Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
OPERATING ACTIVITIES
Net income	$ 160,422	$ 495,607	$ 182,667
Adjustments to reconcile net income to net cash provided by operating activities
Net realized investment gains	(18,174)	(104,595)	(46,607)
Other-than-temporary impairments	1,243	13,386	17,667
Accretion of premiums, discounts and loan origination fees	(6,163)	(2,008)	(2,926)
Net capitalized interest on policy loans and mortgage loans	(39,262)	(32,551)	(32,813)
Depreciation	52,049	53,937	45,278
Interest credited to policyholders’ account balances	315,684	415,190	331,770
Charges to policyholders’ account balances	(285,549)	(248,526)	(306,880)
Deferred federal income tax expense (benefit)	(22,599)	(142,096)	93,082
Equity in earnings of unconsolidated affiliates	(21,281)	(86,674)	(57,200)
Distributions from equity method investments	21,453	21,541	1,096
Policyholder liabilities	288,065	320,743	282,159
Change in deferred policy acquisition costs	(71,497)	(81,484)	1,152
Reinsurance recoverables	(8,886)	(16,880)	12,172
Premiums due and other receivables	(31,360)	(19,445)	(11,691)
Prepaid reinsurance premiums	10,003	(599)	14,881
Accrued investment income	(960)	(7,347)	(2,849)
Current tax receivable/payable	35,315	17,252	(57,332)
Liability for retirement benefits	(69,762)	(14,127)	(53,979)
Fair value of option securities	54,951	(90,357)	(28,401)
Fair value of equity securities	107,188	0	0
Other, net	24,630	4,958	20,331
Net cash provided by operating activities	495,510	495,925	401,577
INVESTING ACTIVITIES
Held-to-maturity securities	629,359	893,977	491,478
Available-for-sale securities	451,292	489,902	348,317
Equity securities	214,737	137,780	111,194
Investment real estate	11,577	67,227	12,833
Mortgage loans	812,239	811,049	587,355
Policy loans	52,606	42,580	59,920
Other invested assets	118,846	80,901	30,743
Disposals of property and equipment	0	554	16,240
Distributions from unconsolidated affiliates	58,287	102,000	55,311
Held-to-maturity securities	(1,349,008)	(1,215,311)	(156,453)
Available-for-sale securities	(680,477)	(737,651)	(656,974)
Equity securities	(79,514)	(108,054)	(26,154)
Investment real estate	(71,732)	(33,844)	(45,631)
Mortgage loans	(1,173,189)	(1,194,672)	(1,428,471)
Policy loans	(26,147)	(23,325)	(25,480)
Other invested assets	(75,233)	(47,134)	(67,571)
Additions to property and equipment	(17,670)	(24,395)	(47,301)
Contributions to unconsolidated affiliates	(151,261)	(27,869)	(135,208)
Change in short-term investments	452,005	(466,539)	268,386
Change in collateral held for derivatives	(68,565)	89,981	24,349
Other, net	7,087	18,030	27,869
Net cash used in investing activities	(884,761)	(1,144,813)	(555,248)
FINANCING ACTIVITIES
Policyholders’ account deposits	1,717,153	2,095,734	1,528,107
Policyholders’ account withdrawals	(1,345,498)	(1,271,128)	(1,313,394)
Change in notes payable	505	1,377	7,643
Dividends to stockholders	(88,228)	(88,335)	(87,741)
Payments to noncontrolling interest	(2,354)	(2,261)	(2,536)
Net cash provided by financing activities	281,578	735,387	132,079
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(107,673)	86,499	(21,592)
Beginning of the period	375,837	289,338	310,930
End of the period	$ 268,164	$ 375,837	$ 289,338