Quarterly report pursuant to Section 13 or 15(d)

BENEFIT PLANS - Narrative (Details)

v3.5.0.2
BENEFIT PLANS - Narrative (Details)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
USD ($)
Sep. 30, 2016
USD ($)
year
Aug. 16, 2016
USD ($)
Dec. 31, 2015
USD ($)
Benefit Plans (Textuals) [Abstract]        
Deferred Compensation Arrangement with Individual, Employer Contribution $ 150,000      
Defined Benefit Plan, Fair Value of Plan Assets $ 1,049,326 $ 1,049,326   $ 594,217
Defined Benefit Plan, Information about Plan Assets [Abstract]        
Fair value of plan assets, Percentage 100.00% 100.00%   100.00%
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]        
Match - Base pay contributed to the plan   matches participant contributions, up to the first 4%    
Base Pay Contributed To Plan Profit Sharing   profit-sharing contribution equal to 1% of eligible participants’ 2015    
Post Retirement Benefits        
Benefit Plans (Textuals) [Abstract]        
Employees retirement age for health care and life insurance benefits under unfunded defined benefit post-retirement plan | year   55    
Deferred Compensation Arrangement With Individual Requisite Service Period   10 years    
Equity Securities        
Benefit Plans (Textuals) [Abstract]        
Defined Benefit Plan, Fair Value of Plan Assets $ 181,909 $ 181,909   $ 120,046
Defined Benefit Plan, Information about Plan Assets [Abstract]        
Fair value of plan assets, Percentage 17.00% 17.00%   20.00%
FirstMerit Bank        
Benefit Plans (Textuals) [Abstract]        
Defined Benefit Plan, Fair Value of Plan Assets $ 279,000 $ 279,000 $ 280,000  
FirstMerit Bank | Pension Benefits        
Benefit Plans (Textuals) [Abstract]        
Defined Benefit Plan, Benefit Obligation     330,000  
FirstMerit Bank | Post Retirement Benefits        
Benefit Plans (Textuals) [Abstract]        
Defined Benefit Plan, Benefit Obligation     $ 7,000