Fair Value Measurements Fair Value Finanical Insruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	$ 1,182,092	$ 1,155,097
Long-term debt, fair value	1,309,855	1,237,151
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	(1,644)
Restricted cash	17,018	6,650
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	0
Restricted cash	17,018	6,650
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	(1,644)
Restricted cash	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	0
Restricted cash	0	0
Fair Value, Measurements, Recurring [Member] | Margin Cash Collateral Offset
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	0
Restricted cash	$ 0