Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities
Net income (loss)	$ (37,553)	$ 186,054
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Interest sensitive and index product benefits	487,735	802,431
Amortization of deferred sales inducements	127,396	152,278
Annuity product charges	(125,304)	(99,066)
Change in fair value of embedded derivatives	694,564	(583,112)
Change in traditional life and accident and health insurance reserves	8,977	3,024
Policy acquisition costs deferred	(423,525)	(464,451)
Amortization of deferred policy acquisition costs	198,486	186,871
Provision for depreciation and other amortization	3,000	3,733
Amortization of discounts and premiums on investments	(2,258)	(10,730)
Realized gains (losses) on investments and net OTTI losses recognized in operations	2,439	(4,173)
Change in fair value of derivatives	(70,002)	404,085
Deferred income taxes	(66,895)	23,640
Share-based compensation	4,849	5,332
Change in accrued investment income	(43,892)	(48,963)
Change in income taxes recoverable/payable	16,947	4,794
Change in other assets	1,930	1,053
Change in other policy funds and contract claims	(27,627)	(36,876)
Change in collateral held for derivatives	254,210	(469,752)
Change in other liabilities	(48,608)	24,766
Other	(10,363)	(9,843)
Net cash provided by operating activities	944,506	71,095
Sales, maturities, or repayments of investments:
Fixed maturity securities - available for sale	1,853,281	1,280,927
Mortgage loans on real estate	302,262	354,391
Derivative instruments	147,887	563,125
Other investments	12,928	11,716
Acquisition of investments:
Fixed maturity securities - available for sale	(5,065,873)	(5,041,263)
Mortgage loans on real estate	(284,186)	(362,123)
Derivative instruments	(444,360)	(427,763)
Other investments	(9,778)	(5,206)
Purchases of property, furniture and equipment	(872)	(913)
Net cash used in investing activities	(3,488,711)	(3,627,109)
Financing activities
Receipts credited to annuity and single premium universal life policyholder account balances	5,712,759	4,913,473
Coinsurance deposits	(1,180,827)	21,623
Return of annuity policyholder account balances	(1,806,895)	(1,638,598)
Financing fees incurred and deferred	(1,456)	0
Repayment of notes payable	0	(48,152)
Net proceeds from settlement of notes hedges and warrants	0	25,775
Proceeds from issuance of debt	100,000	0
Acquisition of common stock	0	(16)
Excess tax benefits realized from share-based compensation plans	487	3,281
Proceeds from issuance of common stock	138,660	111,274
Change in checks in excess of cash balance	(3,458)	(10,546)
Net cash provided by financing activities	2,959,270	3,378,114
Increase in cash and cash equivalents	415,065	(177,900)
Cash and cash equivalents at beginning of period	397,749	701,514
Cash and cash equivalents at end of period	812,814	523,614
Cash paid during period for interest:
Interest expense	35,764	36,136
Cash paid during period for income taxes:
Income taxes	29,961	66,541
Non-cash operating activity:
Deferral of sales inducements	270,991	346,410
Common Stock Issued to Settle Warrants That Have Expired [Member]
Non-cash financing activities:
Common stock issued	$ 93	$ 0