Fair Value Measurements (Fair Value, Investment Securities Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair value of securities at beginning of year	$ 27
Unrealized (loss) gain on fair value of securities	(12)	$ 6
Fair value of securities at end of year	15	27
Level 1 Estimated Fair Value [Member]
Fair value of securities at beginning of year	27	21
Unrealized (loss) gain on fair value of securities	(12)	6
Fair value of securities at end of year	$ 15	$ 27