Fair Value (Details 3) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair value by pricing source
Available-for-sale securities	$ 719,869	$ 713,291
Fair value measurements on a recurring basis
Fair value by pricing source
Available-for-sale securities	719,869	713,291
Total	724,245	717,703
Fair value measurements on a recurring basis | Fixed maturities
Fair value by pricing source
Available-for-sale securities	713,877	707,341
Fair value measurements on a recurring basis | Fixed maturities | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	712,319
Fair value measurements on a recurring basis | Fixed maturities | Priced via market comparables/broker quotes
Fair value by pricing source
Available-for-sale securities	1,558
Fair value measurements on a recurring basis | Common stock
Fair value by pricing source
Available-for-sale securities	5,992	5,950
Fair value measurements on a recurring basis | Common stock | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	5,992
Fair value measurements on a recurring basis | Real estate
Fair value by pricing source
Other investments	4,376	4,412
Fair value measurements on a recurring basis | Real estate | Priced via unobservable inputs
Fair value by pricing source
Other investments	4,376
Fair value measurements on a recurring basis | Level 1
Fair value by pricing source
Available-for-sale securities	5,992	5,950
Total	5,992	5,950
Fair value measurements on a recurring basis | Level 1 | Fixed maturities
Fair value by pricing source
Available-for-sale securities	0	0
Fair value measurements on a recurring basis | Level 1 | Fixed maturities | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	0
Fair value measurements on a recurring basis | Level 1 | Fixed maturities | Priced via market comparables/broker quotes
Fair value by pricing source
Available-for-sale securities	0
Fair value measurements on a recurring basis | Level 1 | Common stock
Fair value by pricing source
Available-for-sale securities	5,992	5,950
Fair value measurements on a recurring basis | Level 1 | Common stock | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	5,992
Fair value measurements on a recurring basis | Level 2
Fair value by pricing source
Available-for-sale securities	704,074	697,989
Total	704,074	697,989
Fair value measurements on a recurring basis | Level 2 | Fixed maturities
Fair value by pricing source
Available-for-sale securities	704,074	697,989
Fair value measurements on a recurring basis | Level 2 | Fixed maturities | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	702,516
Fair value measurements on a recurring basis | Level 2 | Fixed maturities | Priced via market comparables/broker quotes
Fair value by pricing source
Available-for-sale securities	1,558
Fair value measurements on a recurring basis | Level 2 | Common stock
Fair value by pricing source
Available-for-sale securities	0	0
Fair value measurements on a recurring basis | Level 2 | Common stock | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	0
Fair value measurements on a recurring basis | Level 3
Fair value by pricing source
Available-for-sale securities	9,803	9,352
Total	9,803	9,352
Fair value measurements on a recurring basis | Level 3 | Non-binding broker quotes classified within Level 3
Fair value by pricing source
Available-for-sale securities	9,800
Fair value measurements on a recurring basis | Level 3 | Fixed maturities
Fair value by pricing source
Available-for-sale securities	9,803	9,352
Fair value measurements on a recurring basis | Level 3 | Fixed maturities | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	9,803
Fair value measurements on a recurring basis | Level 3 | Fixed maturities | Priced via market comparables/broker quotes
Fair value by pricing source
Available-for-sale securities	0
Fair value measurements on a recurring basis | Level 3 | Common stock
Fair value by pricing source
Available-for-sale securities	0	$ 0
Fair value measurements on a recurring basis | Level 3 | Common stock | Priced via pricing services
Fair value by pricing source
Available-for-sale securities	0
Fair value measurements on a nonrecurring basis
Fair value by pricing source
Total	$ 0