Commitments and Contingencies Restricted Cash Reserves (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash reserves	$ 22,394	$ 21,570
Capital Expenditure [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash reserves	15,167
Operating Expenses and Debt Payments [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash reserves	5,018
Refund Future Liabilities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash reserves	$ 2,209