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Federal Income Taxes Federal Income Taxes (Schedule of Effective Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Statutory corporate tax rate percentage	21.00%	35.00%
Tax at statutory rate	$ 4,185	$ 23,651
Tax advantaged interest	(1,511)	(2,807)
Dividend received deduction	(126)	(331)
Stock-based compensation	(2,466)	(2,949)
Other	924	(430)
Total federal income tax expense	$ 1,006	$ 17,134

X

- Definition

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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