Investments (Details 1) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Cost or Amortized Cost
One year or less	$ 84,559
After one year through five years	267,065
After five years through ten years	105,309
After ten years	149,495
Residential mortgage-backed	135,851
Commercial mortgage and asset-backed	134,420
Redeemable preferred stock	2,025
Total, Cost or Amortized Cost	878,724	$ 737,916
Fair Value
One year or less	85,179
After one year through five years	266,232
After five years through ten years	106,787
After ten years	155,318
Residential mortgage-backed	136,712
Commercial mortgage and asset-backed	136,292
Redeemable preferred stock	1,960
Total, Fair Value	$ 888,480	$ 756,963