Long-Term Debt And Other Long-Term Liabilities (Other Long-Term Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Long-term debt and other long-term liabilites [Abstract]
ARO liability	$ 133,657	$ 146,159	$ 96,446
Workers' compensation	20,041	18,517
Separation benefit plans	9,382	7,972
Gas balancing liability	3,775	3,838
Deferred compensation plan	3,589	2,779
Other liabilities	170,444	179,265
Less current portion	12,113	12,282
Total other long-term liabilities	$ 158,331	$ 166,983