Related Party Transactions Management Agreement (Details) - SP General Services LLC - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Management fee percentage, quartely basis (as a percent)			1.50%
Management agreement renewal, term (in years)			1 year
Notice period prior to management agreement renewal, period (in days)			60 days
Reimbursable Expenses
Related Party Transaction [Line Items]
Services fees and reimbursable expenses	$ 734	$ 326	$ 1,455	$ 1,345
Deferred fees payable to related party	596		596		$ 1,504
Related Party Debt
Related Party Transaction [Line Items]
Settlement of debt			1,800
Management Fee
Related Party Transaction [Line Items]
Services fees and reimbursable expenses	$ 2,184	$ 2,257	$ 4,040	$ 4,569