Cash Equivalents And Restricted Cash And Securities (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities	$ 46,935	$ 35,075	$ 46,935	$ 35,075	$ 37,588	$ 33,375
Gains or losses realized on cash equivalents	0	$ 0	0	$ 0
Money Market Funds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities	753		753		830
Restricted Cash And Securities [Member] | Cash [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities					5,000
Gains or losses realized on cash equivalents
Restricted Cash And Securities [Member] | Cash [Member] | No Maturity Date [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities					5,000
Restricted Cash And Securities [Member] | Money Market Funds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities	753		753		830
Gains or losses realized on cash equivalents
Restricted Cash And Securities [Member] | Money Market Funds [Member] | Maturity Date Within Three Months [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities					595
Restricted Cash And Securities [Member] | Money Market Funds [Member] | Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities	$ 753		$ 753		$ 235
Restricted Cash And Securities [Member] | Minimum [Member] | Money Market Funds [Member] | Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities, period for maturity date			3 months		3 months
Restricted Cash And Securities [Member] | Maximum [Member] | Money Market Funds [Member] | Maturity Date Within Three Months [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities, period for maturity date					3 months
Restricted Cash And Securities [Member] | Maximum [Member] | Money Market Funds [Member] | Maturity Date Between Three Months And One Year [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash and securities, period for maturity date			1 year		1 year