CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Cash flows from operating activities
Net Income (Loss) Attributable to Parent	$ 715,842	$ 1,822,181	$ 701,443
Change in operating assets and liabilities:
Accrued investment income	7,159	(43,142)	(18,761)
Premiums receivable and other reinsurance balances	(764,159)	(346,737)	(156,836)
Deferred policy acquisition costs	(107,325)	154,234	31,024
Reinsurance ceded receivable balances	66,298	(124,056)	(53,221)
Future policy benefits, other policy claims and benefits, and other reinsurance balances	1,593,065	1,320,810	810,474
Deferred income taxes	76,507	(847,304)	293,777
Other assets and other liabilities, net	(162,835)	242,466	(98,675)
Amortization of net investment premiums, discounts and other	(57,378)	(105,382)	(93,952)
Depreciation, Depletion and Amortization	45,127	52,902	26,853
Investment related (gains) losses, net	170,088	(167,880)	(94,195)
Excess tax benefits from share-based payment arrangement	0	0	(162)
Other, net	(1,268)	24,216	117,949
Net cash provided by operating activities	1,581,121	1,982,308	1,465,718
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale	9,339,632	7,308,608	4,584,828
Principal payments on mortgage loans on real estate	626,650	589,214	472,435
Proceeds from Sale of Available-for-sale Securities, Equity	45,863	207,347	434,518
Proceeds from Sale and Collection of Mortgage Notes Receivable	445,360	339,919	442,755
Proceeds from Collection of Policy Loans	57,352	114,586	88,840
Payments to Acquire Available-for-sale Securities	(9,724,190)	(8,941,293)	(7,414,647)
Payments to Acquire Available-for-sale Securities, Equity	(13,428)	(81,254)	(584,532)
Purchases of fixed maturity securities available-for-sale	(1,019,212)	(964,421)	(1,092,876)
Payments to Fund Policy Loans	(44,708)	(44,607)	(47,646)
Cash invested in funds withheld at interest	(53,626)	(22,557)	(32,597)
Purchase of businesses, net of cash acquired of $4,988	(31,441)	0	0
Payments to Acquire Property, Plant, and Equipment	(28,891)	(44,211)	(44,642)
Change in short-term investments	129,329	52,302	465,628
Change in other invested assets	(365,242)	(121,206)	(97,790)
Net cash used in investing activities	(636,552)	(1,607,573)	(2,825,726)
Cash flows from financing activities
Dividends to stockholders	(140,110)	(117,291)	(100,371)
Repayment of collateral finance and securitization notes	(96,354)	(68,429)	(64,571)
Proceeds from long-term debt issuance	0	0	799,984
Debt issuance costs	0	0	(8,766)
Principal payments of long-term debt	(2,690)	(302,582)	(2,479)
Purchases of treasury stock	(299,679)	(43,508)	(122,916)
Excess tax benefits from share-based payment arrangement	0	0	162
Exercise of stock options, net	3,459	7,292	15,321
Change in cash collateral for derivative positions and other arrangements	43,607	(65,422)	26,413
Deposits on universal life and other investment type policies and contracts	864,193	1,017,699	1,041,623
Withdrawals on universal life and other investment type policies and contracts	(694,399)	(752,381)	(529,011)
Net cash used in financing activities	(321,973)	(324,622)	1,055,389
Effect of exchange rate changes on cash	(36,387)	52,693	(19,938)
Change in cash and cash equivalents	586,209	102,806	(324,557)
Cash and cash equivalents, beginning of period	1,303,524	1,200,718	1,525,275
Cash and cash equivalents, end of period	1,889,733	1,303,524	1,200,718
Supplementary information:
Interest paid	170,191	173,471	156,727
Income taxes paid, net of refunds	141,703	37,098	61,085
Transfer to Investments	4,636,099	3,285,837	120,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(38,350)	0	0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 69,791	$ 0	$ 0