Segment Information Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Pre-Tax Operating Income (Loss)										$ 136,277		$ 126,539		$ 146,027
Realized gains losses on investments net of offsets	[1]									7,358		(12,085)		(1,234)
Derivatives unrealized gain net of offsets	[1]									3,422		(7,832)		3,923
Pre-tax Net Income (Loss) Attributable to Parent										147,057		106,622		148,716
Income Tax Expense (Benefit)										19,929		11,650		(39,983)
Income Tax on Equity Income										(919)		(1,179)		(1,394)
Operating Income (Loss)										126,209		93,793		187,305
Operating revenues										739,062		747,871		737,117
Realized gains on investments related to revenue	[1]									7,606	[2]	(12,455)	[2]	(1,469)
Derivative unrealized related to revenues	[1]									28,013		(15,790)		2,263
Revenues		$ 193,561	$ 184,658	$ 192,906	$ 203,556	$ 158,636	$ 188,111	$ 190,449	$ 182,430	774,681		719,626		737,911
Investment Income, Net										398,389		410,098		412,936
Change in net unrealized gains/losses on derivatives										26,609		(15,480)		2,263
Net investment income		$ 108,986	$ 101,478	$ 104,894	$ 109,640	$ 83,865	$ 105,757	$ 103,974	$ 101,022	424,998		394,618		415,199
Other Depreciation and Amortization										19,946		32,875		24,089
Deferred Policy Acquisition Cost, Amortization Expense, Net Investment Gains (Losses)	[1]									241		(184)		(240)
Deferred Policy Acquisition Cost, Unrealized Investment Gain (Loss)	[1]									345		(1,598)		(639)
Depreciation, Depletion and Amortization										20,532		31,093		23,210
Annuity
Segment Reporting, Revenue Reconciling Item [Line Items]
Pre-Tax Operating Income (Loss)										52,834		62,846		68,821
Operating revenues										212,538		223,996		224,184
Investment Income, Net										205,857		218,823		219,700
Other Depreciation and Amortization										14,954		9,335		6,489
Life Insurance
Segment Reporting, Revenue Reconciling Item [Line Items]
Pre-Tax Operating Income (Loss)										67,134		47,680		53,856
Operating revenues										432,294		430,194		418,593
Investment Income, Net										158,230		158,003		158,318
Other Depreciation and Amortization										4,926		16,515		18,720
Corporate and Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Pre-Tax Operating Income (Loss)										16,309		16,013		23,350
Operating revenues										94,230		93,681		94,340
Investment Income, Net										34,302		33,272		34,918
Other Depreciation and Amortization										$ 66		$ 7,025		$ (1,120)

[1] Amounts are net of adjustments, as applicable, to amortization of unearned revenue reserves, deferred acquisition costs, interest sensitive product reserves and income taxes attributable to these items

[2] Beginning in 2018, amount includes changes in fair value of equity securities.