XML 82 R69.htm IDEA: XBRL DOCUMENT v3.8.0.1
Employee Benefit Plans - Summary of Amounts Expected to be Recognized in Net Periodic Cost in Coming Year (Detail) - USD ($)
Dec. 31, 2017
Dec. 31, 2016
Pension Plan [Member]    
Amounts Expected to be Recognized in Net Periodic Cost in the Coming Year    
(Gain) loss recognition $ (992,724)  
Prior service cost recognition 0 $ 0
Net initial obligation (asset) recognition 0 0
Supplemental Employee Retirement Plan [Member]    
Amounts Expected to be Recognized in Net Periodic Cost in the Coming Year    
Prior service cost recognition 0 0
Net initial obligation (asset) recognition 0 0
Postretirement Benefits [Member]    
Amounts Expected to be Recognized in Net Periodic Cost in the Coming Year    
Prior service cost recognition 0 0
Net initial obligation (asset) recognition $ 0 $ 0