Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v3.10.0.1
Income Taxes - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Income Tax Examination [Line Items]    
Federal statutory income tax rate, percent 21.00% 35.00%
Tax Cuts and Jobs Act, Change in tax rate, Provisional income tax expense (benefit)   $ 104.9
Minimum [Member] | State and Local Jurisdiction [Member]    
Income Tax Examination [Line Items]    
Income tax examinations year under examination 2014  
Minimum [Member] | Internal Revenue Service (IRS) [Member]    
Income Tax Examination [Line Items]    
Income tax examinations year under examination 2015  
Maximum [Member] | State and Local Jurisdiction [Member]    
Income Tax Examination [Line Items]    
Income tax examinations year under examination 2018  
Maximum [Member] | Internal Revenue Service (IRS) [Member]    
Income Tax Examination [Line Items]    
Income tax examinations year under examination 2018