Accumulated Other Comprehensive Income (Summary Of Accumulated Other Comprehensive Income) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 12,075,000	[1]
Net current-period other comprehensive income	8,916,000
Balance	20,991,000
Foreign Currency Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	14,784,000	[2]
Net current-period other comprehensive income	8,791,000	[2]
Balance	23,575,000	[2]
Net of income tax expense	659,152
Unrealized Gain (Losses) On Available-For-Sale Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	10,000
Net current-period other comprehensive income	(2,000)
Balance	8,000
Accrued Pension Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(2,719,000)
Net current-period other comprehensive income	127,000
Balance	(2,592,000)
Net of income tax expense	$ 79,572

[1] Certain prior year balances have been reclassified to conform to the 2017 presentation (see Note 2 - Summary of Significant Accounting Policies - Reclassifications).

[2] Net of income tax expense of $659,152.