,737 — — Interest rate caps 17 — 17 — $ 54,265,532 $ 1,447,043 $ 52,818,489 $ — Liabilities Interest rate swap $ 906 $ — $ 906 $ — Fixed index annuities - embedded derivatives 9,381,094 — — 9,381,094 $ 9,382,000 $ — $ 906 $ 9,381,094 December 31, 2018 Assets Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,652 $ 5,900 $ 5,752 $ — United States Government sponsored agencies 1,138,529 — 1,138,529 — United States municipalities, states and territories 4,126,267 — 4,126,267 — Foreign government obligations 230,274 — 230,274 — Corporate securities 28,371,514 7 28,371,507 — Residential mortgage backed securities 1,202,159 — 1,202,159 — Commercial mortgage backed securities 5,379,003 — 5,379,003 — Other asset backed securities 5,464,329 — 5,464,329 — Other investments: equity securities 7,437 — 7,437 — Derivative instruments 205,149 — 205,149 — Cash and cash equivalents 344,396 344,396 — — Interest rate caps 597 — 597 — Interest rate swap 354 — 354 — Counterparty collateral 33,101 — 33,101 — $ 46,514,761 $ 350,303 $ 46,164,458 $ — Liabilities Fixed index annuities - embedded derivatives $ 8,165,405 $ — $ — $ 8,165,405
Schedule of Assumptions Used in Estimating Fair Value	The following table presents average lapse rate and partial withdrawal rate assumptions, by contract duration, used in estimating the fair value of the embedded derivative component of our fixed index annuity policy benefit reserves at each reporting date: Average Lapse Rates Average Partial Withdrawal Rates Contract Duration (Years) September 30, 2019 December 31, 2018 September 30, 2019 December 31, 2018 1 - 5 0.86% 2.05% 3.35% 3.33% 6 - 10 1.30% 7.28% 4.14% 3.33% 11 - 15 3.48% 11.35% 4.17% 3.35% 16 - 20 9.45% 11.90% 4.08% 3.22% 20+ 7.00% 11.57% 3.86% 3.22%
Liabilities Measured at Fair Value on Recurring Basis, Level 3 Reconciliation	The following table provides a reconciliation of the beginning and ending balances for our Level 3 liabilities, which are measured at fair value on a recurring basis using significant unobservable inputs for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Fixed index annuities - embedded derivatives Beginning balance $ 9,281,117 $ 8,351,151 $ 8,165,405 $ 8,790,427 Premiums less benefits 74,979 399,234 333,459 1,354,881 Change in fair value, net 24,998 196,808 882,230 (1,198,115 ) Ending balance $ 9,381,094 $ 8,947,193 $ 9,381,094 $ 8,947,193

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2019
Investments [Abstract]
Schedule of Fixed Maturity Securities	At September 30, 2019 and December 31, 2018 , the amortized cost and fair value of fixed maturity securities were as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,832 $ 511 $ — $ 12,343 United States Government sponsored agencies 663,662 33,420 (2,052 ) 695,030 United States municipalities, states and territories 4,053,836 464,539 (714 ) 4,517,661 Foreign government obligations 186,979 20,441 — 207,420 Corporate securities 30,042,589 2,959,486 (104,948 ) 32,897,127 Residential mortgage backed securities 1,434,116 124,648 (1,608 ) 1,557,156 Commercial mortgage backed securities 5,564,871 279,881 (5,242 ) 5,839,510 Other asset backed securities 6,212,671 107,933 (192,467 ) 6,128,137 $ 48,170,556 $ 3,990,859 $ (307,031 ) $ 51,854,384 December 31, 2018 Fixed maturity securities, available for sale: United States Government full faith and credit $ 11,872 $ 102 $ (322 ) $ 11,652 United States Government sponsored agencies 1,208,468 13,095 (83,034 ) 1,138,529 United States municipalities, states and territories 3,880,703 261,222 (15,658 ) 4,126,267 Foreign government obligations 226,860 7,573 (4,159 ) 230,274 Corporate securities 28,483,138 727,105 (838,729 ) 28,371,514 Residential mortgage backed securities 1,134,623 71,661 (4,125 ) 1,202,159 Commercial mortgage backed securities 5,492,271 21,558 (134,826 ) 5,379,003 Other asset backed securities 5,693,255 41,308 (270,234 ) 5,464,329 $ 46,131,190 $ 1,143,624 $ (1,351,087 ) $ 45,923,727
Schedule of Fixed Maturity Securities by Contractual Maturity Date	The amortized cost and fair value of fixed maturity securities at September 30, 2019 , by contractual maturity, are shown below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. All of our mortgage and other asset backed securities provide for periodic payments throughout their lives and are shown below as separate lines. Available for sale Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 404,010 $ 409,265 Due after one year through five years 5,612,668 5,824,616 Due after five years through ten years 10,399,862 11,063,045 Due after ten years through twenty years 10,051,773 11,398,510 Due after twenty years 8,490,585 9,634,145 34,958,898 38,329,581 Residential mortgage backed securities 1,434,116 1,557,156 Commercial mortgage backed securities 5,564,871 5,839,510 Other asset backed securities 6,212,671 6,128,137 $ 48,170,556 $ 51,854,384
Schedule of Components of Net Unrealized Gains (Losses) on Available for Sale Fixed Maturity Securities Reported as Separate Component of Stockholders' Equity	Net unrealized gains (losses) on available for sale fixed maturity securities reported as a separate component of stockholders' equity were comprised of the following: September 30, 2019 December 31, 2018 (Dollars in thousands) Net unrealized gains (losses) on available for sale fixed maturity securities $ 3,683,828 $ (207,463 ) Adjustments for assumed changes in amortization of deferred policy acquisition costs and deferred sales inducements (1,637,819 ) 112,571 Deferred income tax valuation allowance reversal 22,534 22,534 Deferred income tax benefit (expense) (429,114 ) 19,926 Net unrealized gains (losses) reported as accumulated other comprehensive income (loss) $ 1,639,429 $ (52,432 )
Schedule of Credit Quality of Fixed Maturity Security Portfolio by NAIC Designation	The following table summarizes the credit quality, as determined by NAIC designation, of our fixed maturity portfolio as of the dates indicated: September 30, 2019 December 31, 2018 NAIC Designation Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) 1 $ 27,657,160 $ 30,351,227 $ 26,588,352 $ 26,921,843 2 19,171,556 20,232,420 17,901,161 17,528,072 3 1,179,714 1,145,174 1,396,650 1,269,242 4 126,833 101,830 173,987 137,991 5 29,759 16,920 23,836 19,453 6 5,534 6,813 47,204 47,126 $ 48,170,556 $ 51,854,384 $ 46,131,190 $ 45,923,727
Schedule of Gross Unrealized Losses on Investments, By Category and Length of Time	The following table shows our investments' gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities (consisting of 886 and 2,715 securities, respectively) have been in a continuous unrealized loss position, at September 30, 2019 and December 31, 2018 : Less than 12 months 12 months or more Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: United States Government sponsored agencies $ 119,718 $ (282 ) $ 203,230 $ (1,770 ) $ 322,948 $ (2,052 ) United States municipalities, states and territories 97,111 (668 ) 3,116 (46 ) 100,227 (714 ) Corporate securities: Finance, insurance and real estate 330,617 (3,576 ) 144,633 (2,095 ) 475,250 (5,671 ) Manufacturing, construction and mining 135,697 (1,003 ) 56,550 (3,921 ) 192,247 (4,924 ) Utilities and related sectors 56,274 (2,272 ) 50,072 (4,928 ) 106,346 (7,200 ) Wholesale/retail trade 18,356 (293 ) 121,902 (13,234 ) 140,258 (13,527 ) Services, media and other 188,946 (10,486 ) 424,760 (63,140 ) 613,706 (73,626 ) Residential mortgage backed securities 116,116 (614 ) 11,918 (994 ) 128,034 (1,608 ) Commercial mortgage backed securities 239,503 (1,355 ) 203,268 (3,887 ) 442,771 (5,242 ) Other asset backed securities 1,739,759 (48,538 ) 2,386,760 (143,929 ) 4,126,519 (192,467 ) $ 3,042,097 $ (69,087 ) $ 3,606,209 $ (237,944 ) $ 6,648,306 $ (307,031 ) December 31, 2018 Fixed maturity securities, available for sale: United States Government full faith and credit $ 543 $ (3 ) $ 7,785 $ (319 ) $ 8,328 $ (322 ) United States Government sponsored agencies 30,089 (949 ) 953,421 (82,085 ) 983,510 (83,034 ) United States municipalities, states and territories 340,103 (6,816 ) 162,997 (8,842 ) 503,100 (15,658 ) Foreign government obligations 98,511 (1,748 ) 11,859 (2,411 ) 110,370 (4,159 ) Corporate securities: Finance, insurance and real estate 2,501,640 (87,220 ) 884,870 (77,507 ) 3,386,510 (164,727 ) Manufacturing, construction and mining 2,045,859 (84,972 ) 349,738 (34,635 ) 2,395,597 (119,607 ) Utilities and related sectors 2,313,271 (82,119 ) 591,482 (45,838 ) 2,904,753 (127,957 ) Wholesale/retail trade 1,032,603 (51,228 ) 198,805 (26,326 ) 1,231,408 (77,554 ) Services, media and other 4,618,477 (196,520 ) 1,072,722 (152,364 ) 5,691,199 (348,884 ) Residential mortgage backed securities 145,613 (2,638 ) 22,689 (1,487 ) 168,302 (4,125 ) Commercial mortgage backed securities 2,141,560 (37,150 ) 2,090,835 (97,676 ) 4,232,395 (134,826 ) Other asset backed securities 4,073,249 (252,265 ) 271,994 (17,969 ) 4,345,243 (270,234 ) $ 19,341,518 $ (803,628 ) $ 6,619,197 $ (547,459 ) $ 25,960,715 $ (1,351,087 )
Schedule of Changes in Net Unrealized Gains/Losses on Investments	Changes in net unrealized gains/losses on investments for the three and nine months ended September 30, 2019 and 2018 are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Fixed maturity securities held for investment carried at amortized cost $ — $ 2,947 $ — $ (5,519 ) Fixed maturity securities available for sale carried at fair value $ 990,481 $ (311,954 ) $ 3,891,291 $ (2,122,555 ) Adjustment for effect on other balance sheet accounts: Deferred policy acquisition costs and deferred sales inducements (245,044 ) 172,566 (1,750,390 ) 1,132,853 Deferred income tax asset/liability (155,992 ) 29,270 (449,040 ) 207,837 (401,036 ) 201,836 (2,199,430 ) 1,340,690 Change in net unrealized gains/losses on investments carried at fair value $ 589,445 $ (110,118 ) $ 1,691,861 $ (781,865 )
Net Realized Gains (Losses) on Investments, Excluding Net OTTI Losses	Net realized gains (losses) on investments, excluding net OTTI losses for the three and nine months ended September 30, 2019 and 2018 , are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Available for sale fixed maturity securities: Gross realized gains $ 6,164 $ 505 $ 12,590 $ 2,845 Gross realized losses (1,586 ) (1,913 ) (5,667 ) (43,648 ) 4,578 (1,408 ) 6,923 (40,803 ) Other investments: Gross realized gains — — 7,296 — Gross realized losses — — (14,446 ) — — — (7,150 ) — Mortgage loans on real estate: Increase (decrease) in allowance for credit losses (250 ) (1,255 ) 160 (785 ) Recovery of specific allowance — 467 — 1,189 Gain on sale of mortgage loans — — — 124 (250 ) (788 ) 160 528 $ 4,328 $ (2,196 ) $ (67 ) $ (40,275 )
Other Than Temporary Impairment by Asset Type	The following table summarizes other than temporary impairments for the three and nine months ended September 30, 2019 and 2018 , by asset type: Number of Securities Total OTTI Losses Portion of OTTI Losses Recognized in (from) Other Comprehensive Income Net OTTI Losses Recognized in Operations (Dollars in thousands) Three months ended September 30, 2019 Fixed maturity securities, available for sale: Residential mortgage backed securities 1 $ (101 ) $ — $ (101 ) Three months ended September 30, 2018 Fixed maturity securities, available for sale: Corporate securities: Capital goods 1 $ (719 ) $ — $ (719 ) Consumer discretionary 6 (5,968 ) — (5,968 ) Energy 2 (1,212 ) — (1,212 ) Financials 5 (3,495 ) — (3,495 ) Information technology 1 (550 ) — (550 ) Telecommunications 2 (249 ) — (249 ) Transportation 1 (178 ) — (178 ) Utilities 1 (94 ) — (94 ) Commercial mortgage backed securities 1 (1,908 ) — (1,908 ) 20 $ (14,373 ) $ — $ (14,373 ) Nine months ended September 30, 2019 Fixed maturity securities, available for sale: Residential mortgage backed securities 3 $ (101 ) $ (215 ) $ (316 ) Commercial mortgage backed securities 1 (349 ) — (349 ) Other asset backed securities 1 (649 ) — (649 ) 5 $ (1,099 ) $ (215 ) $ (1,314 ) Nine months ended September 30, 2018 Fixed maturity securities, available for sale: Corporate securities: Capital goods 1 $ (719 ) $ — $ (719 ) Consumer discretionary 7 (6,875 ) — (6,875 ) Energy 2 (1,212 ) — (1,212 ) Financials 5 (3,495 ) — (3,495 ) Information technology 1 (550 ) — (550 ) Telecommunications 2 (249 ) — (249 ) Transportation 1 (178 ) — (178 ) Utilities 1 (94 ) — (94 ) Residential mortgage backed securities 3 (63 ) (295 ) (358 ) Commercial mortgage backed securities 1 (1,908 ) — (1,908 ) Other asset backed securities 1 (682 ) (1,356 ) (2,038 ) 25 $ (16,025 ) $ (1,651 ) $ (17,676 )
Other Than Temporary Impairment, Credit Losses Recognized in Earnings	The cumulative portion of other than temporary impairments determined to be credit losses which have been recognized in operations for debt securities are summarized as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Cumulative credit loss at beginning of period $ (165,651 ) $ (156,469 ) $ (175,398 ) $ (157,066 ) Additions for the amount related to credit losses for which OTTI has not previously been recognized — (14,373 ) (998 ) (16,025 ) Additional credit losses on securities for which OTTI has previously been recognized (101 ) — (316 ) (1,651 ) Accumulated losses on securities that were disposed of during the period 10,775 — 21,735 3,900 Cumulative credit loss at end of period $ (154,977 ) $ (170,842 ) $ (154,977 ) $ (170,842 )
Schedule of Other Than Temporary Impairment Losses, Investments	The following table summarizes the cumulative noncredit portion of OTTI and the change in fair value since recognition of OTTI, both of which were recognized in other comprehensive income, by major type of security, for securities that are part of our investment portfolio at September 30, 2019 and December 31, 2018 : Amortized Cost OTTI Recognized in Other Comprehensive Income (Loss) Change in Fair Value Since OTTI was Recognized Fair Value (Dollars in thousands) September 30, 2019 Fixed maturity securities, available for sale: Corporate securities $ 28,728 $ (3,700 ) $ 10,088 $ 35,116 Residential mortgage backed securities 198,959 (151,562 ) 180,704 228,101 Commercial mortgage backed securities 12,867 — 271 13,138 Other asset backed securities 977 — 326 1,303 $ 241,531 $ (155,262 ) $ 191,389 $ 277,658 December 31, 2018 Fixed maturity securities, available for sale: Corporate securities $ 69,580 $ (3,700 ) $ 6,195 $ 72,075 Residential mortgage backed securities 245,691 (167,846 ) 199,191 277,036 Commercial mortgage backed securities 35,244 — — 35,244 Other asset backed securities 1,692 — 326 2,018 $ 352,207 $ (171,546 ) $ 205,712 $ 386,373

Mortgage Loans on Real Estate (

Mortgage Loans on Real Estate (Tables)	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Summary of Mortgage Loan Portfolio	Our mortgage loan portfolio is summarized in the following table. There were commitments outstanding of $173.3 million at September 30, 2019 . September 30, 2019 December 31, 2018 (Dollars in thousands) Principal outstanding $ 3,221,152 $ 2,952,464 Loan loss allowance (8,079 ) (8,239 ) Deferred prepayment fees (998 ) (1,134 ) Carrying value $ 3,212,075 $ 2,943,091
Mortgage Loan Portfolio Summarized By Geographic Region and Property Type	The mortgage loan portfolio is summarized by geographic region and property type as follows: September 30, 2019 December 31, 2018 Principal Percent Principal Percent (Dollars in thousands) Geographic distribution East $ 600,204 18.6 % $ 586,773 19.9 % Middle Atlantic 240,241 7.5 % 168,969 5.7 % Mountain 372,437 11.6 % 357,642 12.1 % New England 9,220 0.3 % 9,418 0.3 % Pacific 579,831 18.0 % 521,363 17.7 % South Atlantic 739,498 22.9 % 694,599 23.5 % West North Central 281,067 8.7 % 291,890 9.9 % West South Central 398,654 12.4 % 321,810 10.9 % $ 3,221,152 100.0 % $ 2,952,464 100.0 % Property type distribution Office $ 249,703 7.7 % $ 268,932 9.1 % Medical Office 30,930 1.0 % 33,467 1.1 % Retail 1,185,510 36.8 % 1,091,627 37.0 % Industrial/Warehouse 859,410 26.7 % 762,887 25.8 % Apartment 695,726 21.6 % 600,638 20.3 % Agricultural 39,205 1.2 % 25,000 0.9 % Mixed use/other 160,668 5.0 % 169,913 5.8 % $ 3,221,152 100.0 % $ 2,952,464 100.0 %
Rollforward of Allowance for Credit Losses	The following table presents a rollforward of our specific and general valuation allowances for mortgage loans on real estate: Three Months Ended Three Months Ended Specific Allowance General Allowance Specific Allowance General Allowance (Dollars in thousands) Beginning allowance balance $ (229 ) $ (7,600 ) $ (696 ) $ (5,630 ) Charge-offs — — — — Recoveries — — 467 — Change in provision for credit losses — (250 ) (1,255 ) — Ending allowance balance $ (229 ) $ (7,850 ) $ (1,484 ) $ (5,630 ) Nine Months Ended Nine Months Ended Specific Allowance General Allowance Specific Allowance General Allowance (Dollars in thousands) Beginning allowance balance $ (229 ) $ (8,010 ) $ (1,418 ) $ (6,100 ) Charge-offs — — — — Recoveries — — 1,189 — Change in provision for credit losses — 160 (1,255 ) 470 Ending allowance balance $ (229 ) $ (7,850 ) $ (1,484 ) $ (5,630 )
Impaired Mortgage Loans By Basis of Impairment	The following table presents the total outstanding principal of loans evaluated for impairment by basis of impairment method: September 30, 2019 December 31, 2018 (Dollars in thousands) Individually evaluated for impairment $ 1,235 $ 1,253 Collectively evaluated for impairment 3,219,917 2,951,211 Total loans evaluated for impairment $ 3,221,152 $ 2,952,464
Mortgage Loans By Credit Quality Indicator	We analyze credit risk of our mortgage loans by analyzing all available evidence on loans that are delinquent and loans that are in a workout period. September 30, 2019 December 31, 2018 (Dollars in thousands) Credit Exposure - By Payment Activity Performing $ 3,221,152 $ 2,952,464 In workout — — Collateral dependent — — $ 3,221,152 $ 2,952,464
Aging of Financing Receivables	Aging of financing receivables is summarized in the following table, with loans in a "workout" period as of the reporting date considered current if payments are current in accordance with agreed upon terms: 30 - 59 Days 60 - 89 Days 90 Days and Over Total Past Due Current Collateral Dependent Receivables Total Financing Receivables (Dollars in thousands) Commercial Mortgage Loans September 30, 2019 $ — $ — $ — $ — $ 3,221,152 $ — $ 3,221,152 December 31, 2018 $ — $ — $ — $ — $ 2,952,464 $ — $ 2,952,464
Impaired Financing Receivables	Financing receivables summarized in the following two tables represent all loans that we are either not currently collecting, or those we feel it is probable we will not collect all amounts due according to the contractual terms of the loan agreements (all loans that we have worked with the borrower to alleviate short-term cash flow issues, loans delinquent for 60 days or more at the reporting date, loans we have determined to be collateral dependent and loans that we have recorded specific impairments on that we feel may continue to have performance issues). Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) September 30, 2019 Mortgage loans with an allowance $ 1,006 $ 1,235 $ (229 ) Mortgage loans with no related allowance — — — $ 1,006 $ 1,235 $ (229 ) December 31, 2018 Mortgage loans with an allowance $ 1,024 $ 1,253 $ (229 ) Mortgage loans with no related allowance — — — $ 1,024 $ 1,253 $ (229 ) Average Recorded Investment Interest Income Recognized (Dollars in thousands) Three months ended September 30, 2019 Mortgage loans with an allowance $ 1,009 $ 17 Mortgage loans with no related allowance — — $ 1,009 $ 17 Three months ended September 30, 2018 Mortgage loans with an allowance $ 2,337 $ 37 Mortgage loans with no related allowance — — $ 2,337 $ 37 Nine months ended September 30, 2019 Mortgage loans with an allowance $ 1,015 $ 52 Mortgage loans with no related allowance — — $ 1,015 $ 52 Nine months ended September 30, 2018 Mortgage loans with an allowance $ 2,386 $ 136 Mortgage loans with no related allowance — — $ 2,386 $ 136

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments as Presented in the Consolidated Balance Sheets	The fair value of our derivative instruments, including derivative instruments embedded in fixed index annuity contracts, presented in the consolidated balance sheets are as follows: September 30, 2019 December 31, 2018 (Dollars in thousands) Assets Derivative instruments Call options $ 963,081 $ 205,149 Other assets Interest rate caps 17 597 Interest rate swap — 354 $ 963,098 $ 206,100 Liabilities Policy benefit reserves - annuity products Fixed index annuities - embedded derivatives, net $ 9,381,094 $ 8,165,405 Other liabilities Interest rate swap 906 — $ 9,382,000 $ 8,165,405
Schedule of Changes in Fair Value of Derivative Instruments	The changes in fair value of derivatives included in the unaudited consolidated statements of operations are as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands) Change in fair value of derivatives: Call options $ (19,997 ) $ 594,872 $ 442,111 $ 273,946 Interest rate swap (3 ) 258 (1,059 ) 1,658 Interest rate caps (42 ) 181 (580 ) 829 $ (20,042 ) $ 595,311 $ 440,472 $ 276,433 Change in fair value of embedded derivatives: Fixed index annuities - embedded derivatives $ 24,998 $ 196,808 $ 882,230 $ (1,198,115 ) Other changes in difference between policy benefit reserves computed using derivative accounting vs. long-duration contracts accounting 187,280 186,908 423,933 612,650 $ 212,278 $ 383,716 $ 1,306,163 $ (585,465 )
Schedule of Call Options by Counterparty	The notional amount and fair value of our call options by counterparty and each counterparty's current credit rating are as follows: September 30, 2019 December 31, 2018 Counterparty Credit Rating (S&P) Credit Rating (Moody's) Notional Amount Fair Value Notional Amount Fair Value (Dollars in thousands) Bank of America A+ Aa2 $ 3,938,470 $ 46,637 $ 6,518,808 $ 6,704 Barclays A A2 4,549,168 141,155 2,301,414 27,032 Canadian Imperial Bank of Commerce A+ Aa2 4,321,739 126,868 4,856,150 29,313 Citibank, N.A. A+ Aa3 4,064,075 83,451 4,792,208 27,239 Credit Suisse A+ A1 4,739,536 77,910 2,877,916 12,887 J.P. Morgan A+ Aa2 4,772,783 101,072 3,701,964 17,564 Morgan Stanley A+ A1 1,990,733 21,001 3,560,044 1,561 Royal Bank of Canada AA- A2 2,720,343 82,946 1,871,305 14,011 Societe Generale A A1 3,205,393 106,016 2,343,165 21,681 SunTrust A- Baa1 2,017,444 58,986 1,755,030 12,047 Wells Fargo A+ Aa2 3,656,074 112,408 4,618,569 33,398 Exchange traded 201,850 4,631 224,204 1,712 $ 40,177,608 $ 963,081 $ 39,420,777 $ 205,149
Schedule of Interest Rate Derivatives	Details regarding the interest rate swap are as follows: Notional Pay September 30, 2019 December 31, 2018 Maturity Date Amount Receive Rate Rate Counterparty Fair Value (Dollars in thousands) March 15, 2021 $ 85,500 LIBOR 2.415 % SunTrust $ (906 ) $ 354 Details regarding the interest rate caps are as follows: Notional Cap September 30, 2019 December 31, 2018 Maturity Date Amount Floating Rate Rate Counterparty Fair Value (Dollars in thousands) July 7, 2021 $ 40,000 LIBOR 2.50 % SunTrust $ 8 $ 302 July 8, 2021 12,000 LIBOR 2.50 % SunTrust 3 91 July 29, 2021 27,000 LIBOR 2.50 % SunTrust 6 204 $ 79,000 $ 17 $ 597

Notes Payable and Amounts Due_2

Notes Payable and Amounts Due Under Repurchase Agreements (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Notes Payable	Notes payable includes the following: September 30, 2019 December 31, 2018 (Dollars in thousands) Senior notes due 2027 Principal $ 500,000 $ 500,000 Unamortized debt issue costs (4,733 ) (5,102 ) Unamortized discount (285 ) (307 ) $ 494,982 $ 494,591

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of earnings per common share and earnings per common share - assuming dilution: Three Months Ended Nine Months Ended 2019 2018 2019 2018 (Dollars in thousands, except per share data) Numerator: Net income - numerator for earnings per common share $ 37,360 $ 169,328 $ 25,940 $ 404,193 Denominator: Weighted average common shares outstanding 91,251,590 90,485,567 91,080,681 90,278,209 Effect of dilutive securities: Stock options and deferred compensation agreements 190,137 705,465 326,306 750,588 Restricted stock and restricted stock units 268,830 459,854 340,875 326,613 Denominator for earnings per common share - assuming dilution 91,710,557 91,650,886 91,747,862 91,355,410 Earnings per common share $ 0.41 $ 1.87 $ 0.28 $ 4.48 Earnings per common share - assuming dilution $ 0.41 $ 1.85 $ 0.28 $ 4.42

Significant Accounting Polici_3

Significant Accounting Policies (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement, effect of adoption, quantification	$ 3.8

Fair Values of Financial Inst_3

Fair Values of Financial Instruments (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)Basis_Points	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)Basis_Points	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Level 1 to Level 2 transfers, amount	$ 0		$ 0		$ 0
Liabilities, Level 1 to Level 2 transfers, amount	0		0		0
Assets, Level 2 to Level 1 transfers, amount	0		0		0
Liabilities, Level 2 to Level 1 transfers, amount	0		0		$ 0
Assets, transfers into Level 3, amount	0	$ 0	0	$ 0
Liabilities, transfers into Level 3, amount	0	0	0	0
Assets, transfers out of Level 3, amount	0	0	0	0
Liabilities, transfers out of Level 3, amount	$ 0	$ 0	$ 0	$ 0
Maximum | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, sensitivity, discount rate adjustment (basis points) | Basis_Points	100		100
Fixed index annuities embedded derivative, adjustment due to change in discount rate			$ (902,000)
Deferred policy scquisition costs and deferred sales inducements, combined balance, adjustment due to change in discount rate			$ (370,500)
Minimum | Measurement Input, Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, sensitivity, discount rate adjustment (basis points) | Basis_Points	(100)		(100)
Fixed index annuities embedded derivative, adjustment due to change in discount rate			$ 1,100,000
Deferred policy scquisition costs and deferred sales inducements, combined balance, adjustment due to change in discount rate			$ 462,400

Fair Values of Financial Inst_4

Fair Values of Financial Instruments (Fair Values and Carrying Amounts of Financial Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets
Fixed maturity securities, available for sale, fair value	$ 51,854,384	$ 45,923,727
Derivative instruments	963,081	205,149
Other investments	694,416	355,531
Coinsurance deposits	5,072,015	4,954,068
Liabilities
Policy benefit reserves	61,348,138	57,606,009
Carrying Amount
Assets
Fixed maturity securities, available for sale, fair value	51,854,384	45,923,727
Mortgage loans on real estate	3,212,075	2,943,091
Derivative instruments	963,081	205,149
Other investments	694,416	355,531
Cash and cash equivalents	1,138,737	344,396
Coinsurance deposits	5,072,015	4,954,068
Counterparty collateral	0	33,101
Liabilities
Policy benefit reserves	60,996,752	57,249,510
Single premium immediate annuity (SPIA) benefit reserves	259,634	270,406
Notes payable	494,982	494,591
Subordinated debentures	243,311	242,982
Amounts due under repurchase agreements	48,931	109,298
Carrying Amount | Interest Rate Caps
Assets
Interest rate derivative assets	17	597
Carrying Amount | Interest Rate Swap
Assets
Interest rate derivative assets	0	354
Liabilities
Interest rate derivative liabilities	906	0
Fair Value
Assets
Fixed maturity securities, available for sale, fair value	51,854,384	45,923,727
Mortgage loans on real estate	3,293,106	2,920,612
Derivative instruments	963,081	205,149
Other investments	694,416	348,970
Cash and cash equivalents	1,138,737	344,396
Coinsurance deposits	4,602,181	4,553,790
Counterparty collateral	0	33,101
Liabilities
Policy benefit reserves	51,320,260	49,180,143
Single premium immediate annuity (SPIA) benefit reserves	267,876	279,077
Notes payable	526,760	489,985
Subordinated debentures	247,283	215,514
Amounts due under repurchase agreements	48,931	109,298
Fair Value | Interest Rate Caps
Assets
Interest rate derivative assets	17	597
Fair Value | Interest Rate Swap
Assets
Interest rate derivative assets	0	354
Liabilities
Interest rate derivative liabilities	$ 906	$ 0

Fair Values of Financial Inst_5

Fair Values of Financial Instruments (Assets and Liabilities Measured on a Recurring Basis by Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets
Derivative instruments	$ 963,081	$ 205,149
Fair Value, Measurements, Recurring
Assets
Derivative instruments	963,081	205,149
Cash and cash equivalents	1,138,737	344,396
Counterparty collateral		33,101
Assets	54,265,532	46,514,761
Liabilities
Fixed index annuities - embedded derivatives	9,381,094	8,165,405
Liabilities	9,382,000
Fair Value, Measurements, Recurring | Interest Rate Caps
Assets
Interest rate derivative assets	17	597
Fair Value, Measurements, Recurring | Interest Rate Swap
Assets
Interest rate derivative assets		354
Liabilities
Interest rate derivative liabilities	906
Fair Value, Measurements, Recurring | United States Government Full Faith and Credit
Assets
Investments	12,343	11,652
Fair Value, Measurements, Recurring | United States Government Sponsored Agencies
Assets
Investments	695,030	1,138,529
Fair Value, Measurements, Recurring | United States Municipalities, States and Territories
Assets
Investments	4,517,661	4,126,267
Fair Value, Measurements, Recurring | Foreign Government Obligations
Assets
Investments	207,420	230,274
Fair Value, Measurements, Recurring | Corporate Securities
Assets
Investments	32,897,127	28,371,514
Fair Value, Measurements, Recurring | Residential Mortgage Backed Securities
Assets
Investments	1,557,156	1,202,159
Fair Value, Measurements, Recurring | Commercial Mortgage Backed Securities
Assets
Investments	5,839,510	5,379,003
Fair Value, Measurements, Recurring | Other Asset Backed Securities
Assets
Investments	6,128,137	5,464,329
Fair Value, Measurements, Recurring | Equity Securities
Assets
Investments	309,313	7,437
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1)
Assets
Derivative instruments	0	0
Cash and cash equivalents	1,138,737	344,396
Counterparty collateral		0
Assets	1,447,043	350,303
Liabilities
Fixed index annuities - embedded derivatives	0	0
Liabilities	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Interest Rate Caps
Assets
Interest rate derivative assets	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Interest Rate Swap
Assets
Interest rate derivative assets		0
Liabilities
Interest rate derivative liabilities	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | United States Government Full Faith and Credit
Assets
Investments	6,421	5,900
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | United States Government Sponsored Agencies
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | United States Municipalities, States and Territories
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Foreign Government Obligations
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Corporate Securities
Assets
Investments	15	7
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Residential Mortgage Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Commercial Mortgage Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Other Asset Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets (Level 1) | Equity Securities
Assets
Investments	301,870	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets
Derivative instruments	963,081	205,149
Cash and cash equivalents	0	0
Counterparty collateral		33,101
Assets	52,818,489	46,164,458
Liabilities
Fixed index annuities - embedded derivatives	0	0
Liabilities	906
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest Rate Caps
Assets
Interest rate derivative assets	17	597
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest Rate Swap
Assets
Interest rate derivative assets		354
Liabilities
Interest rate derivative liabilities	906
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | United States Government Full Faith and Credit
Assets
Investments	5,922	5,752
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | United States Government Sponsored Agencies
Assets
Investments	695,030	1,138,529
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | United States Municipalities, States and Territories
Assets
Investments	4,517,661	4,126,267
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign Government Obligations
Assets
Investments	207,420	230,274
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Corporate Securities
Assets
Investments	32,897,112	28,371,507
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Residential Mortgage Backed Securities
Assets
Investments	1,557,156	1,202,159
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commercial Mortgage Backed Securities
Assets
Investments	5,839,510	5,379,003
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other Asset Backed Securities
Assets
Investments	6,128,137	5,464,329
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Equity Securities
Assets
Investments	7,443	7,437
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets
Derivative instruments	0	0
Cash and cash equivalents	0	0
Counterparty collateral		0
Assets	0	0
Liabilities
Fixed index annuities - embedded derivatives	9,381,094	8,165,405
Liabilities	9,381,094
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest Rate Caps
Assets
Interest rate derivative assets	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest Rate Swap
Assets
Interest rate derivative assets		0
Liabilities
Interest rate derivative liabilities	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | United States Government Full Faith and Credit
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | United States Government Sponsored Agencies
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | United States Municipalities, States and Territories
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign Government Obligations
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Corporate Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Residential Mortgage Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Commercial Mortgage Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Other Asset Backed Securities
Assets
Investments	0	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Equity Securities
Assets
Investments	$ 0	$ 0

Fair Values of Financial Inst_6

Fair Values of Financial Instruments (Assumptions Used in Estimating Fair Value) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Expected cost of annual call options	2.90%	3.10%
Fixed Index Annuities | Minimum | Contract Duration (Years), Group 1
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	1 year	1 year
Fixed Index Annuities | Minimum | Contract Duration (Years), Group 2
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	6 years	6 years
Fixed Index Annuities | Minimum | Contract Duration (Years), Group 3
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	11 years	11 years
Fixed Index Annuities | Minimum | Contract Duration (Years), Group 4
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	16 years	16 years
Fixed Index Annuities | Minimum | Contract Duration (Years), Group 5
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	20 years	20 years
Fixed Index Annuities | Maximum | Contract Duration (Years), Group 1
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	5 years	5 years
Fixed Index Annuities | Maximum | Contract Duration (Years), Group 2
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	10 years	10 years
Fixed Index Annuities | Maximum | Contract Duration (Years), Group 3
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	15 years	15 years
Fixed Index Annuities | Maximum | Contract Duration (Years), Group 4
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Contract duration (years)	20 years	20 years
Fixed Index Annuities | Average | Contract Duration (Years), Group 1
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Average lapse rates	0.86%	2.05%
Average partial withdrawal rates	3.35%	3.33%
Fixed Index Annuities | Average | Contract Duration (Years), Group 2
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Average lapse rates	1.30%	7.28%
Average partial withdrawal rates	4.14%	3.33%
Fixed Index Annuities | Average | Contract Duration (Years), Group 3
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Average lapse rates	3.48%	11.35%
Average partial withdrawal rates	4.17%	3.35%
Fixed Index Annuities | Average | Contract Duration (Years), Group 4
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Average lapse rates	9.45%	11.90%
Average partial withdrawal rates	4.08%	3.22%
Fixed Index Annuities | Average | Contract Duration (Years), Group 5
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]
Average lapse rates	7.00%	11.57%
Average partial withdrawal rates	3.86%	3.22%

Fair Values of Financial Inst_7

Fair Values of Financial Instruments (Reconciliation of Beginning and Ending Balances of Level 3 Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 9,281,117	$ 8,351,151	$ 8,165,405	$ 8,790,427
Premiums less benefits	74,979	399,234	333,459	1,354,881
Change in fair value, net	24,998	196,808	882,230	(1,198,115)
Ending balance	9,381,094	$ 8,947,193	9,381,094	$ 8,947,193
Coinsurance ceded, fixed index annuities embedded derivatives	5,072,015		5,072,015		$ 4,954,068
Fixed Index Annuities - Embedded Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Coinsurance ceded, fixed index annuities embedded derivatives	$ 614,600		$ 614,600		$ 538,800

Investments (Narrative) (Detail

Investments (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)Securities	Sep. 30, 2018USD ($)	Dec. 31, 2018Securities
Investments [Abstract]
Percentage of fixed maturity portfolio rated investment grade based on NAIC designations	98.00%		97.00%
Number of securities in unrealized loss position | Securities	886		2,715
Percentage of unrealized losses on fixed maturity securities where securities are rated investment grade	68.00%		87.00%
Proceeds from sales of available for sale securities	$ 707.5	$ 1,800
Principal repayments, calls and tenders of available for sale securities	$ 1,500	$ 997.6

Investments (Schedule of Fixed

Investments (Schedule of Fixed Maturity Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	$ 48,170,556	$ 46,131,190
Fixed maturity securities, available for sale, gross unrealized gains	3,990,859	1,143,624
Fixed maturity securities, available for sale, gross unrealized losses	(307,031)	(1,351,087)
Fixed maturity securities, available for sale, fair value	51,854,384	45,923,727
United States Government Full Faith and Credit
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	11,832	11,872
Fixed maturity securities, available for sale, gross unrealized gains	511	102
Fixed maturity securities, available for sale, gross unrealized losses	0	(322)
Fixed maturity securities, available for sale, fair value	12,343	11,652
United States Government Sponsored Agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	663,662	1,208,468
Fixed maturity securities, available for sale, gross unrealized gains	33,420	13,095
Fixed maturity securities, available for sale, gross unrealized losses	(2,052)	(83,034)
Fixed maturity securities, available for sale, fair value	695,030	1,138,529
United States Municipalities, States and Territories
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	4,053,836	3,880,703
Fixed maturity securities, available for sale, gross unrealized gains	464,539	261,222
Fixed maturity securities, available for sale, gross unrealized losses	(714)	(15,658)
Fixed maturity securities, available for sale, fair value	4,517,661	4,126,267
Foreign Government Obligations
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	186,979	226,860
Fixed maturity securities, available for sale, gross unrealized gains	20,441	7,573
Fixed maturity securities, available for sale, gross unrealized losses	0	(4,159)
Fixed maturity securities, available for sale, fair value	207,420	230,274
Corporate Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	30,042,589	28,483,138
Fixed maturity securities, available for sale, gross unrealized gains	2,959,486	727,105
Fixed maturity securities, available for sale, gross unrealized losses	(104,948)	(838,729)
Fixed maturity securities, available for sale, fair value	32,897,127	28,371,514
Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	1,434,116	1,134,623
Fixed maturity securities, available for sale, gross unrealized gains	124,648	71,661
Fixed maturity securities, available for sale, gross unrealized losses	(1,608)	(4,125)
Fixed maturity securities, available for sale, fair value	1,557,156	1,202,159
Commercial Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	5,564,871	5,492,271
Fixed maturity securities, available for sale, gross unrealized gains	279,881	21,558
Fixed maturity securities, available for sale, gross unrealized losses	(5,242)	(134,826)
Fixed maturity securities, available for sale, fair value	5,839,510	5,379,003
Other Asset Backed Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, available for sale, amortized cost	6,212,671	5,693,255
Fixed maturity securities, available for sale, gross unrealized gains	107,933	41,308
Fixed maturity securities, available for sale, gross unrealized losses	(192,467)	(270,234)
Fixed maturity securities, available for sale, fair value	$ 6,128,137	$ 5,464,329

Investments (Fixed Maturity Sec

Investments (Fixed Maturity Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Fixed maturity securities, available for sale, due in one year or less, amortized cost	$ 404,010
Fixed maturity securities, available for sale, due after one year through five years, amortized cost	5,612,668
Fixed maturity securities, available for sale, due after five years through ten years, amortized cost	10,399,862
Fixed maturity securities, available for sale, due after ten years through twenty years, amortized cost	10,051,773
Fixed maturity securities, available for sale, due after twenty years, amortized cost	8,490,585
Fixed maturity securities, available for sale, securities with a single maturity date, amortized cost	34,958,898
Fixed maturity securities, available for sale, amortized cost	48,170,556	$ 46,131,190
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Fixed maturity securities, available for sale, due in one year or less, fair value	409,265
Fixed maturity securities, available for sale, due after one year through five years, fair value	5,824,616
Fixed maturity securities, available for sale, due after five years through ten years, fair value	11,063,045
Fixed maturity securities, available for sale, due after ten years through twenty years, fair value	11,398,510
Fixed maturity securities, available for sale, due after twenty years, fair value	9,634,145
Fixed maturity securities, available for sale, securities with a single maturity date, fair value	38,329,581
Fixed maturity securities, available for sale, fair value	51,854,384	45,923,727
Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, amortized cost	1,434,116
Fixed maturity securities, available for sale, amortized cost	1,434,116	1,134,623
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, fair value	1,557,156
Fixed maturity securities, available for sale, fair value	1,557,156	1,202,159
Commercial Mortgage Backed Securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, amortized cost	5,564,871
Fixed maturity securities, available for sale, amortized cost	5,564,871	5,492,271
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, fair value	5,839,510
Fixed maturity securities, available for sale, fair value	5,839,510	5,379,003
Other Asset Backed Securities
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, amortized cost	6,212,671
Fixed maturity securities, available for sale, amortized cost	6,212,671	5,693,255
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Fixed maturity securities, available for sale, securities without a single maturity date, fair value	6,128,137
Fixed maturity securities, available for sale, fair value	$ 6,128,137	$ 5,464,329

Investments (Net Unrealized Gai

Investments (Net Unrealized Gains (Losses) on Available for Sale Fixed Maturity Securities Reported as a Separate Component of Stockholders' Equity) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investments [Abstract]
Net unrealized gains (losses) on available for sale fixed maturity securities	$ 3,683,828	$ (207,463)
Adjustments for assumed changes in amortization of deferred policy acquisition costs and deferred sales inducements	(1,637,819)	112,571
Deferred income tax valuation allowance reversal	22,534	22,534
Deferred income tax benefit (expense)	(429,114)	19,926
Net unrealized gains (losses) reported as accumulated other comprehensive income (loss)	$ 1,639,429	$ (52,432)

Investments (Credit Quality of

Investments (Credit Quality of Fixed Maturity Security Portfolio by NAIC Designation) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	$ 48,170,556	$ 46,131,190
Fixed maturity securities, available for sale, fair value	51,854,384	45,923,727
NAIC, Class 1 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	27,657,160	26,588,352
Fixed maturity securities, available for sale, fair value	30,351,227	26,921,843
NAIC, Class 2 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	19,171,556	17,901,161
Fixed maturity securities, available for sale, fair value	20,232,420	17,528,072
NAIC, Class 3 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	1,179,714	1,396,650
Fixed maturity securities, available for sale, fair value	1,145,174	1,269,242
NAIC, Class 4 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	126,833	173,987
Fixed maturity securities, available for sale, fair value	101,830	137,991
NAIC, Class 5 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	29,759	23,836
Fixed maturity securities, available for sale, fair value	16,920	19,453
NAIC, Class 6 Designation
Investment Holdings [Line Items]
Fixed maturity securities, available for sale, amortized cost	5,534	47,204
Fixed maturity securities, available for sale, fair value	$ 6,813	$ 47,126

Investments (Gross Unrealized L

Investments (Gross Unrealized Losses on Investments, By Category and Length of Time) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	$ 3,042,097	$ 19,341,518
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(69,087)	(803,628)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	3,606,209	6,619,197
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(237,944)	(547,459)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	6,648,306	25,960,715
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(307,031)	(1,351,087)
United States Government Full Faith and Credit
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value		543
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses		(3)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value		7,785
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses		(319)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value		8,328
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses		(322)
United States Government Sponsored Agencies
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	119,718	30,089
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(282)	(949)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	203,230	953,421
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(1,770)	(82,085)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	322,948	983,510
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(2,052)	(83,034)
United States Municipalities, States and Territories
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	97,111	340,103
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(668)	(6,816)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	3,116	162,997
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(46)	(8,842)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	100,227	503,100
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(714)	(15,658)
Foreign Government Obligations
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value		98,511
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses		(1,748)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value		11,859
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses		(2,411)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value		110,370
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses		(4,159)
Corporate Securities | Finance, Insurance and Real Estate Sectors
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	330,617	2,501,640
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(3,576)	(87,220)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	144,633	884,870
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(2,095)	(77,507)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	475,250	3,386,510
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(5,671)	(164,727)
Corporate Securities | Manufacturing, Construction and Mining
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	135,697	2,045,859
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(1,003)	(84,972)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	56,550	349,738
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(3,921)	(34,635)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	192,247	2,395,597
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(4,924)	(119,607)
Corporate Securities | Utilities and Related Sectors
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	56,274	2,313,271
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(2,272)	(82,119)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	50,072	591,482
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(4,928)	(45,838)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	106,346	2,904,753
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(7,200)	(127,957)
Corporate Securities | Wholesale/Retail Trade
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	18,356	1,032,603
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(293)	(51,228)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	121,902	198,805
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(13,234)	(26,326)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	140,258	1,231,408
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(13,527)	(77,554)
Corporate Securities | Services, Media and Other
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	188,946	4,618,477
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(10,486)	(196,520)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	424,760	1,072,722
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(63,140)	(152,364)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	613,706	5,691,199
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(73,626)	(348,884)
Residential Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	116,116	145,613
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(614)	(2,638)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	11,918	22,689
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(994)	(1,487)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	128,034	168,302
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(1,608)	(4,125)
Commercial Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	239,503	2,141,560
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(1,355)	(37,150)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	203,268	2,090,835
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(3,887)	(97,676)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	442,771	4,232,395
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	(5,242)	(134,826)
Other Asset Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, fair value	1,739,759	4,073,249
Fixed maturity securities, available for sale, continuous unrealized loss position, less than 12 months, unrealized losses	(48,538)	(252,265)
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, fair value	2,386,760	271,994
Fixed maturity securities, available for sale, continuous unrealized loss position, 12 months or more, unrealized losses	(143,929)	(17,969)
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, fair value	4,126,519	4,345,243
Fixed maturity securities, available for sale securities, continuous unrealized loss position, total, unrealized losses	$ (192,467)	$ (270,234)

Investments (Changes in Net Unr

Investments (Changes in Net Unrealized Gains/Losses on Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Investments [Abstract]
Fixed maturity securities held for investment carried at amortized cost	$ 0	$ 2,947	$ 0	$ (5,519)
Fixed maturity securities available for sale carried at fair value	990,481	(311,954)	3,891,291	(2,122,555)
Adjustment for effect on other balance sheet accounts:
Deferred policy acquisition costs and deferred sales inducements	(245,044)	172,566	(1,750,390)	1,132,853
Deferred income tax asset/liability	(155,992)	29,270	(449,040)	207,837
Total adjustment for effect on other balance sheet accounts	(401,036)	201,836	(2,199,430)	1,340,690
Change in net unrealized gains/losses on investments carried at fair value	$ 589,445	$ (110,118)	$ 1,691,861	$ (781,865)

Investments (Net Realized Gains

Investments (Net Realized Gains (Losses) on Invesments, Excluding Other Than Temporary Impairments) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments, excluding other than temporary impairment (OTTI) losses	$ 4,328	$ (2,196)	$ (67)	$ (40,275)
Fixed Maturity Securities
Gain (Loss) on Securities [Line Items]
Gross realized gains	6,164	505	12,590	2,845
Gross realized losses	(1,586)	(1,913)	(5,667)	(43,648)
Realized gains (losses), excluding other than temporary impairment	4,578	(1,408)	6,923	(40,803)
Other Investments
Gain (Loss) on Securities [Line Items]
Gross realized gains	0	0	7,296	0
Gross realized losses	0	0	(14,446)	0
Realized gains (losses), excluding other than temporary impairment	0	0	(7,150)	0
Mortgage Loans on Real Estate
Gain (Loss) on Securities [Line Items]
Increase (decrease) in allowance for credit losses	(250)	(1,255)	160	(785)
Recovery of specific allowance	0	467	0	1,189
Gain on sale of mortgage loans	0	0	0	124
Change in allowance for credit losses and recoveries	$ (250)	$ (788)	$ 160	$ 528

Investments (Other Than Tempora

Investments (Other Than Temporary Impairments by Asset Type) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)Securities	Sep. 30, 2018USD ($)Securities	Sep. 30, 2019USD ($)Securities	Sep. 30, 2018USD ($)Securities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		20	5	25
Total OTTI losses	$ (101)	$ (14,373)	$ (1,099)	$ (16,025)
Portion of OTTI losses recognized from other comprehensive income	0	0	(215)	(1,651)
Net OTTI losses recognized in operations	$ (101)	$ (14,373)	$ (1,314)	$ (17,676)
Corporate Securities | Capital Goods
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1		1
Total OTTI losses		$ (719)		$ (719)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (719)		$ (719)
Corporate Securities | Consumer Discretionary
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		6		7
Total OTTI losses		$ (5,968)		$ (6,875)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (5,968)		$ (6,875)
Corporate Securities | Energy
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		2		2
Total OTTI losses		$ (1,212)		$ (1,212)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (1,212)		$ (1,212)
Corporate Securities | Financials
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		5		5
Total OTTI losses		$ (3,495)		$ (3,495)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (3,495)		$ (3,495)
Corporate Securities | Information Technology
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1		1
Total OTTI losses		$ (550)		$ (550)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (550)		$ (550)
Corporate Securities | Telecommunications
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		2		2
Total OTTI losses		$ (249)		$ (249)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (249)		$ (249)
Corporate Securities | Transportation
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1		1
Total OTTI losses		$ (178)		$ (178)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (178)		$ (178)
Corporate Securities | Utilities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1		1
Total OTTI losses		$ (94)		$ (94)
Portion of OTTI losses recognized from other comprehensive income		0		0
Net OTTI losses recognized in operations		$ (94)		$ (94)
Residential Mortgage Backed Securities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities	1		3	3
Total OTTI losses	$ (101)		$ (101)	$ (63)
Portion of OTTI losses recognized from other comprehensive income	0		(215)	(295)
Net OTTI losses recognized in operations	$ (101)		$ (316)	$ (358)
Commercial Mortgage Backed Securities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities		1	1	1
Total OTTI losses		$ (1,908)	$ (349)	$ (1,908)
Portion of OTTI losses recognized from other comprehensive income		0	0	0
Net OTTI losses recognized in operations		$ (1,908)	$ (349)	$ (1,908)
Other Asset Backed Securities
Other than Temporary Impairment Losses, Investments [Abstract]
Other than temporary impairment, number of securities | Securities			1	1
Total OTTI losses			$ (649)	$ (682)
Portion of OTTI losses recognized from other comprehensive income			0	(1,356)
Net OTTI losses recognized in operations			$ (649)	$ (2,038)

Investments (Cumulative Credit

Investments (Cumulative Credit Loss Portion of Other Than Temporary Impairment Recognized in Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Investments [Abstract]
Cumulative credit loss at beginning of period	$ (165,651)	$ (156,469)	$ (175,398)	$ (157,066)
Additions for the amount related to credit losses for which OTTI has not previously been recognized	0	(14,373)	(998)	(16,025)
Additional credit losses on securities for which OTTI has previously been recognized	(101)	0	(316)	(1,651)
Accumulated losses on securities that were disposed of during the period	10,775	0	21,735	3,900
Cumulative credit loss at end of period	$ (154,977)	$ (170,842)	$ (154,977)	$ (170,842)

Investments (Cumulative Noncred

Investments (Cumulative Noncredit Portion of Other Than Temporary Impairment Recognized in Other Comprehensive Income and Change in Fair Value Since Other Than Temporary Impairment) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Amortized cost	$ 241,531	$ 352,207
OTTI recognized in other comprehensive income (loss)	(155,262)	(171,546)
Change in fair value since OTTI was recognized	191,389	205,712
Fair value	277,658	386,373
Corporate Securities
Investment Holdings [Line Items]
Amortized cost	28,728	69,580
OTTI recognized in other comprehensive income (loss)	(3,700)	(3,700)
Change in fair value since OTTI was recognized	10,088	6,195
Fair value	35,116	72,075
Residential Mortgage Backed Securities
Investment Holdings [Line Items]
Amortized cost	198,959	245,691
OTTI recognized in other comprehensive income (loss)	(151,562)	(167,846)
Change in fair value since OTTI was recognized	180,704	199,191
Fair value	228,101	277,036
Commercial Mortgage Backed Securities
Investment Holdings [Line Items]
Amortized cost	12,867	35,244
OTTI recognized in other comprehensive income (loss)	0	0
Change in fair value since OTTI was recognized	271	0
Fair value	13,138	35,244
Other Asset Backed Securities
Investment Holdings [Line Items]
Amortized cost	977	1,692
OTTI recognized in other comprehensive income (loss)	0	0
Change in fair value since OTTI was recognized	326	326
Fair value	$ 1,303	$ 2,018

Mortgage Loans on Real Estate_2

Mortgage Loans on Real Estate (Narrative) (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)loansportfolio_segment	Dec. 31, 2018USD ($)loans	Sep. 30, 2018USD ($)
Receivables [Abstract]
Number of portfolio segments that make up financing receivables | portfolio_segment	1
Real estate owned	$ 0		$ 0
Impaired mortgage loans, workout terms, interest only payments, six month terms	6 months
Impaired mortgage loans, workout terms, interest only payments, twelve month terms	12 months
Impaired mortgage loans, workout terms, cash flow sweep, number of months	12 months
Number of days past due, non-accrual status	90 days
Non-accrual loans	$ 0	$ 0
Financing receivable, modifications, period of time of delaying principal and/or interest, months	3 months
Number of TDRs | loans	0	0
Minimum
Loans and Leases Receivable Disclosure [Line Items]
Number of days past due, delinquent status	60 days
Commercial Real Estate Portfolio Segment
Loans and Leases Receivable Disclosure [Line Items]
Commitments outstanding	$ 173,300

Mortgage Loans on Real Estate_3

Mortgage Loans on Real Estate (Summary of Mortgage Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Principal outstanding	$ 3,221,152	$ 2,952,464
Loan loss allowance	(8,079)	(8,239)
Deferred prepayment fees	(998)	(1,134)
Mortgage loans on real estate	$ 3,212,075	$ 2,943,091

Mortgage Loans on Real Estate_4

Mortgage Loans on Real Estate (Mortgage Loan Portfolio Summarized by Geographic Region and Property Type) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 3,221,152	$ 2,952,464
Percent	100.00%	100.00%
East
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 600,204	$ 586,773
Percent	18.60%	19.90%
Middle Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 240,241	$ 168,969
Percent	7.50%	5.70%
Mountain
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 372,437	$ 357,642
Percent	11.60%	12.10%
New England
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 9,220	$ 9,418
Percent	0.30%	0.30%
Pacific
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 579,831	$ 521,363
Percent	18.00%	17.70%
South Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 739,498	$ 694,599
Percent	22.90%	23.50%
West North Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 281,067	$ 291,890
Percent	8.70%	9.90%
West South Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 398,654	$ 321,810
Percent	12.40%	10.90%
Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 249,703	$ 268,932
Percent	7.70%	9.10%
Medical Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 30,930	$ 33,467
Percent	1.00%	1.10%
Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 1,185,510	$ 1,091,627
Percent	36.80%	37.00%
Industrial/Warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 859,410	$ 762,887
Percent	26.70%	25.80%
Apartment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 695,726	$ 600,638
Percent	21.60%	20.30%
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 39,205	$ 25,000
Percent	1.20%	0.90%
Mixed Use/Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Principal outstanding	$ 160,668	$ 169,913
Percent	5.00%	5.80%

Mortgage Loans on Real Estate_5

Mortgage Loans on Real Estate (Allowance for Loan Losses Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning allowance balance			$ (8,239)
Ending allowance balance	$ (8,079)		(8,079)
Specific Allowance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning allowance balance	(229)	$ (696)	(229)	$ (1,418)
Charge-offs	0	0	0	0
Recoveries	0	467	0	1,189
Change in provision for credit losses	0	(1,255)	0	(1,255)
Ending allowance balance	(229)	(1,484)	(229)	(1,484)
General Allowance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning allowance balance	(7,600)	(5,630)	(8,010)	(6,100)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Change in provision for credit losses	(250)	0	160	470
Ending allowance balance	$ (7,850)	$ (5,630)	$ (7,850)	$ (5,630)

Mortgage Loans on Real Estate_6

Mortgage Loans on Real Estate (Impaired Mortgage Loans on Real Estate By Basis of Impairment) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Individually evaluated for impairment	$ 1,235	$ 1,253
Collectively evaluated for impairment	3,219,917	2,951,211
Principal outstanding	$ 3,221,152	$ 2,952,464

Mortgage Loans on Real Estate_7

Mortgage Loans on Real Estate (Mortgage Loans by Credit Quality Indicator) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Performing	$ 3,221,152	$ 2,952,464
In workout	0	0
Collateral dependent	0	0
Principal outstanding	$ 3,221,152	$ 2,952,464

Mortgage Loans on Real Estate_8

Mortgage Loans on Real Estate (Schedule of Financing Receivables Past Due) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial mortgage loans, past due	$ 0	$ 0
Commercial mortgage loans, current	3,221,152	2,952,464
Commercial mortgage loans, collateral dependent receivables	0	0
Principal outstanding	3,221,152	2,952,464
30 to 59 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial mortgage loans, past due	0	0
60 to 89 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial mortgage loans, past due	0	0
90 Days and Over
Financing Receivable, Recorded Investment, Past Due [Line Items]
Commercial mortgage loans, past due	$ 0	$ 0

Mortgage Loans on Real Estate_9

Mortgage Loans on Real Estate (Schedule of Impaired Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Mortgage loans with an allowance, recorded investment	$ 1,006		$ 1,006		$ 1,024
Mortgage loans with no related allowance, recorded investment	0		0		0
Impaired mortgage loans, recorded investment	1,006		1,006		1,024
Mortgage loans with an allowance, unpaid principal balance	1,235		1,235		1,253
Mortgage loans with no related allowance, unpaid principal balance	0		0		0
Impaired mortgage loans, unpaid principal balance	1,235		1,235		1,253
Mortgage loans with an allowance, related allowance	(229)		(229)		$ (229)
Mortgage loans with an allowance, average recorded investment	1,009	$ 2,337	1,015	$ 2,386
Mortgage loans with no related allowance, average recorded investment	0	0	0	0
Impaired mortgage loans, average recorded investment	1,009	2,337	1,015	2,386
Mortgage loans with an allowance, interest income recognized	17	37	52	136
Mortgage loans with no related allowance, interest income recognized	0	0	0	0
Impaired mortgage loans, interest income reoognized	$ 17	$ 37	$ 52	$ 136

Derivative Instruments (Narrati

Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative collateral	$ 900	$ 200
Credit risk, maximum exposure	68.4	$ 16.1
Collateral on deposit	$ 0.8
London Interbank Offered Rate (LIBOR) | Interest Rate Caps
Derivative [Line Items]
Cap rate	2.50%

Derivative Instruments (Fair Va

Derivative Instruments (Fair Value of Derivative Instruments as Presented in the Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 963,081	$ 205,149
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative assets	963,098	206,100
Derivative liabilities	9,382,000	8,165,405
Not Designated as Hedging Instrument | Call Options
Derivatives, Fair Value [Line Items]
Derivative assets	963,081	205,149
Not Designated as Hedging Instrument | Interest Rate Caps
Derivatives, Fair Value [Line Items]
Derivative assets	17	597
Not Designated as Hedging Instrument | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative assets	0	354
Derivative liabilities	906	0
Not Designated as Hedging Instrument | Fixed Index Annuities - Embedded Derivatives
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 9,381,094	$ 8,165,405

Derivative Instruments (Change

Derivative Instruments (Change in Fair Value of Derivatives Included in the Consolidated Statement of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivatives	$ (20,042)	$ 595,311	$ 440,472	$ 276,433
Change in fair value of embedded derivatives	212,278	383,716	1,306,163	(585,465)
Call Options
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivatives	(19,997)	594,872	442,111	273,946
Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivatives	(3)	258	(1,059)	1,658
Interest Rate Caps
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivatives	(42)	181	(580)	829
Fixed Index Annuities - Embedded Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of embedded derivatives	24,998	196,808	882,230	(1,198,115)
Other Changes in Difference Between Policy Benefit Reserves Computed Using Derivative Accounting Vs. Long-Duration Contracts Accounting
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of embedded derivatives	$ 187,280	$ 186,908	$ 423,933	$ 612,650

Derivative Instruments (Derivat

Derivative Instruments (Derivative Call Options, Notional Amount and Fair Value, by Counterparty) (Details) - Call Options - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional amount	$ 40,177,608	$ 39,420,777
Fair value	963,081	205,149
Bank of America
Derivative [Line Items]
Notional amount	3,938,470	6,518,808
Fair value	46,637	6,704
Barclays
Derivative [Line Items]
Notional amount	4,549,168	2,301,414
Fair value	141,155	27,032
Canadian Imperial Bank of Commerce
Derivative [Line Items]
Notional amount	4,321,739	4,856,150
Fair value	126,868	29,313
Citibank, N.A.
Derivative [Line Items]
Notional amount	4,064,075	4,792,208
Fair value	83,451	27,239
Credit Suisse
Derivative [Line Items]
Notional amount	4,739,536	2,877,916
Fair value	77,910	12,887
J.P. Morgan
Derivative [Line Items]
Notional amount	4,772,783	3,701,964
Fair value	101,072	17,564
Morgan Stanley
Derivative [Line Items]
Notional amount	1,990,733	3,560,044
Fair value	21,001	1,561
Royal Bank of Canada
Derivative [Line Items]
Notional amount	2,720,343	1,871,305
Fair value	82,946	14,011
Societe Generale
Derivative [Line Items]
Notional amount	3,205,393	2,343,165
Fair value	106,016	21,681
SunTrust
Derivative [Line Items]
Notional amount	2,017,444	1,755,030
Fair value	58,986	12,047
Wells Fargo
Derivative [Line Items]
Notional amount	3,656,074	4,618,569
Fair value	112,408	33,398
Exchange Traded
Derivative [Line Items]
Notional amount	201,850	224,204
Fair value	$ 4,631	$ 1,712

Derivative Instruments (Interes

Derivative Instruments (Interest Rate Swap) (Details) - Interest Rate Swap, Maturity Date, March 15, 2021, 2.415% - Interest Rate Swap - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional amount	$ 85,500
Pay rate	2.415%
Derivative liabilities	$ (906)
Derivative assets		$ 354

Derivative Instruments (Inter_2

Derivative Instruments (Interest Rate Caps) (Details) - Interest Rate Caps - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional amount	$ 79,000
Derivative assets	17	$ 597
Interest Rate Caps, Maturity Date, July 7, 2021, 2.50%
Derivative [Line Items]
Notional amount	$ 40,000
Cap rate	2.50%
Derivative assets	$ 8	302
Interest Rate Caps, Maturity Date, July 8, 2021, 2.50%
Derivative [Line Items]
Notional amount	$ 12,000
Cap rate	2.50%
Derivative assets	$ 3	91
Interest Rate Caps, Maturity Date, July 29, 2021, 2.50%
Derivative [Line Items]
Notional amount	$ 27,000
Cap rate	2.50%
Derivative assets	$ 6	$ 204

Notes Payable and Amounts Due_3

Notes Payable and Amounts Due Under Repurchase Agreements (Schedule of Notes Payable) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Jun. 16, 2017
Debt Instrument [Line Items]
Notes payable	$ 494,982	$ 494,591
June 2027 Notes
Debt Instrument [Line Items]
Debt instrument, face amount	500,000	500,000	$ 500,000
Unamortized debt issue costs	(4,733)	(5,102)
Unamortized discount	$ (285)	$ (307)	$ (300)

Notes Payable and Amounts Due_4

Notes Payable and Amounts Due Under Repurchase Agreements (2027 Notes Narrative) (Details) - June 2027 Notes - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Jun. 16, 2017
Debt Instrument [Line Items]
Debt instrument, face amount	$ 500,000	$ 500,000	$ 500,000
Interest rate			5.00%
Unamortized discount	$ 285	$ 307	$ 300
Debt financing costs			$ 5,800

Notes Payable and Amounts Due_5

Notes Payable and Amounts Due Under Repurchase Agreements (Repurchase Agreements Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Debt Disclosure [Abstract]
Repurchase agreement, average borrowings	$ 9.7	$ 5.1	$ 39.4	$ 41.4
Repurchase agreement, maximum amount borrowed			$ 243.6	$ 544.1
Repurchase agreement, weighted average interest rate	2.25%	0.00%	2.97%	1.66%

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) $ in Millions	Sep. 30, 2019USD ($)
Limited Partnerships
Other Commitments [Line Items]
Unfunded commitments	$ 32.3
Fixed Maturity Securities
Other Commitments [Line Items]
Unfunded commitments	$ 138.5

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic and Diluted [Line Items]
Net income - numerator for earnings per common share	$ 37,360	$ 169,328	$ 25,940	$ 404,193
Weighted average common shares outstanding (shares)	91,251,590	90,485,567	91,080,681	90,278,209
Denominator for earnings per common share - assuming dilution (shares)	91,710,557	91,650,886	91,747,862	91,355,410
Earnings per common share	$ 0.41	$ 1.87	$ 0.28	$ 4.48
Earnings per common share - assuming dilution	$ 0.41	$ 1.85	$ 0.28	$ 4.42
Stock Options and Deferred Compensation Agreements
Earnings Per Share, Basic and Diluted [Line Items]
Effect of dilutive securities: share-based payment arrangements (shares)	190,137	705,465	326,306	750,588
Restricted Stock and Restricted Stock Units
Earnings Per Share, Basic and Diluted [Line Items]
Effect of dilutive securities: share-based payment arrangements (shares)	268,830	459,854	340,875	326,613
Stock Options
Earnings Per Share, Basic and Diluted [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (shares)	551,585	0	0	0
Antidilutive securities excluded from computation of earnings per share, exercise price	$ 24.79