XML 76 R66.htm IDEA: XBRL DOCUMENT v3.10.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Dec. 31, 2017
Income Tax Disclosure [Abstract]          
Income tax expense $ 1,748 $ 1,681 $ 3,440 $ 3,061  
Effective tax rate 23.00% 26.80% 24.40% 27.50%  
Federal income tax rate     21.00%   35.00%