Annual report pursuant to Section 13 and 15(d)

Fair Value - Narrative (Details)

v3.8.0.1
Fair Value - Narrative (Details) - Level 3 - USD ($)
Dec. 31, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets measured at fair value $ 0 $ 0
Liabilities measured at fair value $ 0 $ 0