Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Premiums:
Life insurance	$ 191,342	$ 191,254	$ 187,686
Accident and health insurance	1,392	1,546	1,599
Property insurance	4,986	5,076	5,195
Net investment income	53,146	48,560	45,782
Realized investment gains, net	518	(1,985)	(5,459)
Other income	1,243	955	1,465
Total revenue	252,627	245,406	236,268
Insurance benefits paid or provided:
claims and surrenders	82,905	81,367	78,879
Increase in future policy benefit reserves	76,029	75,881	77,060
Policyholders' dividends	6,268	6,832	10,747
Total insurance benefits paid or provided	165,202	164,080	166,686
Commissions	41,324	44,641	43,625
Other general expenses	46,388	33,356	33,287
Capitalization of deferred policy acquisition costs	(29,120)	(32,732)	(31,104)
Amortization of deferred policy acquisition costs	29,690	28,515	23,400
Amortization of cost of customer relationships acquired	2,129	2,063	2,317
Total benefits and expenses	255,613	239,923	238,211
Income (loss) before federal income tax	(2,986)	5,483	(1,943)
Federal income tax expense (benefit)	35,141	3,514	1,200
Net income (loss)	(38,127)	1,969	(3,143)
Unrealized gains (losses) on available-for-sale securities:
Unrealized holding gains (losses) arising during the period	17,666	(1,659)	(24,217)
Reclassification adjustments for losses included in net income	546	1,974	5,415
Unrealized gains (losses) on available-for-sale securities, net	18,212	315	(18,802)
Income tax expense (benefit) on unrealized gains (losses) on available-for-sale securities	5,672	110	(6,539)
Other comprehensive income (loss)	12,540	205	(12,263)
Total comprehensive income (loss)	$ (25,587)	$ 2,174	$ (15,406)
Common Stock Class A [Member]
Earnings Per Share [Abstract]
Basic and diluted earnings (losses) per share (in dollars per share)	$ (0.77)	$ 0.04	$ (0.06)
Common Stock Class B [Member]
Earnings Per Share [Abstract]
Basic and diluted earnings (losses) per share (in dollars per share)	$ (0.38)	$ 0.02	$ (0.03)