Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net income (loss)	$ 53,939	$ (44,841)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Interest sensitive and index product benefits	419,139	97,671
Amortization of deferred sales inducements	62,325	27,479
Annuity product charges	(43,572)	(36,505)
Change in fair value of embedded derivatives	224,170	265,857
Change in traditional life and accident and health insurance reserves	726	(858)
Policy acquisition costs deferred	(110,574)	(156,934)
Amortization of deferred policy acquisition costs	89,678	49,713
Provision for depreciation and other amortization	957	875
Amortization of discounts and premiums on investments	2,800	(3,103)
Realized gains (losses) on investments and net OTTI losses recognized in operations	(2,197)	3,007
Change in fair value of derivatives	(386,842)	73,657
Deferred income taxes	(3,670)	(45,276)
Share-based compensation	2,403	2,234
Change in accrued investment income	(26,371)	(31,229)
Change in income taxes recoverable/payable	31,161	20,573
Change in other assets	33	(1,164)
Change in other policy funds and contract claims	(6,985)	(12,544)
Change in collateral held for derivatives	233,992	(26,754)
Change in other liabilities	(38,754)	(38,041)
Other	(4,431)	(2,205)
Net cash provided by operating activities	497,927	141,612
Sales, maturities, or repayments of investments:
Fixed maturity securities - available for sale	517,301	581,647
Mortgage loans on real estate	75,110	84,248
Derivative instruments	349,732	6,747
Other investments	4,990	4,274
Acquisitions of investments:
Fixed maturity securities - available for sale	(1,216,014)	(1,383,082)
Mortgage loans on real estate	(100,797)	(118,009)
Derivative instruments	(147,283)	(130,608)
Other investments	(1,550)	(1,046)
Purchases of property, furniture and equipment	(1,402)	(244)
Net cash used in investing activities	(519,913)	(956,073)
Financing activities
Receipts credited to annuity and single premium universal life policyholder account balances	1,073,583	2,089,739
Coinsurance deposits	63,746	(378,412)
Return of annuity policyholder account balances	(727,494)	(581,260)
Excess tax benefits realized from share-based compensation plans	0	440
Proceeds from issuance of common stock	3,717	3,740
Change in checks in excess of cash balance	(10,084)	(10,358)
Net cash provided by financing activities	403,468	1,123,889
Increase in cash and cash equivalents	381,482	309,428
Cash and cash equivalents at beginning of period	791,266	397,749
Cash and cash equivalents at end of period	1,172,748	707,177
Cash paid during period for interest:
Interest expense	18,682	16,278
Cash paid during period for income taxes:
Income taxes	47	200
Non-cash operating activity:
Deferral of sales inducements	65,245	107,673
Non-cash financing activity:
Common stock issued to settle warrants that have expired	$ 0	$ 80