Fair Value (Fair Value of Assets Measured on a Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 348,525	$ 507,279
Total equity securities	53,621	29,388
Total investments	402,146	536,667
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	53,621	29,388
Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,390
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	348,525	507,279
Total investments	402,146	536,667
Fair Value, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities	53,621	29,388
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]
Fair Value	45,407	179,746
Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	191,540	219,368
Fair Value, Recurring [Member] | Corporate bank loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	59,600	52,782
Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,588	50,539
Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,390	4,844
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Total investments	53,621	29,388
Fair Value, Inputs, 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	53,621	29,388
Fair Value, Inputs, Level 1 [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]
Fair Value		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Corporate bank loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	348,171	506,931
Total investments	348,171	506,931
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities		0
Fair Value, 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]
Fair Value	45,407	179,746
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	191,186	219,020
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Corporate bank loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	59,600	52,782
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	48,588	50,539
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,390	4,844
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	354	348
Total investments	354	348
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities		0
Fair Value, Inputs, Level 3 [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]
Fair Value		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 354	348
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Corporate bank loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mortgage Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		$ 0