Supplemental Disclosures Of Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Recorded In Accounts Payable [Member]
Other Significant Noncash Transactions [Line Items]
Property additions	$ 3.9	$ 3.2
Units Issued [Member]
Other Significant Noncash Transactions [Line Items]
Value of units issued	0.3	0.3
Contingent Payments Related To Acquisition [Member]
Other Significant Noncash Transactions [Line Items]
Property additions		$ 2.0