Issuance of Partnership Equity (Details Textuals) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Public Placement [Member]
Subsidiary Sale Of Stock [Line Items]
Common Stock Issuance Date	May 15, 2012
Proceeds from Debt, Net of Issuance Costs	$ 158.0
Limited Partners Unit Price Per Unit	$ 16.28
Partners Capital Account Units Sold In Public Offering	10,120,000
Private Placement [Member]
Subsidiary Sale Of Stock [Line Items]
Common Stock Issuance Date	Sep. 14, 2012
Proceeds from Debt, Net of Issuance Costs	$ 74.8
Limited Partners Unit Price Per Unit	$ 13.25
Partners Capital Account Units Sold In Private Placement	5,660,378