Consolidation and Basis of Presentation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net investment gains (losses)	$ 1,548	$ 2,374
Net OTTI losses recognized in earnings	(35)	(61)
Earnings before Federal income taxes	30,062	25,314
Federal income taxes	10,236	8,682
Net earnings	19,826	16,632
Unrealized Gains and Losses on Available-for-sale Securities [Member] | Amount Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Other net investment gains (losses)	689	2,114
Net OTTI losses recognized in earnings	(35)	(23)
Earnings before Federal income taxes	654	2,091
Federal income taxes	229	732
Net earnings	$ 425	$ 1,359