Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$ 5,451,000	$ 3,725,000	$ 15,789,000	$ 11,525,000
Revenue, Affiliate Percentage	0.64	0.82	0.73	0.82
General and Administrative Expense [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	1,148,000	969,000	3,338,000	3,069,000
Operating Expense [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$ 4,303,000	$ 2,756,000	$ 12,451,000	$ 8,456,000