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Federal Income Taxes (Schedule of Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Statutory corporate tax rate percentage	21.00%	35.00%	21.00%	35.00%
Tax at statutory rate	$ 14,097	$ 23,560	$ 33,513	$ 67,836
Tax advantaged interest	(1,338)	(2,915)	(4,242)	(8,479)
Dividend received deduction	(107)	(382)	(443)	(1,338)
Stock-based compensation	(415)	(86)	(2,963)	(3,409)
Other	(542)	420	542	624
Total federal income tax expense	$ 11,695	$ 20,597	$ 26,407	$ 55,234

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to investment income that is tax advantaged. Tax advantaged investment securities generally are, by statute, tax-reduced, tax-deferred, or tax-free.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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