Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Details)

v3.8.0.1
Income Taxes - Additional Information (Details) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Income Tax Contingency [Line Items]      
Effective tax rate 19.60% 43.80%  
Effective statutory tax rate 21.00%   34.00%
Interest and penalties associated with income taxes $ 0 $ 0  
Other Liabilities      
Income Tax Contingency [Line Items]      
Uncertain tax position $ 903,000   $ 903,000