Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale securities
Amortized cost, fixed maturities	$ 735,993
Amortized cost	735,993	$ 708,555
Gross unrealized gains	11,699	9,899
Gross unrealized losses	3,010	5,163
Estimated fair value, fixed maturities	744,682
Estimated fair value	744,682	713,291
Fixed maturities
Available-for-sale securities
Amortized cost, fixed maturities	735,993	702,403
Gross unrealized gains, fixed maturities	11,699	9,899
Gross unrealized losses, fixed maturities	3,010	4,961
Estimated fair value, fixed maturities	744,682	707,341
U.S. treasury
Available-for-sale securities
Amortized cost, fixed maturities	5,082	5,093
Gross unrealized gains, fixed maturities	0	0
Gross unrealized losses, fixed maturities	31	62
Estimated fair value, fixed maturities	5,051	5,031
Government sponsored entities
Available-for-sale securities
Amortized cost, fixed maturities		2,004
Gross unrealized gains, fixed maturities		22
Gross unrealized losses, fixed maturities		0
Estimated fair value, fixed maturities		2,026
States & political subdivisions
Available-for-sale securities
Amortized cost, fixed maturities	255,244	249,312
Gross unrealized gains, fixed maturities	8,211	6,113
Gross unrealized losses, fixed maturities	758	2,293
Estimated fair value, fixed maturities	262,697	253,132
Corporate debt securities
Available-for-sale securities
Amortized cost, fixed maturities	348,531	321,041
Gross unrealized gains, fixed maturities	2,933	3,293
Gross unrealized losses, fixed maturities	1,284	1,386
Estimated fair value, fixed maturities	350,180	322,948
Residential mortgage-backed securities
Available-for-sale securities
Amortized cost, fixed maturities	13,641	16,232
Gross unrealized gains, fixed maturities	58	61
Gross unrealized losses, fixed maturities	146	191
Estimated fair value, fixed maturities	13,553	16,102
Commercial mortgage-backed securities
Available-for-sale securities
Amortized cost, fixed maturities	35,638	37,723
Gross unrealized gains, fixed maturities	92	59
Gross unrealized losses, fixed maturities	753	933
Estimated fair value, fixed maturities	34,977	36,849
Collateralized debt obligations
Available-for-sale securities
Amortized cost, fixed maturities	75,857	68,998
Gross unrealized gains, fixed maturities	405	351
Gross unrealized losses, fixed maturities	38	96
Estimated fair value, fixed maturities	76,224	69,253
Other debt securities
Available-for-sale securities
Amortized cost, fixed maturities	2,000	2,000
Gross unrealized gains, fixed maturities	0	0
Gross unrealized losses, fixed maturities	0	0
Estimated fair value, fixed maturities	$ 2,000	2,000
Common stock
Available-for-sale securities
Amortized cost, equity securities		6,152
Gross unrealized gains, equity securities		0
Gross unrealized losses, equity securities		202
Estimated fair value, equity securities		$ 5,950

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