Long-Term Debt And Other Long-Term Liabilities (Other Long-Term Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Asset retirement obligation (ARO) liability	$ 120,591	$ 133,657	$ 137,039	$ 146,159
Capital lease obligations	25,799	0
Workers' compensation	18,868	20,041
Separation benefit plans	10,357	9,382
Deferred compensation plan	3,984	3,589
Gas balancing liability	3,775	3,775
Other liabilities	183,374	170,444
Less current portion	14,578	12,113
Total other long-term liabilities	$ 168,796	$ 158,331