Investments - Investments Classified by Contractual Maturity Date (Details) - Fixed Maturities - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Cost or Amortized Cost
Due in one year or less	$ 44,213
Due after one year through five years	267,350
Due after five years through ten years	146,545
Due after ten years	38,761
Cost or adjusted/amortized cost	$ 496,869	$ 497,616
Percent of Total
Due in one year or less	8.90%
Due after one year through five years	53.80%
Due after five years through ten years	29.50%
Due after ten years	7.80%
Total	100.00%
Fair Value
Due in one year or less	$ 44,213
Due after one year through five years	267,187
Due after five years through ten years	146,004
Due after ten years	38,720
Total	$ 496,124	$ 494,516
Percent of Total
Due in one year or less	8.90%
Due after one year through five years	53.90%
Due after five years through ten years	29.40%
Due after ten years	7.80%
Total	100.00%