Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Details)

v3.10.0.1
Income Taxes - Additional Information (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Income Tax Disclosure [Abstract]          
Provision for federal income tax $ 0   $ 0    
Unrecognized tax benefits that would impact effective tax rate $ 4,500,000   4,500,000   $ 4,500,000
Provision for income tax reflect any adjustment to previously assessed tax act enactment effect   $ 1,706,000 $ 0 $ 1,706,000