Investments (Schedule of Fixed Maturities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Marketable Securities [Abstract]
Amortized Cost, Due to mature One year or less	$ 7,259	$ 12,761
Amortized Cost, Due to mature After one year through five years	94,142	86,830
Amortized Cost, Due to mature After five years through ten years	58,294	69,586
Amortized Cost, Due to mature After ten years	6,363	10,569
Amortized Cost, Due to mature Mortgage/asset-backed securities	78,519	55,232
Available-for-sale Securities, Debt Maturities, Amortized Cost	244,577	234,978
Fair Value, Due to mature One year or less	7,254	12,766
Fair Value, Due to mature After one year through five years	93,650	87,642
Fair Value, Due to mature After five years through ten years	57,333	70,680
Fair Value, Due to mature After ten years	6,162	10,607
Fair Value, Due to mature Mortgage/asset-backed securities	77,188	55,063
Available-for-sale Securities, Debt Securities, Estimated Fair Value	$ 241,587	$ 236,758