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Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest	$ 23,992	$ 23,905	$ 22,098
Federal income tax	29,193	62,000	46,405
Corporate actions related to equity securities	944	4,725	3,263
Assets acquired under capital lease arrangements	4,119	278	3,151
Non-cash purchase of property and equipment	291	0	78
AFS Fixed Income Securities [Member]
Corporate actions related to fixed income securities, AFS	$ 52,277	$ 22,511	$ 23,579

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The increase during the period in capital lease obligations due to entering into new capital leases.

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