Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Available-for-sale securities, amortized cost	$ 1,595,817	$ 1,659,760
Available-for-sale securities, allowance for credit losses	10	0
Trading securities, amortized cost	8,916	11,941
Equity securities, cost	63,615	67,529
Allowance for doubtful accounts	947	1,239
Property and equipment accumulated depreciation	52,630	50,183
Reinsurance receivables and recoverables, allowance for credit losses	$ 41	$ 0
Common stock, par value (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)	25,031,234	25,015,963
Common stock, shares outstanding (in shares)	25,031,234	25,015,963