Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Employee Benefit 401(k) Plans (Narrative) (Details) - USD ($)
 3 Months Ended
Mar. 31, 2018
Mar. 31, 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 $ 273,000 $ 342,000
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