Condensed Consolidated Statements of Earnings (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Premiums and other revenues:
Universal life and annuity contract charges	$ 33,523	$ 36,924	$ 111,785	$ 109,776
Traditional life premiums	4,159	4,124	13,241	13,111
Net investment income	141,403	139,074	451,904	366,813
Other revenues	5,822	5,923	17,954	17,444
Net realized investment gains (losses):
Total other-than-temporary impairment (“OTTI”) gains (losses)	214	1,250	524	788
Portion of OTTI (gains) losses recognized in other comprehensive income	(227)	(1,761)	(776)	(1,918)
Net OTTI losses recognized in earnings	(13)	(511)	(252)	(1,130)
Other net investment gains (losses)	3,298	5,451	7,451	9,242
Total net realized investment gains (losses)	3,285	4,940	7,199	8,112
Total condensed consolidated premiums and other revenues	188,192	190,985	602,083	515,256
Benefits and expenses:
Life and other policy benefits	16,941	12,323	48,081	39,858
Amortization of deferred policy acquisition costs	24,244	28,403	83,900	91,463
Universal life and annuity contract interest	87,486	89,386	299,224	216,933
Other operating expenses	22,675	22,143	69,442	64,613
Total benefits and expenses	151,346	152,255	500,647	412,867
Earnings before Federal income taxes	36,846	38,730	101,436	102,389
Federal income taxes	12,064	14,408	33,031	35,080
Net earnings	24,782	24,322	68,405	67,309
Common Class A [Member]
Benefits and expenses:
Net earnings	24,081	23,634	66,470	65,405
Basic earnings per share:
Earnings Per Share, Basic (in dollars per share)	$ 7.01	$ 6.88	$ 19.35	$ 19.04
Diluted earnings per share:
Earnings Per Share, Diluted (in dollars per share)	$ 7.00	$ 6.88	$ 19.32	$ 19.04
Common Class B [Member]
Benefits and expenses:
Net earnings	$ 701	$ 688	$ 1,935	$ 1,904
Basic earnings per share:
Earnings Per Share, Basic (in dollars per share)	$ 3.51	$ 3.44	$ 9.68	$ 9.52
Diluted earnings per share:
Earnings Per Share, Diluted (in dollars per share)	$ 3.51	$ 3.44	$ 9.68	$ 9.52