Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale securities
Amortized cost, fixed maturities	$ 702,403
Amortized cost	708,555	$ 594,837
Gross unrealized gains	9,899	11,137
Gross unrealized losses	5,163	6,033
Estimated fair value, fixed maturities	707,341
Estimated fair value	713,291	599,941
Fixed maturities
Available-for-sale securities
Amortized cost, fixed maturities	702,403	581,972
Gross unrealized gains, fixed maturities	9,899	11,137
Gross unrealized losses, fixed maturities	4,961	5,900
Estimated fair value, fixed maturities	707,341	587,209
U.S. treasury
Available-for-sale securities
Amortized cost, fixed maturities	5,093
Gross unrealized gains, fixed maturities	0
Gross unrealized losses, fixed maturities	62
Estimated fair value, fixed maturities	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	249,312	221,093
Gross unrealized gains, fixed maturities	6,113	10,761
Gross unrealized losses, fixed maturities	2,293	7
Estimated fair value, fixed maturities	253,132	231,847
Corporate debt securities
Available-for-sale securities
Amortized cost, fixed maturities	321,041	254,464
Gross unrealized gains, fixed maturities	3,293	281
Gross unrealized losses, fixed maturities	1,386	4,412
Estimated fair value, fixed maturities	322,948	250,333
Residential mortgage-backed securities
Available-for-sale securities
Amortized cost, fixed maturities	16,232	13,639
Gross unrealized gains, fixed maturities	61	4
Gross unrealized losses, fixed maturities	191	130
Estimated fair value, fixed maturities	16,102	13,513
Commercial mortgage-backed securities
Available-for-sale securities
Amortized cost, fixed maturities	37,723	38,630
Gross unrealized gains, fixed maturities	59	30
Gross unrealized losses, fixed maturities	933	1,089
Estimated fair value, fixed maturities	36,849	37,571
Collateralized debt obligations
Available-for-sale securities
Amortized cost, fixed maturities	68,998	51,905
Gross unrealized gains, fixed maturities	351	61
Gross unrealized losses, fixed maturities	96	221
Estimated fair value, fixed maturities	69,253	51,745
Other debt securities
Available-for-sale securities
Amortized cost, fixed maturities	2,000	2,241
Gross unrealized gains, fixed maturities	0	0
Gross unrealized losses, fixed maturities	0	41
Estimated fair value, fixed maturities	2,000	2,200
Common stock
Available-for-sale securities
Amortized cost, equity securities	6,152	12,865
Gross unrealized gains, equity securities	0	0
Gross unrealized losses, equity securities	202	133
Estimated fair value, equity securities	$ 5,950	$ 12,732

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