Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, authorized shares	0	0
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized shares	50,000,000	50,000,000
Common stock, issued shares	43,034,270	42,965,137
Common stock, outstanding shares	42,822,187	42,753,054
Treasury stock	212,083	212,083
Schedule of Available-for-sale Securities
Other investments, cost	$ 7,884
Fixed Maturities
Schedule of Available-for-sale Securities
Fixed maturities, cost	864,321	$ 763,434
Other Long-term Investments
Schedule of Available-for-sale Securities
Other investments, cost	$ 7,884	$ 8,057