Long-term Debt - Senior Notes (Details) (USD $)				12 Months Ended								12 Months Ended
	Jun. 18, 2011 Propco [Member] Term Loan Facility [Member]	Jan. 03, 2012 Propco [Member] Tranche B-3 [Member]	Jun. 18, 2011 Propco [Member] Tranche B-3 [Member]	Dec. 31, 2012 Propco [Member] Senior Notes [Member]	Jun. 16, 2017 Propco [Member] Senior Notes [Member]	Jun. 16, 2016 Propco [Member] Senior Notes [Member]	Jun. 16, 2014 Propco [Member] Senior Notes [Member]	Jun. 16, 2013 Propco [Member] Senior Notes [Member]	Jun. 16, 2012 Propco [Member] Senior Notes [Member]	Jan. 03, 2012 Propco [Member] Senior Notes [Member]	Mar. 02, 2013 Subsequent Event [Member] Senior Notes [Member]	Dec. 31, 2012 Subsequent Event [Member] Propco [Member] Senior Notes [Member]	Dec. 31, 2012 Minimum [Member] Subsequent Event [Member] Propco [Member] Senior Notes [Member]	Dec. 31, 2012 Maximum [Member] Subsequent Event [Member] Propco [Member] Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, aggregate principal amount	$ 1,575,000,000.000	$ 625,000,000	$ 625,000,000							$ 625,000,000	$ 500,000,000
Debt Instrument, effective interest rate percentage					9.54%	7.22%	4.87%	3.67%	3.66%	3.65%
Debt instrument, duration fee (percentage)				1.00%
Debt instrument, notification for redemption (term)													30 days	60 days
Redemption price of debt instrument, principal (percentage)												100.00%
Debt instrument, requirement to repurchase principal (percentage)				100.00%