Fair Value (Fair Value of Assets Measured on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	$ 533,148	$ 545,870
Total equity securities	94,012	80,896
Total investments	629,745	627,914
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	94,012	80,896
Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	2,585	1,148
Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	9,856
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	533,148	545,870
Total investments	629,745	627,914
Fair Value, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	94,012	80,896
Fair Value, Recurring [Member] | Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	2,585	1,148
Fair Value, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	48,422	48,106
Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	226,343	242,152
Fair Value, Recurring [Member] | Collateralized Corporate Bank Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	132,678	126,528
Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	115,849	115,527
Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	9,856	13,557
Quoted Prices in Active Markets for Identical Assets, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments	96,597	82,044
Quoted Prices in Active Markets for Identical Assets, Level 1 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	94,012	80,896
Quoted Prices in Active Markets for Identical Assets, Level 1 [Member] | Fair Value, Recurring [Member] | Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	2,585	1,148
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	532,615	545,579
Total investments	532,615	545,579
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | U.S. Treasury Securities and Obligations of U.S. Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	48,422	48,106
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	225,810	241,861
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Collateralized Corporate Bank Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	132,678	126,528
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	115,849	115,527
Other Observable Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	9,856	13,557
Unobservable Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	533	291
Total investments	533	291
Unobservable Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities	$ 533	$ 291