XML 104 R60.htm IDEA: XBRL DOCUMENT

Fixed Assets and Asset Retirement Obligations (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fixed Assets And Asset Retirement Obligations [Abstract]
Depreciation expense	$ 37.4	$ 27.5	$ 22.5

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

+ References+ Details