Cash Equivalents And Restricted Cash And Securities (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted Cash and Cash Equivalents Items [Line Items]
Long-term restricted cash and securities	$ 5,000,000	$ 5,000,000
Gains or losses realized on cash equivalents	0	0	$ 0
No Maturity Date [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Long-term restricted cash and securities	5,000,000	5,000,000
Maturity Date Within Three Months [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted securities	$ 595,000	$ 622,000
Restricted securities, period for maturity date	3 months	3 months
Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted securities	$ 235,000	$ 262,000
Money Market Funds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Short-term restricted securities	830,000	884,000
GE Credit Agreement [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Long-term restricted cash and securities	$ 5,000,000	$ 5,000,000
Minimum [Member] | Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted securities, period for maturity date	3 months	3 months
Maximum [Member] | Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted securities, period for maturity date	1 year	1 year