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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total realized and unrealized gains (losses)
Beginning balance	$ 2,353	$ 2,721	$ 2,355	$ 2,721
Included in net income
Included in other comprehensive income (loss)
Purchases, issuances and settlements	(2)	0	(4)	0
Ending balance	2,351	2,721	2,351	2,721
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