Fixed Assets And Asset Retirement Obligations (Schedule Of Reconciliation Of Liability For Asset Retirement Obligations) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning balance	$ 12,695	$ 5,900
Liabilities incurred and assumed in the current period	789	5,995
Accretion expense	848	800
Asset retirement obligations, ending balance	$ 14,332	$ 12,695