Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Investments:
Fixed maturities available-for-sale, cost	$ 1,332,632	$ 1,321,487
Allowance for loan and lease losses	11	11
Private equity	16,982	11,923
Due premiums, allowance for doubtful accounts	$ 304	$ 297
Common Stock Class A [Member]
Liabilities and Stockholders' Equity
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares in treasury (in shares)	3,135,738	3,135,738
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	52,694,778	52,654,016
Common stock, shares outstanding (in shares)	52,694,778	52,654,016
Common Stock Class B [Member]
Liabilities and Stockholders' Equity
Common stock, par value (in dollars per share)	$ 0	$ 0
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