Stockholders Equity AOCI (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Accumulated other comprehensive income		$ 529,087		$ 529,087		$ 354,764
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Net of Tax, Attributable to Parent		68,435	$ 128,511	218,993	$ 406,327
Reclassification out of Accumulated Other Comprehensive Income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Net of Tax, Attributable to Parent					(1,848)
reclassifications into accumulated other comprehensive income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Net of Tax, Attributable to Parent				11,015
AOCI, Gain (Loss), Debt Securities, Available-for-sale, without Allowance for Credit Loss, Parent
Accumulated other comprehensive income	[1]	536,872	412,121	536,872	412,121	363,020	$ 96,921
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, Net of Tax	[1]			163,585	317,677
AOCI, Gain (Loss), Debt Securities, Available-for-sale, without Allowance for Credit Loss, Parent | Reclassification out of Accumulated Other Comprehensive Income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	[2]				(2,477)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, without Allowance for Credit Loss, Parent | reclassifications into accumulated other comprehensive income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	[2]			10,267
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent
Accumulated other comprehensive income	[1]	1,699	2,161	1,699	2,161	1,974	3,133
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, Net of Tax	[1]			(275)	(972)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent | Reclassification out of Accumulated Other Comprehensive Income
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax	[2]				0
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent | reclassifications into accumulated other comprehensive income
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax	[2]			0
Accumulated Defined Benefit Plans Adjustment
Accumulated other comprehensive income		(9,484)	(8,107)	(9,484)	(8,107)	(10,230)	(8,736)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax				(2)	0
Accumulated Defined Benefit Plans Adjustment | reclassifications into accumulated other comprehensive income
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax				748	629
AOCI Attributable to Parent
Accumulated other comprehensive income		$ 529,087	$ 406,175	529,087	406,175	$ 354,764	$ 91,318
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, Net of Tax				163,308	316,705
AOCI Attributable to Parent | Reclassification out of Accumulated Other Comprehensive Income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Net of Tax, Attributable to Parent					$ (1,848)
AOCI Attributable to Parent | reclassifications into accumulated other comprehensive income
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Net of Tax, Attributable to Parent				$ 11,015

[1] Includes the impact of taxes, deferred acquisition costs, value of insurance in force acquired, unearned revenue reserves and policyholder liabilities. See Note 2 to our consolidated financial statements for further information.

[2] See Note 2 to our consolidated financial statements for further information.