Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Fixed maturities, Held-to-maturity, at fair value	$ 150	$ 150
Fixed maturities, Available-for-sale securities, at amortized cost	1,516,610	1,458,235
Fixed maturities, Trading securities, at amortized cost	14,582	13,054
Equity securities, Available-for-sale securities, at amortized cost	57,387	59,994
Equity securities, Trading securities, at amortized cost	5,888	5,434
Allowance for doubtful accounts	1,255	1,255
Property and equipment, accumulated depreciation	$ 51,603	$ 50,925
Common stock, par value per share (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	24,916,806	25,429,769
Common stock, shares outstanding (in shares)	24,916,806	25,429,769