Fair Values of Financial Instruments (Reconciliation of Recurring Fair Value Measurements Recognized in Balance Sheet using Significant Unobservable (Level Three) Inputs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Total realized and unrealized gains (losses)
Beginning balance	$ 2,351	$ 2,721	$ 2,355	$ 2,721
Included in net income		44		44
Included in other comprehensive income (loss)		326		326
Purchases, issuances and settlements	(2)	(883)	(6)	(883)
Ending balance	2,349	2,120	2,349	2,120
Total gains or losses for the period included in net income attributable to the change in unrealized gains or losses related to assets still held at the reporting date