Fair Value Measurements (Schedule of Assets Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	$ 32,215	$ 41,790
State And Municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	10,894	11,206
Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	4,710	5,500
Government Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	16,611	25,084
Recurring Basis [Member] | Significant Other Observable Inputs Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	32,215	41,790
Recurring Basis [Member] | Significant Other Observable Inputs Level 2 [Member] | State And Municipal [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	10,894	11,206
Recurring Basis [Member] | Significant Other Observable Inputs Level 2 [Member] | Asset-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	4,710	5,500
Recurring Basis [Member] | Significant Other Observable Inputs Level 2 [Member] | Government Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in available-for-sale securities (at fair value)	$ 16,611	$ 25,084