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Summary of Significant Accounting Policies - Narrative (Details)
12 Months Ended
Dec. 31, 2016
USD ($)
segment
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Accounting Policies [Abstract]      
Number of operating segments | segment 1    
Impairments | $ $ 0 $ 0 $ 0
Accounts receivable      
Concentration Risk [Line Items]      
Concentration risk 13.00%