Income Taxes (Details) - USD ($)
6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Income Tax Contingency [Line Items]    
Income tax provision
Change in unrecognized tax benefits during the period
Accrual for uncertain tax positions  
Minimum [Member]    
Income Tax Contingency [Line Items]    
Tax years open for examination 2014  
Maximum [Member]    
Income Tax Contingency [Line Items]    
Tax years open for examination 2017