Consolidated Statements of Financial Position (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Investments:
Fixed maturities available-for-sale, cost	$ 967,918	$ 935,977
Fixed maturities held-to-maturity, fair value	218,774	241,377
Equity securities available-for-sale, cost		15,289
Real estate held for investment, accumulated depreciation	1,233	5,479
Real estate held for sale, accumulated depreciation	4,411	0
Due premiums, allowance for doubtful accounts	$ 1,483	$ 1,611
Common Stock Class A [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	52,215,852	52,215,852
Common stock, shares outstanding (in shares)	52,215,852	52,215,852
Common stock, shares in treasury (in shares)	3,135,738	3,135,738
Common Stock Class B [Member]
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.00	$ 0.00
Common stock, shares authorized (in shares)	2,000,000	2,000,000
Common stock, shares issued (in shares)	1,001,714	1,001,714
Common stock, shares outstanding (in shares)	1,001,714	1,001,714