CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 372,205	$ 304,604
Change in operating assets and liabilities:
Accrued investment income	(12,200)	1,834
Premiums receivable and other reinsurance balances	84,599	(345,253)
Deferred policy acquisition costs	(114,895)	20,528
Reinsurance ceded receivable balances	(109,011)	18,245
Future policy benefits, other policy claims and benefits, and other reinsurance balances	736,251	598,015
Deferred income taxes	92,442	48,117
Other assets and other liabilities, net	(122,629)	(98,807)
Amortization of net investment premiums, discounts and other	(33,742)	(25,713)
Depreciation, Depletion and Amortization	22,163	21,554
Investment related (gains) losses, net	(20,260)	11,042
Other, net	75,408	29,422
Net cash provided by operating activities	970,331	583,588
Cash Flows from Investing Activities:
Sales of fixed maturity securities available-for-sale	5,096,692	3,836,575
Maturities of fixed maturity securities available-for-sale	438,749	328,097
Proceeds from Sale of Available-for-sale Securities, Equity	36	29,099
Payments to Acquire Debt Securities, Available-for-sale	5,689,268	3,880,733
Payments to Acquire Available-for-sale Securities, Equity	(56,732)	(11,930)
Payments to Acquire Mortgage Notes Receivable	(598,309)	(376,470)
Proceeds from Sale and Collection of Mortgage Notes Receivable	166,483	213,691
Proceeds from Collection of Policy Loans	43,849	24,793
Payments for (Proceeds from) Policy Loans	4,940	6,421
Increase (Decrease) in Funds Held under Reinsurance Agreements	54,030	42,761
Payments to Acquire Businesses, Net of Cash Acquired	3,561	(29,315)
Payments to Acquire Property, Plant, and Equipment	(17,467)	(14,573)
Change in short-term investments	67,177	(9,843)
Change in other invested assets	(160,204)	(160,824)
Net cash used in investing activities	(764,403)	(100,615)
Cash Flows from Financing Activities:
Dividends to stockholders	(75,347)	(64,370)
Proceeds from (Repayments of) Secured Debt	(52,644)	(53,102)
Payments of Debt Issuance Costs	(4,750)	0
Proceeds from Issuance of Long-term Debt	598,524	0
Repayments of Long-term Debt	(1,387)	(1,331)
Purchases of treasury stock	(67,744)	(165,069)
Exercise of stock options, net	2,590	1,252
Change in cash collateral for derivative positions and other arrangements	(80,214)	17,578
Deposits on universal life and other investment type policies and contracts	256,373	225,876
Withdrawals on universal life and other investment type policies and contracts	(390,295)	(329,899)
Net cash provided by (used in) financing activities	185,106	(369,065)
Effect of exchange rate changes on cash	6,759	(19,753)
Change in cash and cash equivalents	397,793	94,155
Cash and cash equivalents, beginning of period	1,889,733	1,303,524
Cash and cash equivalents, end of period	2,287,526	1,397,679
Supplemental disclosures of cash flow information:
Interest Paid, Excluding Capitalized Interest, Operating Activities	85,829	84,670
Income Taxes Paid, Net	22,632	59,397
Transfer to Investments	3,420,531	604,374
Capital Expenditures Incurred but Not yet Paid	1,105	0
Noncash or Part Noncash Acquisition, Value of Assets Acquired	8,303	65,948
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed	$ (11,864)	$ (36,633)