Investments - Schedule of Fair Value of Financial Instruments Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities
Fair value of financial instruments	$ 499,156	$ 452,714
U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	99,884	81,647
Foreign Government
Schedule of Available-for-sale Securities
Fair value of financial instruments	3,163	2,075
States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Fair value of financial instruments	177,170	155,905
Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	7,424	8,493
Corporate Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	176,236	146,758
Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,848	1,820
Fixed Maturities
Schedule of Available-for-sale Securities
Fair value of financial instruments	465,725	396,698
Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,614	1,352
Common Stock
Schedule of Available-for-sale Securities
Fair value of financial instruments	23,116	20,694
Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	3,022	2,417
Equity Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	27,752	50,806
Other Long-term Investments
Schedule of Available-for-sale Securities
Fair value of financial instruments	5,679	5,210
Mutual Fund
Schedule of Available-for-sale Securities
Fair value of financial instruments		26,343
Level 1
Schedule of Available-for-sale Securities
Fair value of financial instruments	29,900	52,926
Level 1 | U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 1 | Foreign Government
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 1 | States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 1 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 1 | Corporate Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 1 | Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,848	1,820
Level 1 | Fixed Maturities
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,848	1,820
Level 1 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,614	1,352
Level 1 | Common Stock
Schedule of Available-for-sale Securities
Fair value of financial instruments	23,116	20,694
Level 1 | Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	3,022	2,417
Level 1 | Equity Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	27,752	50,806
Level 1 | Other Long-term Investments
Schedule of Available-for-sale Securities
Fair value of financial instruments	300	300
Level 1 | Mutual Fund
Schedule of Available-for-sale Securities
Fair value of financial instruments		26,343
Level 2
Schedule of Available-for-sale Securities
Fair value of financial instruments	467,446	397,933
Level 2 | U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	99,884	81,647
Level 2 | Foreign Government
Schedule of Available-for-sale Securities
Fair value of financial instruments	3,163	2,075
Level 2 | States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Fair value of financial instruments	177,170	155,905
Level 2 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	7,424	8,493
Level 2 | Corporate Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	176,236	146,758
Level 2 | Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 2 | Fixed Maturities
Schedule of Available-for-sale Securities
Fair value of financial instruments	463,877	394,878
Level 2 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 2 | Common Stock
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 2 | Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 2 | Equity Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 2 | Other Long-term Investments
Schedule of Available-for-sale Securities
Fair value of financial instruments	3,569	3,055
Level 2 | Mutual Fund
Schedule of Available-for-sale Securities
Fair value of financial instruments		0
Level 3
Schedule of Available-for-sale Securities
Fair value of financial instruments	1,810	1,855
Level 3 | U.S. Government and Agency Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Foreign Government
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | States, Municipalities and Political Subdivisions
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Corporate Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Redeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Fixed Maturities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Public Utilities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Common Stock
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Nonredeemable Preferred Stocks
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Equity Securities
Schedule of Available-for-sale Securities
Fair value of financial instruments	0	0
Level 3 | Other Long-term Investments
Schedule of Available-for-sale Securities
Fair value of financial instruments	$ 1,810	1,855
Level 3 | Mutual Fund
Schedule of Available-for-sale Securities
Fair value of financial instruments		$ 0