Quarterly report pursuant to Section 13 or 15(d)

Employee Benefit 401(k) Plans (Narrative) (Details)

v3.10.0.1
Employee Benefit 401(k) Plans (Narrative) (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]        
Minimum employee subscription rate, percentage of compensation     1.00%  
Maximum employee subscription rate, percentage of compensation     60.00%  
Employee pre-tax contributions vested percentage     100.00%  
Vesting rate     20.00%  
Percentage vested after total service period     100.00%  
Employees' vesting rights     Participants are always 100 percent vested in their pre-tax contributions and will begin vesting in any matching or profit sharing contributions made on their behalf after two years of service with the Company at a rate of 20 percent per year, becoming 100 percent vested after a total of six years of service with the Company.  
Expenses for employee benefit plan $ 225,000 $ 233,000 $ 498,000 $ 575,000
Minimum [Member]        
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]        
Employer contribution vesting period     2 years  
Maximum [Member]        
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]        
Employer contribution vesting period     6 years