Investments - Schedule of Available-for-sale Securities Reconciliation (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities
Gross unrealized gains	$ 358
Gross unrealized loss	0
Fair Value	848,882	$ 762,855
Equity securities fair value	83,345	63,295
U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	90,391	93,827
Gross unrealized gains	2	40
Gross unrealized loss	1,912	1,241
Fair Value	88,481	92,626
Foreign Government
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	3,002	2,022
Gross unrealized gains	0	14
Gross unrealized loss	24	0
Fair Value	2,978	2,036
States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	161,257	200,706
Gross unrealized gains	555	1,929
Gross unrealized loss	1,997	1,123
Fair Value	159,815	201,512
Public Utilities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	25,892	20,215
Gross unrealized gains	17	127
Gross unrealized loss	738	85
Fair Value	25,171	20,257
Corporate Securities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	290,701	287,025
Gross unrealized gains	224	1,746
Gross unrealized loss	6,597	1,209
Fair Value	284,328	287,562
Mortgage-backed securities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	212,320	143,982
Gross unrealized gains	37	235
Gross unrealized loss	4,711	952
Fair Value	207,646	143,265
Asset-backed Securities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	79,993	14,902
Gross unrealized gains	2	23
Gross unrealized loss	217	20
Fair Value	79,778	14,905
Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	765	755
Gross unrealized gains	7	11
Gross unrealized loss	87	74
Fair Value	685	692
Fixed Maturities
Schedule of Available-for-sale Securities
Cost or adjusted/amortized cost	864,321	763,434
Gross unrealized gains	844	4,125
Gross unrealized loss	16,283	4,704
Fair Value	848,882	762,855
Mutual Fund
Schedule of Available-for-sale Securities
Equity securities cost	44,385	29,079
Equity securities unrealized gain	3,219	2,845
Equity securities unrealized loss	44	0
Equity securities fair value	47,560	31,924
Public Utilities
Schedule of Available-for-sale Securities
Equity securities cost	1,946	1,343
Equity securities unrealized gain	327	359
Equity securities unrealized loss	30	0
Equity securities fair value	2,243	1,702
Common Stock
Schedule of Available-for-sale Securities
Equity securities cost	24,059	18,856
Equity securities unrealized gain	8,188	9,093
Equity securities unrealized loss	446	47
Equity securities fair value	31,801	27,902
Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Equity securities cost	1,718	1,718
Equity securities unrealized gain	39	53
Equity securities unrealized loss	16	4
Equity securities fair value	1,741	1,767
Equity Securities
Schedule of Available-for-sale Securities
Equity securities cost	72,108	50,996
Equity securities unrealized gain	11,773	12,350
Equity securities unrealized loss	536	51
Equity securities fair value	$ 83,345	$ 63,295

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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