Investments (Details 2) $ in Thousands	Mar. 31, 2017 USD ($)
Amortized cost
Due in one year or less	$ 76,219
Due after one year through five years	305,334
Due after five years through ten years	216,377
Due after ten years	108,724
Amortized cost, fixed maturities	706,654
Estimated fair value
Due in one year or less	76,354
Due after one year through five years	308,833
Due after five years through ten years	220,453
Due after ten years	108,237
Estimated fair value, fixed maturities	$ 713,877