Investments - Schedule of Unrealized Loss on Investments (Details) $ in Thousands	Mar. 31, 2019 USD ($) security	Dec. 31, 2018 USD ($) security
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 943,854	$ 943,623
U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 93,429	$ 98,975
Less Than Twelve Months
Number of securities \| security	29	45
Gross unrealized losses	$ 68	$ 111
Fair value	$ 16,092	$ 28,464
Twelve Months or More
Number of securities \| security	47	55
Gross unrealized losses	$ 761	$ 1,204
Fair value	54,641	61,264
States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 139,040	$ 144,468
Less Than Twelve Months
Number of securities \| security	4	49
Gross unrealized losses	$ 2	$ 272
Fair value	$ 3,366	$ 38,469
Twelve Months or More
Number of securities \| security	64	91
Gross unrealized losses	$ 357	$ 1,029
Fair value	53,410	68,115
Public Utilities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 25,058	$ 23,890
Less Than Twelve Months
Number of securities \| security	4	30
Gross unrealized losses	$ 6	$ 374
Fair value	$ 1,109	$ 13,685
Twelve Months or More
Number of securities \| security	35	19
Gross unrealized losses	$ 276	$ 307
Fair value	15,181	7,805
Corporate Securities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 295,243	$ 301,988
Less Than Twelve Months
Number of securities \| security	87	351
Gross unrealized losses	$ 168	$ 3,149
Fair value	$ 31,613	$ 144,769
Twelve Months or More
Number of securities \| security	223	208
Gross unrealized losses	$ 1,273	$ 3,010
Fair value	125,391	117,351
Mortgage-backed securities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 230,780	$ 223,854
Less Than Twelve Months
Number of securities \| security	19	87
Gross unrealized losses	$ 68	$ 1,303
Fair value	$ 21,353	$ 88,754
Twelve Months or More
Number of securities \| security	143	135
Gross unrealized losses	$ 1,264	$ 2,180
Fair value	82,546	70,510
Asset-backed Securities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 62,734	$ 64,037
Less Than Twelve Months
Number of securities \| security	25	67
Gross unrealized losses	$ 22	$ 136
Fair value	$ 12,107	$ 41,871
Twelve Months or More
Number of securities \| security	7	7
Gross unrealized losses	$ 21	$ 3
Fair value	3,143	1,372
Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 1,779	$ 1,151
Less Than Twelve Months
Number of securities \| security	5	8
Gross unrealized losses	$ 12	$ 62
Fair value	$ 1,286	$ 711
Twelve Months or More
Number of securities \| security	2	2
Gross unrealized losses	$ 64	$ 77
Fair value	203	8,377
Fixed Maturities
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 852,086	$ 862,345
Less Than Twelve Months
Number of securities \| security	176	642
Gross unrealized losses	$ 349	$ 5,423
Fair value	$ 88,533	$ 359,701
Twelve Months or More
Number of securities \| security	522	517
Gross unrealized losses	$ 4,016	$ 7,810
Fair value	335,520	334,794
Public Utilities
Schedule of Available-for-sale Securities
Available-for-sale Securities	2,260	1,759
Common Stock
Schedule of Available-for-sale Securities
Available-for-sale Securities	30,794	27,198
Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Available-for-sale Securities	1,681	2,005
Equity Securities
Schedule of Available-for-sale Securities
Available-for-sale Securities	91,468	80,978
Other Long-term Investments
Schedule of Available-for-sale Securities
Available-for-sale Securities	300	300
Mutual Fund
Schedule of Available-for-sale Securities
Available-for-sale Securities	56,733	50,016
Foreign Government
Schedule of Available-for-sale Securities
Available-for-sale Securities	$ 4,023	3,982
Less Than Twelve Months
Number of securities \| security	3
Gross unrealized losses	$ 3
Fair value	$ 1,607	2,978
Twelve Months or More
Number of securities \| security	1
Gross unrealized losses	$ 0
Fair value	$ 1,005	$ 0
Available-for-sale, Securities in Unrealized Loss Positions, Less Than Twelve Months, Qualitative Disclosure, Number of Positions \| security		5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		$ 16
Available-for-sale, Securities in Unrealized Loss Positions, Twelve Months or More, Qualitative Disclosure, Number of Positions \| security		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		$ 0

Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months [Abstract]

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

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Number of investment positions in available-for-sale investments in a continuous unrealized loss position for less than one year or normal operating cycle, if longer, for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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