CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fixed maturities, available for sale, amortized cost	$ 7,152,127	$ 6,785,626
Equity securities, available for sale, cost	$ 134,013	$ 95,722
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.001	$ 0.001	$ 0.001	$ 0.001
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	64,917,683	64,537,554
Treasury stock, shares	24,672,932	23,971,522	23,308,430	23,117,554